Sensory Flashcards
What is the CNS made up of?
The brain and spinal cord
What afferents?
Neurons that deliver information to the CNS(sensory input)
Where are the cell bodies and axons of afferents located?
Cells bodies: Outside of CNS
Axons: Stick into the CNS in the brain or spinal cord
What are the spinal nerve afferents responsible for?
Where somatosensation (touch, temperature and pain) enter the spinal cord
What are the cranial nerve afferents responsible for?
Carry information about visual, olfactory, somatic into the brain
How many cranial nerves and how many go into the brainstem?
12 cranial nerves
10 out of 12 go into the brainstem
What is visceral input?
Somatosensation from within your body
What are efferents?
Neurons that send outputs out of the CNS (motor outputs)
Where are the cell bodies of efferent?
In the CNS and their Axons are outside of the CNS
T/F: cranial nerves and spinal nerves have efferents?
True
What somatic efferents?
Motor neurons with their cell bodies in the CNS and axons innervating the skeletal muscles to make you move
What are autonomic efferents?
Innvervate things other than skeletal muscle such as smooth muscle, interneurons and cardiac muscle
What are gyrus?
Wirnkles in the cerebral cortex responsible for out smartness
What are sulcus?
The cracks in between the gyrus
What is the central sulcus?
Separates the gyrus responsible for primary somatosensory processing from the gyrus responsible for primary motor cortex
What is grey matter?
Location of the cell bodies for the neurons in the cerebral cortex
What is white matter?
Axons travelling from different areas of the brain
What is the basal nuclei/ganglia?
A bunch of cell bodies together inside the cerebral cortex
What do cervical nerves innervate?
-Neck, shoulders, arms and hands
What do Thoracic nerves innervate?
-Shoulders, chest, upper abdominal wall
What do the lumbar nerves innervate?
-Lower abdominal wall, hips, legs
What do the sacral nerve innervate?
-Genital and lower digestive tract
How many spinal nerves?
31
What is the butterfly shape of the spinal cord?
THe grey matter
What is the central canal and where is it located?
In the middle of the gray matter of the spinal cord and it is a canal for CSF
Ventral horn vs Dorsal horn
Ventral horn: Area of the grey matter closest to the stomach
Dorsal horn: Area of the grey matter closest to the back
What does the dorsal root carry?
Sensory afferent (inputs) into the spinal cord
What does the ventral root carry?
Motor efferent axons (output)
Where are the cell bodies of the seonsory afferents located?
Dorsal root ganglion
Where are the cell bodies of the motor efferents located?
Ventral horn
What would happen if you damage the dorsal root?
Somatosensory input would be affected bu motor output would be fine
What two nerves don’t go into the brainstem?
- Olfactory nerve
- Optic Nerve
What is brain edema?
Brain bleeding`
How does a brain bleed affect pupillary response?
When your brain bleeds there is increase intercranial pressure which compresses the brain stem and cranial nerves that regulate the pupillary response. Now you pupil will no longer dilate when light is flashed into it
What are the three layers of the embryonic disk?
- Ectoderm
- Mesoderm
- Endoderm
What occurs during week 3 and 4 of embryonic development?
The ectoderm folds up into a neural groove and then becomes the neural tube
Where do the cells of the CNS come from in development?
Ectoderm
Where do the cells that become the organs and muscles come from during development?
Mesoderm
Where does the digestive system come from during development?
Endoderm
What does the neural tube become?
THe CNS and part of the PNS
Neural crest cells become?
Part of the PNS
What is the dura, where does it come from and what does it become?
Cells from the mesoderm become the dura which is the covering/liniing of the CNS
What occurs during week 4 of embryonic development?
The neural tube forms vesicles with a cavity in the middle that later become parts of the brain (forebrain, midbrain and Hindbrain)
The neural tube also form a part with no vesicles that becomes the spinal cord
What is the cavitiy used for in the neural tube?
Becomes the ventricles of the brain and central canal of the spinal cord
What produces CSF?
The ventricles
What are the four ventricles?
- Lateral ventricles
- Third ventricle
- Fourth ventricle
What are the largest types of ventricles?
Lateral ventricles
There is one in each hemisphere of the brain
Which ventricles produce the most CSF?
The lateral ventricles
Do all ventricles produce CSF?
Yes
What is the choroid plexus?
Lines the inside of all of the ventricls and is repsonsible for oozing out CSF(produces CSF) produces 500mL per day
How much CSF is in the brain?
