Nervous System Features Quiz
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Questions and Answers

Which drug decreases the amount of norepinephrine in the synapse?

  • MDMA
  • SSRIs
  • SNRIs
  • Both B & C (correct)

    • In the mesocortical pathway, where is dopamine primarily released?

  • Ventral tegmental area (VTA) (correct)
  • Limbic system
  • Frontal cortex
  • Substantia nigra

    • What natural ligand binds to nicotinic receptors?

  • Dopamine
  • Acetylcholine (correct)
  • Nicotine
  • Norepinephrine

    • What type of ACh receptor is ionotropic and fast-acting?

    <p>Nicotinic ACh receptor</p> Signup and view all the answers

    Which sensory system is an exception in the contralateral processing of sensory information?

    <p>Olfactory system</p> Signup and view all the answers

    What happens to acetylcholine after it is released into the synapse?

    <p>It is actively taken back into the presynaptic terminal.</p> Signup and view all the answers

    How do monoamine oxidase inhibitors affect dopamine in the synapse?

    <p>They prevent dopamine reuptake, allowing it to remain longer.</p> Signup and view all the answers

    What effect does a drug blocking acetylcholinesterase have on acetylcholine levels?

    <p>It maintains increased levels of acetylcholine.</p> Signup and view all the answers

    Which of the following drugs increases the availability of serotonin in the brain?

    <p>Selective serotonin reuptake inhibitors (SSRIs)</p> Signup and view all the answers

    What is the role of the dopamine transporter (DAT) in synaptic transmission?

    <p>It removes dopamine from the synapse, facilitating reuptake.</p> Signup and view all the answers

    Which class of drugs is commonly used to treat depression by targeting serotonin levels?

    <p>Selective serotonin reuptake inhibitors (SSRIs)</p> Signup and view all the answers

    Which drug is associated with a decrease in norepinephrine levels in the synapse?

    <p>Both B and C</p> Signup and view all the answers

    What is an effect of a drug that acts as an acetylcholinesterase inhibitor?

    <p>It prolongs the action of acetylcholine.</p> Signup and view all the answers

    What is the primary role of the left hemisphere of the brain?

    <p>Language production and comprehension</p> Signup and view all the answers

    What does lateralization refer to in the context of brain function?

    <p>The specialization of each hemisphere for different functions</p> Signup and view all the answers

    Which structure connects the two hemispheres of the brain?

    <p>Corpus callosum</p> Signup and view all the answers

    What is a potential outcome of lesions in the basal ganglia?

    <p>Uncontrolled movements</p> Signup and view all the answers

    Which part of the limbic system is primarily involved in emotion and emotional memory formation?

    <p>Amygdala</p> Signup and view all the answers

    What are the '4 F’s' controlled by the hypothalamus?

    <p>Fighting, fleeing, feeding, and mating</p> Signup and view all the answers

    What role does the hippocampus play in the brain?

    <p>Processing of memory</p> Signup and view all the answers

    How can lateralization effects be observed in a split-brain patient?

    <p>Through the disruption of communication between the two hemispheres</p> Signup and view all the answers

    What is the primary purpose of Nissl stain in brain imaging?

    <p>To visualize cell bodies only</p> Signup and view all the answers

    Which imaging technique provides a higher resolution than a CT scan?

    <p>MRI Scan</p> Signup and view all the answers

    What type of imaging is specifically designed to visualize bundles of axons?

    <p>Diffusion Tensor Imaging</p> Signup and view all the answers

    What is the main advantage of using immunohistochemistry in staining?

    <p>Binds specifically to antigens in biological tissues</p> Signup and view all the answers

    Which of the following methods allows for recording neural activity during tasks?

    <p>Electrophysiological recordings</p> Signup and view all the answers

    What is the primary purpose of producing brain lesions in experimental ablation studies?

    <p>To examine the impact of lesions on behavior</p> Signup and view all the answers

    Which method for producing brain lesions involves the application of heat to kill cells?

    <p>Radio frequency lesions</p> Signup and view all the answers

    What distinguishes excitotoxic lesions from other types of brain lesions?

    <p>They stimulate neurons to death</p> Signup and view all the answers

    What is a sham group in neuroscience research?

    <p>A group that has surgical procedures without any injections</p> Signup and view all the answers

    What is the significance of the Bregma in stereotaxic surgery?

    <p>It serves as a reference point for brain coordinates</p> Signup and view all the answers

    What is the purpose of placing brain tissue in a fixative during histological methods?

    <p>To prevent postmortem decay</p> Signup and view all the answers

    Which tool is commonly used to cut brain tissue into thin sections for histological analysis?

    <p>Microtome</p> Signup and view all the answers

    What is the typical thickness range for brain tissue sections prepared for histological examination?

    <p>10-80 m</p> Signup and view all the answers

    What is the method used for recording the activity of individual neurons?

    <p>Single unit recordings</p> Signup and view all the answers

    What should you include when emailing faculty to inquire about research opportunities?

    <p>Your availability to volunteer</p> Signup and view all the answers

    Which type of electrode is used in multi-unit recordings?

    <p>Macroelectrodes</p> Signup and view all the answers

    What is a limitation of using constitutive knockout mice?

    <p>Compensatory mechanisms may obscure effects.</p> Signup and view all the answers

    Where can one find faculty interests to identify potential labs for neuroscience research?

    <p>Online faculty pages at universities</p> Signup and view all the answers

    What are Immediate Early Genes (IEGs) commonly known for?

    <p>They turn on when neurons become active.</p> Signup and view all the answers

    Which imaging method provides the best spatial and temporal resolution?

    <p>Functional MRI (fMRI)</p> Signup and view all the answers

    What is a key feature of electrophysiological recordings in research?

    <p>They allow recording of neural activity during tasks.</p> Signup and view all the answers

    What does the BOLD signal indicate in functional MRI imaging?

    <p>Blood oxygen level changes.</p> Signup and view all the answers

    What type of tracer is used in Positron Emission Tomography (PET)?

    <p>2-deoxyglucose</p> Signup and view all the answers

    What advantage do conditional knockout mice provide over constitutive knockout mice?

    <p>They allow for temporal control over gene expression.</p> Signup and view all the answers

    What aspect characterizes Immediate Early Genes (IEGs) like Fos and Arc?

    <p>They can be induced by behavioral activities.</p> Signup and view all the answers

    What does the increased uptake of 2-deoxyglucose in PET indicate?

    <p>Increased metabolic activity in specific brain regions.</p> Signup and view all the answers

    What are the two types of photoreceptors in the human retina?

    <p>Rods and Cones</p> Signup and view all the answers

    What does the fovea specialize in within the retina?

    <p>Mediating acute vision</p> Signup and view all the answers

    How do photoreceptors transform light energy into electrical signals?

