Chapter 2: The Brain and Behavior

plasticity

The brain’s special capacity for change

When during the lifespan is the brain more plastic

During the early years of life

What are the major divisions of the nervous system

Central nervous system and Peripheral nervous system

Identify the two structures of the central nervous system.

The brain and spinal cord

What is the peripheral nervous system

The network of nerves that connects the brain and spinal cord to other parts of the body. Brings information to and from the brain and spinal cord and carries out the commands of the CNS to execute various muscular and glandular activities.

Somatic nervous system

The body system consisting of the sensory nerves, whose function is to convey information from the skin and muscles to the central nervous system about conditions such as pain and temperature, and the motor nerves, whose function is to tell muscles what to do. (Voluntary control of body movements)

Autonomic nervous system

The body system that takes messages to and from the body’s internal organs, monitoring such processes as breathing, heart rate, and digestion

Sympathetic nervous system

The part of the autonomic nervous system that arouses the body to mobilize it for action and thus is involved in the experience of stress.

Parasympathetic nervous system

The part of the autonomic nervous system that calms the body.

stress

The responses of individuals to environmental stressors.

stressors

Circumstances and events that threaten individuals and tax their coping abilities and that cause physiological changes to ready the body to handle the assault of stress

fight-or-flight reaction to stress

One of the functions of the sympathetic nervous system. This reaction quickly mobilizes the body’s physiological resources to prepare the organism to deal with threats to survival.

neurons

One of two types of cells in the nervous system; the nerve cells that handle the information-processing function.

Dendrites

Treelike fibers projecting from a neuron, which receive information and orient it toward the neuron’s cell body.

Cell body

The part of the neuron that contains the nucleus, which directs the manufacture of substances that the neuron needs for growth and maintenance.

Axon

The part of the neuron that carries information away from the cell body toward other cells

Myelin sheath

A layer of fat cells that encases and insulates most axons speeding up transmission of nerve impulses

Synapse

Tiny spaces between neurons; the gaps between neurons are referred to as synaptic gaps

Resting potential

The stable, negative charge of an inactive neuron.

Action potential

The brief wave of positive electrical charge that sweeps down the axon. When a neuron sends, it is commonly said to be “firing.”

All or nothing principle

The principle that once the electrical impulse reaches a certain level of intensity (its threshold), it fires and moves all the way down the axon without losing any intensity

neurotransmitters

Chemical substances that are stored in very tiny sacs within the neuron’s terminal buttons and involved in transmitting information across a synaptic gap to the next neuron.

Acetylcholine

Usually stimulates the firing of neurons and is involved in the actions of muscles, learning, and memory. It is found throughout the CNS and PNS. (decrease in alzheimer’s disease)

GABA

Is found throughout the CNS. Believed to be the neurotransmitter in one-third of the brain’s synapses. It keeps many neurons from firing, helping to control the precision of the signal being carried from one neuron to the next. Helps you relax. (decrease in anxiety)

Glutamate

Has a key role in exciting many neurons to fire and is especially involved in learning and memory. Is also a factor in anxiety, depression, schizophrenia, Alzheimer disease, and Parkinson's disease

Norepinephrine

Inhibits the firing of neurons in the central nervous system, but excites the heart muscle, intestines, and urogenital tract. Stress stimulates the release of it. It also helps to control alertness.

Dopamine

(Outgoing/extraversion) Helps to control voluntary movement and affects sleep, mood, attention, learning, and the ability to recognize rewards and other important signals in the environment (decrease in parkinsons/increase in schizophrenia)

Serotonin

Involved in the regulation of sleep, mood, attention, and learning. A key to maintaining the brain’s neuroplasticity. (decrease in depression)

Endorphins

Natural opiates that mainly stimulate the firing of neurons. Shield the body from pain and elevate feelings of pleasure (decrease in depression)

Oxytocin

A hormone and neurotransmitter that plays an important role in the experience of love and social bonding

What happens when someone has too much or too little of serotonin?

Lowered levels are associated with depression.

What happens when someone has too much or too little of dopamine?

Low levels of dopamine deteriorate physical movement.

Agonist

A drug that mimics or increases a neurotransmitter’s effects

Antagonist

A drug that blocks a neurotransmitter’s effects

medulla

Connects the brain and spinal cord. Controls many vital unconscious functions, such as breathing, heart rate, and blood pressure. It also plays a role in reflexes (coughing, sneezing, swallowing, gag reflex)

cerebellum

Plays an important role in motor coordination, particularly balance, posture, and coordinated movements

brain stem

Connects at its lower end with the spinal cord and then extends upward to encase the reticular formation in the midbrain. Determine alertness and regulate basic survival functions such as breathing, heartbeat, and blood pressure

reticular formation

A system in the midbrain comprising a diffuse collection of neurons involved in stereotyped patterns of behavior such as walking, sleeping, and turning to attend to a sudden noise (arousal and consciousness).

limbic system

A set of subcortical brain structures central to emotion, memory, and reward processing

amygdala

An almond-shaped structure within the base of the temporal lobe that is involved in the discrimination of objects that are necessary for the organism’s survival, such as appropriate food, mates, and social rivals

hippocampus

• The structure in the limbic system that has a special role in the storage of memories.

• Individuals who suffer extensive damage cannot retain any new conscious memories after the damage.

thalamus

The forebrain structure that sits at the top of the brain stem in the brain’s central core and serves as an important relay station.

basal ganglia

Large neuron clusters located above the thalamus and under the cerebral cortex that work with the cerebellum and the cerebral cortex to control and coordinate voluntary movements.

hypothalamus

A small forebrain structure, located just below the thalamus, that monitors three pleasurable activities—eating, drinking, and sexual behavior—as well as emotion, stress, and reward

cerebral cortex

Part of the forebrain, the outer layer of the brain, responsible for the most complex mental functions, such as thinking and planning

Frontal lobes

The portion of the cerebral cortex behind the forehead, involved in personality, intelligence, and the control of voluntary muscles

Parietal lobe

Structures at the top and toward the rear of the head that are involved in registering spatial location, attention, and motor control

Temporal lobes

Structures in the cerebral cortex that are located just above the ears and are involved in hearing, language processing, and memory.

Occipital lobes

Structures located at the back of the head that respond to visual stimuli

Somatosensory cortex

A region in the cerebral cortex that processes information about body sensations, located at the front of the parietal lobes.

Motor cortex

A region in the cerebral cortex, located just behind the frontal lobes, that processes information about voluntary movement

corpus callosum

The large bundle of axons that connects the brain’s two hemispheres, responsible for relaying information between the two sides

Brenda Milner, Ph.D.

She conducted groundbreaking research on the brain. She studied memory and damage to temporal lobes, mapped the function of areas of the frontal lobe, determined the lateralization of function in the hemispheres, and demonstrated plasticity after damage. She proved that there are different memory systems, specifically episodic memory and procedural memory. ​​She is considered the founder of clinical neuropsychology.