Unit Two: Biological Bases of Behavior

central nervous system (CNS)

Division of the nervous system that consists of the brain and spinal cord

peripheral nervous system (PNS)

the sensory and motor neurons that connect the CNS to the rest of the body

somatic nervous system

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

neuron

a nerve cell; basic cell of the nervous system

sensory (afferent) neurons

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

motor (efferent) neurons

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

autonomic nervous system (ANS)

division of the peripheral nervous system involved in the control of (generally unconscious/automatic) bodily functioning through organs and glands; its sympathetic division arouses while the parasympathetic division calms

sympathetic nervous system

subdivision of the autonomic nervous system responsible for mobilizing the body in times of stress, and preparing for flight or fight

parasympathetic nervous system

subdivision of the autonomic nervous system responsible for calming the body

reflex

automatic behavior in response to a specific stimulus; does not involve communication with the brain

brainstem

the oldest part and central core of the brain; responsible for automatic survival functions and composed of medulla, pons, and reticular formation.

pons

structure of the brainstem that allows for communication between the cerebellum, cerebral cortex, & brain stem; has nuclei that are important for sleep and arousal

medulla

base of the brainstem; controls heartbeat & breathing

reticular formation

band of nerve fibers that run through the center of the brain stem; important in controlling arousal levels

cerebellum

structure of the hindbrain that coordinates voluntary muscular movements

corpus callosum

wide band of neural fibers that connects the two hemispheres of the brain

limbic system

a group of structures located beneath the cerebral cortex that are involved in regulating emotions and motivated behaviors

thalamus

subcortical structure that relays incoming sensory information to the cerebral cortex and other parts of the brain; a.k.a "sensory switchboard"

electroenchephalogram (EEG)

device that monitors and records waves of electric activity within the brain; measured by electrodes placed on the scalp

positron emission tomography (PET scan)

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

computed tomography (CT scan)

imaging technique that involves the production of a large number of X-rays interpreted by a computer

MRI (magnetic resonance imaging)

imaging technique that involves the use of radio waves and a strong magnetic field to produce a signal that can be interpreted by computer

dendrites

short, branchlike structures of a neuron that receive information from receptors and other neurons

fMRI

technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans; capable of showing BOTH structure and function of the brain

soma

cell body of a neuron

axon

part of a neuron that transmits information to other neurons and to muscles and glands

myelin sheath

fatty protein substance that covers some axons, increasing speed of transmission

neurotransmitters

chemical messengers that cross the synaptic gap between neurons

synapse

site where two or more neurons interact but do not touch

reuptake

method of clearing a neurotransmitter from the synaptic cleft, in which the neurotransmitter is reabsorbed into the terminal buttons

synaptic vesicles

small pockets or sacs located in terminal buttons that contain a neurotransmitter

agonist

a molecule (e.g., drug) that enhances the operation of a neurotransmitter

antagonist

a molecule (e.g., drug) that blocks or inhibits the operation of a neurotransmitter

endorphins

"morphine within"; natural, opiate-like neurotransmitters linked to pain control and to pleasure

resting potential

electrical charge (negative) of a neuron when it is not firing

action potential

brief electrial charge that travels down the axon; a process also called "depolarization"

threshold

the level of stimulation required to trigger a neural impulse

refractory period

period, after firing, during which the neuron is unable to fire because it is repolarizing

aphasia

loss of ability to speak or understand written or spoken language

endocrine system

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

hormones

chemicals produced by the glands of the endocrine system that are carried by the bloodstream to other body tissues

pituitary gland

gland located below the thalamus and hypothalamus; called the "master gland" of the endocrine system because it controls many other glands

biological psychology

branch of psychology concerned with the links between biology and behavior

acetylcholine (ACh)

a neurotransmitter that enables muscle action, learning and memory; an undersupply is linked with Alzheimer's disease

dopamine

a neurotransmitter that influences movement, learning and attention; overactivity of receptors linked to schizophrenia while an undersupply linked to Parkinson's disease

serotonin

a neurotransmitter that affects mood, hunger, sleep, and arousal. An undersupply of this neurotransmitter is linked with depression.

norepinephrine

a neurotransmitter that controls alertness and arousal; undersupply can depress mood

