BioPsych Ch. 5

Which of the following factors seems to be particularly important for branching of neurons during brain development?

Physical activity

Describe how experience can alter brain development (give a specific example).

Experience can alter brain development by directing the birth and survival of neurons and the strengthening or weakening of synaptic connections. Examples include the correlation between neurogenesis (birth of neurons) in the hippocampus and learning and memory; increased density of dendritic spines, dendritic branching and enhanced learning and memory for individuals raised in a sensory enriched environment compared to those that were not. Furthermore, exposure to drugs like alcohol interferes with synaptic plasticity and the neural connections and is associated with neurodevelopmental disorders.

True or False: The human central nervous system begins to form when the embryo is about 10 weeks old.

False

An impairment of eating, drinking, temperature regulation, or sexual behavior suggests possible damage to which brain structure?

Hypothalamus

True or False: A rat in a more stimulating environment develops a thicker cortex, more dendritic branching, and improved learning.

True

True or False: Exercise may account for some of the neural benefits that come from rearing rats in an enriched environment.

True

At later stages of the neuron's development, neurotrophins:

increase the branching of axons.

Necrosis:

is cell death caused by an injury or a toxic substance.

Describe how axons reach their targets during development.

Axons reach their target by following a chemical gradient. Sperry's research with newts indicated that axons reach their targets by following a gradient of chemicals in which they are attracted by some chemicals and repelled by others. The chemicals are released by target cells. Activity in neurons causes the release of trophic factors that further strengthens the growing axon's connection to its target.

Which of the following is NOT a function of neurotrophins?

Induce apoptosis of neurons.

A group of forebrain structures is important for motivated and emotional behavior. What is the name given to this group of structures?

Limbic system

Describe the five main stages of growth and development of neurons.

The first stage is proliferation. Proliferation refers to the production of new cells/ neurons in the brain primarily occurring early in life. When new cells mature to become neurons we call the process neurogenesis. The second stage is refers to the movement of the newly formed neurons and glia to their eventual locations called migration. Some cortical neurons do not arrive at their target until long after birth. The third stage is the formation of axons and dendrites as well a distinctive neuron shape called differentiation. The fourth stage is myelination, in which glia cells form the fatty insulation that wraps around some axons. Myelination continues well into adulthood. The formation of the synapses between neurons is the fifth and final stage called synaptogenesis. Synaptogenesis occurs throughout life.

Organize the following divisions of the nervous system in a hierarchy to show the relationships between them: central, peripheral, autonomic, sympathetic, parasympathetic, somatic.

The complete nervous system can be divided into the central and peripheral nervous systems. The peripheral is further divided into the somatic and autonomic. The autonomic is divided into the sympathetic and parasympathetic. The central nervous system consists of the brain and the spinal cord.The peripheral nervous system is outside the central nervous system and includes the somatic nervous system (nerves to muscle organs of the body) as well as the autonomic nervous system. The autonomic nervous system is further divided into the sympathetic (activating stress response) and the parasympathetic (calm, rest and digest) divisions.

After cells have differentiated as neurons or glia, they:

migrate

The stages of neurogenesis that occur for the longest duration are:

myelination and synaptogenesis.

Competition of neurons for postsynaptic sites results in survival of only the most successful axons. This general principle is called:

neural Darwinism

Stem cells are important for which of the following developmental processes?

proliferation

Musicians who use the left hand to finger the violin strings have some alterations in one brain area, which is the:

right hemisphere postcentral gyrus.

What brain abnormalities are found in children with fetal alcohol syndrome?

short dendrites with few branches

Roger Sperry cut a newt's optic nerve and rotated the eye. Axons from what used to be the dorsal part of the retina (now located on the ventral side) grew back to the target areas:

that ordinarily get input from the dorsal retina.