IBN week 6

Why do neuroscientists compare different species that engage in the same behavior?

To identify relationships between brain structures and specific behaviors

In some warbler species, what correlates with the number of songs they can sing?

Size of the HVC, a song-related brain region

Why do food-storing birds often have a relatively large hippocampus?

It helps them remember food locations

Why are rat whiskers important to sensory processing?

They provide tactile information about the surrounding environment

Which feature is shared by vertebrate nervous systems?

A hollow dorsal neural tube during development

What does bilateral symmetry mean?

The body has corresponding left and right sides

What does segmentation refer to in body organization?

The organization of the body into repeated structural units

What is hierarchical control in the nervous system?

Different levels of the nervous system contribute to control, from lower circuits to higher brain regions

Why is the rat olfactory bulb proportionally larger than the human olfactory bulb?

Smell is particularly important to rats' behavior and survival

What is the difference between allocortex and neocortex?

Allocortex generally has fewer cortical layers than neocortex

What is an important feature of the reptilian cortex compared with mammalian neocortex?

The reptilian cortex typically has three layers in the comparison from your notes

Why must body size be considered when comparing brain sizes across species?

Larger animals generally require more neural tissue to control larger bodies

What does the encephalization quotient (EQ) estimate?

How large a brain is relative to the brain size expected for an animal of its body size

If two species have different brain sizes, what is the best way to interpret the difference?

Consider body size, brain organization, and the species' ecological demands

What does nonlinear scaling of cortex size mean?

Cortex size does not increase in a simple, constant proportion as species size or complexity changes

What is a major implication of brain regions that develop later becoming proportionally larger across species?

Changes in later developmental processes may contribute substantially to differences in brain structure

When did Australopithecus first appear, according to your notes?

About 4 million years ago

Which characteristic is associated with Australopithecus?

Bipedal walking and a cerebral volume of roughly 300-400 cm³

How might early stone-tool use have influenced jaw and tooth evolution?

It may have reduced reliance on large jaws and teeth by making food processing easier

Approximately when did Homo species begin appearing, according to your notes?

Within the last 2 million years

What cerebral volume is associated with Homo habilis in your notes?

600-700 cm³

Which description best matches Homo erectus in your notes?

700-1,400 cm³, elaborate stone tools, use of fire, and hunting large animals

What brain volume is associated with Homo sapiens in your notes?

1,400 cm³

What does the social brain hypothesis propose?

Larger brains were favored partly because complex social relationships require substantial cognitive abilities

What does the sexual selection hypothesis propose about brain evolution?

Mate attraction and courtship may favor abilities that attract, stimulate, or surprise potential mates

Why might rapid expansion of brain size indicate a survival advantage?

A costly trait may spread if its benefits improve survival or reproductive success enough to offset its costs

Which is a cost of having a large brain?

Long gestation, difficult childbirth, prolonged dependency, and high energy use

Why is childbirth particularly challenging for humans?

A relatively large infant head must pass through the maternal birth canal

What is one reason human infants require prolonged care?

Much brain growth and development continue after birth

What percentage of DNA do humans and chimpanzees share approximately, according to your notes?

95%

How can humans and chimpanzees differ substantially despite sharing much of their DNA?

Differences in gene expression and genes involved in brain development can affect brain structure and function

What is the significance of genes such as ASPM in studies of human brain evolution?

They are involved in brain development and have been studied in relation to brain size

What two broad influences interact to shape development?

Genes and environment

What is a genotype?

The genetic information an individual carries

What is a phenotype?

Observable characteristics produced through interactions between genotype and environment

Which embryonic germ layer gives rise to the nervous system?

Ectoderm

Which structures are primarily associated with mesoderm development?

Muscles, heart, and blood cells

Which structures are associated with endoderm?

The lining of many internal organs, including parts of the digestive and respiratory systems

What is a transcription factor?

A protein that binds DNA and helps regulate gene expression

Why are transcription factors important in early development?

They coordinate cascades of gene expression that help establish tissues and cell types

What are homeotic proteins involved in?

