Wiring The Brain

Front 1

First position

Back 1

A cell in the ventricular zone extends a process that reaches upward toward the pia

Front 2

Second position

Back 2

The nucleus of the cell migrates upwards from the ventricular surface toward the pial surface; the cell's DNA is copied

Front 3

Third position

Back 3

The nucleus, containing two complete copies of the genetic instructions, settles back to the ventricular surface

Front 4

Fourth position

Back 4

The cell retracts its arm from the pial surface

Front 5

Fifth position

Back 5

The Cell divides in two

Front 6

Daughter cells

Back 6

The newly formed cells after cell proliferation process completes 5th position

Front 7

Subplate

Back 7

The first cells to migrate away from the dorsal ventricular zone reside in the subplate layer

Front 8

Radial glial cells

Back 8

Daughter cells migrate along fibers derived from these specialized cells. They provide the scaffold upon which the cortex is built.

Front 9

Neuroblasts

Back 9

Immature neurons

Front 10

Cortical plate

Back 10

The second layer beyond the subplate where the neuroblasts who are destined to become adult cortex

Front 11

Cell differentiation

Back 11

The process in which a cell takes on the appearance and characteristics of a neuron

Front 12

Oligodendrocytes

Back 12

The last cells to differentiate

Front 13

Pathway selection

Back 13

The tract that a neuron picks to follow

Front 14

Target selection

Back 14

Which part of whatever area of the brain a neuron has selected in pathway selection. The second step of cell differentation

Front 15

Address selection

Back 15

Third specifying step in cell differentiation. Where a cell will reside specifically within the selected target.

Front 16

Extracellular matrix

Back 16

Spaces between cells. Must contain appropriate proteins

Front 17

Fasciculation

Back 17

A mechanism that causes axons growing together to stick together. Due to cell-adhesion molecules (CAMs)

Front 18

Cell-adhesion molecules

Back 18

Facilitate fasciculation. In the membrane of neighboring axons bind tightly to one another, causing the axons to grow together.

Front 19

Chemoattractant

Back 19

A diffusible molecule that acts over a distance to attract growing axons toward their targets

Front 20

Netrin

Back 20

Secreted by neurons in the ventral midline of the spinal cord. Attracts the axons of the dorsal horn neurons that will cross the midline to form the spino thalamic tract.

Front 21

Chemorepellent

Back 21

Chases axons away (opposite of chemoattractant)

Front 22

Chemoaffinity Hypothesis

Back 22

Chemical markers on growing axons are matched with complementary chemical markers on their targets to establish precise connections

Front 23

Ephrins

Back 23

Chemorepellent for temporal retinal axons. Specific ephrin molecules are secreted in a gradient across the surface of ephrin intereacts witha receptor, called eph, on the growin axon. The interaction of ephrin with its receptor inhibits further axonal growth, similar to the slit-robo interaction.

Front 24

Trophic factors

Back 24

Life-sustaining substances that are provided in limited quantities by the target cells.

Front 25

Nerve Growth Factor (NGF)

Back 25

First trophic factor to be identified

Front 26

Neurotrophins

Back 26

Family of related trophic factors

Front 27

Apoptosis

Back 27

Process of natural cell death because cells compete for trophic factors

Front 28

Monocular deprivation

Back 28

One eyelid is sealed closed, leading to an expansion of the open eye's columns. Closed eye columns shrink.

Front 29

Critical period

Back 29

Period in which monocular deprivation can occur and be reversed. (Structural plasticity)

Front 30

Ocular dominance shift

Back 30

Change in the binocular organization of the cortex

Front 31

Binocular competition

Back 31

The inputs from the two eyes actively compete for synaptic control of the postsynaptic neuron.

Front 32

Strabismus

Back 32

Cross-eyed

Front 33

Long-term Potentiation

Back 33

A consequence of strong NMDA receptor activation is a strengthening of synaptic transmission

Front 34

Long-term Depression

Back 34

Opposite form of synaptic plasticity. The active synapses are decreased in effectiveness. Loss of AMPA receptors from the synapses, the exact opposite of LTP.