    <p>Via sensory transduction</p> Signup and view all the answers

    What structure allows light to enter the eye?

    <p>Pupil</p> Signup and view all the answers

    What is characteristic of rods in comparison to cones?

    <p>Rods are more sensitive to low light</p> Signup and view all the answers

    What is the purpose of the optic disk in the retina?

    <p>To produce the blind spot in vision</p> Signup and view all the answers

    Which statement regarding the structure of the eye is incorrect?

    <p>The sclera allows light to easily pass through</p> Signup and view all the answers

    What role does the lens play in vision?

    <p>Focuses light on the retina</p> Signup and view all the answers

    What is a significant advantage of conditional knockout mice compared to constitutive knockout mice?

    <p>They allow for temporal control over gene expression.</p> Signup and view all the answers

    What process transforms stimuli from the external world into electrical changes within sensory neurons?

    <p>Sensory transduction</p> Signup and view all the answers

    What limitation is associated with constitutive knockout mice?

    <p>They can develop compensatory mechanisms.</p> Signup and view all the answers

    Which opsin protein moves chloride ions into cells when activated by yellow light?

    <p>NpHR</p> Signup and view all the answers

    How does Channelrhodopsin-2 (ChR2) differentiate itself from halorhodopsin in function?

    <p>ChR2 opens sodium and calcium channels.</p> Signup and view all the answers

    What type of mutation does the Bad Hair Day (Bhrd) mouse represent?

    <p>Targeted mutation</p> Signup and view all the answers

    In sensory systems, what role do specialized neurons called sensory receptors play?

    <p>They detect physical stimuli from the external environment.</p> Signup and view all the answers

    What structure in the eye focuses light onto the retina?

    <p>Lens</p> Signup and view all the answers

    Which type of photoreceptor is primarily responsible for color vision?

    <p>Cones</p> Signup and view all the answers

    Where in the retina are the majority of cones concentrated?

    <p>Fovea</p> Signup and view all the answers

    What part of the eye contains no receptors and creates a blind spot?

    <p>Optic disk</p> Signup and view all the answers

    Which of the following best describes the function of rods in vision?

    <p>Detecting light in low-light conditions</p> Signup and view all the answers

    What term describes the process by which photoreceptors turn light into electrical signals?

    <p>Phototransduction</p> Signup and view all the answers

    The ocular muscles work to position light on which part of the retina?

    <p>Fovea</p> Signup and view all the answers

    Which structure controls the amount of light entering the eye?

    <p>Iris</p> Signup and view all the answers

    What is the primary function of channelrhodopsin-2 (ChR2) in optogenetic research?

    <p>Opening sodium and calcium channels in response to light</p> Signup and view all the answers

    What is a key limitation of constitutive knockout mice?

    <p>They may face compensatory mechanisms that mask the effects of the mutation.</p> Signup and view all the answers

    How does halorhodopsin (NpHR) function in optogenetics?

    <p>It inhibits neural activity by moving chloride ions into cells when exposed to yellow light.</p> Signup and view all the answers

    What is the benefit of using conditional knockout mice in research?

    <p>They allow researchers to control the timing of gene deletion.</p> Signup and view all the answers

    What role do sensory receptors play in the nervous system?

    <p>Detecting physical stimuli and initiating sensory transduction</p> Signup and view all the answers

    What does sensory transduction specifically refer to?

    <p>The conversion of physical stimuli into electrical changes</p> Signup and view all the answers

    What challenge is often faced when using knockout mice for neural circuit exploration?

    <p>They may develop compensatory mechanisms that obscure the intended study.</p> Signup and view all the answers

    Which component of the visual system is primarily responsible for transforming light energy into neural signals?

    <p>Photoreceptors</p> Signup and view all the answers

    What occurs during posterior vitreous detachment (PVD)?

    <p>The vitreous gel separates from the retina.</p> Signup and view all the answers

    Which of the following best describes the role of ganglion cells in the retina?

    <p>Their axons form the optic nerve carrying information to the brain.</p> Signup and view all the answers

    What is the primary function of photopigments found in photoreceptors?

    <p>To initiate the hyperpolarization process when light is absorbed.</p> Signup and view all the answers

    What happens to photoreceptors in the dark?

    <p>They release high amounts of neurotransmitters.</p> Signup and view all the answers

    How do ganglion cell axons behave at the optic chiasm?

    <p>Axons from the inner halves of each retina cross to the opposite side.</p> Signup and view all the answers

    Which cells in the retina produce action potentials?

    <p>Ganglion cells</p> Signup and view all the answers

    What is the role of the retinal in photopigments?

    <p>It is responsible for hyperpolarization upon light exposure.</p> Signup and view all the answers

    What symptom is NOT commonly associated with posterior vitreous detachment?

    <p>Increased acute vision</p> Signup and view all the answers

    What occurs at the optic chiasm in the visual processing pathway?

    <p>Contralateral processing of visual information begins at the optic chiasm.</p> Signup and view all the answers

    How does the arrangement of photoreceptors contribute to the differences in acuity between the fovea and the periphery?

    <p>Foveal photoreceptors have less convergence, providing greater visual acuity.</p> Signup and view all the answers

    What type of response do 'ON' cells exhibit in the presence of light?

    <p>They respond with an excitatory burst when illuminated.</p> Signup and view all the answers

    What characterizes the receptive fields of ganglion cells?

    <p>They show a center-surround organization, responding oppositely to light.</p> Signup and view all the answers

    What is the primary function of the lateral geniculate nucleus (LGN) in the visual pathway?

    <p>It acts as the first synapse for retinal ganglion cell axons.</p> Signup and view all the answers

    What is a common consequence of the organization of information in the retina regarding visual acuity?

    <p>The fovea provides higher acuity due to specialized photoreceptor arrangement.</p> Signup and view all the answers

    Which statement about the processing of visual information after passing through the optic chiasm is accurate?

    <p>Visual information is transmitted to the lateral geniculate nucleus before reaching the cortex.</p> Signup and view all the answers

    How does the convergence of photoreceptors in the periphery affect visual perception?

    <p>It decreases visual acuity compared to that of the fovea.</p> Signup and view all the answers

    What percentage of the primary visual cortex (V1) is dedicated to processing information from the fovea?

    <p>25%</p> Signup and view all the answers

    What type of information do retinal ganglion cells primarily encode?

    <p>How much light falls on their receptive fields</p> Signup and view all the answers

    What feature sensitivity characterizes most neurons in the primary visual cortex (V1)?

    <p>Orientation</p> Signup and view all the answers

    Which term is often used interchangeably with the primary visual cortex due to its specific structural features?

