Neuroscience
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Questions and Answers

What is the primary role of the Peripheral Nervous System?

  • To protect the brain from harmful substances
  • To connect the brain and spinal cord to the rest of the body (correct)
  • To process sensory information
  • To control involuntary bodily functions

    • Which neurotransmitter is primarily associated with the Sympathetic Nervous System?

  • GABA
  • Dopamine
  • Serotonin
  • Norepinephrine (correct)

    • What does the Blood-Brain Barrier primarily do?

  • Prevent all substances from entering the brain
  • Allow the free flow of all neurotransmitters within the brain
  • Facilitate the movement of beneficial substances into the brain while blocking toxins (correct)
  • Ensure only oxygen and glucose can enter the brain

    • Which system is responsible for controlling voluntary muscle movements?

    <p>Somatic Nervous System</p> Signup and view all the answers

    Which branch of the Autonomic Nervous System is responsible for the 'rest and digest' functions?

    <p>Parasympathetic Nervous System</p> Signup and view all the answers

    What is the primary function of the cerebellum?

    <p>Precision movements and learned actions</p> Signup and view all the answers

    Which of the following structures is involved in the regulation of action and thought?

    <p>Basal ganglia</p> Signup and view all the answers

    What role does the thalamus play in the brain?

    <p>It serves as a sensory relay to the cortex, excluding smell.</p> Signup and view all the answers

    Which lobe of the brain is primarily associated with vision?

    <p>Occipital lobe</p> Signup and view all the answers

    What is the consequence of a blockage in the ventricles of the brain?

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

    What characterizes the neocortex?

    <p>It has a convoluted structure to fit into the skull.</p> Signup and view all the answers

    How many layers does the neocortex consist of?

    <p>6 layers</p> Signup and view all the answers

    Which of the following best describes the function of the corpus callosum?

    <p>It connects the two hemispheres of the brain.</p> Signup and view all the answers

    What is the primary function of myelin in neurons?

    <p>To enhance neurotransmission speed by preventing depolarization</p> Signup and view all the answers

    How do action potentials travel down a neuron?

    <p>By causing a continuous wave of depolarization throughout the axon</p> Signup and view all the answers

    What role do neurotransmitters play in neuron communication?

    <p>They are released into the synapse to transmit signals to other neurons</p> Signup and view all the answers

    Which statement about the action potential is accurate?

    <p>It provides a digital signal representing only one bit of information</p> Signup and view all the answers

    What happens to neurotransmitters after they have fulfilled their function in the synapse?

    <p>They are reabsorbed by the presynaptic neuron or degraded by enzymes</p> Signup and view all the answers

    Which statement correctly describes the effect of opiates on neural function?

    <p>They mimic the action of neurotransmitters at receptor sites</p> Signup and view all the answers

    How does caffeine affect neurotransmission?

    <p>It blocks adenosine receptors, leading to increased neural activity</p> Signup and view all the answers

    What distinguishes short axons in terms of myelin coverage?

    <p>They do not require myelin due to their inherent speed of action potential travel</p> Signup and view all the answers

    Which technique is known for its good temporal resolution but poor spatial resolution when measuring brain activity?

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

    What is the primary advantage of using Transcranial Magnetic Stimulation (TMS) in studying the brain?

    <p>It briefly interferes with brain activity, helping to identify functions.</p> Signup and view all the answers

    Which brain imaging technique involves bombarding the head with high-frequency radio waves?

    <p>Magnetic Resonance Imaging (MRI)</p> Signup and view all the answers

    Which of the following methods provides a functional map of brain response based on magnetic fields?

    <p>Magnetoencephalography (MEG)</p> Signup and view all the answers

    What physiological change does Functional MRI primarily measure?

    <p>Changes in O2 in blood</p> Signup and view all the answers

    Which neural mechanism is primarily involved in regulating hunger and satiety in the brain?

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

    Which imaging technique is described as having good spatial resolution but poor temporal resolution?

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

    What is a major drawback of using Magnetoencephalography (MEG) in studies of brain function?

    <p>It is very expensive and sensitive to interference.</p> Signup and view all the answers

    What neurotransmitter is found in the Pre-optic Area that promotes sleep?

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

    How does caffeine affect the sleep process?

    <p>It blocks adenosine receptors.</p> Signup and view all the answers

    Which brain structure is primarily responsible for regulating REM sleep?

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

    What is the effect of sleep deprivation on cognition?

    <p>It negatively impacts mood and function.</p> Signup and view all the answers

    Which of the following substances negatively impacts REM sleep?

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

    What happens to the amount of REM sleep throughout the lifespan?

