Brainscape's Knowledge GenomeTM

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


See full index

Systems Neurobiology > Edge Detection > Flashcards

Edge Detection Flashcards

1
Q

What is the first place along the visual pathway that has orientation-selective neurons?

A

the primary visual cortex

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

What are the 3 main points of the visual pathway?

A
  1. retina
  2. lateral geniculate nucleus (LGN)
  3. primary visual cortex (V1)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How are retinotopic regions organised?

A

such that the upper part of the visual field is represented in the ventral retinotopic regions, and the lower part of the visual field is represented in the dorsal retinotopic regions

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

Describe the receptive fields in the retina and LGN

A

they are round and respond best to small, round spots of contrast

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

What does one retinal ganglion cell generally project to?

A

one LGN cell

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

What do all V1 neurons have?

A

oriented receptive fields i.e. they respond best to a bar of particular orientation

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

What are the 2 types of neurons in V1?

A

simple and complex cells

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

What are simple cells?

A

phase-sensitive i.e. they respond best to either a bright or dark bar, but not both

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

What are complex cells?

A

phase-invariant i.e. they respond equally well to a bright or dark bar

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

What is the neocortex involved in?

A

higher-order brain functions such as sensory perception, cognition, generation of motor commands, spatial reasoning and language

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

How does the neocortex appear in light microscopy?

A

a light, unstained sheet of unmyelinated neurons

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

How many layers are in the neocortex?

A

6

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

What do V1 neurons in the same cortical columns have?

A

the same preferred orientation

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

Where do LGN neurons mainly project?

A

layer 4 of the neocortex where most simple cells are found

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

What may simple cell orientation selectivity be due to?

A

selective connections from LGN cells

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

What may complex cells be due to?

A

connections from simple cells with varied phase selectivities

17
Q

For every part of the visual field, what is there?

A

a different complex cell

18
Q

In real life, what must there be to make a response relatively constant?

A

8-10 simple cells signalling to one complex cell

19
Q

How can a simple cell be created?

A

an LGN neuron synapsing onto a cortical neuron

20
Q

How can a complex cell be created?

A

a simple cell synapsing onto a cortical neuron

21
Q

How can phase-invariant responses be created?

A

from phase-selective responses

22
Q

What are the 2 classical transmitters?

A
  • excitatory glutamate
  • inhibitory GABA
23
Q

What is glycine?

A

an inhibitory neurotransmitter in the brainstem and midbrain, not present in the thalamus and the cortex

24
Q

What are the neuromodulators of the cortex?

A
  • dopamine from the ventral tegmental area
  • ACh from the nucleus basalis
25
Q

What is the finest level of synaptic organisation?

A

monosynaptic connectivity and its synaptic strength

26
Q

What happens in an excitatory presynaptic neuron?

A

each AP in P1 causes P1 to release glutamate onto P2, causing an EPSP in P2

27
Q

What happens in an inhibitory presynaptic neuron?

A

AP in I1 causes I1 to release GABA onto I2, causing an IPSP in I2

28
Q

What are the 3 main methods to investigate neural connectivity?

A
  1. anatomical methods
  2. paired intracellular recordings
  3. correlations between spikes recorded with extracellular electrodes
29
Q

For dyes that do not cross the synapse, how can post-synaptic neurons be identified?

A

electron microscopy

30
Q

What is the main limitation of purely anatomical methods for investigating neural connectivity?

A

they cannot tell us the strength of the synapse

31
Q

What is the limitation of paired intracellular recordings?

A

visual responses from neurons cannot be recorded in a brain slice

32
Q

What is the order of information in a cortical column?

A

LGN → L4 → L2/3 → L5/6

33
Q

What must be recorded to determine the synapse strength?

A

the membrane potential

34
Q

What is recorded with extracellular electrodes?

A

only spikes (APs)

35
Q

What is the size of the tip length of the electrode used for extracellular recordings?

A

roughly the size of a neuronal cell body

36
Q

How can a single AP be recorded using extracellular electrodes?

A

filter the frequency of signals to between 300-5000Hz and adjust the electrode placement

37
Q

What is the main idea of extracellular spike correlations?

A

when a reference neuron excites a target neuron, the target neuron will have an increased probability of spiking for a short time after the reference neuron spikes

38
Q

How does correlation not imply causation with extracellular spike correlations?

A

the spikes of A and B could be correlated even if there is no monosynaptic connection from A to B

Systems Neurobiology (11 decks)

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