intro to behavioral neuroscience unit 2

What are the three primary cell layers that develop in the embryo?

Ectoderm, mesoderm, and endoderm.

What does the ectoderm develop into?

The nervous system.

What is neurogenesis?

The process where cells in the inner side of the neural tube divide to form neurons and glial cells.

What are the two sets of factors that determine a cell's fate during neurogenesis?

Intrinsic factors (genetic determination) and extrinsic factors (cell-cell interactions).

How does neurogenesis differ between vertebrates and invertebrates?

Vertebrates rely more on extrinsic factors, while invertebrates, like C. elegans, depend more on intrinsic factors.

What happens to the number of neurons in vertebrates after birth?

They are born with most neurons they will ever have, with increases in brain size due to cell size, processes, glial cells, and myelination.

What is cell migration?

The process where cells move to their final positions in the nervous system, often completed by birth in primates.

What role do cell adhesion molecules (CAMs) play in cell migration?

They guide migrating cells and axons during development and after injury.

What is cell differentiation?

The process by which cells become specialized in structure and function, influenced by intrinsic and extrinsic factors.

What is synaptogenesis?

The growth of neuronal processes (axons and dendrites) and the formation of synapses.

What guides the growth cones of axons and dendrites?

Chemicals known as chemoattractants and chemorepellants.

What is apoptosis?

Natural cell death that occurs throughout the body, including during early development.

What determines whether a neuron survives during development?

Availability of synaptic targets and neurotrophic factors.

What is the role of Nerve Growth Factor (NGF)?

It is provided by target organs to prevent sympathetic neurons from dying.

What is synaptic rearrangement?

The process where early synapses are retracted and new synapses are formed.

How do neurotrophic factors influence synaptic rearrangement?

Cells that uptake enough neurotrophic factors survive, leading to competition and rearrangement of synapses.

What continues to develop after birth in many animals?

Glial cells and myelination.

What is myelination and why is it important?

The formation of myelin around nerve fibers, crucial for the speed of neural transmission.

What are intrinsic factors in nervous system development?

Genetic factors that influence the development of the nervous system.

What is the phenotype?

The sum of all physical characteristics resulting from the interaction of genotype with environment/experience.

In C. elegans, what is responsible for neural development?

The genotype is entirely responsible.

In vertebrates, what influences neural development?

A combination of intrinsic factors and neurotrophic factors.

What is behavioral teratology?

The study of how maternal environment influences fetal nervous system development.

What are teratogens?

Exogenous agents that may harm development, affecting not just the nervous system.

What major risk is associated with hypoxia at birth?

Increased risk of disabilities and schizophrenia.

What is the impact of prenatal food scarcity?

Increased risk of schizophrenia later in life.

What is Fragile X syndrome?

A genetic disorder caused by more than 200 trinucleotide repeats in the X chromosome, leading to cognitive impairments.

What is phenylketonuria (PKU)?

A disorder resulting in intellectual disability due to the buildup of phenylalanine in the brain, occurring in 1 in 10,000 births.

How do knockout (KO) mice differ from transgenic mice?

KO mice have a selectively inactivated gene, while transgenic mice have an introduced gene.

What is epigenetics?

The study of gene expression regulation, including how environmental factors can influence genetic activity.

What is ocular dominance?

The degree to which a visual cortical cell responds to light from one eye versus the other.

What is amblyopia?

A condition where one eye turns inward or outward, impairing vision if untreated by age 7 or 8.

What are amyloid plaques?

Extracellular accumulations of beta-amyloid that begin in the hippocampus and can lead to Alzheimer's disease.

What are neurofibrillary tangles?

Tangles of protein tau found inside neurons, associated with Alzheimer's disease.

What is the significance of the basal forebrain nuclei in Alzheimer's?

It is where acetylcholine neurons are located, and its loss is associated with Alzheimer's disease.

What is the long-standing hypothesis regarding beta-amyloid in Alzheimer's?

That amyloid precursor protein is cleaved to release beta-amyloid, which forms plaques that impair neuronal function.

What is the sensitive period in visual development?

A critical time frame during which visual experiences must occur to develop normal vision.

What happens to the visual cortex during binocular deprivation?

Loss of dendritic spines and synapses, potentially leading to blindness despite functional eyes.

What is the relationship between aging and the nervous system?

Not all individuals show the same changes in the nervous system with aging; some brain regions may not decline in neuron numbers.

What is the connection between developmental influences and psychiatric disorders?

Many psychiatric disorders appear to have a developmental component, with age of onset often at the end of adolescence.

What are the effects of drugs during pregnancy?

They can lead to long-term behavioral changes and developmental risks for the fetus.

What is the role of methylation in epigenetics?

Methylation reduces gene expression by adding a methyl group to DNA.

What is the impact of cataracts removed in adulthood?

Removal of cataracts at adulthood is ineffective if they were present at birth.

What is the significance of the visual cortex mapping the visual field?

Cortical cells respond to light from both eyes, allowing for depth perception and visual clarity.

What is the effect of maternal environment on fetal brain development?

It can significantly influence the development of the nervous system and lead to various disorders.

What are the implications of intrinsic genetic factors in development?

Mutations and chromosomal abnormalities can lead to various developmental disorders.

What is the prevalence of Alzheimer's disease?

It is the most common form of dementia, characterized by memory loss and personality changes.

What is the relationship between Down syndrome and Alzheimer's disease?

