3 - Brain Circuits

Question 1

Genetic blueprint

Answer 1

Initial establishment of brain circuits.

Question 2

Basic circuits

Answer 2

Initially established by molecular cues guiding axons to their targets.

Question 3

Neurite

Answer 3

Extending axon

Question 4

Filopodia

Answer 4

Extended and retracted from…Lamellopodia by the polymerization and depolarization of actin.

Question 5

Once axon is moving in the right direction microtubule subunits:

Answer 5

Bind together to solidify extending axon.

Question 6

Axons are guided along they way by:

Answer 6

1) Contact-mediated repulsion
2) Chemoattraction
3) Chemorepulsion

Question 7

Axons are guiding to their final destination by:

Answer 7

Specific trophic support (NT3- muscle spindles)

Fox P1 mutant…

Question 8

Over expression of neurons

Answer 8

Initially over expressed
Too numerous
Too many connections

Question 9

Pruning

Answer 9

Finally stages of development, excessive neurons and connections pruned away

Question 10

Example of motor system

Answer 10

Muscle fibers initially receive input form multiple motoneurons in the SC, reduced to 1 motoneuron per muscle cell before birth.

Question 11

Experience-dependent plasticity (2)

Answer 11

1) Unsupervised learning

2) Supervised learning

Question 12

Unsupervised learning

Answer 12

Organism just gathers info from the environment

Question 13

Supervised learning

Answer 13

Organism interacts with a tutor to perform specific actions

Question 14

Birdsong

Answer 14

Juvenile learns to replicate tutor by repeated practice. Spectrogram quantifies sound characteristics. Neural circuits specific to songbirds encode behavior. Bird is using auditory feedback to adjust pitch.

Question 15

Ocular dominance columns are formed of:

Answer 15

Experience-dependent plasticity

- Without light shining on eyes at specific times in development plasticity won’t occur

Question 16

Right visual field is represented in which visual cortex?

Answer 16

Left

Question 17

Right visual field comes form which eye(s)?

Answer 17

Both left & right

Question 18

Cells in the Left visual cortex receives input from which eyes?

Answer 18

Both left & right

Question 19

T/F. The neurons in primary visual cortex that responds to the left eye are somewhat spatially segregated form the neurons that responds to the right eye.

Answer 19

True

Question 20

T/F. Neurons representing one eye cluster together into bands (ocular dominance columns) which alternated w/ bands of neurons representing the OPPOSITE eye.

Answer 20

True

Question 21

What does the Ocular Dominance Columns depend on?

Answer 21

Presence of light on the retina during critical periods pf development.

Question 22

Is the purpose of the Ocular Dominance Columns known?

Answer 22

No, it may simply be an example of critical periods in development that apply to other neural systems as well.