AP Psychology Chapter 3

Wernicke's Area

A part of the left temporal lobe that plays an important role in the comprehension of language.

Genotype

A person's genetic makeup (twins: 100% identical).

Transcranial Magnetic Stimulation (TMS)

A new technique that permits scientists to temporarily enhance or depress activity in a specific area of the brain. A coil is used to create a magnetic field that can either increase or decrease the excitability of neurons in the local tissue. It allows for "virtual lesions." Research is usually done by having a subject work on a certain task while a certain part of the brain is suppressed.

Broca's Area

A part of the left frontal lobe that plays an important role in the production of speech.

Pons

A bridge of fibers that connects to the brainstem with the cerebellum. They also contain several clusters of cell bodies involved with sleep and arousal.

Agonist

A chemical that mimics the action of a neurotransmitter (i.e. nicotine and ACh). They "fool" the receptor sites.

Antagonist

A chemical that opposes the action of a neurotransmitter (i.e. curare and ACh). Key fits in the lock but doesn't turn.

Computerized Tomography Scan (CT)

A computer-enhanced X-ray of brain structure. Of all the techniques it is the cheapest, but it only gives a 2-D view of the brain.

Electroencephalograph Recording (EEG)

A device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp. Measured in brain waves, the EEG recordings provide an overview of the electrical activity in the brain (different brain wave patterns are associated with different states of mental activity).

Stereotaxic Instrument

A device used to implant electrodes at precise locations in the brain.

Parkinson's

A disease marked by tremors, muscular rigidity, and reduced control over voluntary movements that is caused by decreased levels of dopamine.

Axons

A long, thin fiber that transmits signals away from the soma to other neurons or to muscles or glands. They are often very long and branch out to communicate with a number of other cells.

Limbic System (54-56)

A loosely connected network of structures located roughly along the boarder between the cerebral cortex (outer layer of brain) and deeper subcortical areas. It includes parts of the thalamus and hypothalamus, the hippocampus, the amygdala, and other structures.

Synaptic Cleft

A microscopic gap between the terminal button of one neuron and the cell membrane of another neuron. Signals have to jump this gap to permit neurons to communicate. The presynaptic neuron sends the message and the postsynaptic neuron receives it.

Inhibitory Postsynaptic Potential

A negative voltage shift that decreases the likelihood that the postsynaptic neuron will fire action potentials. Depends upon which receptor sites are activated.

Resting Potential

A neuron's stable, negative charge of about 70 millivolts when the cell is inactive. Negative ion: Chloride.

Excitatory Postsynaptic Potential

A positive voltage shift that increases the likelihood that the postsynaptic neuron will fire action potentials. Depends upon which receptor sites are activated.

Hypothalamus

A structure found near the base of the forebrain that is involved in the regulation of basic biological needs. It controls the autonomic nervous system and it serves as a vital link between the brain and the endocrine system. Regulates the 4 F's (fighting, feeding, fleeing, mating), thirst, sexual motivation, and temperature regulation.

Thalamus

A structure in the forebrain through which all sensory information (except smell) must pass to get to the cerebral cortex. It is a way station made up of clusters of cell bodies (somas). It integrates information from various senses.

Action Potential

A very brief shift in a neuron's electrical charge that travels along an axon. The charge changes from negative (chloride ions) to positive (sodium and potassium ions). This happens when the neuron is stimulated and the channels in its cell membrane open, briefly allowing the positive ions to rush in.

Postsynaptic Potential (PSP)

A voltage change at a receptor site on a postsynaptic cell membrane. They vary in size and they increase or decrease the probability of a neural impulse (the signal that moves through the neuron) in the receiving cell in proportion to the amount of voltage change.

Afferent Nerves

Axons that carry information inward to the central nervous system from the periphery of the body.

Efferent Nerves

Axons that carry information outward from the central nervous system to the periphery of the body.

