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Questions and Answers
What cell sends inhibitory signals?
What cell sends inhibitory signals?
What is the main source of colour vision?
What is the main source of colour vision?
When is the visual system developed?
When is the visual system developed?
What color theory can explain an afterimage?
What color theory can explain an afterimage?
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When trying to infer how you can move around, you use the __ stream that sends information to the __ lobe.
When trying to infer how you can move around, you use the __ stream that sends information to the __ lobe.
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Why is the fovea specialized in details?
Why is the fovea specialized in details?
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What is the blind spot and why do we not notice it?
What is the blind spot and why do we not notice it?
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Is vision contralateral, like how your left hand is connected to your right hemisphere?
Is vision contralateral, like how your left hand is connected to your right hemisphere?
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What are the two types of photoreceptors?
What are the two types of photoreceptors?
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What causes colour vision deficiency?
What causes colour vision deficiency?
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Damage to the Ventral Stream can cause visual agnosia.
Damage to the Ventral Stream can cause visual agnosia.
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What theory of pitch perception is correct?
What theory of pitch perception is correct?
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How does the vestibular system help with balance?
How does the vestibular system help with balance?
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What is the dermatome?
What is the dermatome?
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The vomeronasal organ contains receptors that detect:
The vomeronasal organ contains receptors that detect:
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What statement is incorrect?
What statement is incorrect?
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Which motor cortex is similar in function to the prefrontal cortex?
Which motor cortex is similar in function to the prefrontal cortex?
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A patient has an overly active thalamus. Is it more likely that the person has Parkinson's or Huntington's disease? Why?
A patient has an overly active thalamus. Is it more likely that the person has Parkinson's or Huntington's disease? Why?
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What is not true about the cerebellum?
What is not true about the cerebellum?
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Autoreceptors are located on the _______
Autoreceptors are located on the _______
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Which of the following is true of Oligodendrocytes and Schwann cells?
Which of the following is true of Oligodendrocytes and Schwann cells?
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What is required for the control group when performing a lesion?
What is required for the control group when performing a lesion?
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Neurotransmitters are secreted from the
Neurotransmitters are secreted from the
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Hyperpolarization is _____ because of how slow ____ is
Hyperpolarization is _____ because of how slow ____ is
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What is an advantage of myelination?
What is an advantage of myelination?
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What happens if a stimulus reaches -60 mV?
What happens if a stimulus reaches -60 mV?
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Match up the correct receptor type and effect
Match up the correct receptor type and effect
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Cerebrospinal fluid is produced within ____
Cerebrospinal fluid is produced within ____
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The basal ganglia does not consist of
The basal ganglia does not consist of
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What procedure uses magnetic waves to alter brain neural activity?
What procedure uses magnetic waves to alter brain neural activity?
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What is a key advantage of a reversible lesion?
What is a key advantage of a reversible lesion?
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A unique feature of the fovea is that it
A unique feature of the fovea is that it
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The ventral visual stream projects to ____ and is involved in _____
The ventral visual stream projects to ____ and is involved in _____
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Put the parts of the auditory system in the correct order from where the sound enters
Put the parts of the auditory system in the correct order from where the sound enters
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Study Notes
Biopsychology: Vision
- The process of vision involves:
- Light entering through the pupil and being focused by the lens and cornea
- Projection of light onto the retina
- Recognition of different wavelengths by photoreceptors
- Activation of bipolar and ganglion cells
- Refinement of the image by amacrine cells and horizontal cells
- The fovea is specialized for detail because each photoreceptor is connected to one bipolar cell, which is connected to a single midget ganglion cell
- The blind spot is where the optic nerve leaves the retina, but it is compensated for by the other eye
Photoreceptors
- There are two types of photoreceptors: rods and cones
- Rods are found throughout the retina, while cones are only found in the fovea
- Both types of photoreceptors release photopigments when struck by light, modifying receptor sensitivity to different wavelengths
Colour Vision
- There are three theories of colour vision:
