~Class 15 - Brain Development

Question 1

What part of Michels brain did Dr’s remove, and why?

Answer 1

Doctors removed the left hemisphere of Michael’s brain to treat severe epilepsy.

The left hemisphere is centrally involved in speech, language, and attention.

Over time, his right hemisphere reorganized & took over functions

Question 2

When is the brain most plastic?

Answer 2

Infancy and Adolesence

Question 3

Is the brain plastic in adulthood?

Answer 3

Yes, just not as much as in Infancy and Adolesence

Question 4

Periods of heightened brain plasticity provide ___ as well as ___.

Answer 4

positive opportunities // vulnerabilities

Question 5

What are the features of Developmental Plasticity?

Answer 5

• “Exuberant” growth of new brain circuits & synaptic connections
• Predisposed to be modified
• Brain development is easily influenced by a wide range of experiences

Question 6

What are features of Adult Plasticity?

Answer 6

• Relatively minor modification of existing brain circuits/connections
• Predisposed to stability
• For enduring changes, you need to pay more attention/give special meaning to experiences

Question 7

Brain development begins in earnest during the ___ period of ___ development.

Answer 7

embryonic // prenatal

Question 8

The embryonic period starts at the point of ___, so around ___ weeks from the start of the pregnancy, and lasts till ___ weeks gestation.

Answer 8

implantation // 2 // 8

Question 9

The major event that’s occurring during the Embryonic period is the development of the ___.

Answer 9

Neural Tube

Question 10

The way the neural Tube forms is that it starts out as the ___, a ___ structure, which then curves up around itself creating a tube-shape.

Answer 10

Neural Plate // flat

Question 11

When is the embryo most susceptible to Teratogens?

Answer 11

During the Embryonic period

Question 12

The Neural Tube forms the ___ and ___.

Answer 12

Brain // Central Nervous System (CNS)

Question 13

When neural tube defects occur toward the bottom of the neural tube, the most likely outcome is ___, which typically involves weakness or full paralysis of the ___.

Answer 13

spina bifida // lower limbs,

Question 14

When the neural tube does not close up where the brain would be forming tends to result in ___, which occurs when major parts of the developing fetuses brain just don’t develop. The fetus is unlikely to survive, they may reach full-term, but cannot survive beyond the first few hours or days.

Answer 14

Anencephaly

Question 15

The ___ is important for things like regulating bodily functions.

Answer 15

brain stem (hindbrain and midbrain)

Question 16

What are the 4 process that occur during the fetal period of prenatal development (9+ weeks)?

Answer 16

1. Neurogenesis
2. Neuronal Migration
3. Neuronal Differentiation
4. Synaptogenesis

Question 17

What is Neurogenesis?

Answer 17

The formation of new neurons in the brain (starts in 5th week)

Question 18

What is Neuronal Migration?

Answer 18

Neurons move from the centre of the neural tube outward

Question 19

What is Neuronal Differentiation?

Answer 19

Neurons are genetically pre-programmed to go to specific areas of the brain

Question 20

What is Synaptogenesis?

Answer 20

The formation of synaptic connections between neurons

Question 21

What is Synaptic Pruning?

Answer 21

Eliminating unused neural pathways

Question 22

As babies, we make more ___ and form more connections than we’ll need, and over time, unneeded ones are ___.

Answer 22

neurons // pruned away

Question 23

What is Myelination?

Answer 23

A process in which the axon is coated with layers of fatty insulation (myelin sheath)

Question 24

What are Glial Cells?

Answer 24

Some Glial cells produce a waxy fatty substance called Myelin, which will wrap itself around the Axon of a neuron, which serves a couple of functions that make neural communication more efficient.

Question 25

A Myelinated cell can propagate a signal down the axon ___ than an unmyelinated axon.

Answer 25

faster

Question 26

Myelin, as it wraps around the axon, allows electrical signals to jump from one point to another, between the Myelin Sheaths in little gaps called ___.

Answer 26

Nodes of Ranvier

Question 27

Myelination tends to start in the ___ and ___ parts of the brain, like the brainstem and cerebellum.

Answer 27

lower // deeper

Question 28

Myelination in the frontal lobe continues until ___.

Answer 28

25

Question 29

During childhood, there is gradual and ongoing change in all regions of the brain, in ___.

Answer 29

localized spurts

Question 30

Brain development in childhood involves specialization of ___ and ___ of different regions

Answer 30

neural structures // integration

Question 31

Rapid synaptogenesis/grey matter peaks at age ___, then Synaptic pruning takes over

Answer 31

10

Question 32

White matter (myelin) increases through to ___.

Answer 32

early adulthood

Question 33

In the first year there is a large increase in synaptic density in the ___ cortex, which peaks relatively early before tapering off and declining in the childhood years.

Answer 33

visual

Question 34

There is a bunch of Synaptogenesis in the ___ cortex early on, but the peak extends into year 3 before it more gradually begins to decline.

Answer 34

auditory

Question 35

At age ___years, grey matter in sensory and motor regions thin.

Answer 35

5-8

Question 36

At age ___year, grey matter in parietal and temporal regions thin

Answer 36

6-11

Question 37

At ages ___, grey matter in the frontal lobe gradually thins.

Answer 37

11 to adulthood

Question 38

What reorganization happens from ages 12-18 in the brain?

Answer 38

• Gradual refinement of neural networks
• Development of the “social brain” (puberty hormones ↑sensitivity to oxytocin)
• Development of subcortical (limbic) regions, including reward network
• Maturation of the prefrontal cortex

Question 39

What part of the brain becomes hypersensitive to emotional experiences between ages 12-18?

Answer 39

The Amygdala

Question 40

What occurs to the Corpus Callosum between the ages of 12-18?

Answer 40

During adolescence, the nerve fibres that connect the hemispheres are getting thicker, and that allows the adolescent to process info more efficiently between the two hemispheres (Corpus Callosum)

Question 41

What is the dual systems model of adolescent brain development and risk-taking?

Answer 41

The Prefrontal Cortex (which controls self-regulation) isn’t working fast enough to do its job to say STOP to the Limbic System, which is sensitive to reward.

Question 42

The ___ are the sensitive gas pedal, and the slow-developing ___ are the bad brakes.

Answer 42

Limbic regions // Prefrontal Cortex