Chp 10: Neuroplasticity

Question 1

Neuroplasticity

Answer 1

The nervous system’s potential for physical or chemical change that enhances its adaptability to environmental change and its ability to compensate for injury

Question 2

Past cases mentioned on neuroplasticity

Answer 2

Michelle
- Stroke in utero
- Missing left hemisphere
- Language shift to right hem.

Jody
- Rasmussen’s Encephalitis
- Right hemispherectomy
- Dexterity issues with left hand

Question 3

Stages of neurodevelopment (7)

Never Make Dog Mom Smell Cat’s Farts

Answer 3

• Neurogenesis
• Migration
• Differentiation
• Maturation
• Synaptogenesis
• Cell death and synaptic pruning
• Formation of myelin

Question 4

Neurogenesis: Neural Tube (Development of Brain) (4)

Answer 4

• Rolled up sheet of cells that will form the brain and spinal cord
• Begins developing about 3 weeks after conception

Neural groove folds to become neural tube

7 months: Sulci and syri start to form
100 days and 7 months: most obv for external apparence

Question 5

Neurogenesis: Neural Stem Cells (Development of Brain) (4)

Answer 5

• Grow out of the neural tube
• Capacity for Self-renewal
• Produce progenitor cells that produce neuroblasts and glioblasts

Ventricular zone

• Lined with neural stem cells

Question 6

Damage susceptibility at developing brain

Answer 6

4 and a half months: finish neuro blast,

• Less susceptible to damage: still generate neurons

After 4 ½:

• More susceptible to damage

Question 7

Cell Migration (4)

Answer 7

• Continues to about 8 months after birth
• Brain is more sensitive to trauma during migration

Radial Glial Cells

• Extend from the ventricular zone to cortex
• Neurons migrate out by traveling along the cells

Question 8

Differentiation (2)

Answer 8

• Neuroblasts become specific types of neurons
• Complete at birth

Question 9

Neural Maturation: Development of the dendrites (3)

Answer 9

• Dendritic arborisation
• Growth of dendritic spines
• Slow process, continues after birth

Question 10

Neural Maturation: Development of the axons (3)

Answer 10

• Have specific targets to reach
• Grow away from the cell body
• Some follow chemical or electrical signals

Question 11

Postnatal differentiation of human cerebral cortex around Broca’s area (3)

Answer 11

• Neurons first show simple dendritic fields
• Fields increase in complexity until child reaches approximately 2 years of age
• This parallels the development of language

Question 12

Synapse Formation and Pruning, 5 phases

Good Rabbit Poops Pleasantly

Answer 12

– 10^14 connections – 100 000 000 000 000
Genes, cues, and signals guide the formation of synapses

Five phases

• 1 and 2: Generated independently of experience (40000 synapses/ sec)
• 3: Rapid growth (Related to experience)
• 4: Plateau and rapid elimination through puberty (100000 synapses per second: being moody)
• 5: Plateau in middle age and steady decline with age

Question 13

Synapse Formation and Pruning: Experience Expectant

Answer 13

• Development depends on the presence of sensory experiences
• Phases 3 and 4

Question 14

Synapse Formation and Pruning: Experience Dependent

Answer 14

• Generation of synapses that are unique to the individual
• Phases 3,4, and 5

Question 15

Glial Development (4)

Answer 15

Begins after neuronal birth and continues through life

Myelination (Myelogenesis)

• Allows for normal adult function
• Begins after birth and continues until 18 years old
• Different areas of the cortex are myelinated at different times

Question 16

Myelination

Answer 16

Tertiary areas myelinate last

Highest levels of cognitive functioning

Question 17

Cortical thinning (3)

Answer 17

• Over course of development, thickness of cortex decreases
• Pattern of cortical thinning mirrors the myelination patterns
• Found thinner grey matter functioning was associated and increasing verbal ability and reading comprehension

Question 18

The Adolescent Brain (5)

Answer 18

• Increased neural plasticity
• Decreased cortical thickness
• Increases in glial cells
• Changes in connectivity/synapse reduction