    <p>It decreases as one ages.</p> Signup and view all the answers

    Which hormones are affected by sleep deprivation?

    <p>Leptin, ghrelin, and insulin</p> Signup and view all the answers

    Which brain region is associated with controlling the release of melatonin?

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

    What effects occur as a result of damage to Broca's Area?

    <p>Problems with speech production but comprehension remains intact</p> Signup and view all the answers

    Which function is primarily associated with the right hemisphere of the brain?

    <p>Interpreting emotional content in speech</p> Signup and view all the answers

    What occurs in split-brain patients when an object is held in their left hand?

    <p>They can only identify it by touch</p> Signup and view all the answers

    What is a characteristic feature of hippocampal amnesia based on the case of Henry Molaison (HM)?

    <p>Retention of older memories but inability to form new declarative memories</p> Signup and view all the answers

    What type of language deficits are typically seen in individuals with Wernicke's Area damage?

    <p>Fluent speech that lacks meaning</p> Signup and view all the answers

    What is a primary role of the hippocampus?

    <p>Formation of new memories</p> Signup and view all the answers

    Which of the following best describes the outcome of having the hippocampus removed, as seen in HM's case?

    <p>Severe amnesia affecting long-term memory retrieval</p> Signup and view all the answers

    What kind of amnesia is Wernicke Korsakoff Syndrome associated with?

    <p>Amnesia related to severe alcoholism and nutritional deficiencies</p> Signup and view all the answers

    Study Notes

    The Brain

    • The brain is the control center of the body, responsible for complex behaviors.
    • It is comprised of 86 billion neurons and is divided into two symmetrical hemispheres.

    Ventricles

    • Ventricles are fluid-filled spaces in the brain containing cerebrospinal fluid (CSF).
    • They act as a sewage system for the brain, removing waste products.
    • There are three ventricles in the middle of the brain, all connected.
    • Blockage of these ventricles can lead to hydrocephalus.
    • The blood-brain barrier regulates the flow of substances into and out of the brain, creating a "sewage system" via the ventricles.

    Subdivisions of the Brain

    • Brain Stem: Controls basic life-sustaining functions like breathing and heart rate.
    • Cerebellum ("Small Brain"): Highly dense with neurons, responsible for precise movements, including learned ones. Dictates which neurons affect things and to what extent.
    • Thalamus and Hypothalamus (Diencephalon):
      • Thalamus acts as a sensory relay to the cortex, channeling all sensory inputs except smell.
      • It prioritizes and regulates the flow of sensory information to the cortex.
    • Limbic System: Controls emotions and memory.
      • Consists of structures including the amygdala, hippocampus, thalamus, mammillary bodies, olfactory bulb, and cingulate cortex.
    • Basal Ganglia: Involved in the initiation and planning of actions and thoughts.
      • Consists of the thalamus, caudate (left and right), putamen, and globus pallidus.
      • Parkinson's disease primarily affects the basal ganglia.
    • Neocortex: Convoluted sheet on the top of the brain, responsible for higher-level cognitive functions.
      • The wrinkles allow for a greater surface area within the skull.
      • It comprises six layers called laminae.
      • It is highly adaptable, and more folds correlate with greater adaptability.
      • Contains four lobes:
        • Frontal Lobe: Responsible for planning, decision-making, and executive functions.
        • Parietal Lobe: Represents space for action and movement.
        • Temporal Lobe: Processes memory and language.
        • Occipital Lobe: Responsible for vision; larger in humans compared to other lobes.
    • Corpus Callosum: Connects the two hemispheres of the brain, facilitating communication between them.

    General Nervous System Facts

    • Plants and fungi do not have a nervous system.
    • The nervous system is a defining characteristic of animals.
    • Vertebrates have a central nervous system (CNS) and a peripheral nervous system (PNS).
    • The size of an animal's brain and neocortex significantly impact its structure and function.

    Neuron Structure & Function

    • Soma (cell body): Contains the nucleus and is responsible for the neuron's metabolic processes.
    • Axon: A long, slender fiber that extends from the soma and transmits nerve impulses to other neurons, muscles, or glands.
    • Dendrites: Short, branched fibers that receive signals from other neurons.
    • Myelin: A fatty substance that insulates the axon, speeding up the transmission of nerve impulses.
    • Neurons transmit signals through action potentials, which are brief electrical impulses that travel down the axon.
    • Action potentials involve the opening and closing of ion channels in the neuron's membrane, causing a rapid change in the electrical potential across the membrane.
    • Neurons can be considered digital as they convey information in an "on" or "off" state, represented by the presence or absence of an action potential.