150mL
What are the functions of the CSF?
- Supports and cushions the CNS (the brain floats in CNS)
- Provides nourishment to the brain (contains glucose)
- Removes metabolic waste through absorption at the arachnoid villi
How is CSF removed from the brain?
Absorption by the arachnoid villi
Composition of the CSF?
-Sterile, colourless fluid that contains glucose
How does the CSF flow throughout the brain?
Passively flows throughout the brain and ventricles and requires no energy
What is the Foramen of Monro?
COnnects the two lateral ventricles to the third ventricle
What is the cerebral aqueduct?
Connects the third ventricle to the fourth ventricle
What is the role of the subarachnoid space?
THe CSF created by the chroid plexus passively moves around the subarachnoid space until it gets to the very top(midline). Where the arachnoid villi are located
Where does the subarachnoid space come from in development?
The dura
What is the role of the arachnoid villi?
Found at the midline of the brain, the acrachnoid villi take CSF out of the subarachnoid space and empty it into the venous blood supply
How hoes the CSF enter the subarachnoid space?
Via 3 foramens and 2 lateral and magendie
What happens if the CSF is not taken up by the arachnoid villi?
If the ventricle cannot empty CSF, yet it continues to produce it this will cause pressure on the brain
Communicating hyrocephalus vs noncommunicating?
Hydrocephalus - Water on the brain
Communication - blockage outside of the ventricles
Noncommunicating - blockage between ventricles
What are meninges?
Membranes that cover the CNS(brain and spinal cord)
What are the three meninges?
1.Dura
2. Arachnoid membrane
3. Pia matter
What helps produce the subarachnoid space?
- Arachnoid membrane
- Trabeculae( legs)
What is the pia matter?
Thin membrane that attaches to the brain below it
What is the dural venous sinus?
Dura open and creates a cavity at the midline of the head. Arachnoid villi line the dural sinus and take up CSF from the subarachnoid space and empty it into the dural sinus which goes to the venous blood supply
Where does CSF return to the blood?
At the dural sinus
Only substrate metabolized by the brain?
Glucose
Do neurons keep a back up supply of glycogen in the brain ?
No
Does the brain reuqire insulin to uptake glucose?
No
The brain needs a constant supply of…
Glucose and oxygen
What happens if there is a lack of blood supply to the brain?
Few seconds: Loss of conciousness
Few minutes: stroke which leads to neuronal death
Is glucose transported into neurons?
No, it diffuses in
Describe blood flow to brain?
Aorta diverges into the common carotid artery which then diverges into the external carotid (supplies blood to outside of the skull) and the internal carotid(supplies bloos to the base of the brain).
What is the basilar artery?
Where the two vertebral arteries come together
What is the circle of Willis?
Where the basilar artery and the two internal carotid arteries come together and form a loop and then they branch off to different parts of the brain
How is the cricle of willis a safety factor?
If an internal carotid artery or vertebral artery is blocked blood is still able to flow to the other side of the brain due to the loop
What is between the endothelial cells of the capillaries in the brain and what do they do?
There are tight junctions between endothelial cellsthat prevent anything from leaving/entering the blood from the ECF of the brain.
What can pass through the blood-brain barrier?
Lipid soluble substance
- things such as O2, CO2, H2O, alcohol, caffeine, nicotine, heroine
Can ions cross the blood brain barrier?
Barely
How does glucose cross the blood-brain barrier?
Active transport brings glucose into the ECF of the brain from the blood
What are astrocytes ?
Cells that maintain the blood-brain barrier(induce tight junctions)
-Non neuronal cells of the CNS(glial)
Role of astrocytes?
- Induce tight junctions by putting their foot processes on capillaries
- Provide structural support for the brain
- Take up extra neurotransmitters/ions to keep everything regulated
- Phagocyte debris
Sensation vs Perception?
Sensation: Awarness of sensory information(im aware something is hurting)
Perception:Understanding of a sensation’s meaning (My finger hurts because I bumped it)
T/F: We percieve the energy of a seonsory stimulus?
False, we do not percieve the photons striking out retina
T/F: We perveice the neural activity that is produced by a sensory stimulation
True
What is the law of specific nerve energies and give an example?
Does not matter how you activate the receptor on an afferent, what your brain perceives is what it is designed to detect
ex. When you rub your eeyes in the dark you may see some light becaus eyou are putting pressure on the retina
What is the law of projection?