Most individuals with Down syndrome develop Alzheimer's disease, with symptoms appearing before age 50 in some cases.

What was the original belief about the creation of species?

Each species was believed to have been created separately.

What evidence suggested that species evolved rather than being created separately?

Homology and paleontology provided evidence of relationships among species and fossils of no-longer living species.

Who are the two key figures associated with the theory of evolution?

Charles Darwin and Alfred Russel Wallace.

What is the title of Darwin's seminal work on evolution?

On the Origin of Species by Means of Natural Selection.

What are the four observations that form the basis of Darwin's theory of evolution?

1. Reproduction increases population unless limited. 2. Individuals in a species are not identical. 3. Some variation is inherited. 4. Not all offspring survive to reproduce.

What major inference did Darwin make from his observations?

Heritable variations affect the probability of surviving and reproducing.

What is Darwin's major contribution to the theory of evolution?

Natural selection.

What does evolution refer to?

Change in the properties of a species over generations, including speciation.

Define natural selection.

The differential survival and reproduction of organisms with heritable characteristics.

What does the phrase 'survival of the fittest' refer to?

How well a species or member of a species fits into its niche.

What is convergence in evolutionary biology?

The development of similar traits in different species independently.

What is homoplasy?

Similar features that evolved separately.

Contrast homology and analogy.

Homology refers to features based on common ancestry, while analogy refers to similar functions.

Who created the laws of inheritance?

Gregor Mendel.

What is the role of mutations in evolution?

Mutations are spontaneous changes in an organism's characteristics.

How many pairs of chromosomes do humans have?

23 pairs of chromosomes.

What does it mean for genes to be highly 'conserved'?

There is little change or difference among species.

What is taxonomy?

The classification system of animals based on similarities.

What is phylogeny?

The evolutionary history of species.

How can changes in DNA serve as a 'clock'?

They can estimate when two species diverged from a common ancestor.

What are some factors to consider when choosing species for study in evolution?

Outstanding features, convenience, comparison, preservation, and economic importance.

What is the difference between invertebrate and vertebrate nervous systems?

Invertebrates usually have fewer neurons but possess incredible complexity in nervous system types.

What is one method of studying the evolution of the brain?

Comparative analysis of brain structures across different species.

What is the HVC in birds?

HVC stands for higher vocal center, important for song production.

How does the amount of brain devoted to a structure relate to its function?

Generally, the amount of brain devoted to a particular structure indicates the importance of that function.

What brain structure is associated with food-storing in birds?

The hippocampus.

What is a key feature of vertebrate nervous systems?

Basic similarities include development from a hollow dorsal neural tube, bilateral symmetry, segmentation, hierarchical control, and separate systems (central vs. peripheral).

How has the function of the midbrain optic tectum changed in mammals?

It has become a visual reflex center, whereas it was responsible for visual processing in lower vertebrates.

What is the significance of the neocortex in mammals?

All mammals have a neocortex with 6 layers, and more recent mammals have over 50% of their brain devoted to it.

What does the term 'encephalization factor' refer to?

It accounts for each class's deviation from the center line when comparing brain size to body size.

What is the relationship between brain size and body size?

When looking at brain size, it is important to account for body size.

What hypothesis suggests that larger brains are necessary for complex social relationships?

The social brain hypothesis.

What are some factors that may have driven the increase in human brain size?

Social relationships, behavioral innovations, tool use, social learning, and possibly sexual selection.

What accounts for differences in primate brains?

Differential gene expression and the timing of gene activation can account for these differences.

What significant evolutionary milestones occurred 4 million and 2.5 million years ago in human evolution?

4 million years ago: began walking on two feet; 2.5 million years ago: development of stone tools.

How do later-developing brain regions relate to brain size?

Regions that develop later tend to become larger, suggesting small genetic changes can lead to significant brain changes.

What is the significance of cortical pyramidal cells in mammalian species?

They provide insight into the differences in brain structure and function across species.

What does the evolution of the brain reflect?

It reflects changes in behavior across different species.

What is the role of gene expression in brain development?

Gene expression can vary, affecting the development and function of brain regions.

What is a common misconception about brain size and intelligence?

That larger brains always equate to higher intelligence; brain-to-body ratio is also important.

What does the study of warblers' HVC size indicate?

It indicates a relationship between the number of songs a warbler can produce and the size of its HVC.

What evolutionary trend is observed in mammalian brains compared to reptiles?

Mammals have a more complex neocortex, while reptiles have a simpler 3-layered cortex.

What is the importance of studying brain structures across vertebrates?

It helps to understand the evolutionary adaptations and functional specializations of different species.

What does the term 'functional specialization' refer to in the context of vertebrate brains?

It refers to the differentiation of brain regions to perform specific functions.

How does the evolution of the brain challenge linear perspectives?

Evolution is not linear; it involves complex adaptations and changes in response to environmental pressures.

What can be inferred from the proportions of brain regions in different species?

They provide insights into the relative importance of various cognitive functions in those species.

What is sound?

An oscillation of increases and decreases in air pressure, typically discussed as waves.

How is frequency measured?

In Hertz (Hz), which represents cycles per second.

What does frequency perception correspond to?

Pitch; higher frequency is perceived as higher pitch.

What is amplitude in relation to sound?

It refers to the loudness of sound, measured in decibels (dB).

What is a pure tone?

A sound that consists of a single frequency.

What is the role of mechanoreceptors in hearing?

They are sensitive to mechanical or physical forces and detect sound.