Glia

Cells found throughout the nervous system that provide various types of support for neurons. They are much smaller than neurons, but outnumber them 10:1 and they account for over 50% of the brain's volume. They supply nourishment to neurons, help remove neurons' waste products, and provide insulation around many axons. They also play a role in developing the nervous system in the human embryo. Some studies have shown that some glia cells can detect neural impulses and send signals to other glial cells.

Neurotransmitters

Chemicals that transmit information from one neuron to another. They are released the vesicles fuse with the membrane of the presynaptic cell and its contents spill into the synaptic cleft. They bind with molecules in the postsynaptic cell at receptor sites.

Spinal Cord

Connects the brain to the rest of the body through the peripheral nervous system.

Endocrine System

Consists of glands that secrete chemicals into the bloodstream that help control bodily functioning.

Central Nervous System (CNS)

Consists of the brain and spinal cord.

Cell Body (Soma)

Contains the cell nucleus and much of the chemical machinery common to most cells.

Dopamine (DA)

Contributes to control of voluntary movement and pleasurable emotions; decreased levels associated with Parkinson's disease; overactivity at DA synapses associated with schizophrenia; cocaine and amphetamines elevate activity at DA synapses.

Norepinephrine (NE)

Contributes to modulation of mood and arousal; cocaine and amphetamines elevate activity at NE synapses.

Medulla

Controls largely unconscious but vital functions, including circulating blood, breathing, maintaining muscle tone, and regulating reflexes (sneezing coughing, etc...)

Frontal Lobe

Controls the movement of muscles - primary motor cortex. Most of this cortex is given to the body parts we have fine control over (i.e. fingers). The prefrontal cortex contributes to memory.

Cerebellum

Critical to the coordination of movement and to the sense of equilibrium (physical balance). Damage disrupts fine motor skills such as writing, typing, or playing an instrument).

Temporal Lobe

Devoted to auditory processing - primary auditory cortex.

Positron Emission Tomography Scan (PET)

Examines function in the brain by mapping activity in the brain over time. Radioactively tagged chemicals are introduced into the brain that serve as markers for blood flow. They provide color-coded map indicating which areas of the brain become active when certain tasks are performed.

Hindbrain (47-50)

Includes the cerebellum and to structures found in the lower part of the brain stem: the medulla and the pons.

Neuron

Individual cells in the nervous system that receive, integrate, and transmit information. They are the basic links that permit communication within the nervous system. The vast majority of them communicate with other neurons.

Myelin Sheath

Insulating material that encases some axons. It speeds up the transmission of signals that move along the axons (large myelin sheath = faster transmission).

Lesioning

Involves destroying a piece of the brain by passing a high-frequency current through an electrode to burn the tissue and disable the structure It allows scientists to see how different parts of the brain effect behavior.

Electrical Stimulation of the Brain (ESB)

Involves sending a weak electric current into a brain structure to stimulate (activate) it. The electric stimulation in close enough to the actual signal in the brain to activate and to see what effect is has on behavior.

Synaptic Pruning

Involves the gradual elimination of less active synapses and it is a key process in the formation of neural networks.

Cerebrum (59-64)

Largest part of the brain, it is responsible for most complex mental activities, including learning, remembering, thinking, and consciousness itself. It is divided into 2 hemispheres: Left (Verbal processing, language, etc.) and Right (non-Verbal processing, creativity, etc.).

Amygdala

Learning of fear and processing of other basic emotional responses, such as aggression.

Reticular Formation

Located in between the midbrain and hindbrain, it contributes to the modulation of muscle reflexes, breathing, and pain perception. It is best known for its role in regulating sleep and arousal.

Occipital Lobe

Located in the back of the head, it is where must visual signals are sent and most visual processing begun. The area is called the primary visual cortex.

Peripheral Nervous System

Made up of all those nerves that lie outside the brain and spinal cord. It is divided into the somatic and autonomic nervous systems.

Somatic Nervous System

Made up of nerves that connect to voluntary skeletal muscles sensory receptors. These nerves are the cables that carry information from the receptors in the skin, muscles, and joints to the CNS and carry commands from the CNS to the muscles.