Regardless of where in the brain you stimulate a sensory pathway, the sensation is always felt at the sensory receptors location
Ex. Phantom limb pain, axons carry the somatosensory information regrow in the wrong spots and then are activated for the worng reasons
What is the labeled line code?
Every afferent that arrives in the CNS carrying sensory information is labeled both on the modality and location
What is modality?
Class of stimulus (ex. pain, auditory, visual)
T/F: THe brain knows the modality and location of every sensory afferent?
True
What is an adequate stimulus?
In order for the membrane receptor channels to open the stimulus must match what the membrane is designed to transduce. If it is not a match channels will not open
- Ex. Somatosensory receptors in the finger are designed to detect deforamtions of the skin
What happens to sensory receptors when they are activated?
- Stimulus energy
- Receptor Membrane is depolarized by opening/closing ion channels
- Transduction
- Ion channel activation
- Afferent
How is a weak stimulus encoded by the afferent?
- Lower magnitude of receptor potential
- Frequency of action potentials decreases
- Less neurostransmitter is released
How is a strong stimulus encoded by the afferent?
- Bigger magnitude of receptor potential
- Frequency of action potentials increases
- Lots of neurotransmitter released
How is a subthreshold stimulus encoded by the afferent?
-Produces a receptor potential that is not strong enough to produce an action potential
- No neurostransmitter is released
What is adaptation?
Change in the frquency of action potentials, even though the stimulus is constant
What are non-adapting afferents?
Continuously discharges action potentials due to an ongoing stimulus
-Not coomon
-Encodes stimulus energy just as it is
What are slowly adapting afferents?
-Starts as a strong action potential than as time goes on the action potentials occur less frequently
-Moderate stimulus changes
What is a rapidly adapting stimulus?
-Fires rapidly when a stimulus is presented, then falls silent in the prescence of the stimulus
What is a receptive field?
Region in space that activates a sensory receptor or neuron
What happens when there is is a deformation in the middle of the RF vs the outskirts of the RF?
Middle of the RF will produce more action potentials
Outsides of the receptive field will produce less action potentials
This explains the graded response of the RF
What happens if an action potential occurs outside of the Receptive Field ?
No action potentials will be fired by that receptor
What is a population code how is it produced?
Receptive Fields overlap. When a stimulus is presented it will mainly activate one afferent but it will also activate other afferents around it slightly less(less action potentials) because it will be at the edge of its RF
How does the brain utilize the population code?
The brain knows where every receptive field is located. The brain uses the population code to determine which afferents are active and which receptive fields were activated in the middle vs edge to determine the precise location of the stimulus
Define acuity?
Ability to differentiate one stimulus from another
How do receptive fields relate to acuity?
Small RF = High Acuity
Large RF = Low acuity
What is lateral inhibition?
When afferents adjacent to eachother try to inhibit each other
How does lateral inhibition occur ?
The main receptive field afferent (B) has inhibitory interneurons that inhibit the 2nd order neurons of the afferents nearby (reducing their activity)
What is the goal of lateral inhibition?
“sharpen” the population code, makes it easier for the brain to distiguish where the stimulus is
How is lateral inhibition a bottom up mechanism?
Way of making sense of the stimuli starting with the receptors and working its way up to the brain(happens automatically)
Does lateral inhibition inhibit first order neurons?
No, only second order neurons are inhibited , the first order will still fire more action potentials when the stimulus is at the edge of their RF
How is sensory information shaped?
By both bottom-up(lateral inhibition) and top-down mechanisms(descending pathways)
What are the modalities of somatosensory information?
-Touch
-Pain
-Proprioception
-Thermal
Receptors classes for somatosensory information?
- Chemoreceptors
- Mechanoreceptors(touch)
- Thermoreceptors(thermal)
- Nociceptors(pain)
What are the two types of touch mechanoreceptors in the deep layers?
Pacinian corpuscle
Ruffini endings
Where are the pacinian corpuscle and ruffini endings found?
In the deep layers of the skin
Pacinian Corpuscle Vs Ruffini Endings
Pacinian Corpuscle: Rapidly Adapting. Detects vibrations
Ruffini endings: Slowly adapting afferents. Signal how the body is bending/stretching (tells you the shape of an object you are touching)
What is proprioception?
Sense of body awareness (the state of your body)
How are mechanoreceptors activated?
