Biology and Behavior

Biological Psychology

The scientific study of the links between biological and psychological proceses.

Neuron

A nerve cell; the basic building block of the nervous system.

Dendrites

Branching extensions that receive chemical messages from other neurons.

Axon

After threshold level is reached, depolariztion begins down this portion of the neuron.

Myelin Sheath

A fatty layer of glial cells that encases axon. Allows for speedier communication.

Action Potential

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

Refractory Period

A period of inactivity after a neuron has fired. The neuron can't fire until it pushes the positive ions back out and "resets" itself.

Threshold

The level of stimulation required to trigger a neural impulse-excitatory signals outweigh inhibitory.

All-Or-None Response

Neuron either fires or doesn't fire.

Synapse

Place where chemical communication happens-sending neuron releases neurotransmitters & some connect to dendrite of receiving neuron.

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons.

Acetylcholine (ACh)

Enables muscle action, learning, memory. If transmission is blocked, muscles won't contract and paralysis ensues. Also plays a role in Alzheimer's disease.

Dopamine

Influences movement, rewarded learning, attention, emotion. Oversupply linked to schizophrenia. Undersupply is linked to Parkinson's.

Serotonin

Affects mood, hunger, sleep, arousal. Undersupply linked to depression. Many antidepressant drugs raise its level.

Norepinephrine

Helps control alertness, arousal, fight or flight. Undersupply can depress mood (like serotonin)..

GABA (gamma-aminobutyric acid)

Inhibitory neurotransmitter-nature's Valium.. Undersupply linked to seizures, tremors, insomnia.

Glutamate

Excitatory neurotransmitter; involved in memory. Oversupply can overstimulate brain, producing migraines or seizures.

Reuptake

Extra neurotransmitters return to sending neuron-sucked backed up into synaptic vesicles.

Endorphins

Natural morphine linked to pain control and to pleasure-

"runner's high"

Agonist

Drug that mimics neurotransmitter. Fits receptor well and neural firing ensues. Ex: Opiate drugs produce a "high". Black widow spider poison produces muscle spasms.

Antagonist

Drug that inhibits/blocks neural transmission. Fits receptor site poorly. Ex: Botox blocks ACh.

Central Nervous System (CNS)

Brain and spinal chord.

Peripheral Nervous System (PNS)

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

Sensory (afferent) Neurons

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

Motor (efferent) Neurons

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

Interneurons

Neurons within brain and spinal cord.

Somatic Nervous System

Division of the peripheral nervous system-controls the body's skeletal muscles. It can be voluntarily manipulated.

Autonomic Nervous System (ANS)

"Automatic" part of peripheral nervous system that controls the glands and the muscles of the internal organs.

Sympathetic Nervous System

Division of autonomic nervous system. Arouses body, prepares one to run away or to fight

Parasympathetic Nervous System

Division of autonomic nervous system. Calms body, conserving energy. Decreases heartbeat and lowers your blood sugar.

Reflex

Simple, automatic response to a sensory stimulus, processed by spinal cord.

Endocrine System

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

Hormones

Chemical messengers that are manufactured by the endocrine glands travel through the bloodstream.

Adrenal Gland

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

Pituitary Gland

The endocrine system's most influential gland. Under the influence of the hypothalamus, it regulates growth and controls other endocrine glands.

Lesion

Brain tissue destruction- naturally or experimentally caused.

EEG

Amplified recording of brain's electrical waves. Helpful in diagnosing seizures.

CT Scan

X-ray photographs of brain illustrating structure. Can show brain tumors.

PET Scan

Visual display of brain function shown by injection of radioactive glucose..

MRI

Technique that uses magnetic fields/radio waves to produce detailed computer-generated images of brain tissue structure. Useful for showing enlarged ventricles in schizophrenia.

fMRI

Research technique used to highlight both brain function and structure. Used in mirror neuron video to illustrate areas of brain that are active when both seeing and mimicking a face.

Brainstem

The oldest part of brain-composed of medulla, pons, and RAS.

Medulla

The base of the brainstem. Controls heartbeat and breathing.

Pons

Part of the brainstem involved in REM sleep.

Thalamus

The brain's sensory control center, located at the top of the brainstem. Receives information for all the senses except smell.

Reticular Formation

Neural network located in both hindbrain and midbrain. Plays an important role in arousal.

Cerebellum

"Little brain" at the rear of the brainstem; functions include coordinating movement and balance, and processing implicit memory.

Limbic System

Neural system located below the cerebral hemispheres; associated with motivated survival functions. Contains hippocampus, amygdala, hypothalamus.

Hippocampus

Processes explicit memories.

Amygdala

Two bean-sized nerve clusters in the limbic system linked to emotion such as anger and fear.

Hypothalamus

A neural structure lying below the thalamus; it directs several maintenance activities such as eating, drinking, sexual behavior and body temperature. It help govern the endocrine system via the pituitary gland, and is liked to emotion and reward.

Cerebral Cortex

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

Glial Cells

Cells that help neurons by providing nutrients, creating myelin, and mopping up ions and neurotransmitters.

Frontal Lobes

Portion of the cerebral cortex lying in the front, behind the forehead. It is involved with speaking and muscle movements and in making plans and judgements. It aso impacts personality.

Parietal Lobes

Portion of the cerebral cortex which is at the top to the back of the head. Receives sensory input for touch and body position. Handles math and spatial reasoning.

Occipital Lobes

Portion of the cerebral cortex located at the back and bottom of the head. It includes areas that receive information from the visual fields. It processes vision.

Temporal Lobes

Portion of the cerebral cortex lying roughly above the ears and near the temples, on the side. 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 movement and motions by sending impulses from the brain to the body.

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

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

Neurogenesis

The formation 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 connecting them.

Left Brain

Handles rational, logical thought, and language.

Right Brain

Handles images, emotions, intuition, and drawing inferences.

Cognitive Neuroscience

The interdisciplinary study of the brain activity linked with cognition; including perception, thinking, memory, and language.

Dual Processing

Information is often simultaneously processed on separate conscious and unconscious tracks. Ex: Blindsight

Behavior Genetics

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

Chromosomes

Threadlike structures made of DNA molecules that contain the genes.

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

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 (monozygotic)

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms. Similar temperaments, personality, interests, intelligence.

Fraternal Twins (dizygotic)

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

Heritability

Proportion of variation among individuals that we can attribute to genes. If people grow up in similar environments, heritability is high. This is because any differences are likely due to genes.

Molecular Genetics

Tries to single out how specific genes influence the body or behavior.

Epigenetics

Study of environmental influences on gene expression that occur without DNA change.

Mutation

A random error in gene replication that leads to a change.

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

selective attention

the focusing of conscious awareness on a particular stimulus.

inattentional blindness

failing to see visible objects when our attention is directed elsewhere.

change blindness

failing to notice changes in the environment.

psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time.

signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

subliminal

information transmitted beneath our absolute threshold for awareness, i.e., picture of a skinny woman is imperceptibly flashed during a weight loss video.

priming

the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.

difference threshold

the minimum difference between two stimuli required for detection 50 percent of the time. Also called the just noticeable difference (jnd).

Weber's law

the principle that, to be perceived as different, two stimuli must differ by a constant percentage (rather than a constant amount).

sensory adaptation

diminished sensitivity as a consequence of constant stimulation.

transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

wavelength

the distance from the peak of one light or sound wave to the peak of the next. Electromagnetic versions of this vary from the short blips of cosmic rays to the long pulses of radio transmission.

hue

the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth.

intensity

the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude.

pupil

the adjustable opening in the center of the eye through which light enters.