Ch. 5 Evolving Brains: Neural Development, Neuroplasticity, and Recovery of Function

AHHHHH

Conservative process

many similarities are seen among the brains of various species

(principles have been conserved

what proides a good reason for use of animals in behviral nueroscience resarch?

commanilites in brain devleopemnt across species

what is unique about the human brain

our cenbreal cortex has the most nuerons of any known mammal

what are epigentics

how the environment directly imapcts genes

What was the key experiment by Frances Champagne and Michael Meaney at McGill University about?

It studied how maternal licking/grooming behavior in rats affects their offspring’s stress response and anxiety.

How did offspring of high-licking maternal rats behave compared to low-licking ones?

They showed less anxiety in the elevated plus maze.

What human behavior is rat licking similar to?

It’s similar to a human hug or attentiveness.

What physiological differences did offspring of high-licking/grooming mothers have?

They had lower stress hormone levels and more glucocorticoid receptors in the hippocampus.

How did the stress hormone system differ in high-licking offspring?

It was more sensitive, efficient, and led to a healthier stress-response system.

What genetic process was altered by maternal care in the experiment?

DNA methylation – the addition of a methyl group to DNA that prevents gene expression.

How does DNA methylation relate to stress response in the study?

Maternal care changed methylation patterns, influencing how stress-related genes were expressed.

What happened when rats born to low-licking mothers were raised by high-licking foster mothers?

They acted more like the foster mother when they became parents and developed a healthier, more sensitive stress response.

What is the term for passing down maternal behaviors through experience rather than genes?

Non-genomic transmission.

What does the study suggest about lifestyle experiences?

They can alter genetic programming, even without changing the DNA sequence.

histone acetylation

adding an acetyl group to a histone

What happens when an acetyl group is added to a histone?

It changes the shape of nearby DNA, making those genes more likely to be expressed.

What is the effect of removing an acetyl group from a histone?

It makes the gene less likely to be expressed.

zygote

fusion of egg and sperm

gastrulation

the process where an embryo transforms from a single-layered sheet of cells into a multi-layered structure

when does gasturlation occur

between 13-19 days of a pregenancy

what are the 3 germ layers

ecoterm, mesoderm, endoderm

ectoderm

outermost layer that gives rise to the nervous system and outer skin.

mesoderm

middle layer, responsible for the musculoskeletal system, circulatory system, and kidneys

endoderm

the innermost layer and forms the lining of the digestive and respiratory systems, as well as glands like the liver and pancreas

neuroectoderm

specialized type of embryonic tissue that gives rise to the nervous system (derevied from ectoderm)

What happens to neuroectodermal precursor cells in early development?

They thicken to form the neural plate.

What is the neural crest and what does it produce?

Tissue at the border of the neural tube and non-neural ectoderm that gives rise to cells of the peripheral nervous system (PNS).

Where do all neurons with cell bodies in the PNS come from?

The neural crest (specifically sensory neurons).

How does the neural tube form?

the ends of the neural plate fold inward to create the neural tube.

What does the neural tube give rise to?

The central nervous system (CNS) and most of the peripheral nervous system (PNS).

Neurogenesis

formation of neurons and glia. orginate from cells in the ventircualr zone

Progenitor cells

can differentiate only into a specific type of cell

What happens after cells are created in the ventricular zone of the neural tube?

They migrate to their appropriate target location in the brain.

What are migrating neurons like?

They are immature cells that lack axons and dendrites.

What guides migrating neurons to their destinations?

Radial glia.

Are cortical neurons born in the cortex?

No, none of the cortical neurons in mammals are born in the cortex—they migrate there from other regions.

Nerve growth factor (NGF)

neurochemical which helps in the growth of axons and dendrites; aids in neuronal survival

Brain-derived neurotrophic factor (BDNF

promotes the maturation of neurons and synapse formation throughout the brain

Synaptogenesis

formation of new synapses which aid in creation of functional circuits

Apoptosis

programmed cell death

How long does white matter continue to develop?

Into early adulthood

What cognitive abilities become more consistent with age as white matter develops?

Executive functioning and the ability to inhibit impulses.

What did Luna and colleagues find in their study of response inhibition

The right dorsolateral prefrontal cortex (DLPFC) showed more activity in teens than in adults.

What happens to ventral striatum activity during adolescence?

It increases, reflecting stronger reward processing.

How does activity in the amygdala and prefrontal cortex (PFC) change during adolescence?

There’s a decrease or less activity, reducing regulatory control and harm avoidance.

with age we see

reductions in processing speed and a general decline in cognitive abilities

alzhemiers dieases primarly affects which area of the brain

hippocampus and entorhinal cortex

What happens as Alzheimer’s disease advances?

It progressively impairs and can eliminate vital functions.

What are the three main biological markers of Alzheimer’s disease?

Amyloid plaques that clump and tau tangles that impair communciaiton and axon structure, and shrinkage of key brian areas

What happens to axons during a TBI (tramuamtic brain injury)

They twist and tear — a process called axon shearing.

What is a subdural hematoma?

A blood clot that forms after a traumatic brain injury.

What is an ischemic stroke in the context of TBI?

It occurs when blood flow to parts of the brain is disrupted.

What happens to brain cells when blood flow is impaired after TBI?

Cells begin to die due to disrupted ion concentrations and excitotoxicity.

What ion changes occur with impaired cerebral blood flow?

Calcium (Ca²⁺) increases, while magnesium (Mg²⁺) and potassium (K⁺) decrease.

How does glutamate contribute to cell death after a TBI?

Excess glutamate release overstimulates neurons, leading to excitotoxicity.

How do astrocytes help after a traumatic brain injury?

They absorb glutamate to prevent further neuronal damage and buffer K⁺ ions.

what is used to meausre the severity of TBI?

glasgow coa scale (eye opening, verbal respones, motor responses) , duration of loss consicouness (LOC), and post traumatic anmnesia (PTA)

what is essential for recovery?

training

what is the main goal of constraint-induced therapy?

To require patients to use their affected limb(s) instead of compensating with the healthy ones.

How does constraint-induced therapy promote recovery?

It forces the brain to form new neural circuits that improve control and performance of the impaired limb.

What is “punch-drunk syndrome” also known as?

Dementia pugilistica or chronic traumatic encephalopathy (CTE).

How can small brain injuries lead to long-term problems?

Repetitive mild TBIs or subconcussive hits can accumulate and cause chronic brain damage.

What are some key features of chronic traumatic encephalopathy (CTE)?

Atrophy in several brain regions, behavioral and personality changes, and movement difficultie

How is the brain pathology of CTE similar to that of Alzheimer’s disease?

Both show abnormal protein buildup and neurodegeneration in affected brain regions.