Stretching the cytoskeletal strands
Describe the transduction mechanism of somatosensory receptors?
- Deformation of the skin results in deformation of the cell membrane of an afferent
- Afferents have cytoskeletal strands that attach to ion channels, when the cell membrane deforms it causes sytoskeletal strands to pull on the ion channels and open them
- Open ion channels causes a receptor potential. If it is big enough it will produce an action potential sent to the brain/CNS
What kind of ion channels are found in the afferents cell membrane?
Mechanically-gated(this is why they open due to cytoskeletal strands pulling)
What are the two types of mechanoreceptors of touch in the superficial layers?
- Meissner’s corpuscle
- Merkel disk
What is the role of specialized end organs on mechanoreceptors?
Only allow selective mechanical information to activate the nerve terminal
Describe the Meissner’s Corpuscle?
-Superficial layers
- Rapidly adapting
- Signal light stroking and fluttering
Describe the Merkel disk?
- Superficial layers
- Slowly Adapting
- Sensitive to pressure and texture
What are the two types of thermoreceptors?
- Cold Afferents
- Warm Afferents
Sense of temperature is mediated by….
Free nerve endings
Afferents that don’t have specialized end organs wrapped around them
T/F : Free nerve endings of the thermoreceptors are located near the surface of the skin?
True
-This allows them to ge the most accurate reading of temperature
T/F: Free nerve endings have ion channels?
True, they open/close depending on temperature
Describe the cold afferents?
-Ion channels open between 0 and 35 degrees
-Also activated by menthol (Vick’s)
Describe the warm afferents?
-Ion channels open between 30 and 50 degrees
-Also activated by capsaicin and ethanol
What are the pain receptors?
Nociceptors
Are pain receptors free nerve endings or do they have specialized ned organs?
They are free nerve endings with ion channels that open in response to intense mechanical deformation, excessive temperature or chemicals
What does it mean when pain afferents are highly modulated?
Either enhanced or surpressed
Where are nociceptors located?
Close to the surface of the skin
What are visceral pain receptors?
Receptors inside you (stomach hurts, internal inflammation)
Describe what happens when you poke your finger?
- Nociceptors activate
- Nociceptors prodcue action potentials
- These action potential go to the spinal cord and release substance P
- Substance P activates second order neurons that go to the brain
- Brain then registers the the poke in the thumb hurt
What is enhancement in terms of nociceptors?
A process by which the nociceptors become more sensitive to stimuli after having been previously activated
Give an example of nociceptor enhancement?
After you poked your finger, the next morning when you pick up an object with that finjet you will experience pain because the nociceptor became more sensotive
How does enhancement of nociceptors work ?
When the afferents were first activated they not only sent axons to the spinal cord but they also sent them to the surrounding tissue of the site of injury.
They released substance P on mast cells which causes the release of histamine which increases sensitivity of the nociceptors. They also release substance P which causes the blood vessels to dilate and the skin at the site of injury to be swollen and red. Mechanical swelling also causes nociceptors to be more sensitive
What is hyperalgesia?
-Bottom up mechanism
-When a stimulus activates nociceptors that the stimulus normally would not.
-Occurs at previous sites of injury
Body is telling you to not use it till it is healed
Describe the touch and proprioception pathway
- Activation of the receptor
- Afferent of the receptor then goes from the finger into the spinal nerve and then into the dorsal root ganglion
- Afferent then enters the spinal cord and goes up through the dorsal columns(white matter)
- Afferent then crosses the midline in the medula and synapses onto second order neurons
- They then synapse onto the thalamus which then goes to the somatosensory cortex
What does the dorsal column carry in terms of touch and proprioception?
Ipsilateral touch and proprioception
Ipsilateral vs Contralateral
Ipsilateral : same side
Contralateral: opposite side
What does the somatosensory coretx recieve?
Contralateral touch and proprioception
If a patient has no sense of touch on the left side of the body from chest down, where could there be a lesion.
Thoracic damage to the dorsal columns
Describe the temperature and pain pathway?
- Afferent enters through the dorsal root
- Afferent synapses onto 2nd order neuron in the grey matter of the spinal cord and crosses the midline in the spinal cord
- Afferent axons then go up a white matter track in the anterolateral column
- Then synapses onto the thalamus which goes to the somatosensory cortex
Anterolateral columns carry what?
Contralateral temperature and pain
How does a lesion at the anterolateral column affect the body?
