Biological Psychology Ch. 5-8

Front 1

When does CNS develop?

Back 1

2 weeks after conception.

Front 2

6 steps of brain development

Back 2

1. proliferation
2. migration & path finding
3. differentiation
4. myelination
5. synaptogenesis
6. apoptosis

Front 3

Describe CNS development

Back 3

Dorsal surface thickens, lips rise and form neural tube. Tube sinks under skin and the forward end enlarges and differentiates into the hind-, mid-, and forebrain. The rest becomes spinal cord. Fluid-filled cavity inside neural tube = central canal of spinal cord and 4 ventricles of brain.

Front 4

Describe proliferation

Back 4

Production of new cells.
Cells lining the ventricles of the brain divide:
Some stay where they are - STEM CELLS
Some become NEURONS and GLIA and begin migration.

Front 5

Chemicals guiding migration

Back 5

immunoglobins
chemokines

Front 6

How does a cell know where to migrate? (path finding)

Back 6

-DNA expression
-Guiding cells: one cell is a pathfinder and other cells follow it
-Chemical paths: cells use chemical signals as landmarks
-Cell adhesion molecules: adhere and guide cells

Front 7

Describe differentiation

Back 7

Axon grows towards target. When destination is reached, dendrites form.

Front 8

Describe myelination

Back 8

Glia produce the insulating fatty sheaths that accelerate transmission in axons. Forms in this order: spinal cord, hindbrain, midbrain, forebrain. Continues for decades.

Front 9

Describe synaptogenesis.

Back 9

Formation of new synapses & discarding of old ones

Front 10

Can an adult brain generate new neurons?

Back 10

Olfactory receptors (stem cells in nose are immature throughout life).
In areas of songbird brains necessary for singing & hippocampus granule cells (in birds)

Front 11

Paul Weiss Experiment

Back 11

Graft extra leg to salamander. Extra leg moved in synchrony with leg next to it, because each axon found exactly the correct muscle.

Front 12

Findings of Weiss experiment about chemical gradients

Back 12

Axons with x chemical gradient attach to cells with x chemical gradient.Cut and inverted eye reconnected with original locations because of chemical gradients.

Front 13

Competition among axons

Back 13

Neural Darwinism - most successful axons and combinations survive, and the others fail.

Front 14

Spontaneous activity in neurons

Back 14

helps fine-tune adjustments based on experience

Front 15

NGF - Nerve Growth Factor

Back 15

a protein that promotes survival and growth of an axon. delivered by muscles.

Front 16

3-8 weeks after conception, __

Back 16

massive proliferation of cells

Front 17

No NGF =

Back 17

apoptosis. Axon without NGF will degenerate, and cell body dies. If axon cannot contact the appropriate postsynaptic cell, it kills itself.

Front 18

Apoptosis results

Back 18

Massive cell death that actually indicates maturation.

Front 19

Neurotrophins

Back 19

"Nourish brain"
essential for growth of axons & dendrites, forming new synapses, and learning.
NGF and BNDF (brain derived neurotrophic factor)

Front 20

When does a person have the most neurons?

Back 20

before birth

Front 21

Fetal Alcohol Syndrome effects

Back 21

hyperactivity, impulsiveness, difficulty maintaining attention, mental retardation, motor problems, heart defects, facial abnormalities
-impaired learning, memory, language, attention

Front 22

Fetal Alcohol Syndrome causes

Back 22

Alcohol suppresses GLU release (excitatory) and increases GABA release (inhibitory) and neurons receive less excitation and neurotrophins than needed, so apoptosis increases. Also alters migration patterns of small neurons.

Front 23

Differentiation of the cortex metaphor

Back 23

Speech of immigrant children -- young children master correct pronunciation; older children retain an accent.

Front 24

Differentiation of the cortex experiment

Back 24

Ferret experiment. Optic nerve attached to auditory areas. Auditory thalamus and cortex reorganized and developed SOME characteristics of the visual areas. Weasel uses old auditory areas to recognize light.

Front 25

Do axons/dendrites change? Why? What is a main cause?

Back 25

Yes, throughout life, because of experiences. Gain/loss of dendritic spines =turnover of synapses = learning. Physical activity is a main cause; it enhances axon and dendrite growth. Activity improves learning and memory.

Front 26

Near vs. Far Transfer

Back 26

Near transfer: training on one task and finding improvement on a similar task.
Far transfer: training on something difficult will enhance intellect in general (hard to prove).

Front 27

How to maintain intellectual vigor in old age

Back 27

Physical activity - enhances cognitive processes and brain anatomy

Front 28

Why does an enriched environment promote axon and dendrite growth?

