AP psych unit 2: biological bases of behavior

neuron

a nerve cell; the basic building block of the nervous system

cell body

the part of a neuron that contains the nucleus; the cell's life-support center

dendrites

a neuron's often bushy, branching extensions that receive messages and conduct impulses toward the cell body

axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands

myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

glial cells

cells in the nervous system that support, nourish, and protect neurons; they also play a role in learning, thinking, and memory

action potential

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

threshold

the level of stimulation required to trigger a neural impulse

refractory period

in neural processing, a brief resting pause that occurs after a neuron has fired; subsequent action potentials cannot occur until the axon returns to its resting state

all-or-none response

a neuron's reaction of either firing (with a full-strength response) or not firing

synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse

reuptake

a neurotransmitter's reabsorption by the sending neuron

endorphins

"morphine within" - natural, opiate-like neurotransmitters linked to pain control and to pleasure. Many addictive drugs use endorphin channels

agonist

a molecule that increases a neurotransmitter's action

antagonist

a molecule that inhabits or blocks a neurotransmitter's action

nervous system

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems

central nervous system (CNS)

brain and spinal cord

peripheral nervous system (PNS)

the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

nerves

bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs

sensory neurons

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

motor neurons

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

interneurons

neurons within the brain and spinal cord; communicate internally and process information between the sensory inputs and motor outputs

somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy

reflex

a simple, automatic response to a sensory stimulus, such as the knee-jerk response

endocrine system

chemical communication system; a set of glands that secrete hormones into the bloodstream

hormones

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues

lesion

tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue

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.

MEG (magnetoencephalography)

a brain imaging technique that measures magnetic fields from the brain's natural electrical activity

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. Also called CAT scan

PET (positron emission tomography) scan

Display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task

MRI (magnetic resonance imaging)

a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy

fMRI (functional MRI)

A technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function

brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions

medulla

the base of the brainstem; controls heartbeat and breathing

thalamus

the brain's sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

reticular formation

a nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal

cerebellum

the "little brain" at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory

limbic system

neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives

amygdala

two lima bean-sized neural clusters in the limbic system; linked to emotion

hypothalamus

A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward

hippocampus

a neural center located in the limbic system; helps process explicit memories for storage

cerebral cortex

the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center

frontal lobes

the portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments

parietal lobes

portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position

occipital lobes

the portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields

temporal lobes

the portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear

motor cortex

an area at the rear of the frontal lobes that controls voluntary movements

somatosensory cortex

an area at the front of the parietal lobes that registers and processes body touch and movement sensations

association areas

areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking

plasticity

the brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience

neurogenesis

the development of new neurons

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

split brain

a condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them

consciousness

our subjective awareness of ourselves and our environment

cognitive neuroscience

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

behavior genetics

the study of the relative power and limits of genetic and environmental influences on behavior

heredity

the genetic transfer of characteristics from parents to offspring

environment

every nongenetic influence, from prenatal nutrition to the people and things around us

genes

the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins

genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

identical twins

develop from a single fertilized egg that splits in two, creating two genetically identical organisms

fraternal twins

develop from separate fertilized eggs. They are genetically no closer than ordinary brothers and sisters, but they share a prenatal environment

interaction

the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity)

epigenetics

"above" or "in addition to" genetics; the study of environmental influences on gene expression that occur without a DNA change

evolutionary psychology

the study of the evolution of behavior and the mind, using principles of natural selection

natural selection

the principle that inherited traits that better enable an organism to survive and reproduce in a particular environment will most likely be passed on to succeeding generations

mutation

a random error in gene replication that leads to a change

ESB (electrical stimulation of the brain)

involves introduction of a weak electrical current into specific locations of the brain. Intended to mimic the natural flow of neural impulses through neural pathways. Used in research and threapeutic settings

TMS (transcranial magnetic simulation)

imaging technique that allows scientist to temporarily enhance or depress activity in specific areas of the brain. Performed on awake patients. Can disrupt electrochemical brain patterns of depression

biological psychology

scientific study of the links between biological and psychological processes

levels of analysis

the differing complementary views (biological, psychological, and social cultural) for analyzing any given phenomenon

right hemisphere

controls the left side of your body. Sees overall patterns, used in spatial and creative tasks

left hemisphere

controls the right side of your body. Sees details, used in logic and sequential tasks

hindbrain

includes the medulla, pons, and cerebellum. Directs essential survival functions like breathing, sleeping, and wakefulness as well as balance and coordination

midbrain

on top of the brain stem, connects hindbrain to forebrain. Controls some motor movement and transmits auditory and visual information

forebrain

includes the cerebral cortex, thalamus, and hypothalamus. Manages complex cognitive activities, sensory and associative functions, and voluntary motor activities