- Trichromatic theory: colour is determined by comparing the response of three types of cones with different wavelength sensitivities
- Opponent-process theory: colour is perceived in terms of opposites (e.g. blue-yellow, red-green, black-white)
- Retinex theory: the ability to see colour despite changes in lighting, by comparing visual input with previously encountered information
Anatomy of Visual Processing
- The optic nerve pathway involves:
- The optic nerve leaving the eye
- The optic nerve crossing in the optic chiasm
- The optic nerve traveling to the lateral geniculate nucleus (part of the thalamus)
- The lateral geniculate nucleus sending information to the visual cortex
Lateral Inhibition
- Lateral inhibition allows for optimal object-background differentiation by:
- Activating neighbouring neurons to heighten contrast
- Inhibiting bipolar cells in the middle of the illuminated area
- Allowing bipolar cells on the border to receive only a slight inhibitory signal
Cells
- There are several types of cells involved in visual processing, including:
- Photoreceptors: activate bipolar and horizontal cells
- Bipolar cells: activate ganglion cells
- Ganglion cells: have a doughnut-shaped receptive field and respond to movement and large patterns
- Parvocellular neurons: detect details and colour, found near the fovea
- Magnocellular neurons: respond to movement and large patterns, found throughout the retina
- Koniocellular neurons: have some colour sensitivity, found throughout the retina
Development of Visual Cortex
- The visual system develops before birth, but requires experience to develop, particularly:
- Synchronizing activity of neighbouring receptors to form connections with cells
- Visual-experience for fine-tuning
- Retinal disparity (discrepancy between left and right eye) for stereoscopic depth perception
Ventral and Dorsal Pathway
- The ventral stream (what pathway) is involved in recognizing objects, while the dorsal stream (how pathway) guides movement with visual input
- Damage to the ventral stream can cause visual agnosia (inability to recognize objects)
Visual Hierarchy
- The visual hierarchy involves:
- Receptive fields becoming larger and more specialized
- V1 (primary visual cortex): basic features (such as lines and edges)
- V2 (secondary visual cortex): patterns
- V3: colour
- V4: recognition
- V5 (middle temporal cortex): motion
Object Recognition
- Most brain areas do not respond more to one object than another, but exceptions include:
- Parahippocampal cortex: responds more to pictures of places
- Fusiform gyrus: responds more to faces, and damage in this area can cause prosopagnosia (face blindness)
Mechanical and Chemical Senses
- The auditory system involves:
- Sound waves differing in amplitude, frequency, and timbre
- Sound entering at the pinna and traveling through the auditory canal
- Vibration of the oval window creating motion in the liquid in the cochlea
- Recognition of different sounds by the auditory cortex### Pitch Perception
- Theories of pitch perception:
- Place theory: certain hair cells respond to specific frequencies, but limited as individual areas of the basilar membrane cannot vibrate on their own.
- Frequency theory: the entire basilar membrane vibrates at the same frequency as the sound, but limited for low frequencies.
- Volley principle: several neural populations fire simultaneously, but out of phase with each other.
Auditory Cortex
- 2 pathways of auditory processing:
- Pathway to process identity: anterior temporal cortex (ventral stream).
- Pathway to process location: posterior temporal cortex (dorsal stream).
- Primary auditory cortex (A1): processes complex sounds.
- A2: processes nature sounds.
- Superior temporal cortex: processes motion and is responsible for motion deafness when damaged.
Sound Localization
- Methods for sound localization:
- Difference in time of arrival.
- Difference in intensity (shadow of the head).
- Phase difference between the ears.
Hearing Loss
- Types of hearing loss:
- Deafness: due to environmental factors (e.g., exposure to loud sounds).
- Conductive deafness: middle ear unable to send soundwaves to cochlea, usually temporary, and treatable with surgery or implants.
- Nerve deafness: damage to cochlea, hair cells, or auditory nerve, can be inherited or due to exposure.
Vestibular System
- Responsible for balance and distinguishing between self and external movement.
- Semicircular canals filled with fluid and lined with hair cells.
Somatosensation
- Experience of touch, pressure, pain, itch, temperature, and movement.
- Somatosensory receptors:
- Pacinian corpuscles: detect vibration and sudden displacement on skin.
- Merkel's disks: detect light touch.
- Meissner's corpuscle: detect skin movement and object handling.
- Ruffini ending: detect skin stretching, movement, and finger position.
Awareness of Touch
- Information in the CNS:
- Info from the head to the brain via cranial nerves.
- Touch info from periphery to brain via spinal nerves (dermatome).
- Pain:
- Same pathway as touch.
- Starts from bare nerve endings in the skin.
- Dull pain is slow due to unmyelinated axons.
- Sharp pain is fast due to myelinated axons.
Pain Relief
- Mechanisms of pain relief:
- Opioid mechanism: opiates and endorphins bind to receptors in the spinal cord and midbrain.
- Gate theory: pain differs from time to time, and the body closes the 'gate' for pain with endorphins.
- Anti-inflammatory drugs: reduce release of chemicals in damaged tissue.
- Placebo: the mere expectation of pain relief.
Taste
- Taste receptors:
- 50 receptors for 5 different tastes.
- Located in papillae.
- Combination of taste and smell (endopiriform cortex).
- Experience:
- Adaptation: reduction of taste due to fatigue of receptor.
- Cross-adaptation: reduction in response to a different taste.
- Taste coding in the brain:
- Taste nerves go to the nucleus of the tractus solitarius (NTS) in the medulla.
- To somatosensory cortex for touch.
- To insula (primary taste cortex).
Olfaction
- Smell:
- Olfactory cells line the epithelium.
- Cilia (threadlike dendrites) and metabotropic effects.
- Info sent to olfactory bulb.
- Women generally have a better sense of smell.
- Pheromones:
- Unconsciously affect behavior.
- Only respond to vomeronasal organ.