Temperature and pain from the segment with the lesion and down will be lost on the contrlateral side
What would happen if you cut a dorsal root?
Loss of temperature, pain, touch and proprioception at the level of the cut on the ipsilateral side
What regions of the body have higher acuity ?
Lips, face, fingers
Why do certain regions of the body have higher acuity?
These regions of the body have more neurons in the somatosensory cortrx that represent these parts of the body
Where is the somatosensory cortex located?
Behind the central sulcus
What would a lesion to the somatosensory cortex do ?
Loss of temperature, touch , proprioception and pain to the contralateral side
When is label line code not true?
For referred pain
What is referred pain caused by ?
Nociceptive afferents from the surface of the skin share the same 2nd order neurons as the nociceptors that are visceral
What is referred pain ?
When the brain puts the location of the pain of the skin rather than the visceral organ
ex. Heart attack = pain in right arm
What are descending pathways?
Originate in the brainstem and come down the spinal cord
Inhibit the neural transmission of substance P at the 2nd order neurons that are recieving pain information
What is analgesia?
Top-down mechanism
-Under your control
The reduction in pain
Describe a situation where descending pathways occur?
If you get injured during a race but don’t realize till after the race due to adrenaline
What are opiate receptors and how are they involved in the descending pathways?
Descending pathways of the brain release opiate neurostransmitters that bind to the opiate receptor and stop the release of substance P. Now you will feel no pain
T/F: Opiate receptors are sites for drugs such as morphine?
True, morphine is used to reduce pain
What is the stimulus energy for the visual system?
Light
What are the recepotrs for the visual system?
Photoreceptors
What controls the pupil?
Iris
What is the retinal pigment epithelium?
Lines behind the retina and helps with transduction
What is the Fovea Centralis?
-Point of highest visual acuity (smallest RF)
-Center of vision
-This is where you do all of your detailed looking and reading
-Photorecptors are only cones
What is the optic disk?
-Blind spot
- Where the optic nerve leaves
-No photoreceptors
What opens/closes ion channels in the eyes?
Photons
What is the retina?
-Lines back of eye
-Contains the photoreceptors where transduction occurs
-Contains neurons that start processing the visual information before it is sent out via the optic nerve
Role of the cornea and lens?
Focus light on the retina
T/F: refraction occurs at the cornea and lens?
True, photons light bends due to the cornea and lens
T/F: Cornea refracts light more than the lens?
True
What does it mean when something is in focus?
All of the different light rays are projected to a single point at the retina
Projection on the retina is upsidedown ?
Lnes inverts the image
What happens to the lens when an object is further away from you?
Lens becomes thinner to change refraction
What happens to the lens when an object is really close to you?
Lens becomes rounder so that there is more refraction of light
T/F: Lenses accomodate for changes in object location
True
What happens if an object is close to the eye but the lens does not become rounder?
Object will be out of focus
What is a myopic eye?
Nearsightedness
-When you can see objects up close just fine but at a distance there is too much refraction and the focus is in front of your retina
What is a hyperopic eye?
Farsightedness
-Can see things at a distance but objects thar are up close are focuse behind the retina
What is astigmatism?
The lens or cornea are not spherical
What is presbyopia?
When the lens gets stiff and is unable to accomodate for near vision as you get older
What is cataract?
Changes in the lens colour, it becomes opaque which blocks photons from the retina
What are the two types of photoreceptors?
- Cones
- Rods
Where are the photoreceptors found?
Lining the back of the retina
Right next to the retinal pigment epithelium since they undergo a biochemical reaction
How does light travel through the eye?
Photons travel through the cornea then the lens and then through the vitreous humor and then to the retina
What must photons go through before reaching the retina?
Must go through the neurons in the retina. The Bipolar, Horizontal and Amacrine neurons are transparent but help process the photons
What is convergence?
THe idea that the optic nerve has one million axons but there are 100 million photoreceptors. The ganglion cells (axons of the optic nerve) recieve information from many photoreceptors and put it together
Describe convergence in the fovea?
Since the fovea has higher acuity there are only 1-2 cones driving a ganglion cell
Describe convergence in the periphery(outside of the fovea)?
Since there is less acuity, there are lots of rods driving one single ganglion cell
Why is the fovea the clearest image?
All of the cells that distort the image normally are pushed out of the way at the fovea, this creates the little notch and creates the clearest image because photons do not need to pass by all of those cells
What are opsin molecules?
