Exam 2 - Practice Test

Question 1

the primary motor cortex is located in the ____ of the neocortex

a) precentral frontal gyrus
b) calcarine fissure
c) superior temporal gyrus
d) posterior parietal lobe

Answer 1

• *a) precentral frontal gyrus**
  b) calcarine fissure
  c) superior temporal gyrus
  d) posterior parietal lobe

Question 2

2. Magnocellular inputs from the lateral geniculate nucleus (LGN) terminate primarily in layer _______________of the primary visual cortex.
   a) IVc-beta
   b) IVc-alpha
   c) layers 2 and 3
   d) none of the above

Answer 2

2. Magnocellular inputs from the lateral geniculate nucleus (LGN) terminate primarily in layer _______________of the primary visual cortex.

☐ a) IVc-beta

☒ b) IVc-alpha

☐ c) layers 2 and 3

☐ d) none of the above

Question 3

3. All of the following are structures of the basal ganglia EXCEPT:
   a) globus pallidus
   b) caudate nucleus
   c) pons
   d) putamen

Answer 3

3. All of the following are structures of the basal ganglia EXCEPT:

☐ a) globus pallidus

☐ b) caudate nucleus

☒ c) pons

☐ d) putamen

Question 4

4. Damage to the ___________can produce the phenomenon of blindsight.
   a) posterior parietal lobe
   b) area V4
   c) MT
   d) area V1

Answer 4

4. Damage to the ___________can produce the phenomenon of blindsight.

☐ a) posterior parietal lobe

☐ b) area V4

☐ c) MT

☒ d) area V1

Question 5

5. Buildup of cerebrospinal fluid in the ventricles can produce:
   a) hydrocephalus
   b) spina bifida
   c) anencephaly
   d) none of the above

Answer 5

5. Buildup of cerebrospinal fluid in the ventricles can produce:

☒ a) hydrocephalus

☐ b) spina bifida

☐ c) anencephaly

☐ d) none of the above

Question 6

6. Balint’s syndrome, which involves damage to the posterior parietal area, includes a visual perceptual alteration known as:
   a) prosopaganosia
   b) astereognosis
   c) simultagnosia
   d) none of the above

Answer 6

6. Balint’s syndrome, which involves damage to the posterior parietal area, includes a visual perceptual alteration known as:
   a) prosopaganosia
   b) astereognosis

c) simultagnosia

d) none of the above

Question 7

7. Which of the following binds to sodium permeable channels in the photoreceptor, causing them to open?
   a) phosphodiesterase (PDE)
   b) cGMP
   c) rhodopsin
   d) transducin

Answer 7

7. Which of the following binds to sodium permeable channels in the photoreceptor, causing them to open?

a) phosphodiesterase (PDE)

b) cGMP

c) rhodopsin
d) transducin

Question 8

8. In the retina, these cells are most directly responsible for mediating the antagonistic surround of bipolar receptive fields:
   a) horizontal cells
   b) cone photoreceptor cells
   c) rod photoreceptor cells
   d) ganglion cells

Answer 8

8. In the retina, these cells are most directly responsible for mediating the antagonistic surround of bipolar receptive fields:

☒ a) horizontal cells

☐ b) cone photoreceptor cells

☐ c) rod photoreceptor cells

☐ d) ganglion cells

Question 9

9. The cochlear amplifier is most directly mediated by contractions of the following cells:
   a) inner hair cells
   b) bipolar cells
   c) outer hair cells
   d) spiral ganglion cells

Answer 9

9. The cochlear amplifier is most directly mediated by contractions of the following cells:

☐ a) inner hair cells

☐ b) bipolar cells

☒ c) outer hair cells

☐ d) spiral ganglion cells

Question 10

10. Which of the following is most responsible for maintaining the endocochlear potential?
    a) the reticular lamina
    b) the organ of corti
    c) the stria vascularis
    d) the scala vestibuli

Answer 10

10. Which of the following is most responsible for maintaining the endocochlear potential?

☐ a) the reticular lamina

☐ b) the organ of corti

☒ c) the stria vascularis

☐ d) the scala vestibuli

Question 11

11. The _______________________nervous system consists of sympathetic and parasympathetic divisions.

Answer 11

11. The ____autonomic____________________nervous system consists of sympathetic and parasympathetic divisions.

Question 12

12. LGN layers 1 and 2 are the _____________________layers while LGN layers 3-6 are the ___________________layers. Layers ___________ (layer #s) of the left LGN receive input from the right eye.

