Chapter 2: The Brain and Behavior

Nervous system

body's electrochemical communication circuitry

Nervous system characteristics

Complexity, integration, adaptability, electrochemical transmission

Plasticity

special capacity of brain for modification and change

Cause of epileptic seizures

flow of information disrupted because electrochemical system is short circuited

Afferent nerves

Sensory nerves that transport information to the brain and spinal cord via sensory receptors

Efferent nerves

Motor nerves that carry info out of the brain and spinal cord to other areas of the body

Central Nervous System (CNS)

Brain and spine; location of 99% of all nerve cells

Peripheral Nervous System (PNS)

Nerves connecting CNS (brain and spinal cord) to the rest of the body (Splits into somatic and autonomic)

Somatic nervous system

consisting of the sensory nerves, whose function is to convey info from the skin and muscles to the CNS about conditions such as pain and temp, and the motor nerves, whose function is to tell muscles what to do

Autonomic nervous system

takes messages to and from the body's internal organs, monitoring such processes as breathing, heart rate, and digestion (Splits into sympathetic and parasympathetic)

Neurons

one of two types of cells in the nervous system; Nerve cells that are specialized for processing info

Sympathetic nervous system

Arouses body to mobilize it for action; involved in the experience of stress

Parasympathetic nervous system

Calms body

Glial cells

Provide support, nutritional benefits, and other functions and keep neurons running smoothly in nervous system

Cell Body

contains the nucleus which directs the manufacture of substances that the neuron needs for growth and maintenance

Dendrites

teelike fibers projecting from a neuron, receive and orient information to the cell body

Axon

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

Myelin sheath

a layer of fat cells, encases and insulates axons; speed up transition of nerve impulses; MS is caused by a hardening of this

Ion Channels

gates that open and close to let ions pass into/out of cell

All-or-none principle

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

Synapses

junctions between two neurons- axon meets dendrites/cell body

Neurotransmitters

chemicals that are stored in very tiny sacs within the terminal buttons and involved in transmitting info across a synaptic gap to the next neuron

Acetylcholine

Stimulates the firing of neurons and is involved in the action of muscles, learning, and memory; found throughout the central and peripheral nervous systems; deficiency of this causes Alzheimer's disease

GABA (gamma aminobutyric acid)

Keeps neurons from firing, controls preciseness of signal; found throughout the central nervous system; low levels linked with anxiety

Norepinephrine

Inhibits firing of neurons in CNS, excites heart, intestines, and urogenital tract; helps to control alertness; too little is associated with depression and too much triggers agitated, manic states

Dopamine

Helps control voluntary movement, affects sleep, mood, attention and learning; cocaine and amphetamines activate dopamine receptors; low levels=parkinson's disease; high levels=schizophrenia

Serotonin

Regulation of sleep, mood, attention, and learning; teams with acetylcholine and norepinephrine; lower levels=depression; Prozac increases brain levels of this

Endorphins

Natural opiates that stimulate firing of neurons; shield the body from pain and elevate feelings of pleasure; opium and morphine

Electroencephalograph (EEG)

records the brain's electrical activity; uses electrodes placed on the scalp to detect brain wave activity; can access brain damage, epilepsy, and other problems

Computerized Tomography (CT)

3-D images of head, location and extent of brain damage

Magnetic Resonance Imaging (MRI)

creates a magnetic field around a person's body and using radio waves to construct images of the person's tissues and biochemical activities; Clear images of brain's interior; no radiation problems; can't portray brain functions

Medulla

controls breathing, heart rate and reflexes

Cerebellum

just above the medulla; Motor coordination (leg and arm movements)

Pons

a bridge in the hindbrain that connects the cerebellum and the brain stem; involved in sleep and arousal

Reticular formation

system in the midbrain comprising a diffuse collection of neurons involved in stereptyped patterns of behavior such as walking, sleeping, and turning to attend to a sudden noise

Brain stem

includes most of the hindbrain (not the cerebellum) and the midbrain; encases the rectangular formation; Alertness and basic survival

Limbic system

under the cerebral cortex; important in both memory and emotion; includes the amygdala and the hippocampus

Amygdala

one on each side of the brain; Activities needed for survival, urge to eat, mate, or fight; involved in fear and emotional awareness

Hippocampus

role in the storage of memories

Thalamus

forebrain structure; Relay function throughout brain

Basal ganglia

works with the cerebellum and cerebral cortex; Controls and coordinates voluntary movements; enable people to engage in habitual behaviors

Hypothalamus

Monitors three pleasurable activities: eating, drinking, sex as well as emotion, stress, and reward; helps direct the endocrine system

Cerebral cortex

part of the forebrain; outer layer of the brain; Highest mental functions; thinking and planning

Occipital lobe

Back of head- involved in vision; wound to this can cause blindness or wipe out visual field

Temporal lobe

Involved in hearing, language processing, and memory; connections to the limbic system; people with damage to this can't file experiences into long term memory

Frontal lobe

Involved in control of voluntary muscles, intelligence, and personality

Parietal lobe

Involved in spatial location, attention, and motor control

Somatosensory cortex

region in the cerebral cortex that processes bodily sensations

Motor cortex

Voluntary movement

neural networks

networks of nerve cells that integrate sensory input and motor output

stress

the response 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"

beginning of stress response; a function of the sympathetic nervous system; mobilizes the body's physiological resources to prepare the organism to deal with threats to survival

corticosteroids

powerful stress hormones released when we undergo stress; they allow us to focus our attention on what needs to be done now

mirror neurons

special type of neuron that plays a role in imitation and are activated when we perform an action but also when we watch someone else perform that same task

oxytocin

hormone and neurotransmitter; plays an important role in the experience of love and social bonding; released in mothers who have just given birth; thought to play a role in the human tendency to feel pleasure during orgasm and form emotional bonds with romantic partners

functional magnetic resonance imaging (fMRI)

allows scientists to see what is happening in the brain while it is working; exploits changes in blood oxygen that occur in association with brain activity

hindbrain

located at the skull's rear, lowest portion of the brain, consisting of the medulla, cerebellum, and pons

midbrain

located between the hindbrain and forebrain, an area in which many nerve-fiber systems ascend and descend to connect the higher and lower portions of the brain; relays info between the brain and the eyes and ears

forebrain

the brain's largest division and most forward part; includes the limbic system, thalamus, basal ganglia, hypothalamus, and cerebral cortex

neocortex

outermost part of the cerebral cortex; makes up 80% of the human brain's cortex

Broca's area

left hemisphere; production of speech

wernicke's area

left hemisphere; role in language; if damaged, causes problems in comprehending language

corpus callosum

large bundle of axons that connects the brain's two hemispheres; responsible for relaying info b/w the two sides

left hemisphere

speech and grammar localized here; much language processing and production; involved in singing the words of a song

right hemisphere

processing nonverbal info such as spatial perception, visual recognition and emotion

pituitary gland

pea-sized gland just beneath the hypothalamus that controls growth and regulates other glands

adrenal glands

located at the top of each kidney; responsible for regulating moods, energy level, and the ability to cope with stress

pancreas

a dual process gland under the stomach that performs both digestive and endocrine functions

3 ways to repair the damaged brain

collateral sprouting, substitution of function, neurogenesis