    <p>Striate cortex</p> Signup and view all the answers

    What aspect of light information is primarily transmitted by retinal ganglion cells to the primary visual cortex?

    <p>Color and brightness</p> Signup and view all the answers

    What is the primary function of the ventral stream in visual processing?

    <p>It processes 'what' an object is</p> Signup and view all the answers

    Which structure acts as the border between the outer and middle ear?

    <p>Tympanic membrane</p> Signup and view all the answers

    Which component of the middle ear is responsible for amplifying sound before it reaches the inner ear?

    <p>Ossicles</p> Signup and view all the answers

    Which part of the ear collects sound from the environment?

    <p>Pinna</p> Signup and view all the answers

    What occurs to the sound waves as they pass through the ear canal?

    <p>They are filtered to enhance certain frequencies</p> Signup and view all the answers

    What is the primary role of the inner ear in sound processing?

    <p>To convert sound pressure changes into neural signals.</p> Signup and view all the answers

    Which structure contains the hair cells essential for hearing?

    <p>Organ of Corti</p> Signup and view all the answers

    How do inner hair cells differ from outer hair cells?

    <p>Inner hair cells move in response to fluid motion but do not touch the tectorial membrane.</p> Signup and view all the answers

    What initiates the release of neurotransmitters in the auditory system?

    <p>Flexing of the basilar and tectorial membranes.</p> Signup and view all the answers

    What is the structure that separates the three canals of the cochlea?

    <p>Basilar membrane and Reissner's membrane</p> Signup and view all the answers

    What determines which part of the basilar membrane bends the most?

    <p>The frequency of the sound</p> Signup and view all the answers

    What fluid medium is present within the cochlea that aids in sound transduction?

    <p>Endolymph in the vestibular canal</p> Signup and view all the answers

    What is the function of the tectorial membrane in the Organ of Corti?

    <p>To lie over the hair cells and assist in their movement.</p> Signup and view all the answers

    What is the primary function of the dorsal stream in the auditory system?

    <p>Sound localization</p> Signup and view all the answers

    Which structure is the first synapse in the auditory pathway?

    <p>Cochlear nucleus</p> Signup and view all the answers

    In regards to auditory information processing, which of the following correctly describes how both hemispheres of the brain receive auditory input?

    <p>Both hemispheres primarily receive information from the contralateral ear</p> Signup and view all the answers

    Which part of the auditory system is responsible for processing complex sounds?

    <p>Ventral stream</p> Signup and view all the answers

    What structure follows the cochlear nucleus in the auditory central pathways?

    <p>Inferior colliculus</p> Signup and view all the answers

    Which stage of sleep has the highest percentage of recovery after sleep deprivation?

    <p>Stage 4</p> Signup and view all the answers

    What hypothesis suggests that slow-wave sleep (SWS) reflects a restoration process in the brain?

    <p>Delta activity hypothesis</p> Signup and view all the answers

    What type of memory is primarily consolidated during slow-wave sleep in adults?

    <p>Declarative memory</p> Signup and view all the answers

    Which stage of sleep is believed to be particularly important for brain development in infants and children?

    <p>REM sleep</p> Signup and view all the answers

    What does research suggest about the recovery of sleep stages following deprivation?

    <p>Stage 1 and 2 have minimal recovery</p> Signup and view all the answers

    Which neurotransmitter is primarily involved in muscle movement control?

    <p>Acetylcholine</p> Signup and view all the answers

    What is the primary role of the Nucleus Basalis in cortical arousal?

    <p>Producing desynchrony of the EEG</p> Signup and view all the answers

    Which brain region is clustered with most norepinephrine neurons?

    <p>Locus Coeruleus</p> Signup and view all the answers

    What effect does stimulation of the noradrenergic cells in the locus coeruleus have?

    <p>Promotes arousal and wakefulness</p> Signup and view all the answers

    Which of the following neurotransmitters is NOT associated with promoting arousal?

    <p>Serotonin</p> Signup and view all the answers

    What is the approximate duration of each sleep cycle?

    <p>90 minutes</p> Signup and view all the answers

    How many periods of REM sleep typically occur during an 8-hour sleep cycle?

    <p>4-5</p> Signup and view all the answers

    What characterizes narcolepsy in individuals?

    <p>Involuntary sleep attacks</p> Signup and view all the answers

    What is cataplexy, associated with narcolepsy?

    <p>Loss of muscular strength during strong emotions</p> Signup and view all the answers

    Which sleep disorder involves acting out dreams?

    <p>REM Sleep Behavior Disorder</p> Signup and view all the answers

    What outcome was observed in rats subjected to sleep deprivation studies?

    <p>Deterioration in coordination and eventual death</p> Signup and view all the answers

    How do sleep deprivation effects in humans primarily manifest?

    <p>Normal motor skills with no visible effects</p> Signup and view all the answers

    What is the main function of REM sleep?

    <p>Memory consolidation</p> Signup and view all the answers

    What is the characteristic of slow-wave sleep in terms of respiratory patterns?

    <p>Light and even respiration</p> Signup and view all the answers

    What brain activity is measured by an electroencephalogram (EEG)?

    <p>Collective activity of brain cells</p> Signup and view all the answers

    Which of the following is true about REM sleep?

    <p>It is characterized by vivid dreams.</p> Signup and view all the answers

    What typically happens to EEG synchronization as sleep progresses through stages 1-4?

    <p>It becomes more synchronized.</p> Signup and view all the answers

    Which stage of sleep is known for the presence of low-frequency delta waves?

    <p>Slow-wave sleep (stage 3-4)</p> Signup and view all the answers

    What defines the loss of muscle tone during REM sleep?

    <p>Complete paralysis of muscles</p> Signup and view all the answers

    What does the electrooculogram (EOG) monitor during sleep studies?

    <p>Eye movements</p> Signup and view all the answers

    How frequently does REM sleep occur throughout the night?

    <p>Every 90 minutes</p> Signup and view all the answers

    What type of brain activity is associated with the alpha state?

    <p>State of relaxation</p> Signup and view all the answers

    What role do muscle tone and arousal difficulty play in stages 3-4 of sleep?

    <p>Presence of muscle tone and difficulty in arousal</p> Signup and view all the answers

    Which structure serves as the first synapse for cochlear axons in the auditory system?

    <p>Cochlear nucleus</p> Signup and view all the answers

    What is primarily processed by the dorsal stream of the auditory information flow?

    <p>Sound localization</p> Signup and view all the answers

    How does the auditory cortex process information from the ears?

    <p>Information primarily comes from the contralateral ear in each hemisphere.</p> Signup and view all the answers

    What role does the medial geniculate nucleus play in the auditory pathways?

    <p>It is the final stage of auditory processing before it reaches the cortex.</p> Signup and view all the answers

    Where is the primary auditory cortex located in the brain?