    Myelin & Action Potential Speed

    • Myelin acts as an insulator, preventing the depolarization of the axon except at gaps called nodes of Ranvier.
    • Action potentials "jump" between these nodes, significantly increasing the speed of transmission.
    • Short axons do not require myelin because the action potential travels fast enough without it.

    Complexity of Brain Function

    • The brain's sophisticated functions arise from:
      • High speed of information transmission: Enabled by myelin and the rapid propagation of action potentials.
      • Large number of neurons: The human brain contains billions of neurons, allowing for complex processing and interconnectedness.
      • Complexity of connections between neurons: Neurons form intricate networks and circuits, facilitating information flow and complex cognitive processes.

    Neurotransmission

    • Synapse: The small gap between neurons where communication occurs.
    • Neurotransmitters: Chemical messengers released from the terminal of one neuron and bind to receptors on the receiving neuron, transmitting signals across the synapse.
    • Removal of neurotransmitters: After transmission, neurotransmitters are rapidly removed from the synapse by enzymes or reuptake mechanisms to prevent continuous signaling.

    Drug Effects on Neurotransmission

    • Drugs can influence neurotransmission by:
      • Mimicking neurotransmitters: Opiates act like opioid neurotransmitters, binding to their receptors and producing similar effects.
      • Promoting neurotransmitter release: Stimulants like cocaine and ecstasy increase the release of various neurotransmitters, leading to heightened activity.
      • Stimulating receptors: Nicotine activates acetylcholine receptors, resulting in various physiological and psychological effects.
      • Blocking receptors: Caffeine blocks adenosine receptors, leading to increased alertness and wakefulness.

    Therapeutic Drug Mechanisms

    • Valium: Enhances the effects of GABA, an inhibitory neurotransmitter, producing calming and anxiety-reducing effects.
    • Anti-schizophrenia drugs: Block dopamine receptors, reducing the symptoms of schizophrenia associated with excessive dopamine activity.
    • Antidepressants: Increase the availability of serotonin, a neurotransmitter involved in mood regulation, helping to alleviate depression.

    Studying The Brain

    • Observing brain damage helps us understand the function of different brain regions.
    • Transcranial Magnetic Stimulation (TMS) temporarily disrupts brain activity to study its function.
      • TMS uses magnetic pulses to create electrical currents in the brain, causing neuron depolarization (action potential).
      • TMS offers good temporal resolution (accurate timing of brain activity).
    • Single-cell recording measures voltage and current changes in individual neurons.
    • Electrical stimulation involves stimulating neurons to observe the effects of disrupting specific brain functions.
    • More modern techniques include optogenetics, fiber photometry, and targeted microinjections into specific brain regions.

    Functional Imaging of the Brain

    • Functional brain imaging aims to identify which brain areas are active during specific tasks.
    • It reveals correlations between brain activity and psychological function, but cannot establish causal relationships.

    Electroencephalography (EEG)

    • EEG uses electrodes placed on the scalp to record electrical fields generated by the brain.
    • Offers excellent temporal resolution (precise timing of brain activity) but has poor spatial resolution (cannot pinpoint exact location of activity).

    Magnetic Resonance Imaging (MRI)

    • MRI scans use strong magnetic fields and radio waves to measure the alignment of protons in water molecules.
    • This allows visualization of brain structures and differentiation between different brain tissue types.
    • MRI has poor temporal resolution but good spatial resolution.

    Functional Magnetic Resonance Imaging (fMRI)

    • fMRI measures changes in oxygen levels in blood flow.
    • Detects variations in magnetic properties between oxygen-rich and oxygen-poor blood.
    • Offers good spatial resolution but poor temporal resolution.

    Magnetoencephalography (MEG)

    • MEG measures magnetic fields produced by brain activity.
    • These magnetic fields are used to create a 3D reconstruction of brain activity, generating a functional map of brain response.
    • Advantages of MEG include high spatial and temporal resolution, non-invasive nature, greater signal penetration compared to EEG.
    • Disadvantages include high cost, extreme sensitivity to electromagnetic interference, and limited availability.

    Regulation of Feeding

    • Hunger and satiety (feeling full) are triggered by stomach contents and circulating substances in the blood.
    • The actual sensations of hunger and fullness are perceived in the brain.
    • The hypothalamus plays a critical role in regulating hunger.