GABA

a major inhibitory neurotransmitter; undersupply linked to seizures, tremors, and insomnia

glutamate

a major excitatory neurotransmitter; oversupply can overstimulate brain, producing migraines or seizures

nerves

bundled axons that form neural "cables" connecting the CNS to the rest of the body

interneurons

central nervous system neurons that internally communicate and intervene between sensory inputs and motor outputs

lesion

brain destruction; can be naturally caused or created for experimentation

hippocampus

structure in the limbic system important in processing memories

hypothalamus

structure in the limbic system responsible for directing several maintenance activities (eating, drinking, body temp); helps govern endocrine system via the pituitary gland

Paul Broca

responsible for discovering the area on the left frontal lobe responsible for coordinating muscle movements involved in spoken language

Carl Wernicke

discovered a brain area responsible for interpreting meaning of language

depolarization

process of neural firing; when action potential is generated and the neuron briefly takes on a positive charge

all-or-none response

neuron will only fire (if threshold is reached) OR not fire (if stimulation is insufficient)

amygdala

the two almond-shaped nerve clusters in the limbic system believed to be responsible for fear and aggressive responses

cerebral cortex

wrinkled, gray covering of the brain that accounts for 80% of brain weight is responsible for complex processing of information, planning, learning, memory storage, etc.

Phineas Gage

famous case study in neuroscience; sustained catastrophic damage to his frontal lobes

motor cortex

located on the rear of the frontal lobes; responsible for directing voluntary movement on the opposite side of the body

somatosensory cortex

located on the front of the parietal lobes; registers and processes body touch and movement sensations

occipital lobes

portion of the cerebral cortex at the "back" of the head; contains the visual cortex

temporal lobes

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

Roger Sperry & Michael Gazzaniga

studied split brain patients

phrenology

early, misguided attempt at studying the functions of parts of the brain; held that bumps on the skull revealed the person's personality traits

Franz Gall

early comparative brain anatomist; developed phrenology

Broca's area

area (usually in the left frontal lobe) that directs the muscle movements involved in speech

Wernicke's area

brain area involved in language comprehension; usually in left temporal lobe

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

angular gyrus

transforms visual representations into an auditory code; damage to this leaves the person unable to speak and understand, but able to read

neuroplasticity

Brain's ability to reorganize and change its structure and function throughout the life span, in reponse to injury or new learning

Traumatic Brain Injury (TBI)

blow to head or a penetrating head injury that damages brain

hemispheric specialization

This is also called lateralization; refers to the fact that the left and right hemispheres of the brain have some specific functions that exist only in those hemispheres.

contralateral control

The left hemisphere controls the right side of the body and the right hemisphere controls the left side.

nervous system

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

adrenal glands

A pair of endocrine glands that sit just above the kidneys and secrete hormones that help arouse the body in times of stress.

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.

glial cells (glia)

Cells in the nervous system that support, nourish, and protect neurons.

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

neurogenesis

formation of new neurons

split brain

A condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them

consciousness

Awareness of ourselves and our environment

cognitive neuroscience

The interdisciplinary study of the 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; also known as "parallel processing"

multiple sclerosis

a progressive disease of the nervous system that involves a degeneration of the myelin that surrounds nerve fibers in the brain and spinal cor

adoption studies

Assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents.

behavior genetics

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

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection

chromosomes

Threadlike, gene-carrying structures found in a cell's nucleus (46 in body cells; 23 in sex cells). Each chromosome consists of one very long DNA molecule and associated proteins.

concordance rates

The percentage of cases where both twins share the same trait or disorder

Dmitry Belyaev

Russian geneticist who, through artificial selection, bred tame foxes

DNA (deoxyribonucleic acid)

a complex molecule containing the genetic information that makes up chromosomes

epigenetics

study of how the environment can alter gene expression or function (e.g. light, nutrition, temperature, presence of other species); example of interaction of nature & nurture

evolutionary psychology

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

fraternal twins

Twins who develop from separate eggs; dizygotic (DZ) twins. They are genetically no closer than brothers and sisters, but they share a fetal environment.

genes

biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein

genome

All the genetic information in an organism; all of an organism's chromosomes.

heritability

the proportion of variation among individuals that is related to genetic variation; estimates may vary depending on the range of populations and environments studied