- Synchronize menstrual cycles.
Movement
- Muscle contractions:
- Muscle control by axon releasing acetylcholine.
- In neuromuscular junction (synapse motor neuron).
- Types of muscles:
- Smooth muscles: digestive system.
- Skeletal/striated muscles: movement of body.
- Cardiac muscles: heart.
- Aerobic or anaerobic:
- Slow-twitch fibers: aerobic, do not fatigue, oxygen as energy source.
- Fast-twitch fibers: anaerobic, create oxygen debt, ATP and glycogen as energy source.
Muscle Proprioceptors
- Proprioceptors:
- Detects the stretch and tension of muscles.
- Signals to spinal cord to adjust muscle.
- Stretch reflex.
- 2 types of proprioceptors:
- Muscle spindles: located parallel to muscles, respond to stretch, and provide negative feedback.
- Golgi tendon organs: located in tendons, respond to increase in tension, and inhibit further contraction to prevent damage.
Motor Patterns
- Reflex:
- Consistent, automatic response to a stimuli.
- Ballistic (once they occur, they cannot be stopped or corrected).
- Sequential movements:
- Central pattern generators: neural mechanisms of rhythmic patterns of movement.
- Motor program: a fixed sequence of movements.
Primary Motor Cortex
- Orders movement outcome.
- Posterior parietal cortex: monitors position of body in environment.
- Supplementary motor cortex: planning, rapid sequence movements, and habits.
- Prefrontal cortex: planning, habits, and stores relevant movement info.
- Premotor cortex: active immediately before movement.
Spinal Cord
- Corticospinal tract: pathway from cerebral cortex to spinal cord.
- Lateral corticospinal tract: axons from primary motor cortex and the red nucleus.
- Medial corticospinal tract: axons from midbrain, tectum, and vestibular nucleus.
Cerebellum
- Balance, coordination, timing of action, and attention.
- Cerebellar cortex:
- Receives sensory input from spinal cord through cranial nerves.
- Contains Purkinje cells.
- Parallel fibers activate Purkinje cells one after another.
- The more Purkinje cells activated, the longer their inhibitory message.
- Inhibits nuclei in cerebellum and vestibular nuclei in the brain stem.
Basal Ganglia
- Spontaneous behavior, habits, and reward.
- Striatum (caudate nucleus and putamen):
- Receives input from cerebral cortex and substantia nigra.
- Sends info to globus pallidus.
- Globus pallidus:
- Sends info to thalamus and frontal cortex.
- 2 pathways:
- Direct pathway: striatum inhibits globus pallidus, further inhibiting the thalamus.
- Indirect pathway: inhibits competing movements.
Movement Disorders
- Parkinson's disease:
- Gradual loss of dopamine-releasing axons from the substantia nigra.
- Less inhibitory input to globus pallidus increases inhibitory signal to thalamus.
- Symptoms: muscle tremors, slow movement, and difficulty initiating voluntary movements.
- Treatment options: L-dopa treatment and experimenting with brain implants.
- Huntington's disease:
- Severe neurological disorder due to damaging protein huntington.
- Symptoms: jerks, facial twitches, and tremors.
- Extensive brain damage in basal ganglia and cerebral cortex.
- Confirmed causal genetic relationship.### Oligodendrocytes and Schwann Cells
- Oligodendrocytes are found within the brain and provide myelin for nerve cells
- Schwann cells provide myelin for peripheral nerve cells
- A single Schwann cell wraps a single segment of a peripheral nerve cell
Neurotransmitters
- Neurotransmitters are secreted from the axon terminal
- Autoreceptors are located on the presynaptic membrane
Lesions
- A sham lesion is required for the control group when performing a lesion
- A key advantage of a reversible lesion is that axons of passage are not affected by reversible procedures and each animal can serve as its own control
Myelination
- Myelination allows for quick and efficient transmission of action potential
- Myelination does not change the height of action potential
- Myelination does not increase the energy requirement of a nerve cell
Action Potential
- Hyperpolarization is when the potential becomes overly negative, usually due to potassium (K+) ions
- If a stimulus reaches -60 mV, no action potential occurs
Receptors
- Ionotropic receptors directly open an ion channel
- Metabotropic receptors use G protein activation to activate a second messenger, leading to a longer-lived effect on ion channels
Brain Structure
- Cerebrospinal fluid is produced within the ventricles
- The parietal lobe is involved in somatosensory function
- The occipital lobe is involved in visual function
- The temporal lobe is involved in auditory function
- The basal ganglia consists of the putamen, globus pallidus, and caudate nucleus, but not the amygdala
- The ventral visual stream projects to the temporal lobe and is involved in object recognition
Auditory System
- The correct order of the auditory system is: auditory canal, eardrum, stirrup, anvil, and hammer, oval window and cochlea, hair cells
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Description
This quiz covers the material from lectures 5-7 of session 2 in a biopsychology course, including practical information and preparation for a partial exam.