    Sleep

    • Even basic organisms like jellyfish and worms sleep
    • Sleep patterns vary widely across species based on physical factors
    • Most animals sleep at night, which presents them as vulnerable and comes with the opportunity cost of lost time

    Sleep and Health

    • Sleep is essential for optimal cognitive function
    • Sleep deprivation negatively affects mood, function, speed, attention and memory
    • Lack of sleep increases the risk of eating disorders and obesity (auto diabetes)
    • Sleep deprivation affects ghrelin, leptin and insulin levels
    • Lack of sleep impacts all body functions, even the sympathetic nervous system
    • There is a 20% increase in heart attacks the day after daylight saving time

    What Keeps Us Awake

    • Norepinephrine in the Locus Coeruleus (in the brain stem)
    • Serotonin in the Raphe nuclei
    • Acetylcholine in the pons
    • These neurons are more active when awake compared to asleep
    • Drugs like ecstasy and cocaine mimic these neurons

    What Sends Us To Sleep

    • Pre-optic Area (anterior hypothalamus) is responsible for sleep
    • The neurons here contain GABA
    • GABA inhibits actions, which explains why we are awake when it's not active
    • The longer we are awake, the more adenosine builds up in the brain
    • Increased adenosine leads to sleepiness by inhibiting alertness centers and stimulating sleep centers
    • Caffeine blocks adenosine receptors
    • Suprachiasmatic nucleus controls the release of melatonin from the pineal gland
    • Melatonin signals night-time to the body

    Sleep Cycles

    • Brain waves become slower as we enter deeper sleep
    • The thalamus is responsible for coordinating slow wave sleep
    • It does this by communicating with the entire brain through two-way communication

    REM Sleep

    • Brain waves in REM sleep resemble those of someone who is awake
    • People who are woken up during REM sleep report they were dreaming
    • The amount of REM sleep increases throughout the night and decreases across the lifespan
    • Newborns spend 50% of their sleep in REM, while adults spend 20%
    • Drugs for sleep and alcohol negatively impact REM sleep

    Brain Regions

    • Neurons in the Pons that release acetylcholine stimulate neurons in the thalamus, which then project to the visual cortex and cause REM sleep
    • fMRI studies show that during REM sleep:
      • Active areas:
        • Visual regions of the frontal lobes
        • Back of the brain
      • Suppressed areas:
        • Motor regions
        • Lateral prefrontal cortex
        • Limbic system
    • We are paralyzed during REM sleep

    Hemispheric Lateralisation

    • The brain has two hemispheres: right and left
    • Each hemisphere receives sensory input from and controls motor skills on the opposite side of the body
    • Hemispheric dominance refers to one hemisphere being better at certain functions than the other, for example, right-handedness
    • Left hemisphere is dominant for language and speech comprehension
    • Evidence for lateralisation includes aphasia, which is a language disorder that can occur after stroke
    • Evidence from stroke patients shows both hemispheres of the brain impacted the left side

    Speech Areas

    • Broca's Area: Located in the lower posterior region of the left frontal lobe
      • Damage to Broca's Area impacts speech production, but the person can generally understand speech
      • Patients struggle to talk but can still sing, write (but not draw) and deaf signers lose the ability to sign
    • Wernicke's Area: Located in the posterior region of the temporal lobe
      • Damage to Wernicke's Area causes problems with comprehension of speech
      • Patients produce fluent but meaningless speech and cannot read.

    The Split Brain

    • Information is normally shared between the right and left hemispheres, allowing for integrated functions
    • Some patients have their brains surgically separated to alleviate severe epilepsy
    • Despite the split, these patients are still able to walk, talk and generally suffer little to no impairments
    • Roger Sperry was a major researcher in the field
    • Split brain patients can name an object held in their right hand, but not their left
    • Right hemisphere functions:
      • Can comprehend simple language
      • Contributes more than the left to adding and interpreting emotional content to speech
      • Better than the left at producing and interpreting facial expressions

    Memory & Hippocampus

    • Hippocampus is the brain's best memory structure
    • It is core to the temporal lobe
    • Henry Molaison had brain surgery to treat severe epilepsy and had his hippocampus removed
      • He also had his amygdalae and surrounding cortex removed
    • The removal of the hippocampus alleviated seizures, but caused severe amnesia
    • HM's older memories were spared, but he could not form new memories (anterograde amnesia)
    • Deficit is specific to declarative learning and memory
      • HM could demonstrate procedural learning, even though he had no recall of performing the task
      • Declarative memory does not work
      • Procedural memory does work

    Wernicke Korsakoff Syndrome

    • Amnesia can be caused by disease or brain damage
    • Wernicke Korsakoff Syndrome is a type of amnesia caused by a thiamine deficiency, often associated with chronic alcohol abuse.
      • It can result in anterograde and retrograde amnesia, confusion, and confabulation (creating false memories).
      • Treatment involves thiamine supplementation and addressing the underlying alcohol abuse.

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