Vision

Question 1

How many layers comprise the cerebral cortex?

Answer 1

6 layers (cortical column) I molecular II external granule III external pyramidal cell layer IV internal granule cell layer V internal pyramidal cell layer VI multiform layer

Question 2

(t/f) the dendrites of a neuron are restricted to the layer where the cell body is found

Answer 2

false; dendrites may extend between layers or be restricted to a student

Question 3

Who discovered the cortical column?

Answer 3

Vernon Mountcastle; discovered that most neurons proceeding down the cortex make up an elementary unit of organization

Question 4

primary visual cortex is also known as ____

Answer 4

area 17 / V1 , striate cortex

Question 5

neurons in a column of primary visual cortex share _____ and _________

Answer 5

response field (topographic representation) + orientation of stimulus

Question 6

neurons in adjacent columns have similar _______ but different __________

Answer 6

adjacent response fields, different preference for orientation of stimulus

Question 7

optogenetics

Answer 7

new technique taking
genetic manipulations (viral vector) to
create neurons that have ion channels
that can be controlled with laser
stimuluation (Na+ to , Cl- in to silence them)

Callway lab at Salk institute

Question 8

What Callway (Salk Institute) learned about the visual cortex using the optogentic and calcium imaging techniques?

Answer 8

Cortical columns not as simple as we think; learned that there are subnetworks within cortical
columns; and in some cases inhibition of competing networks

Question 9

Calcium imaging

Answer 9

measures the flow
of calcium into neurons (indicator of flow
of Ca, which is required to fire an AP)
tells you which neurons are active

Question 10

how many types of retinal ganglial cells?

Answer 10

four:

parvocellular X ON

parvocellular X OFF

magnocellular Y ON

magnocellular Y OFF

Question 11

which retinal ganglian cells are transitory (rapidly adapting)?

Answer 11

mangocellular Y cells (OFF and ON) respond to changes in the light, respond when light starts and light ends

Question 12

what are the first cells in the visual system in which we find action potentials?

Answer 12

retinal ganglion cells

Question 13

which retinal ganglian cells are sustained (slow responding)

Answer 13

the parvocelluar x (ON and OFF) cells offer a sustained response when light is on (ON cells) or off (OFF cells)

Question 14

how many types of photoreceptors are in the visual system?

Answer 14

rods

cones (S-cone, M-cone, L-cone)

Question 15

What kinds of cells are photoreceptors connected to?

Answer 15

photoreceptors (rods and cones) connect to bipolar cells, which

Question 16

Are bipolar cells transitory or sustained?

Answer 16

Neither! Trick question! They respond based on the hyperpolarization of the photoreceptor, not on the temporal dynamics of the stimulus

Question 17

what kind of cells in the visual system can have surround inhibition and surround excitation fields?

Answer 17

ganglian cells