    <p>Upper bank of the lateral fissure in the temporal lobe</p> Signup and view all the answers

    What percentage of REM sleep is typically recovered after sleep deprivation?

    <p>53%</p> Signup and view all the answers

    What is one primary function of slow-wave sleep (SWS)?

    <p>Restoration of brain regions that are highly stimulated during the day</p> Signup and view all the answers

    Which type of memory is primarily associated with REM sleep in adults?

    <p>Declarative memory</p> Signup and view all the answers

    Which statement regarding sleep stage recovery after sleep deprivation is true?

    <p>Stage 4 sleep has the highest recovery rate</p> Signup and view all the answers

    Which population is known to spend the most time in REM sleep?

    <p>Newborns and infants</p> Signup and view all the answers

    What role does acetylcholine (ACh) play in the brain's functioning?

    <p>It activates areas of the brain involved in learning and memory.</p> Signup and view all the answers

    Which brain region is primarily associated with the release of norepinephrine (NE) during arousal and increased vigilance?

    <p>Locus Coeruleus</p> Signup and view all the answers

    What happens to norepinephrine levels during REM sleep?

    <p>They drop to zero.</p> Signup and view all the answers

    Which neurotransmitter is primarily involved in controlling muscle movements?

    <p>Acetylcholine</p> Signup and view all the answers

    Which of the following neurotransmitters is NOT commonly associated with arousal?

    <p>Dopamine</p> Signup and view all the answers

    How long is each sleep cycle approximately?

    <p>90 minutes</p> Signup and view all the answers

    What percentage of a sleep cycle is typically spent in REM sleep?

    <p>20-30 minutes</p> Signup and view all the answers

    What characterizes a sleep attack in narcolepsy?

    <p>Usually lasts 2-5 minutes</p> Signup and view all the answers

    What happens during sleep paralysis?

    <p>Temporary inability to move while conscious</p> Signup and view all the answers

    What is REM Sleep Behavior Disorder characterized by?

    <p>Acting out dreams while asleep</p> Signup and view all the answers

    How does sleep deprivation appear to affect humans as opposed to animals?

    <p>Has minimal outward physical effects</p> Signup and view all the answers

    What is the primary function of sleep according to sleep studies?

    <p>Not primarily recuperation of the muscles</p> Signup and view all the answers

    What is a common trigger for cataplexy in individuals with narcolepsy?

    <p>Strong emotions</p> Signup and view all the answers

    What is the primary method used to record brain activity during sleep studies?

    <p>Electroencephalogram (EEG)</p> Signup and view all the answers

    Which type of sleep is characterized by rapid eye movements and vivid dreams?

    <p>REM sleep</p> Signup and view all the answers

    Which of the following statements correctly describes slow-wave sleep?

    <p>It involves low-frequency delta activity.</p> Signup and view all the answers

    What happens to the EEG as sleep progresses from stages 1-4?

    <p>It becomes more synchronized and slower.</p> Signup and view all the answers

    What defines the transitional states of non-REM sleep?

    <p>The subject typically is not aware s/he is asleep.</p> Signup and view all the answers

    Which frequency range indicates beta activity in the brain?

    <p>13-30 Hz</p> Signup and view all the answers

    What is a distinguishing feature of REM sleep compared to other sleep stages?

    <p>Enhanced respiration and blood pressure</p> Signup and view all the answers

    How often do REM sleep episodes typically occur throughout the night?

    <p>Every 90 minutes</p> Signup and view all the answers

    What is the primary method of monitoring muscle activity during sleep studies?

    <p>Electromyogram (EMG)</p> Signup and view all the answers

    Which physiological response is typically NOT associated with REM sleep?

    <p>Presence of muscle tone</p> Signup and view all the answers

    Study Notes

    Exam # 2 - Basic Features of the Nervous System

    • The class median score for Exam # 2 was 76%.
    • The highest score was 100%, achieved by 3 students.
    • The second highest score was 98%, achieved by 5 students.
    • The third highest score was 96%, achieved by 6 students.

    Acetylcholine

    • Acetylcholine is terminated in the synapse by an enzyme called acetylcholinesterase.
    • The choline from the breakdown of acetylcholine is actively transported back into the presynaptic terminal.

    ### Monoamine oxidase (MAO)

    • MAO inhibitors are commonly used to treat depression.
    • They block the breakdown of dopamine.
    • They increase the amount of dopamine available in the synapse.

    Norepinephrine & Serotonin

    • MDMA, SNRIs and SSRIs increase the amount of norepinephrine and/or serotonin in the synapse.
    • SSRIs, like Prozac, inhibit serotonin reuptake.
    • SNRIs, like Effexor, inhibit both serotonin and norepinephrine reuptake.

    Dopamine

    • Dopamine mesocortical pathway: dopaminergic neurons project from the ventral tegmental area (VTA) to frontal cortex and limbic system.

    Nicotinic Receptors

    • nicotine is an agonist at nicotinic receptors.
    • Nicotinic receptors are ionotropic receptors.
    • Nicotinic receptors cause rapid neuronal depolarization.

    Lateralization

    • Sensory information originating on one side of the body is sent to the contralateral primary sensory cortex, except for olfactory and gustatory systems.
    • The primary motor cortex controls the contralateral side of the body.
    • The left hemisphere is specialized more for language production and comprehension.
    • The right hemisphere is specialized for non-verbal and spatial abilities.

    Corpus Callosum

    • The two hemispheres of the brain are connected by the corpus callosum.

    Split-Brain Patients

    • Split-brain patients allow researchers to study lateralization.
    • The corpus callosum has been surgically severed in split-brain patients.
    • Communication between the two hemispheres is disrupted.

    Basal Ganglia

    • The basal ganglia control movement.
    • Lesions in the basal ganglia result in uncontrolled movements.
    • The basal ganglia includes the caudate nucleus, putamen, globus pallidus.

    Limbic System

    • The limbic system plays a role in emotions and memory formation.
    • The limbic system includes the cingulate cortex, amygdala, septum, and hippocampus.

    Hypothalamus and Pituitary

    • The hypothalamus controls the endocrine and autonomic nervous systems.
    • The pituitary gland is connected to the hypothalamus, and controls the endocrine system of the body.

    Experimental Ablation

    • Researchers remove or destroy brain tissue in laboratory animals to observe the consequences on behavior.
    • Oldest method used in neuroscience.
    • Also known as lesion studies.

