Unit 1 - Biological Bases of Behavior

Heredity

The genetic transfer of characteristics from parents to offspring.

Nature

Refers to the influence of genetics and biology on behavior, personality, intelligence, and mental processes

Nurture

Refers to the influence of the environment — including family, culture, education, and experiences — on behavior and mental processes

Genetic Predisposition

A genetic characteristic that increases the likelihood of developing a particular trait or disorder, but does not guarantee it

evolutionary perspective

A psychological approach that explains behavior and mental processes as products of natural selection. Traits and behaviors that helped ancestors survive and reproduce are more likely to be passed on.

Natural Selection

the principle that the inherited traits enabling an organism to survive and reproduce in a particular environment will (in competition with other trait variations) most likely be passed on to succeeding generations

Eugenics

the idea of selectively breeding humans to promote certain "ideal" characteristics in the human population

Twin Studies

Research method that compares similarities between identical and fraternal twins to estimate the relative influence of nature (genetics) and nurture (environment).

Family Studies

a study that searches for traits and diseases that tend to be shared by family members

Adoption Studies

Research method that compares adopted children to their biological and adoptive parents. Used to separate the effects of genetics (biological parents) and environment (adoptive parents).

Central Nervous System

brain and spinal cord - the nervous system's decision maker

peripheral nervous system

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

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).

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy.

parasympathetic nervous system

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

somatic nervous system

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

neuron

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

glial cell

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

reflex arc

a simple spinal reflex pathway; when a sensory organ directs the message to the spinal cord instead of the brain; an automatic, rapid response to a stimulus

sensory neuron

neurons that carry incoming information from the body's tissues and 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.

interneuron

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

neural transmission

the process by which neurons communicate information to each other, involving the transmission of electrical and chemical signals across synapses

action potential

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

all-or-nothing principle

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

depolarization

when a neuron's charge becomes less negative, leading to firing.

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.

resting potential

the state of a neuron when it's ready to fire but hasn't yet.

Reuptake

a neurotransmitter's reabsorption by the sending neuron.

threshold

the level of stimulation required to trigger a neural impulse.

multiple sclerosis

the myelin sheath is damaged, slowing down or blocking signals

myasthenia gravis

An autoimmune disorder where acetylcholine receptors are attacked, leading to muscle weakness.

excitatory neurotransmitters

increase the likelihood of a neuron firing an action potential

inhibitory neurotransmitters

decrease the likelihood of a neuron firing an action potential

dopamine

influences movement, learning, attention and emotion; involved in reward and motivation; oversupply linked to schizophrenia, undersupply linked to tremors and decreased mobility in Parkinson's disease.

serotonin

affects mood, sleep, arousal and appetite; undersupply linked to depression.

norepinephrine

helps control alertness and arousal; undersupply can depress mood

glutamate

most common excitatory neurotransmitter, linked to learning and memory; oversupply can overstimulate the brain, producing migraines or seizures

GABA

a major inhibitory neurotransmitter, calms the nervous system; undersupply linked to seizures, tremors, and insomnia

endorphin

influence the perception of pain or pleasure; natural painkillers.

substance P

involved in transmitting pain perception and immune response; undersupply can lead to chronic pain

acetylcholine

Enables muscle action, learning, and memory. With Alzheimer's disease, ACh-producing neurons deteriorate.

hormone

chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect behavior and mood.

adrenaline

triggers "fight-or-flight" response: increases heart rate, blood pressure, and energy availability.

leptin

Suppresses hunger; tells hypothalamus that the body has enough stored energy.

Ghrelin

Stimulates hunger; sends signals to hypothalamus to increase appetite.

melatonin

Regulates sleep-wake cycles.

oxytocin

Influences bonding and social behaviors.

psychoactive drugs

a chemical substance that alters the brain, causing changes in perceptions and moods.

agonist

a molecule that increases a neurotransmitter's action; drugs that mimic neurotransmitters or enhance their action.

antagonist

a molecule that inhibits or blocks a neurotransmitter's action.