Answer 12

12. LGN layers 1 and 2 are the __magnocellular_____________________layers while LGN layers 3-6 are the ______parvocellular________________layers. Layers __1,4,6________________ (layer #s) of the left LGN receive input from the right eye.

Question 13

13. The_______________________________________ (three words), of each spinal nerve consists of cell bodies of neurons responsible for transferring sensory information from the periphery into the central nervous system.

Answer 13

13. The_______dorsal root ganglion__________________________________________ (three words), of each spinal nerve consists of cell bodies of neurons responsible for transferring sensory information from the periphery into the central nervous system.

Question 14

14. The ___________________\_ is a structure in the brainstem surrounding the cerebral aqueduct with nuclei crucial for visual and auditory reflexes as well as motor control.

Answer 14

14. The midbrain ___________________\_ is a structure in the brainstem surrounding the cerebral aqueduct with nuclei crucial for visual and auditory reflexes as well as motor control.

Question 15

14. An off-center retinal ganglion cell _________________________its action potential firing when shade is cast to the center of its visual field and ___________________________its action potential firing when shade is cast to the periphery of its visual field (“CHANGES” IS NOT AN ACCEPTABLE ANSWER).

Answer 15

14. An off-center retinal ganglion cell ___increases_________________________its action potential firing when shade is cast to the center of its visual field and ___decreases__________________________its action potential firing when shade is cast to the periphery of its visual field (“CHANGES” IS NOT AN ACCEPTABLE ANSWER).

Question 16

15. The third ventricle in the brain is immediately surrounded by the_________ ________________________ _____.

Answer 16

15. The third ventricle in the brain is immediately surrounded by the__thalamus/hypothalamus/diencephalon____\_

Question 17

16. The limbic system consists of three major neural structures, the ____\_ , _______________ _____** and **_ _____ _____ ____\_.

Answer 17

16. The limbic system consists of three major neural structures, the amygdala __\_ , ____hippocampus________________ ______ and __fornix/cingulate gyrus/hypothalamus______ _____ ____\__.

Question 18

17. In the three vesicle stage of neural development what is called the hindbrain becomes the __________________________ (name one structure) in the mature brain.

Answer 18

17. In the three vesicle stage of neural development what is called the hindbrain becomes the \_cerebellum/pons/medulla/fourth ventricle___________________________ (name one structure) in the mature brain.

Question 19

18. Area MST of the dorsal extra-striate visual stream is specialized for processing ________________in our visual fields.

Answer 19

18. Area MST of the dorsal extra-striate visual stream is specialized for processing ___circular motion/radial motion______________________in our visual fields.

Question 20

19. In a rod photoreceptor, an increase in light directly increases the activity of , which then activates a g-protein (transducin). This activated g-protein then activates , which actively breaks down cGMP.

Answer 20

19. In a rod photoreceptor, an increase in light directly increases the activity of rhodopsin**, which then activates a g-protein (transducin). This activated g-protein then activates **PDE, which actively breaks down cGMP.

Question 21

20. With regards to the different types of photoreceptors, the periphery area of the retina has a smaller proportion of compared to the fovea.

Answer 21

20. With regards to the different types of photoreceptors, the periphery area of the retina has a smaller proportion of conescompared to the fovea.

Question 22

21. With regards to cell highlighted in bold letters, write “depolarization” or “hyperpolarization” in the following blanks:
    a) a decrease in glutamate released onto an ON bipolar cell
    b) an increase in light onto the surround receptive field of an OFF bipolar cell _\_.

Answer 22

21. With regards to cell highlighted in bold letters, write “depolarization” or “hyperpolarization” in the following blanks:
    a) a decrease in glutamate released onto an ON bipolar cell depolarization.
    b) an increase in light onto the surround receptive field of an OFFbipolar cell depolarization.

Question 23

22. Outer hair cells (OHCs) differ from inner hair cells (IHCs) in that outer hair cells are responsible for the motion of the basilar membrane. This is accomplished because the OHCs in response to depolarization.

Answer 23

22. Outer hair cells (OHCs) differ from inner hair cells (IHCs) in that outer hair cells are responsible for amplifying [or increasing]** the motion of the basilar membrane. This is accomplished because the OHCs **contract [or shorten] in response to depolarization.