    Methods For Producing Brain Lesions

    • Radio frequency lesion:
      • Involves passing alternating current through a wire electrode.
      • Heat kills cell bodies and axons.
    • Excitotoxic lesions:
      • Inject a chemical (e.g., kainic acid) through a cannula.
      • Stimulates neurons to death.
      • Kills cell bodies, not axons.
    • Reversible lesion:
      • Temporary disruption of brain activity.
      • Inject a muscimol through a cannula.
      • Blocks action potentials by stimulating GABA receptors.
    • Sham group:
      • Animals undergo surgery with electrode or cannula inserted but receive no current or chemical injection.
      • Control for incidental damage.

    Stereotaxic Surgery

    • Bregma:
      • Junction of the sagittal and coronal bones of the skull, serving as a reference point for brain targeting.
      • Used with a brain atlas to obtain coordinates for targeting specific brain regions.

    Histological Methods

    • Goal is to visualize brain tissue as it was during the organism's life.
    • Brain tissue is placed in a fixative (e.g., formalin) to prevent decay and preserve it.
    • Tissue is cut into thin sections (10-80 micrometers thick).
    • Sections are stained and mounted for microscopic examination.

    Immunohistochemistry

    • Antibodies bind specifically to antigens in biological tissues.
    • Antibodies are produced by injecting animals with the protein of interest and isolating antibodies from their serum.
    • Tissue is incubated with antibodies, which bind to their specific targets, allowing visualization of these targets.

    Visualizing The Human Brain

    • CT Scan:
      • Oldest method, involves passing X-ray beams through the head.
      • Blood absorbs a lot of radiation, making it appear brighter in scans.
    • MRI Scan:
      • Offers higher resolution than CT scans.
      • Does not use X-rays.
      • Uses strong magnetic fields and radio waves to produce images.
    • Diffusion Tensor Imaging:
      • Modification of MRI scanner.
      • Based on the movement of water molecules.
      • Visualizes bundles of axons by tracing water movement along them.

    Electrophysiological Recordings

    • Allows for recording neural activity while an animal is performing a task.

    Finding Neuroscience Research Opportunities

    • Search for faculty interests online at Hunter College using the provided links.
    • Look for faculty at nearby institutions like Mount Sinai School of Medicine, NYU, Cornell Medical Center, Albert Einstein Medical Center, The Rockefeller University, and other CUNY schools.
    • Email faculty and express interest in their research, attaching your transcript and providing your GPA, Hunter year, and volunteer availability.

    Measuring Neural Activity: Electrophysiological Recordings

    • Single Unit Recordings: Utilize microelectrodes to record activity of individual neurons, allowing for electrode movement.
    • Multi-Unit Recordings: Use macroelectrodes to record postsynaptic potentials of thousands of cells in a single location.
    • Electroencephalogram (EEG) Recordings: These recordings are used in humans and offer a non-invasive method similar to multi-unit recordings, collecting neural activity from the scalp.

    Measuring Neural Activity: Ex Vivo Brain Tissue

    • Immediate Early Genes (IEGs): IEGs like Fos and Arc are activated when neurons become active.
    • Fos Protein Expression: The expression of Fos can be induced behaviorally or by applying current.

    Measuring Neural Activity: In Humans

    • Positron Emission Tomography (PET): The first functional imaging method, PET involves administering a radioactive tracer (2-deoxyglucose) that is taken up by active cells and emits a signal.
    • PET Imaging: Increased uptake of 2-deoxyglucose in brain regions indicates higher metabolic rates.
    • Functional Magnetic Resonance Imaging (fMRI): This method provides the best spatial and temporal resolution and involves detecting oxygen levels in brain blood vessels using the BOLD signal.

    Manipulating Specific Circuits: Targeted Mutations in Mice

    • Mutated Genes: Genes can be mutated in the lab and inserted into mouse chromosomes.
    • Constitutive Knockout Mice: These mice have a target mutation that prevents the production of a certain protein.
    • Conditional Knockout Mice: These mice allow for temporal control over gene expression, enabling normal development before the specific gene is targeted.

    Targeted Mutations in Mice

    • Mutated genes can be produced in a laboratory setting and inserted into mouse chromosomes.
    • Constitutive Knockout Mice: The mutation prevents the production of a specific protein.
      • Limitation: Compensatory mechanisms can occur.
    • Conditional Knockout Mice: Temporal control over the gene expression allows for normal development.
      • Advantage: Mice can develop normally.

    Manipulating Circuits Using Optogenetics

    • Channelrhodopsin-2 (ChR2): A photosensitive protein found in green algae.
      • Function: Controls ion channels.
      • Activation: Responds to blue light by opening sodium and calcium channels.
    • Halorhodopsin (NpHR): A photosensitive protein found in bacterium.
      • Function: Controls transporter.
      • Activation: Responds to yellow light by moving chloride into the cell.

    The Visual System

    • Sensory Receptors: Specialized neurons that detect physical stimuli in the external world.
    • Sensory Transduction: The process of converting external stimuli into electrical changes.
      • Outcome: Changes in membrane potential.
      • Example: Light is transformed into electrical signals in the eye by photoreceptors.

    The Eye

    • The eye is part of the central nervous system (CNS).
      • The retina is a part of the brain.
    • Location: Suspended in the orbits of the skull.
    • Movement: Six extraocular muscles attach the eye to the skull, allowing for eye movements.

    Eye Structure:

    • Outer White Covering: Sclera (no entry of light).
    • Hole where Light Enters: Pupil.
    • Muscular Ring Controlling Light Entry: Iris.
    • Lens-like structure that focuses light on the retina: Lens.
    • Location of Sensory Receptors & Transduction: Retina.
    • Part of the Retina that Produces Output to the Brain: Optic Nerve.

    Photoreceptors

    • Function: Convert light into electrical signals.
    • Types:
      • Cones (6 million): Provide most of the visual information about our environment.
        • Function: Responsible for daytime vision; high visual acuity; process color.
      • Rods (120 million): More sensitive to light.
        • Function: Better for nighttime vision; provide vision of poor acuity.

    The Fovea

    • Location: Central region of the retina.
    • Significance: Contains almost all of the cones in the retina, mediating our most acute vision.
    • Function: When we look at something, our ocular muscles work to position the light emitted from the object directly on our fovea.

    Optic Disk

    • Location: Part of the retina where axons carrying visual information leave the eye to form the optic nerve.
    • Characteristics: Contains NO receptors, producing a blind spot.

