Chapter 3: Biopsychology Key Terms

action potential - electrical signal that moves down the neuron’s axon

adrenal gland - sits atop our kidneys and secretes hormones involved in the stress response

agonist drug - that mimics or strengthens the effects of a neurotransmitter

all-or-none - phenomenon that incoming signal from another neuron is either sufficient or insufficient to reach the threshold of excitation

allele - specific version of a gene

amygdala - structure in the limbic system involved in our experience of emotion and tying emotional meaning to our memories

antagonist - drug that blocks or impedes the normal activity of a given neurotransmitter

auditory cortex - strip of cortex in the temporal lobe that is responsible for processing auditory information

autonomic nervous system - controls our internal organs and glands

axon - major extension of the soma

biological perspective - view that psychological disorders like depression and schizophrenia are associated with imbalances in one or more neurotransmitter systems

Broca’s area - region in the left hemisphere that is essential for language production

central nervous system (CNS) - brain and spinal cord

cerebellum - hindbrain structure that controls our balance, coordination, movement, and motor skills, and it is thought to be important in processing some types of memory

cerebral cortex - surface of the brain that is associated with our highest mental capabilities

chromosome - long strand of genetic information

computerized tomography (CT) scan - imaging technique in which a computer coordinates and integrates multiple x-rays of a given area

corpus callosum - thick band of neural fibers connecting the brain’s two hemispheres

dendrite - branch-like extension of the soma that receives incoming signals from other neurons

deoxyribonucleic acid (DNA) - helix-shaped molecule made of nucleotide base pairs

diabetes - disease related to insufficient insulin production

dominant allele - allele whose phenotype will be expressed in an individual that possesses that allele

electroencephalography (EEG) - recording the electrical activity of the brain via electrodes on the scalp

endocrine system - series of glands that produce chemical substances known as hormones

epigenetics - study of gene-environment interactions, such as how the same genotype leads to different phenotypes

fight or flight response - activation of the sympathetic division of the autonomic nervous system, allowing access to energy reserves and heightened sensory capacity so that we might fight off a given threat or run away to safety

forebrain - largest part of the brain, containing the cerebral cortex, the thalamus, and the limbic system, among other structures

fraternal twins - twins who develop from two different eggs fertilized by different sperm, so their genetic material varies the same as in non-twin siblings

frontal lobe - part of the cerebral cortex involved in reasoning, motor control, emotion, and language; contains motor cortex

functional magnetic resonance imaging (fMRI) - MRI that shows changes in metabolic activity over time

gene - sequence of DNA that controls or partially controls physical characteristics

genetic environmental correlation - view of gene-environment interaction that asserts our genes affect our environment, and our environment influences the expression of our genes genotype genetic makeup of an individual

glial cell - nervous system cell that provides physical and metabolic support to neurons, including neuronal insulation and communication, and nutrient and waste transport

gonad - secretes sexual hormones, which are important for successful reproduction, and mediate both sexual motivation and behavior

gyrus (plural: gyri) - bump or ridge on the cerebral cortex

hemisphere - left or right half of the brain

heterozygous - consisting of two different alleles

hindbrain - division of the brain containing the medulla, pons, and cerebellum

hippocampus - structure in the temporal lobe associated with learning and memory

homeostasis - state of equilibrium—biological conditions, such as body temperature, are maintained at optimal levels

homozygous - consisting of two identical alleles

hormone - chemical messenger released by endocrine glands

hypothalamus - forebrain structure that regulates sexual motivation and behavior and a number of homeostatic processes; serves as an interface between the nervous system and the endocrine system

identical twins - twins that develop from the same sperm and egg

lateralization - concept that each hemisphere of the brain is associated with specialized functions

limbic system - collection of structures involved in processing emotion and memory

longitudinal fissure - deep groove in the brain’s cortex

magnetic resonance imaging (MRI) - magnetic fields used to produce a picture of the tissue being imaged

medulla - hindbrain structure that controls automated processes like breathing, blood pressure, and heart rate

membrane potential - difference in charge across the neuronal membrane

midbrain - division of the brain located between the forebrain and the hindbrain; contains the reticular formation

motor cortex - strip of cortex involved in planning and coordinating movement

mutation - sudden, permanent change in a gene

myelin sheath - fatty substance that insulates axons

neuron - cells in the nervous system that act as interconnected information processors, which are essential for all of the tasks of the nervous system

neuroplasticity - nervous system's ability to change

neurotransmitter - chemical messenger of the nervous system

Nodes of Ranvier - open spaces that are found in the myelin sheath that encases the axon

occipital lobe - part of the cerebral cortex associated with visual processing; contains the primary visual cortex

pancreas - secretes hormones that regulate blood sugar

parasympathetic nervous system - associated with routine, day-to-day operations of the body

parietal lobe - part of the cerebral cortex involved in processing various sensory and perceptual information; contains the primary somatosensory cortex

peripheral nervous system (PNS) - connects the brain and spinal cord to the muscles, organs and senses in the periphery of the body

phenotype - individual’s inheritable physical characteristics

pituitary gland - secretes a number of key hormones, which regulate fluid levels in the body, and a number of messenger hormones, which direct the activity of other glands in the endocrine system

polygenic - multiple genes affecting a given trait

pons - hindbrain structure that connects the brain and spinal cord; involved in regulating brain activity during sleep

positron - emission tomography (PET) scan involves injecting individuals with a mildly radioactive substance and monitoring changes in blood flow to different regions of the brain

prefrontal cortex - area in the frontal lobe responsible for higher-level cognitive functioning

psychotropic - medication drugs that treat psychiatric symptoms by restoring neurotransmitter balance

range of reaction - asserts our genes set the boundaries within which we can operate, and our environment interacts with the genes to determine where in that range we will fall

receptor - protein on the cell surface where neurotransmitters attach

recessive allele - allele whose phenotype will be expressed only if an individual is homozygous for that allele

resting potential - the state of readiness of a neuron membrane’s potential between signals

reticular formation - midbrain structure important in regulating the sleep/wake cycle, arousal, alertness, and motor activity

reuptake - neurotransmitter is pumped back into the neuron that released it

semipermeable membrane - cell membrane that allows smaller molecules or molecules without an electrical charge to pass through it, while stopping larger or highly charged molecules

soma - cell body

somatic nervous system - relays sensory and motor information to and from the CNS

somatosensory cortex - essential for processing sensory information from across the body, such as touch, temperature, and pain

substantia nigra - midbrain structure where dopamine is produced; involved in control of movement

sulcus (plural: sulci) - depressions or grooves in the cerebral cortex

sympathetic nervous system - involved in stress-related activities and functions

synaptic cleft - small gap between two neurons where communication occurs

synaptic vesicle - storage site for neurotransmitters

temporal lobe - part of cerebral cortex associated with hearing, memory, emotion, and some aspects of language; contains primary auditory cortex

terminal button - axon terminal containing synaptic vesicles

thalamus - sensory relay for the brain

theory of evolution by natural selection - states that organisms that are better suited for their environments will survive and reproduce compared to those that are poorly suited for their environments

threshold of excitation - level of charge in the membrane that causes the neuron to become active

thyroid - secretes hormones that regulate growth, metabolism, and appetite

ventral tegmental area (VTA) - midbrain structure where dopamine is produced: associated with mood, reward, and addiction

Wernicke’s area - important for speech comprehension