Biopsychology Chapter 9

Front 1

Phases of Neural Development, phase 1
About _____ weeks after conception, a patch of _____ on the dorsal surface of the embryo becomes distinguishable from the rest of the ectoderm. This patch is the _____, and it eventually develops into the nervous system; seems induced by the underlying _____.

Back 1

3 weeks
Ectoderm
Neural Plate
Mesoderm

Front 2

Phases of Neural Development, phase 2
Prior to induction of the neural plate, the cells of the dorsal ectoderm are _____ (that is, if transplanted to a new site in the embryo, develops the same way as cells at the new site).

Back 2

Totipotential

Front 3

Phases of Neural Development, phase 3
After neural plate induction, the cells there lose some of their totipotentiality; can develop into any kind of neuron, by not any other kind of cell; _____; _____.

Back 3

Multipotent; Stem cells

Front 4

Phases of Neural Development, phase 4
The neural plate develops into the _____ and then in to the _____, which subsequently develops into the _____. By 40 days, the anterior end of the neural tube develops 3 swellings that become the _____, ______, and _____.

Back 4

Neural groove
Neural tube
CNS
Forebrain, Midbrain, and Hindbrain

Front 5

Neural Proliferation, pase 1 and 2
*After the neural tube is formed, the developing nerves system cells rapidly increase in number.
*Cell division occurs in the _____ of the neural tube (the zone next to the ventricle); when they leave the cell division cycle, cells migrate into other layers.

Back 5

Ventricle zone

Front 6

Neural Proliferation, pase 3
Migration and Aggregation, cell migration can be _____ or _____; cells in the CNS usually do both as they move towards their final destination.

Back 6

Radial Migration or Tangential Migration

Front 7

Neural Proliferation, pase 4
Migration of the cells of the _____ of particular interest - cells ultimately form the PNS, and thus many have a long way to migrate.

Back 7

Neural Crest

Front 8

Neural Proliferation, pase 5
Once migration is complete, cells mud _____ correctly to form various neural structures. Hypothesized to be mediated by specialized neural cell _____ in the cell membranes (NCAMs).

Back 8

Aggregate
Adhesion Molecule

Front 9

Neural Proliferation, pase 6
_____ between adjacent cells have been found to be particularly prevalent during brain development; increasing evidence that gap junctions play a role in migration and aggregation.

Back 9

Gap Junctions

Front 10

Axon Growth and Synapse Formation (Axon Growth)
Once the aggregation of developing neurons is complete, _____ and _____ grow out from the neurons; growing to the correct target is particularly difficult for axons that have a long way to grow. Studies in which the same recognizable developing neuron has been labeled in different subjects demonstrate that the axons of some particular neurons grow to the same destination by the same route in every member of a species.

Back 10

Axons and Dendrites

Front 11

Once an axon reaches its target, _____ must occur. Glial cells, particularly _____, are critically important; increase the survival of developing synaptic connections.

Back 11

Synaptogenesis
Astrocytes

Summary: All the evidence on axon growth and regeneration suggests that a variety of mechanisms can guide axon growth; the growth of different axons appears to be guided by different combinations of there mechanisms.

Front 12

Up to _____% of neurons that develop die during the course of normal development; cell death increases the overall accuracy of synaptic connections.

Back 12

50%

Front 13

Most of this cell death is due to _____; preprogrammed cell death that is believed to result from the lack of an appropriate trophic factor.

Back 13

Apoptosis

Front 14

There appears to be two types of riggers for apoptosis, explain.

Back 14

1) Some developing neurons appear to be genetically programmed for an early death -- once their functions are fulfilled, groups of neurons die together in the absence of any obvious physical stimulus
2) Some die because they fail to obtain life-perserving chemicals that are supplied by their targets.

Note: Necrosis is bad because causes inflammation that can go into other extracellular regions.

Front 15

The human brain develops more slowly that other species, not mature until _____.

Back 15

Late adolescence

Front 16

In particular, the _____ is the last part of the brain to reach maturity, and it is thought to mediate many _____.

Back 16

Prefrontal cortex
Higher cognitive abilities

Front 17

Brain volume quadruples between birth and adulthood; most of this increase in volume comes from increased number of synapses (_____); _____ of axons; and increased _____.

Back 17

Synaptogenesis
Myelination
Dendritic Branching

Front 18

Synaptogenesis is assumed to indicate increased analytic ability in a brain region; synaptogenesis in the visual cortex peaks at about _____ postnatal, whereas in prefrontal cortex maximal density is reached in the _____.

Back 18

Four months
Second year

Front 19

Myelination increases the _____; again, sensory and motor areas are myelinated in the _____ of life while the prefrontal cortex is not fully myelinated until _____.

Back 19

Speed of axonal connection
First few months
Late adolescence

Front 20

Many synapses that form early in development are eventually lost; overproduction of synapses int eh young brain may contribute to its greater _____.

Back 20

Plasticity

Front 21

The development of prefrontal cortex parallels the course of _____.

Back 21

Human cognitive development

Front 22

The development of prefrontal cortex is linked to _____; (define them).

Back 22

Working Memory - the ability to keep information accessible for short periods of time

Planning and Completing - sequences of actions

Inhibiting Inappropriate Responses -

Following Rules for Social Behavior -

Front 23

Diamond (1991) found that damage to the prefrontal cortex leads to _____ in adults, so that their behavior looks more like an infant's.

Back 23

Perseverative Errors

Front 24

Neurodevelopment results from an _____ between neurons and their environment.

Key Rule: Neurons and synapses that are not activated by experience do not usually survive.

Back 24

Interaction

Front 25

One question asked about experience is whether the effects are _____ or _____.

Back 25

Permissive or Instructive

Front 26

If it is absolutely essential for an experience to occur within a particular time interval, it is called a _____. If experience can have an effect outside of this interval, it is called a _____. (Remember the case of Genie)

Back 26

Critical Period
Sensitive Period

The majority of experiential effects occur in a sensitive period. One major advantage of the slowness of the developing brain is that it provides opportunities for experience to fine-tune development.

Front 27

Clearly experience fine-tunes neurodevelopment in innumerable ways.
Experience alters neural development in at least three different ways: (what are they?)

Back 27

1) By influencing gene expression fro CELL ADHESION MOLECULES
2) By influencing the release of NEUROTROPHINS
3) By altering the SPONTANEOUS ACTIVITY of certain brain regions

Front 28

Adult rats in _____ had increased _____ in hippocampus.

Back 28

Enriched environment
Neurogenesis

Front 29

The adult brain is capable of considerable _____.
Experience in adulthood can lead to a reorganization of sensory and motor cortical maps.
For example: Adult musicians who play stringed instrument that are fingered with the left hand have an enlarged hand representation in the right somatosensory area.

Back 29

Neuroplasticity