    Optogenetics

    • Optogenetics uses light to control the activity of neurons
    • Channelrhodopsin-2 (ChR2) is a photosensitive protein that opens sodium and calcium channels in response to blue light
    • Natronomonas pharaonis halorhodopsin (NpHR) is a photosensitive protein that moves chloride into the cell in response to yellow light

    Targeted Mutations In Mice

    • Mutated genes can be produced in the laboratory and inserted into the chromosomes of mice
    • Constitutive knockout mice have a mutated gene that prevents the production of a certain protein
    • Conditional knockout mice allow for temporal control of gene expression

    The Visual System

    • The eye is part of the central nervous system (CNS)
    • The retina is part of the brain
    • Six extraocular muscles attach the eye to the skull
    • The lens focuses light on the retina
    • The retina contains photoreceptors that convert light into electrical signals
    • There are 2 types of photoreceptors: cones and rods
    • Cones are responsible for daytime vision and color perception
    • Rods are more sensitive to light and provide vision in low light conditions
    • The fovea is the central region of the retina and contains a high concentration of cones
    • The optic disk is the part of the retina where axons carrying visual information leave the eye to form the optic nerve
    • The optic disk contains no receptors and creates a blind spot.

    Retina Anatomy

    • The retina has three main layers: photoreceptors, bipolar cells, and ganglion cells.
    • Photoreceptors are responsible for detecting light and include cones and rods.
    • Bipolar cells receive input from photoreceptors and synapse with ganglion cells.
    • Ganglion cells receive input from bipolar cells and are responsible for sending visual information to the brain via the optic nerve.
    • Posterior vitreous detachment (PVD) is a common condition where the vitreous humor detaches from the retina, causing symptoms such as floaters, flashes of light, and reduced vision.

    Photoreceptors

    • Photoreceptors are composed of an outer segment containing lamellae and an inner segment.
    • Lamellae contain photopigments which are responsible for detecting light.
    • Photopigments consist of opsin (a protein) and retinal (a lipid synthesized from vitamin A).
    • When light strikes the photopigment, it splits into its two components and causes hyperpolarization of the photoreceptor.
    • Light exposure decreases neuronal activity, causing a release of neurotransmitter.

    Neural Circuitry in the Retina

    • Photoreceptors and bipolar cells do not generate action potentials, but instead signal information through changes in neurotransmitter release.
    • Photoreceptors are depolarized in the dark and continuously release neurotransmitter.
    • When photoreceptor neurotransmitter binds to bipolar cells, it leads to a change in their activity.
    • Ganglion cells, however, do generate action potentials to transmit visual information to the brain.

    Beyond the Retina

    • Ganglion cell axons form the optic nerve, which leaves the retina and travels towards the brain.
    • The optic nerve crosses at the optic chiasm, at the base of the brain.
    • Axons from the inner halves of each retina (nasal side) cross to the opposite (contralateral) side of the brain.
    • Axons from the outer halves of each retina (temporal side) do not cross and stay on the ipsilateral side.
    • Information from the right visual field ends up on the left side of the brain and vice versa.

    Lateral Geniculate Nucleus

    • After the optic chiasm, ganglion cells travel to the lateral geniculate nucleus (LGN) of the thalamus, where the first synapse occurs.
    • LGN neurons send their axons via the optic radiations to the primary visual cortex.

    Information Coding in the Visual System: The Retina

    • Foveal vision has greater visual acuity than peripheral vision due to less convergence of photoreceptors onto a single ganglion cell.
    • The retina contains three types of ganglion cells, but we are concerned with two: ON cells and OFF cells.
    • ON cells respond with an excitatory burst when the retina is illuminated.
    • OFF cells respond with an excitatory burst when the light is turned off.
    • These cells are responsible for encoding changes in illumination as you move and look at things.

    Receptive Fields

    • The receptive field of a neuron in the visual system is the part of the visual field that affects the neuron's firing rate.
    • The location of a receptive field depends on the location of photoreceptors that provide visual information.
    • The receptive fields of ganglion cells have center-surround organization, meaning that the center and surround regions respond to light in opposite ways.

    Light

    • Retinal ganglion cells encode the amount of light falling on the center and surround of their receptive fields
    • They carry information about the wavelength of light, which is color

    Primary Visual Cortex

    • The primary visual cortex, also known as the striate cortex, is found in the occipital lobe
    • The primary visual cortex is characterized by its dark staining layer
    • Approximately 25% of V1 processes info from the fovea, which represents a small part of the visual field
    • Cells in V1 respond to specific features of the visual world
    • Each V1 cell receives information from several retinal ganglion cells

    Orientation & Movement

    • Most neurons in V1 are sensitive to orientation
    • A cell is maximally responsive to a particular orientation, for example a vertical line

    Visual Association Cortex

    • V1 cannot “see” a whole object, only features
    • The output of V1 is sent to the adjacent extrastriate cortex (V2)
    • V2 cells receive input from several V1 cells, and information from V1 begins to be reassembled to “rebuild” the visual scene
    • Two pathways emerge from V2:
      • The Ventral Stream, projecting to the inferior temporal lobe, processes "what" an object is
      • The Dorsal Stream, projecting to the posterior parietal lobe, processes "where" an object is

    Sound as a Stimulus

    • Sounds are produced by objects that vibrate
    • Vibrating objects cause air molecules to condense together and pull apart, creating a sound wave

    Structure of the Human Ear

    • The outer ear collects sound from the environment
    • The pinnae funnel sound waves into the ear canal
    • The length and shape of the ear canal enhances certain sound frequencies
    • The tympanic membrane (ear drum) is a thin membrane at the end of the outer ear canal
    • It vibrates in response to sound, defining the border between the outer and middle ear

    Middle Ear

    • The ossicles (malleus, incus and stapes) are three tiny bones that amplify and transmit sound to the inner ear
    • The malleus (hammer) connects with the incus (anvil).
    • The incus (anvil) connects to the stapes (stirrup).
    • The stapes (stirrup) is attached to the oval window of the cochlea and is the smallest bone in the body
    • Vibrations from the tympanic membrane first reach the malleus

    Inner Ear

    • The inner ear converts fine changes in sound pressure into neural signals
    • The inner ear is analogous to the retina
    • It contains the cochlea, which is a spiral structure that contains the organ of Corti
    • The cochlea is filled with fluid in three parallel canals: the vestibular, tympanic, and middle canals
    • The three canals are separated by two membranes: Reissner's membrane and the basilar membrane.

    The Organ of Corti

    • The Organ of Corti has 3 major parts:
      • Hair cells, which are the receptive cells of the auditory system
      • Basilar membrane which anchors the hair cells
      • Tectorial membrane that lies over the hair cells

    Hair Cells

    • Hair cells are embedded in the basilar membrane
    • Each hair cell contains a soma and cilia that protrude from the top
    • There are two major types of hair cells:
      • Inner hair cells are less numerous and do not touch the tectorial membrane but move when fluid moves.
      • Outer hair cells are more numerous and attached directly to the tectorial membrane.
    • Hair cells synapse with bipolar cells whose axons bring the information from the inner ear to the brain.