Question 24

23. Determining the location of sound in the dimension depends on integrating auditory information from both ears.

Answer 24

23. Determining the location of sound in the horizontal [or azimuth or left/right] dimension depends on integrating auditory information from both ears.

Question 25

24. The basilar membrane is the first structure in the auditory system to demonstrate in that lower frequency sounds produce more movement at the apex, while higher frequency sounds produce more movement at the base.

Answer 25

24. The basilar membrane is the first structure in the auditory system to demonstrate tonotopy in that lower frequency sounds produce more movement at the apex, while higher frequency sounds produce more movement at the base.

Question 26

25. Diagram or list how information regarding color carried by visual system is segregated in our visual pathway as it passes from the: 1) retinal ganglion cells, 2) dorso-lateral geniculate nucleus (DLGN), 3) the primary visual cortex (V1, striate cortex) and 4) one extra-striate visual area. A correct answer will include the terms “center/surround” and “blobs” (10 points).

Answer 26

At the retina, color is processed mostly by nonM-nonP type ganglion cells (and also some P-type ganglion cells). Retinal ganglion cells processing color have a center/surround organization, with color-opponent processing (blue/yellow; green/red). These color-opponent ganglion cells function in such a way that responses to one wavelength in the receptive field center in the retina can be cancelled by another wavelength in the receptive field surround for each cell. The nonM-nonP type ganglion cells synapse at the DLGN at the koniocellular layers (“dust layers”), which lie underneath all layers of the DLGN (K1-K6). The koniocellular layers project directly to layers II and III in V1, where cytochrome oxidase staining blobs are located (these blobs eare present in layers 5 and 6 as well). These blobs process color typically with color-opponent or double-color opponent center-surround organizations. The ventral “what” pathway of extrastriate parallel processing is the next major stage of color processing. Specifically, V4 is where cells are largely color responsive. Damage to V4 results in achromatopsia, which is an inability to perceive color.

Question 27

26. The primary visual cortex (V1, striate cortex, area 17) has been described as consisting of separate columns or groups of cells carrying information regarding different aspects of the visual world. Describe how 1) line orientation, 2) information from the right vs. left eye, and 3) motion are processed in the primary visual cortex (10 points)

Answer 27

1) Orientation: Many neurons in the V1 are sensitive to orientation and are organized into columns. Orientation selectivity occurs when cells fire APs most strongly to bars of light directed to their receptive field on the retina at a specific angle.
2) Left vs. right eye: V1 has ocular dominance columns to separate information from the right and left eye. At layer IVC, cells only respond to information from the left or right eye and this information is organized in a series of alternate columns. However, as you go up or down the ocular dominance column, into other layers of the V1, the cells begin to respond to stimuli from both eyes but are always driven most strongly by the right or left eye.
3) Motion: Direction sensitive cells. Frequently found in V1 cell layer IVB and receiving inputs from cell layer IVC beta, these cells respond most strongly (change firing of APs) by a line or bar stimulus of a specific angle sweeping along the cells receptive field in the retina. Cells will respond most strongly when a bar of light at a specific angle is moving in one direction but not other direction.

Question 28

27. A sound wave can cause movement of the basilar membrane towards the tectorial membrane.

Describe how this movement can cause a depolarization in an auditory inner hair cell (IHC). A correct answer will correctly use the terms “E_K”, “endolymph”, “endocochlear potential”, “tip links”, and “stereocilia” in the context of answering this question. (10 points)

Answer 28

This movement, probably via compression of endolymph bathing the stereocilia, causes the stereocilia of an IHC to be deflected towards the tallest stereocilia of the IHC. Tip links between stereocilia are stretched by this deflection, pulling open K⁺ channels and thereby causing a depolarization in the IHC. This depolarization occurs because K⁺ of the endolymph = 150 mM, which is the same as [K⁺] inside the IHC, thus yielding an E_K=0 mV with respect to the IHC and endolymph. Furthermore, due to excess + charge in the endolymph, there is an endocochlear potential of +80mV in the endolymph with respect to all other extracellular spaces in the brain, including the perilymph which bathes the IHC cell body. This endocochlear potential increases the potential difference between the inside of the IHC and endolymph, adding even greater driving force to the depolarizing K⁺ current when tip-linked K⁺ channels are opened.