The proteins that capture photons
T/F: Photons cause ion channels to close?
True
What is phototransduction?
Process by which light is converted into electrical energy so that it can be understood by the nervous system
Explain phototransduction?
- Photon is absorbed by chromophore which causes a conformational change and the chromophore to dettach
- This then triggers a G-protein cascade which converts cGMP to GMP
- As cGMP concentrations fall the sodium ion channels start closing
- This results in the hyperpolarization of the photoreceptor and stops the release of neurotransmitters
When to photoreceptors release neurtransmitters?
In the dark when the cGMP activates the sodium ion channels and the membrane is depolarized
Where are opsin molecules foundd?
In both rods and cones (photoreceptors)
Rod properties?
- High sensitivity to photons (used as night vision)
- Have more rhodopsin to capture as much light as possible at night
- High amplification (one photon may close many Na+ channels)
- Slow response time
- More sensitive to scattered light
Cone properties?
- Low sensitivity to photons(used as day visions)
- Less opsin because photons are numerous during the day
- Lower amplification
- Faster response time
- Most sensitive to direct axial rays
Describe the rod system?
-Low acuity: not present in the central fovea, highly convergent
-Achromatic: one type of opsin molecule(don’t see colour at night)
Describe the cone system?
-High acuity: concentrated in the central fovea. less convergent
-Chromatic: three types of opsin molecules (colour perception)
Describe Dark Adaptation
- Start with bright lights where the rods are inactivated and the cones are activated
- IF you turn the light off you will have temporary blindness until the rods “reactivate”(opsin reattaches to chromophores) and take over
Why are rod inactive in bright lights?
Due to all of the photons which have broken down the opsin molecules in the rods (no more opsin attached to chromophore)
Why are cones inactive in the dark?
Not enough photons present
Describe Light Adaptation
- Start in the dark where rods are active and cones are inactive
- Turn on the lights this results in temporary blindness until the rods “inactivate” and the cones take over
The rods are initially saturated (all activated) when the lights turn on which is why it is incredibly bright.
Why are the rods near the retinal pigment epithelium?
When light breaks the chromophore from the opsin in rods, they have to go into the retinal epithelium is that they can be put back together
What determines the intensity of light ?
Depends on what is next to the image(contrast)
What is the role of the ganglion cells in contrast?
Compare the middle of the Receptive field to the surrounding and signal the relative difference of light (contrast) across their receptive fields
Patterns retinal ganglion cells like best with excitatory centre?
- Bright center dark surround (fires a lot of action potentials)
- Dark center bright surround(stops firing action potentials)
- Uniforma light(center and surround cancel out, doesnt do anything when stimulus comes on)
Patterns retinal ganglion cells like best with inhibitory centers?
- Bright center dark surround(stop firing action potentials)
- Dark center bright surround(fires a lot of action potentials)
- Uniform(center and surround cancel out, doesnt do anything when stimulus comes on)
Where does colour perception come from?
Cones
What determines the chromatic sensitivity of the photoreceptor?
The opsin molecule
T/F: Retinal ganglion cells don’t only compare brightness between center and surrround but they also compare colour
True
Where is colour transmitted?
In the fovea because that is where the cones are
What are the two types of colour comparisons?
- Red-Green
- Blue-Yellow
Why is colourblindness common in males?
Opsin molecules are found on the X chromosome, since females have two X’s they are less likely to be colour blind
What is colourblindness?
Missing an opsin molecule (only have two/one cones)
What is the optic chiasm?
Where both optic nerves come together (fibers that cross come from the nasal side of the retina)
What is the optic tract carrying?
Visual information from the contralateral visual fields
What is optic nerve carrying?
Information from one eye but with both visual fields
What does the left and right visual cortex recieve?
Left visual cortex recieves info about the right visual field
Left visual cortex recieves info about left visual field
What is the primary visual cortex?
-Region of small RFs
-These RFs are sensitive to edges, the edges get put together to form a more complex strcuture
Two pathways after the primary visual cortex ?
- Parietal visual stream
- Temporal visual stream
What is the parietal visual stream?
-The “where” pathway
-RFs are larger
-Brain uses this pathway to determine where things are located and whether or not they are moving
-Get mixed up with touch
What is the temporal visual stream?
-The “what” pathway
-RFs are larger (the entire image)
-Respond to complex features such as faces, hands and landmarks