Determining body plan organization and segment identity

Why is the conservation of developmental genes across vertebrates important?

It suggests that many vertebrates share ancient developmental mechanisms

What early structure develops into the central nervous system?

The neural tube

What happens to the anterior end of the developing neural tube?

It develops into major brain regions

What does the remaining posterior neural tube primarily become?

The spinal cord

What is gastrulation?

A process that establishes the embryonic germ layers and body plan

Which statement best describes early nervous system development?

It involves coordinated genetic programs and interactions with the developing environment

What is neurogenesis?

The creation of new neurons

Where do many neural precursor cells divide during early brain development?

Ventricular zone (VZ)

What determines which type of neural cell a precursor becomes?

Genetic programs, transcription factors, and extracellular signals

What does the birth date of a neuron refer to in developmental neuroscience?

The point when the neuron stops dividing

Where can limited adult neurogenesis occur, according to your notes?

Olfactory bulb and dentate gyrus of the hippocampus

What accounts for much brain growth after birth?

Cell growth, branching, glial development, and myelination

What is radial migration?

Neurons moving from the ventricular zone toward outer cortical layers

What is tangential migration?

Neurons moving sideways, often along the rostral-caudal axis or across developing regions

Which is an example of a neuron type commonly associated with radial migration?

Cortical pyramidal neuron

What is cell differentiation?

A cell developing specialized characteristics and functions

In the general sequence of neuronal development, which structure grows first?

Axons generally grow before dendrites

What is one role of neural cell adhesion molecules such as NCAM?

Supporting cell interactions and neurite growth during development

What is a growth cone?

A structure at the tip of a growing axon that helps guide its path

What are filopodia?

Small finger-like extensions of a growth cone that help detect guidance cues

What do chemoattractants and chemorepellents do?

Guide axons by attracting or repelling them through chemical signals

What is synaptogenesis?

The formation of synapses between neurons

What is apoptosis?

Programmed cell death that is a normal part of development

What is necrosis?

Cell death associated with injury, trauma, or disease

What are neurotrophins?

Chemicals that support neuronal growth and survival

What may happen when a developing neuron fails to receive enough neurotrophic support from its target cells?

It may undergo apoptosis

Which neurotrophin is especially associated with the peripheral nervous system in your notes?

NGF (nerve growth factor)

Which neurotrophin is particularly important in the neocortex and hippocampus according to your notes?

BDNF (brain-derived neurotrophic factor)

What is synaptic rearrangement?

The refinement of neural circuits by strengthening some connections and removing others

What is generally true of connections that are repeatedly active and useful?

They are more likely to be strengthened

What effect can environmental enrichment have on the rodent cortex?

It can increase synapse number

How does learning generally affect synapses?

It can involve relatively small amounts of synaptic turnover and refinement

Which statement best describes synapse loss in neurodegenerative disorders?

Severe synapse loss can occur in Alzheimer's and Parkinson's disease

What is gliogenesis?

The formation of glial cells

What is myelination?

The formation of insulating myelin around axons

What is an important consequence of increased myelination?

Faster action potential conduction and better coordination of neural activity

What does diffusion MRI help researchers investigate during brain development?

Patterns of water diffusion in tissue that can provide information about white matter and myelination

What do your notes suggest about frontal-lobe myelination during adolescence?

It continues through adolescence and into adulthood

What is behavioral teratology?

The study of how the maternal environment can influence nervous system development in a fetus

What is a gene knockout (KO)?

A gene is selectively inactivated

What is a knock-in experiment?

Introducing a gene or a specific genetic change into an organism's genome

What is an overexpression mutant?

An organism in which a gene is expressed at an increased level

What is a major limitation of conventional knockout or transgenic animal models?

The genetic change may affect many cell types and may disrupt embryonic development

What is an advantage of a conditional knockout or transgenic model?

Gene expression can be targeted to particular cell types, tissues, or times

What is epigenetics?

Changes in gene expression or regulation that do not require changing the underlying DNA sequence

How can early-life experiences affect later behavior through epigenetic mechanisms?

Experiences can influence gene expression, potentially producing lasting effects on development