Biological Bases of Behavior

neuron

a cell that conducts electrochemical signals; the basic unit of the nervous system; also called a nerve cell

neuron diagram

do you know the parts? [ans: neuron diagram]

sensory neuron

neurons that carry information from the sensory receptors to the brain and spinal cord

motor neuron

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs an the motor outputs

dendrite

receive messages from other cells

soma

cell body (of a neuron)

axon hillock

specialized part of the soma that connects to the axon

axon

passes messages away from the cell body to other neurons, muscles, or glands

axon terminal

form junctions with other cells

myelin sheath

covers the axon of some neurons and helps speed neural impulses

action potential

a neural impulse; a brief electrical charge that travels down an axon

threshold

the minimum level of stimulus needed to trigger an action potential

summation

the sum total of charges on a neuron

refractory period

the time it takes for positive ions to be pumped back out (returning to a polarized state)

neurotransmitter

a chemical messenger that crosses the synaptic gaps between neurons

undersupply of GABA (gamma-aminobutyric acid)

linked to seizures, tremors, and insomnia

acetylcholine

enables muscle action, learning, and memory; associated with Alzheimer's

dopamine

influences movement, learning, attention, and emotion

glutamate

a major excitatory neurotransmitter; involved in memory

norepinephrine

helps control alertness and arousal

serotonin

affects mood, hunger, sleep, and arousal

reuptake

a neurotransmitter's re-absorption by sending the neuron

endorphins

chemical substances in the nervous system that are involved in pain reduction, pleasure, and memory; can act as a neurotransmitter or can prolong or limit the effect of a neurotransmitter

agonists

mimics a neurotransmitter

antagonists

inhibits a neurotransmitter, by blocking the receptor

nervous system

the body's speedy, electrochemical communication network (nerve cells of the peripheral __ __ and the central __ __)

central nervous system

the brain and the spinal cord

peripheral nervous system

transmits information to and from the central nervous system

nerves

a bundle of nerve fibers (axons and dendrites) in the peripheral nervous system

somatic nervous system

carries sensory information and controls movement of the skeletal muscles

autonomic nervous system

automatically regulates glands, internal organs and blood vessels, pupil dilation, digestion, and blood pressure

sympathetic nervous system

prepares the body to react and expend energy in times of stress

parasympathetic nervous system

maintains body functions under ordinary conditions; saves energy

reflex

an involuntary and nearly instantaneous movement in response to a stimulus

endocrine system

the body's slow chemical communication system; a set of glands which secrete hormones into the bloodstream

hormones

chemical substances secreted by organs called glands, that affect the functioning of other organs (chemical messengers)

adrenal glands

works with the sympathetic nervous system; helps trigger the "fight-or-flight" response by releasing epinephrine and norepinephrine

pituitary gland

secretes many different hormones, some of which affect other glands; regulates the rest of the body

lesion

tissue destruction; both naturally occurring and experimentally-caused

EEG (electroencephalogram)

an amplified recording of the waves of electrical activity that sweep across the brain's surface. These waves are measured by electrodes placed on the scalp

CT (computed tomography) scan

a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body; shows brain structure

PET (positron emission tomography)

a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task; shows brain activity

MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue; shows the brain's structure/anatomy (more detailed than CT)

fMRI (functional MRI)

a technique revealing blood flow and, therefore brain activity by comparing successive MRI scans (essentially a video)

medulla

controls heartbeat and breathing

pons

involved in sleeping, walking, and dreaming

reticular formation

screens incoming information, arousal of higher centers and conscious

thalamus

relay center for incoming and outgoing sensory information (except olfactory--smell); relays messages between lower brain centers and cerebral cortex

cerebellum

responsible for balance, muscular, coordination, memory, and reflexes

limbic system

a group of brain areas involved in emotional reactions and motivated behavior

amygdala

involved in arousal and regulation of emotions and the initial response (approach or withdraw), meditates anxiety and depression

