Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuroscience 1: cells and circuits > Sensory: vision > Flashcards

Sensory: vision Flashcards

1
Q

How many different opsins can the cones express, and how do they differ?

A

Three: OPN1SW (short waves=blue), OPN1MW (midlength waves=green), OPN1LW (long waves=red)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of rods and cones?

A

Rods: spatial resolution, more light sensitive
Cones: colour vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the retinal molecules bind to?

A

Opsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the signaling pathway in cilliary photoreceptors

A

Photon stimulates the conversion of 11-cis-retinal bound to the opsin to all-trans-retinal –> release of retinal, and activation of the opsin receptor. Opsin is coupled to a Gt protein, and by activation the G_alpha is released from G-beta-gamma. G-alpha activates PDE –> reduction of cGMP –> inhibition of CNG Na+ channel –> inhibition of Ca^2+ influx (and AP) –> inhibition of glutamine release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is the signal inhibited in cilliary cells, and when does this happen?

A

GRK1 phosphorylates opsin –> inactivation of opsin –> increase of cGMP –> increase of Ca^2+ –> depolarization of Vm –> release of glutamate
During darkness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the dynamic range of an eye refer to and how is it controlled in the human eye?

A

The number of photons the rods and cones can absorb depending on the brightness of a habitat.
It’s controlled by the number of active opsins in the retina (called adaptation), by controlling the process of conversion all-trans-retinal to 11-cis-retinal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the lens involved in?

A

Accomodation: making sure the resolution matches the distance by contracting or extending the lens. Near/long sigthness is caused by a flaw in this mechanism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the fovea?

A

Cones lined in the back of the eye directly in line with the lens (in the centre of the optical axis of the eye) not covered by any other cells –> no interference. It is packed densely with cone cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does the pupil dialate, and which neuronss innervate the muscles responsible for this?

A

The radially smooth muscles of the iris (the dialator pupillae) contract, dialating the pupil. The dialator pupillae are innervated by adrenergic, sympathetic neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does the pupil constrict, and which neuronss innervate the muscles responsible for this?

A

The circular smooth muscles of the iris (the sphincter pupillae) contract, constricting the pupil. The sphincter pupillae are innervated by cholinergic, parasympathetic neurons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many layers is the retina consisting?

A

3 layer: rods and cones in the back, bipolar, horizontal and amacrine cells in the middel and retinal ganglion cells in the front (+ ipRGCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe a rod cell.

A

Glutamatergic, rod-shaped neuron containing discs. Discs are organels lined with rhodopsin. The ros are depolarized in the darkness, and hyperpolarized in the light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is rhodopsin?

A

GPCR of the rods (opsin), with a bound retinal molecule (11´cis-retinal). They are light activated. When light hits the retinal, it converts from 11´cis- to all-trans-retinal, pushing the TM regions of the opsin. This configuration change activates the GPCR. Rhodopsin is tranducin coupled.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are ipRGCs involved in?

A

The circadian rhytm and pupillary light reflexes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which regions of the brain does ipRGCs and rod cells project to, respectively.

A

ipGRCs project to the non-image forming center, the pineal gland (RHT -> suprachiasmatic nucleus -> paraventricular nucleus -> spinal cord -> SCG -> pineal gland).
Rod cells project to the image-forming center, the primary visual cortex (through the nucleus geniculatus).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is the retina formed?

A

As an outpocekting of the diencephalon

17
Q

What is accomodation?

A

When the eye is adjusted for sharp vision at short distances

18
Q

How are the response to light?

A

Graded: mirroring the light intensity

19
Q

What is the function of the pigment epithelium?

A

To move worn out photoreceptor discs

20
Q

What is the center-surround organization?

A

Can either be center on/off

21
Q

What type of NT does the horizotal cells use?

A

GABA

22
Q

What type of NT does the bipolar cells use?

A

Glutamate

23
Q

What type of NT does ganglion cells use?

A

Glutamate

24
Q

What types of ganglion cells are there, and how do they differ?

A

3:
P-type: parvocellular cells/midget cells
- small RF and dendrite tree
- slowly adapting, slow conduction of APs, low light sensitivity
- 90 % of ganglion cells
- specializes in visual acuity

M-type: magnocellular cells/parasol cells
- large RF, and dendritic tree
- fast adaption and conduction of APs, high light sensitivity
- 5 % of ganglion cells
- specializes in movement

K-type
- non-P, non-M type cells

25
Q

What is the term for having three types of cones?

A

Trichromat

26
Q

Describe the signal route from the retina to the brain.

A

–> optic nerve –> optic chiasm –> optic tract –> hypothalamus/pretectum/superior colliculus/lateral geniculate nucleus –> optic radiation –> primary visual cortex

27
Q

Which axons cross in the optic chiasm?

A

Axons from the nasal half of the retina

28
Q

Describe layer IV of the primary visual cortex.

A
  • main input layer for thalamic projections
  • edge detectors
  • oriented in ocular dominance columns (right/left eye) and orientation columns
  • P- and M-type ganglion cells project to layer IV
29
Q

Describe the non-input layers of V1.

A
  • binocularity
  • ON/OFF system convergence
  • partial M/P systems
30
Q

True/false: there are one visual area in the human brain.

A

False, there are multiple

31
Q

What are some of the other visual layers called, and what are their function?

A

V2 (corners, surfaces), V3, V4 (complex shapes) and inferior temporal cortex (faces etc)

32
Q

What are the dorsal and ventral stream perceiving, and where are they projecting to?

A

Dorsal: where? –> V1–> MT–> parietal lobe –> motor areas
Ventral: what? –> V1 –> V4–> inferior temporal lobe –> limbic system

33
Q

What are cerebral akinetopsia, and what symptoms can it cause?

A

Bilateral damage to area MT from a stroke:
- dorsal stream defect –> lack of ability to perceive movement
- ventral stream defect –> lack of ability to perceive color

34
Q

What are prosopagnosia, and what can it be caused by?

A

Face blindness
Can result from damage to the inferior temporal cortex (ventral stream)

Neuroscience 1: cells and circuits (42 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions