Unit 1 Vocabulary: The Brain

Nature vs. Nurture

the longstanding controversy over the relative contributions that genes and experience make to the development of psychological traits and behaviors. Today’s science views traits and behaviors, as arising from the interaction of nature and nurture.

Genetic Predisposition

to be susceptible to it or more likely to encounter it due to inherited genes

Evolutionary Perspective

related to the scientific understanding of evolution. Considers the way that different traits will change throughout different generations and eras.

Eugenics

the practice advocacy of improving the human species by selectively mating people with specific desirable heredity.

Twin Studies

research designs used in psychology to measure the influence of genetic factors on human behavior by comparing identical (monozygotic) twins with fraternal (dizygotic) twins.

Central Nervous System

the brain and spinal cord

Peripheral Nervous System

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

Somatic Nervous System

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

Automatic 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 vs. Parasympathetic Nervous System

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

Glial Cells

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

Neurons

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

Reflex Arc

the pathway that a reflex takes in the body

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 muscle and glands

Interneurons

neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.

Neural Transmission

occurs when a neuron is activated, or fired (sends out an electrical impulse)

All-or-Nothing principle

signal transmission between neurons is not dependent on the strength of the stimuli but, rather, only that the initial threshold is met.

Action potential

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

Depolarization

when there’s a shift in a neuron’s electrical charge that allow an action potential (nerve impulse) to occur.

Refractory Period

a period of inactivity after a neuron has fired

Resting potential

the value its membrane potential keeps as long as it is not receiving stimulation or undergoing an action potential.

Reuptake

a neurotransmitter’s reabsorption by the sending neuron.

Firing Threshold

the level of stimulation required for a neuron to fire an action potential

Multiple Sclerosis

the loss of muscle control resulting from a deterioration of myelin sheaths

Myasthenia Gravis

a relatively rare acquired, autoimmune disorder caused by an antibody-mediated blockade of neuromuscular transmission.

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.

Excitatory vs. Inhibitory Neurotransmitters

causes a postsynaptic neuron to propagate more action potentials; causes a postsynaptic neuron to propagate fewer action potentials.

Hormones

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

Agonist vs. Antagonist

a molecule that, by binding to a receptor site, stimulates a response; a molecule that by binding to a receptor site, inhibits or blocks a response

Reuptake Inhibitors

drugs that prevent a neurotransmitter from being reabsorbed by presynaptic axons, causing greater activation of postsynaptic receptors.

Psychoactive Drugs

substances that cause changes in the normal activities of the central nervous system

Stimulants

chemicals known to stimulate the nervous system

Depressants

drugs that slow the activity of the central nervous system

Hallucinogens

a group of drugs that alter a person’s perception of reality

Opioids

depress neural functions

Tolerance

a diminished response to a drug

Addiction/Dependence

compulsive drug craving and use, despite adverse consequences

Withdrawal Symptoms

the symptoms that occur when a person ends the use of an addictive substance

Brainstem

oldest part of the brain and the central core, 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

Reticular Activating System

responsible for sensation, consciousness, attention, and the sleep-wake cycle.

Reward Center

a complex network of neural circuits that help regulate motivation, reinforcement, and pleasure responses

Cerebellum

processes sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory

Cerebral Cortex

the intricate fabric of interconnected neural cells covering the cerebral hemispheres the body’s ultimate control and information processing center

Hemispheres

left and right side of the brain

Limbic System

neural system located below the cerebral hemispheres; associated with emotions and drives.

Thalamus

the brain’s sensory control center, located on the 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 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

Pituitary Gland

the endocrine system’s most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands

Amygdala

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

Hippocampus

responsible for the formation of memory and processes explicit memories for storage

Corpus callosum

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

Lobes of the cortex

separated by prominent fissures, or folds; frontal lobes, parietal lobes, occipital lobes, and temporal lobes.

Occipital Lobes

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

Frontal Lobes

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

Prefrontal Cortex

the forward part of the frontal lobes enables judgement, planning, and processing of new memories

Motor Cortex

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

Temporal Lobes

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

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 positions

Somatosensory Cortex

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

Split Brain Research

the corpus callosum connecting the two hemispheres of the brain is severed to some degree

Right Hemisphere Specialization

more associated with creativity, intuition, and spatial abilities

Left Hemisphere Specialization

linked to language, logic, and analytical skills

Broca’s Area

responsible for speech production and language comprehension.

Wernicke’s’ Area

a region in the brain that plays a key role in language comprehension

Aphasia

impairment if language, usually caused by the left-hemisphere damage either to Broca’s area or to Wernicke’s area

Contralateral Organization

the property that the hemisphere of the cerebrum and the thalamus represent mainly the contralateral side of the body

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

CT Scan

a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain’s structure.

MRI

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

fMRI

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

Case Studies

a research design involving an in-depth and detailed examination of a single subject, or case, usually an individual or small group.

Leisoning Procedures

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