Back 28

physical activity

Front 29

Brain's adaptation to blindness

Back 29

Occipital cortex (normally used just for vision) is also used for touch in blind people. Not in normal people. But, can be learned in adulthood even over 5 days

Front 30

Stringed instrument practice increases representation of the left hand in this area of the brain

Back 30

Postcentral gyrus (somatosensory cortex) of the right hemisphere

Front 31

Brain reorganization goes too far

Back 31

focal hand dystonia (musician's cramp)
difficult to move fingers independently, because representations of fingers spread out and overlap.

Front 32

Antisaccade Task

Back 32

Looking away from a powerful attention-getter. Very difficult before age 5 to 7. Ability to do so increases sharply btwn ages 7 - 11, then gradually thru adolescence.

Front 33

Impulsive decisions in adolescents

Back 33

When they must decide quickly in the presence of peers, more impulsive. Small pleasure now > large pleasure later.

Front 34

How do older brains compensate for less efficient functioning?

Back 34

More brain areas activate, ex: BOTH hemispheres of prefrontal cortex for memory task instead of 1.

Front 35

Closed head injury

Back 35

Most common brain damage in young people. Slow blow to head. Injury = rotational forces drive brain against skull, or blot clots interrupt flow to brain.

Front 36

Types of stroke

Back 36

Ischemia - blood clot / obstruction of artery. neurons are deprived of oxygen and glucose.
Hemorrhage - ruptured artery (usually fatal). neurons are flooded with excess blood, oxygen, & chemicals.

Front 37

Effects of stroke

Back 37

EDEMA - accumulation of fluid & pressure on brain.
Impair K+/Na+ Pump --> too much sodium --> therefore too much glutamate which overexcites the neurons to death.

Front 38

Stroke treatment

Back 38

--Tissue Plasminogen Activator (tPA) breaks up clots (for ischemia). within first 3 hrs.
--increase GABA
--cool the brain (slows harm)
--cannibinoids (decrease GLU)
--omega 3 fatty acids

Front 39

What happens after a stroke?

Back 39

When one area is damaged, other areas lose some of their normal input and become less active. Damage in 1 hemisphere declines activity in other.
DIASCHISIS - decreased activity of surviving neurons after damage to other neurons.

Front 40

After diaschisis, _______

Back 40

Treatments need to change; increase stimulation for the opposite side of the brain. Stimulant drugs can promote recovery, and should be directed to the cells that used to receive info from damaged cells.

Front 41

Why don't axons regrow much in mammals?

Back 41

Glial cells form scar tissue and prevent axon from going to original location. Neurons pull apart. Glia release chemicals to inhibit axon growth.

Front 42

Axon regrowth

Back 42

Happens in fish and in certain circumstances. If axon is crushed, slowly grows back. If cut, tries to grow back, but may reattach to wrong muscle.

Front 43

Axon sprouting

Back 43

When a spot has been vacated, axons put out collateral sprouts that take over the vacant synapses.

Front 44

Collateral sprouting - helpful or harmful?

Back 44

Helpful when 1 hemisphere is damaged but the other hem's axons sprout, and restore behavior.
Harmful if both hems are damaged and axons from other locations sprout into the vacant synapses and convey different info, therefore interfering with behavior & recovery.

Front 45

Denervation supersensitivity

Back 45

when cells become super sensitive to incoming inputs. Can compensate for decreased inputs and allow normal behavior after losing a lot of axons.

Front 46

When one set of synapses strengths, __

Back 46

another set weakens. Keeps arousal from going overboard.

Front 47

Collateral sprouting changes ____ and denervation supersensitivity changes ____.

Back 47

axons;
dendritic receptors

Front 48

Phantom Limb

Back 48

reorganized sensory representations. synapses became vacant and axons representing diff part of body took them over. portion of the somatosensory cortex becomes responsive to alternative inputs. Adjacent areas like face and hands.

Front 49

Deafferented limbs

Back 49

has lost its afferent (sensory) input. Can be used if necessary.

Front 50

Damage to visual cortex - result

Back 50

does not destroy memory trace, but impairs a rat's ability to find it

Front 51

When is plasticity increased?

Back 51

during the first days after damage

Front 52

The law of specific nerve energies

Back 52

Whatever excites a particular nerve always sends the same kind of info to the brain. Action potentials from auditory nerve = sounds, from olfactory nerve = odors, etc.

Front 53

Sensory systems

Back 53

take physical energy from the world and translate it into something the brain can use (action potentials, NTs)

Front 54

Pupil

Back 54

where light enters eye

Front 55

Light is focused by __ & __

Back 55

lens (adjustable) and cornea (not adjustable)

Front 56

Cornea

Back 56

protects, 1st place where light is bent (refraction)