hypothalamus

involved in drives connected to survival: hinge, thirst, emotion, sex, and reproduction; regulates body temperature

hippocampus

involved in the storage of new information and memories

cerebral cortex

ultimate control and information-processing center

cerebrum

the largest brain structure, consisting of the upper part of the brain; divided into two hemispheres, it is in charge of most sensory, motor, and cognitive processes

glial cells

hold neurons in place, providing them with nutrients, insulation, and protection

frontal lobe

responsible for abstract thought (reasoning, planning, and problem-solving) and emotional control; contains the motor cortex, broca's area (which controls the muscles responsible for speech)

parietal lobes

contains the somatosensory cortex, which receives information about pressure, pain, touch, and temperature

occipital lobes

deals with vision; contains the visual cortex, which interprets messages from our eyes into images we can understand (the thalamus sends input to there)

temporal lobes

process sound sensed by our ears, which is interpreted in the auditory cortex; contains wernike's area which is responsible for interpreting written and spoken speech

motor cortex

issues orders to the 600 muscles of the body that produce voluntary motion

sensory cortex

the visual cortex, the auditory cortex, the olfactory cortex, the gustatory, and the somatosensory cortex

association areas

any area not associated with receiving sensory information or coordinating muscle movements

aphasia

a disturbance of the comprehension and formulation of language caused by dysfunction in specific brain regions

Broca's aphasia

unable to make movements to talk; broken speech

Wernicke's aphasia

unable to understand language; when speaking, the syntax and grammar are jumbled

corpus callosum

axon fibers connecting two cerebral hemispheres

split brain

in cases of extreme seizures induced by birth or unique circumstances, the corpus callosum is severed

hemispheric specialization

refers to the control of distinct neurological functions by the right and left hemispheres of the brain. In most people, the left hemisphere controls language use, analytical thought, and abstract thinking, while the right manages visual and spatial relations, musical abilities, and other functions

localization of function

different parts of the brain perform different (but overlapping) tasks

hemispherectomy

a very rare surgical procedure where one cerebral hemisphere (half of the brain) is removed or disabled

plasticity

the brains ability to change and adapt in response to experience--for example, by reorganizing or growing new neural connections

neurogenesis

immature cells can give birth to new neurons in a process called ___

cognitive neuroscience

the interdisciplinary study of brain activity linked with cognition (including perception, thinking, memory, and language)

dual processing

the principle that information is often simultaneously processed on separate conscious and unconscious tracks

Paul Broca

a French physician, surgeon, anatomist, and anthropologist who studied/researched Broca's area

Michael Gazzaniga

researched split brains, argued that left hemisphere was necessary for the right hemisphere

Roger Sperry

defended the importance of the right hemisphere, especially because of its spatial and potential language ability

Karl Wernicke

a German physician, anatomist, psychiatrist and neuropathologist who found aphasia went beyond Broca's area, and labeled another region (later known as Wernicke's area) that caused aphasia

Phineas Gage

a railroad worker who's brain was pierced, destroying most of the frontal cortex, yet he survived with a changed personality

Kim Peek's brain

no corpus callosum and macrocephaly (abnormally large head)

Einstein's brain

strong corpus callosum, enlarged cortices, many gilal cells, enlarged parietal lobe

excess dopamine

linked to schizophrenia

undersupply of dopamine

causes the brain to produce tremors; is responsible for the decreased mobility of Parkinson's disease

undersupply of Serotonin

linked to depression

undersupply of norepinephrine

depresses mood

excess glutamate

overstimulates the brain, producing migraines or seizures

GABA (gamma-aminobutyric acid)

an inhibitory neurotransmitter

visual cortex

in the first step of language production, this area receives written words as visual stimulation

Angular Gyrus

in the second step of language production, this area transforms visual representations into auditory code

Wernicke's Area

in the third step of language production, this area interprets auditory code

Broca's area

in the fourth step of language production, this area controls speech muscles via the motor cortex