    Transduction of Sound

    • Sound waves entering the ear cause the tympanic membrane to vibrate at the same frequency.
    • Vibrations are transmitted to the ossicles, which transfer them to the oval window of the cochlea.
    • Vibrations at the oval window cause the basilar membrane and tectorial membrane to flex up and down
    • Bending cilia of the hair cells initiates release of neurotransmitters
    • The portion of the basilar membrane that bends the most is determined by the frequency of the sound.

    Anatomy of the Ear

    • The auditory system processes sound waves
    • The ear is composed of three parts: the outer ear, the middle ear, and the inner ear
    • Sound waves enter the ear through the outer ear
    • The outer ear consists of the pinna (the flap of cartilage that captures sounds) and the auditory canal (the tunnel that leads to the middle ear)
    • The sound waves hit the tympanic membrane (eardrum) at the end of the auditory canal
    • This causes the ossicles, the three smallest bones in the body (malleus, incus, and stapes) to vibrate
    • The stapes pushes against the oval window, a membrane that separates the middle ear from the inner ear
    • This causes the fluid inside the cochlea to move which stimulates the hair cells of the organ of Corti
    • The organ of Corti is the structure inside the cochlea that contains the hair cells
    • The hair cells transform the mechanical energy of the vibrations into electrical signals
    • These electrical signals travel to the brain through the auditory nerve.

    Central Auditory Pathways

    • Auditory information travels from the cochlear nucleus to the inferior colliculus, then the medial geniculate nucleus, and finally to the auditory cortex
    • The auditory cortex is the final destination of auditory information in the brain
    • Most cochlear axons cross over to the other side of the brain and synapse in the cochlear nucleus.

    Auditory Cortical Areas

    • The primary auditory cortex is responsible for processing basic auditory information
    • The auditory association cortex surrounds the primary auditory cortex and processes more complex auditory information, such as language
    • There are two streams of auditory information flow: the dorsal stream and the ventral stream
    • The dorsal stream is involved in sound localization ("where" the sound is coming from)
    • The ventral stream is involved in processing the characteristics of sounds ("what" the sound is)

    What is Sleep?

    • Sleep is a state of altered consciousness characterized by reduced sensory awareness and a decrease in muscle activity
    • Sleep is studied in a lab by measuring brain activity and muscle activity using the following instruments:
      • Electroencephalogram (EEG)
      • Electromyogram (EMG)
      • Electrooculogram (EOG)

    The Study of Sleep

    • Brain activity during sleep can be categorized into two patterns:
      • Alpha Activity (state of relaxation)
      • Beta Activity (state of arousal)
    • The EEG becomes more synchronized as sleep progresses through stages 1-4, and the brain waves become slower
    • REM sleep looks like the awake state.

    Non-REM Sleep

    • Stages 1-4 of sleep are called "non-REM sleep"
    • Stages 1-2 are transitional, and the person is usually not aware that they are asleep
    • Stages 3-4, or slow-wave sleep, are characterized by the presence of low-frequency delta activity
    • Slow-wave sleep is characterized by:
      • Light, even respiration
      • Presence of muscle tone
      • Difficulty in arousing the subject

    REM Sleep

    • REM Sleep occurs every 90 minutes throughout the night
    • It is characterized by:
      • Enhanced respiration and blood pressure
      • Rapid eye movements (REMs)
      • Complete loss of muscle tone (paralysis)
      • Vivid, emotional dreams

    Cycles of Sleep

    • We alternate between REM and non-REM sleep cycles.
    • Each cycle is approximately 90 minutes long and contains about 20-30 minutes of REM sleep.
    • There are 4 to 5 periods of REM sleep in a night (8 hours).

    Disorders of Sleep

    • Sleep disorders can significantly impact a person's well-being and daily functioning.

    Insomnia

    • Difficulty falling asleep after going to bed or waking up during the night.
    • Sleep Apnea is a form of insomnia where the individual falls asleep and stops breathing. This is usually caused by an obstruction in the airway
    • Narcolepsy is characterized by uncontrollable sleepiness and an inability to regulate sleep-wake cycles.
    • Cataplexy is a symptom of narcolepsy involving sudden muscle weakness or paralysis, often triggered by emotions.
    • Sleep Paralysis is a symptom of narcolepsy where a person feels unable to move or speak while falling asleep or waking up.
    • Hypnagogic Hallucinations are vivid dreams that occur just before falling asleep and may be accompanied by sleep paralysis.

    REM Sleep Behavior Disorder

    • The sleeper acts out their dreams.
    • This occurs because the brain is unable to produce paralysis during REM sleep.
    • This may be caused by a neurological disease that damages the brain mechanisms responsible for producing REM sleep paralysis.

    Why Do We Sleep?

    • Sleep appears to serve essential functions for both physical and cognitive health.

    Sleep Deprivation Studies

    • Studies on animal sleep deprivation demonstrate harmful consequences, including physical weakness, impaired coordination, and death.
    • In humans, sleep deprivation doesn't have obvious physical effects, but it significantly impairs cognitive functioning, leading to hallucinations, difficulty concentrating, and memory problems.
    • When sleep-deprived people are allowed to sleep again, they never recover all the sleep they lost.
    • REM sleep is not associated with the recovery or restoration of muscles, but is more important than other stages for cognitive function.

    Functions of Slow-Wave Sleep

    • One theory suggests that slow-wave sleep (SWS) is a restorative process.
    • Areas of the brain that are stimulated during the day show more delta activity and lower metabolic activity during SWS.
    • SWS may indicate that a brain region is resting.

    Functions of REM Sleep

    • REM sleep may promote brain development, especially in infants and children who spend a high percentage of their sleep in REM.
    • In adults, REM and slow-wave sleep may be involved in memory consolidation.
    • Nondeclarative memory (learning skills, procedures, and habits - like how to drive a car or recognize a face) may be strengthened during REM sleep.
    • Declarative memory (memories of past experiences) may be strengthened during SWS.

    Neural Regulation of Arousal

    • To understand what produces sleep, we must understand what causes us to stay awake.
    • Electrical stimulation of the brainstem induces arousal and vigilance.
    • Several neurotransmitters play crucial roles in arousal, including:
      • Acetylcholine (ACh)
      • Norepinephrine (NE)
      • Serotonin (5-HT)
      • Histamine (HA)

    Acetylcholine (ACh)

    • Acetylcholine is the primary neurotransmitter secreted by the motor axons of the peripheral nervous system.
    • It controls muscle movements.
    • Acetylcholine is also widely distributed in the brain, with significant concentrations in three regions:
      • Dorsolateral pons: Involved in REM sleep and dreaming.
      • Medial Septum: Involved in hippocampal function and certain types of memory.
      • Basal Forebrain: Plays a key role in activating the cortex, facilitating learning, and is important for arousal.