Reuptake Inhibitors

Drugs that prevent the reabsorption of neurotransmitters, increasing their activity.

stimulants

drugs that excite neural activity and speed up body functions.

caffeine

a stimulant drug that blocks the action of adenosine, a neurotransmitter that promotes sleep and relaxation; promotes wakefulness, mental alertness, and faster thought processes by stimulating release of dopamine

cocaine

a powerful stimulant drug that increases levels of dopamine; make users feel excited, energetic, talkative and even euphoric

depressants

drugs that reduce neural activity and slow body functions.

alcohol

lessens inhibitions by depressing brain centers responsible for judgment and self-control - agonist of GABA

hallucinogens

psychedelic ("mind-manifesting") drugs that distort perceptions and evoke sensory images in the absence of sensory input.

marijuana

a psychoactive drug that contains compounds known as cannabinoids, such as THC, which can produce sense of well-being, mild euphoria, and dreamy state of relaxation

opioids

opium and its derivatives; they depress neural activity, temporarily lessening pain and anxiety.

heroin

extremely addictive opium that typically act as pain relievers - mimic of endorphin

tolerance

the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect.

addiction

A compulsive craving for a substance despite harmful consequences.

withdrawal

the discomfort and distress that follow discontinuing an addictive drug or behavior.

Brain Stem

the 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 hindbrain structure that is the brainstem's base; controls heartbeat and breathing.

reticular activating system (RAS)

a network of neurons in the brainstem that regulates arousal and consciousness, filtering sensory information to focus attention on relevant stimuli while suppressing less important input

Reward center

A region of the brain, especially in the hypothalamus, associated with the release of dopamine and feelings of pleasure when certain behaviors are performed.

cerebellum

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

cerebral cortex

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

limbic system

neural system located mostly in the forebrain — below the cerebral hemispheres — that includes the amygdala, hypothalamus, hippocampus, thalamus, and pituitary gland; associated with emotions and drives.

thalamus

the forebrain'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.

hypothalamus

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

pituitary gland

An endocrine gland in the brain, under the influence of the hypothalamus, that regulates growth and controls other endocrine glands; often called the "master gland."

hippocampus

a neural center located in the limbic system; helps process explicit (conscious) memories — of facts and events — for storage.

amygdala

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

corpus callosum

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

occipital lobe

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

temporal lobe

the portion of the cerebral cortex lying roughly above the ears; it includes the auditory areas, each of which receives information primarily from the opposite ear. They also enable language processing.

parietal lobe

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

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.

somatosensory cortex

a cerebral cortex area at the front of the parietal lobes that registers and processes body touch and movement sensations.

frontal lobe

the portion of the cerebral cortex lying just behind the forehead. They enable linguistic processing, muscle movements, higher-order thinking, and executive functioning (such as making plans and judgments).

linguistic processing

The brain's ability to comprehend, interpret, and produce language; involves areas such as Broca's area (speech production) and Wernicke's area (language comprehension).

high-order thinking

Complex forms of thought beyond basic memorization or recall, including reasoning, problem-solving, critical thinking, and abstract thought.

executive functioning

Cognitive processes managed primarily by the frontal lobes that enable planning, decision-making, self-control, working memory, and flexible thinking.

prefrontal cortex

forward part of the frontal lobe. enables judgment, planning, social interactions, and processing of new memories.

motor cortex

a cerebral cortex area at the rear of the frontal lobes that controls voluntary movements.

split brain research

confirmed that in most people, the left hemisphere is the more verbal. The right hemisphere excels in visual perception and making inferences, and helps us modulate our speech and orchestrate our self-awareness.

hemispheric specialization (lateralization)

The tendency for some neural functions or processes to be more dominant in one hemisphere of the brain than the other

Broca's area

An area of the left frontal lobe, usually in the left hemisphere, that directs muscle movements involved in speech and is linked to language production.

Wernicke's area

A region of the left temporal lobe involved in language comprehension and expression.

Aphasia (Broca's and Wernicke's)

An impairment of language, usually caused by damage to the left hemisphere:

Broca's aphasia - difficulty speaking but comprehension remains relatively intact.

Wernicke's aphasia - fluent but nonsensical speech with impaired understanding.

Contralateral hemispheric organization

The principle that each hemisphere of the brain controls the opposite side of the body

(neuro)plasticity

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

EEG

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

fMRI

a technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as structure.

lesioning

tissue destruction. Brain lesions may occur naturally (from disease or trauma), during surgery, or experimentally (using electrodes to destroy brain cells).