Sensitive to damage

• Stress, psychoactive drugs, brain trauma, harmful relationships

Question 19

Experience plays role in sculpting the brain (4) Speaking:

Answer 19

how much the child is being spoken to:

• Promotes cortical thinning
• Serve and return one-on-one

Parentese: speaking in high voice

• Can help speaking ability

Question 20

Lack of experience: Case of Genie

Answer 20

Kept in room and no speaking
Kept in crib, inability to walk

Aft 6 months, passed critical period
More than 18 months, has a generally lower IQ, (15 less)

Question 21

Adverse Childhood Experiences (3)

Answer 21

• Abuse
• Neglect
• Household challenges

Question 22

Deprive animal of visual stimulation in one eye

Answer 22

Ocular dominance:

Input come in left and right eye,

Sew left eye shut, prune the unused and extend the one terminal being used

Question 23

Terminal arborization (3)

Answer 23

arborization describes the tree-like branching out of dendrites.

• This branching out allows dendrites to make new synaptic connections.
• extensive arborization can be considered a sign of complexity due to the increased number of synaptic connections it allows for

Question 24

Do domestic animals and wild animals have a different brain growth?

Answer 24

Yes

• Cortical areas are smaller in domestic animals
• Biggest reduction in size in the visual cortex (35%)
• General size reduction is 10-20%

Question 25

Environmental complexity and the brain (4)

Answer 25

Increases in: - Glial density - Dendritic length - Dendritic Spines (more potentials for connections) - Synapse size

Question 25

Environmental enrichment: key ingredients (rats) (3+3)

Answer 25

1) Opportunities of physical activities 2) Social interactions 3) Changing environment (novelty) Showed: - Better at learning memory tasks - Showed better skilled motor movements Not all rats respond to complex environments the same

Question 26

Response of dendrite and spine (2) to environment encrichment

Answer 26

Dendritic length: - Increase regardless of age Spine density: - Decrease in spine density when young - Not all animal respond the same

Question 27

Prenatal effect of mother’s enrichment

Answer 27

Pregnant dams receiving tactile stimulation or environmental enrichment produced big brained babies Tactile Stimulation = Same Effect as env enrichment

Question 28

Plasticity in representational zones: Individuals who played stringed instrument

Answer 28

- Left hand used more - Fingers used a lot more, the amount of brain space devoted will increase - Expansion in representation in somatosensory cortex - Start very young, expansion is larger than starting later in life

Question 29

Brain Injury and Plasticity (5) (age and recovery)

Answer 29

- Mid 1800’s observation of language development in children with left frontal lesions, but still developed normal adult language IDEA: brain injury milder and effects more short lived when sustained in childhood - Kennard principles (children has better recovery) - Hebb – studied poor outcomes following childhood prefrontal damage (Not always true, depend on where the brain in damaged Prefrontal damage is worse, But Kennard principle is generally true )

Question 30

Which year of life is most sensitive to damage?

Answer 30

1st

Question 31

Potential Treatment (4)

Answer 31

A potentially very potent treatment - tactile stimulation Soft brush strokes promoting recovery - Synaptogenesis - Increases BFGF: Basic-fibroblast growth factor - Increases acetylcholine

Question 32

Neurotrophic Factor (4)

Answer 32

- Also known as growth factor - Chemical compound that supports growth and differentiation in developing neurons - May be important for supporting survival of neurons in adulthood - bFGF is one example of a neurotrophic factor

Question 33

BDNF: brain derived neurotrophic factor

Answer 33

Another neuotrophic factor More important than bFGF

Question 34

What physical changes underlie growth? (6)

Answer 34

- Neurogenesis (new neurons) - Axon terminal arborization - Dendrites spines grow (arborization) - Expansion of cell body (soma) - Increased synaptic connections - Long Term Potentiation: neurons that fire together, wire together

Question 35

Once neural tissue has been destroyed and lost...

Answer 35

through neuron death, that brain tissue won’t be regenerated, it is lost forever, like an amputation

Question 36

Neurogenesis persists in the adult brain (on slides)

Answer 36

Subventricular zone : new neurons are born here too