    The Nucleus Basalis

    • The ACh neurons in the nucleus basalis (in the basal forebrain) appear to be crucial for cortical arousal.
    • Stimulation of ACh neurons produces cortical activation and desynchrony of the EEG.
    • Levels of ACh in various brain regions are elevated during wakefulness and alertness.

    Norepinephrine (NE)

    • Most NE effects are excitatory.
    • Release of NE by the sympathetic nervous system prepares the body for “fight or flight" responses.
    • Most NE neurons in the brain are clustered in the locus coeruleus (LC) in the brainstem.
    • Activation of the LC produces alertness, vigilance, and anxiety.

    Norepinephrine and the Sleep-Wake Cycle

    • Catecholamine agonists, such as amphetamine, cocaine, and MDMA, induce arousal and wakefulness by stimulating the noradrenergic cells in the LC.
    • The activity of LC neurons closely corresponds with arousal and wakefulness.
    • Activity of LC neurons decreases during sleep and becomes zero during REM sleep.

    Anatomy of the Ear

    • The Organ of Corti is located in the inner ear and is responsible for converting sound waves into neural signals.

    Central Auditory Pathways

    • The auditory nerve synapses in the cochlear nucleus.
    • Most cochlear axons cross over and synapse in the inferior colliculus.
    • The next synapse is in the medial geniculate nucleus.
    • The cortex is the last synapse in the central auditory pathway.

    Auditory Cortical Areas

    • The primary auditory cortex is located in the temporal lobe.
    • The auditory association cortex surrounds the primary auditory area.
    • There are two streams of auditory information flow:
      • The dorsal stream terminates in the posterior parietal region and is involved in sound localization.
      • The ventral stream terminates in the temporal lobe and is involved in processing of complex sounds.

    What is Sleep?

    • Sleep is studied by measuring the activity of the brain and two muscle groups:
      • The Electroencephalogram (EEG) measures the collective activity of thousands of brain cells, usually on the cortical surface.
      • The Electromyogram (EMG) monitors muscle activity.
      • The Electrooculogram (EOG) monitors eye movements.

    The EEG

    • Alpha activity is associated with relaxation and has a frequency of 8-12 Hz.
    • Beta activity is associated with arousal and has a frequency of 13-30 Hz.
    • Delta activity is associated with slow-wave sleep and has a frequency of <3.5 Hz.
    • During sleep, the EEG becomes more synchronized as sleep progresses from stages 1-4.
    • The waves become slower as sleep progresses from stages 1-4.
    • During REM sleep, the EEG looks like the awake state.

    Non-REM Sleep

    • Stages 1-4 of sleep are called non-REM sleep.
    • Stages 1-2 are transitional and the subject is typically not aware they are asleep.
    • Stages 3-4 are known as slow wave sleep and are characterized by the presence of low-frequency delta activity.
    • Slow-wave sleep is characterized by:
      • Light, even respiration.
      • Presence of muscle tone.
      • Difficulty in arousing the subject.

    REM Sleep

    • REM sleep occurs approximately every 90 minutes throughout the night.
    • It is characterized by:
      • Enhanced respiration and blood pressure.
      • Rapid eye movements (REMs).
      • Complete loss of muscle tone (paralysis).
      • Vivid, emotional dreams.

    Cycles of Sleep

    • We alternate between periods of REM and non-REM sleep.
    • Each cycle of sleep is approximately 90 minutes long.
    • Each cycle of sleep contains 20-30 minutes of REM sleep.
    • In an 8-hour night, there will be 4-5 periods of REM sleep.

    Sleep Deprivation Studies

    • In animals, sleep deprivation appears to be harmful.
      • Rats forced to lose sleep became weak, uncoordinated, lost the ability to regulate their body temperature, and eventually died.
    • In humans, sleep deprivation appears to have no outward physical effects.
      • Motor skills remain intact.
      • Stress hormones are at normal levels.
      • The primary function of sleep is not the recuperation of muscles.
      • Cognitive function is impaired (hallucinations, trouble concentrating, memory, etc).
    • When sleep-deprived people are allowed to sleep again, they never regain all the lost sleep.
      • The percentage of recovery is not equal for all stages of sleep.
        • 7% of stages 1 and 2 are made up.
        • 68% of stage 4 sleep is made up.
        • 53% of REM sleep is made up.

    Functions of Slow-Wave Sleep

    • Slow-wave and REM sleep may serve different functions.
    • One hypothesis is that SWS may reflect a restoration process.
      • Areas of the brain that are more stimulated during the day show more delta activity and the lowest levels of metabolic activity during slow-wave sleep.
      • The presence of SWS in a brain region indicates that region is resting.

    Functions of REM Sleep

    • REM sleep in children may reflect promotion of brain development.
      • Infants and children show the highest amounts of REM sleep.
      • Newborns spend about 70% of their sleep in REM.
    • In adults, REM and slow-wave sleep may reflect a memory consolidation process.
      • Nondeclarative memory (learning to drive a car or recognize a person’s face) may be consolidated during REM sleep.
      • Declarative memory (memories of past episodes) may be consolidated during SWS..

    Mechanisms: The Neural Basis of Arousal

    Neural Regulation of Arousal

    • Electrical stimulation of the brainstem induces arousal and vigilance.
    • Several common neurotransmitters are involved in arousal:
      • Acetylcholine
      • Norepinephrine
      • Serotonin
      • Histamine

    Acetylcholine (ACh)

    • ACh is the primary neurotransmitter secreted by the motor axons of the PNS.
      • All muscle movements are controlled by ACh.
    • ACh is also widely distributed in the brain.
    • There are three brain regions that contain cholinergic neurons:
      • Dorsolateral Pons: involved in REM sleep (dreaming).
      • Medial Septum: involved in hippocampal function and certain types of memory.
      • Basal Forebrain: involved in activating the cortex and facilitating learning.

    Norepinephrine

    • Almost all NE effects are excitatory.
    • The release of NE by the sympathetic nervous system prepares you for “fight or flight.”
    • In the brain, most NE neurons are clustered in the brainstem in a region called the locus coeruleus (LC).
      • Activation of the LC produces vigilance and anxiety.

    Norepinephrine and the Sleep-Wake Cycle

    • Many catecholamine agonists, including amphetamine, cocaine, and MDMA, produce arousal and wakefulness.
    • These effects are mimicked by stimulation of the noradrenergic cells in the locus coeruleus (LC) (dorsal pons).
    • Activity of LC neurons shows a close correspondence with arousal and wakefulness.
    • Activity of LC neurons falls during sleep until it reaches zero during REM sleep.

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    Description

    Test your knowledge on the basic features of the nervous system, including neurotransmitters like acetylcholine, norepinephrine, and serotonin. Understand their functions and importance in treating conditions like depression. This quiz will help reinforce key concepts discussed in class.

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