Autonomic Nervous System (ANS)

Made up the nerves that connect to the heart, blood vessels, smooth muscles, and glands. It controls automatic, involuntary, and visceral functions that people don't normally think about.

Cerebrospinal Fluid (CSF)

Nourishes the brain and the spinal cord and provides a protective cushion for it. Ventricles are hollow cavities in the brain that are filled with CSF.

Dominant Gene

One that is expressed when paired genes are different (i.e. brown eyes).

Recessive Gene

One that is masked when paired genes are different (i.e. blue eyes).

Hippocampus

Plays a role in memory processes. Some believe it is responsible for consolidation of memories for factual information.

Gonads

Prior to birth, they direct the formation of the external sexual organs. At puberty, the increased levels of sexual hormones are responsible for the emergence of secondary sexual characteristics (male's facial hair, female breasts, etc.)

Phenotype

Refers to the ways in which a person's genotype is manifested in observable characteristics.

Parietal Lobe

Registers the sense of touch - the primary somatosensory cortex. Also involved in integrating visual input and monitoring body's position in space.

Acetylcholine (ACh)

Released by motor neurons controlling skeletal muscles; contributes to the regulation of attention, arousal, and memory; some ACh receptors stimulated by nicotine.

Pituitary Gland

Releases a great variety of hormones that fan out around the body, stimulating actions in other endocrine glands ("the master gland").

Endorphins

Resemble opiate drugs in structure and effects; contribute to pain relief and perhaps some pleasurable emotions.

Adrenal Gland

Secrete hormones throughout the body, preparing it to cope with an emergency.

Thyroid Gland

Secretes hormone thyroxin, which regulates metabolism. Overactive thyroids cause sudden weight loss and insomnia. Not enough thyroxin cause extreme weight gain and desire to always sleep.

Pineal Gland

Secretes melatonin, which plays a key role in adjusting biological clocks.

Synaptic Vesicles

Small sacs in which most neurotransmitters are stored. They release the neurotransmitters when they fuse with the membrane of the presynaptic cell and its contents spill into the synaptic cleft.

Parasympathetic Division

The branch of the ANS that generally conserves bodily resources. It allows the body to save and store energy. It slows heart rate, reduces blood pressure, and promotes digestion.

Sympathetic Division

The branch of the autonomic nervous system that mobilizes the body's resources for emergencies. It creates the fight-or-flight response. It slows the digestive process and drains blood from the periphery, lessening bleeding in case of injury. It also triggers the release of hormones that ready the body for exertion.

Split-Brain Surgery

The bundle of fibers that connects the cerebral hemispheres (corpus callosum) is cut to reduce the severity of epileptic seizures. Only performed in severe cases, it gives some understanding as to what the job of each hemisphere is.

Meninges

The enclosing sheaths that protect the spinal cord and the brain. (Causes meningitis when inflamed.)

Forebrain (53-64)

The largest and most complex region of the brain, encompassing a variety of structures, including the thalamus, hypothalamus, limbic system, and cerebrum.

Multiple Sclerosis

The loss of muscle control resulting from a deterioration of myelin sheaths.

Hormones

The messengers of the endocrine system, they are the chemical substances released by the endocrine glands.

Absolute Refractory Period

The minimum length of time after an action potential during which another action potential cannot begin (about 1-2 milliseconds). It is followed by a brief refractory period during which the neuron can fire but its threshold for firing is elevated (more stimulation is required initiate an action potential).

Negative Feedback System

When hormone levels increase to a certain level, signals are sent to the hypothalamus to inhibit further hormone output.

Dizygotic

When two eggs are fertilized simultaneously by different sperm cells forming two separate zygotes (Fraternal twins).

Dendrites

The parts of a neuron that are specialized to receive information. Multiple dendrites from a single neuron branch out to form dendritic trees.

Electrical Charge

The resting potential is a negative 70 millivolts, and the action potential creates a less negative or even positive charge in the cell.

Midbrain (51-52)

The segment of the brainstem that lies between the hindbrain and the forebrain. Contains an area that is concerned with integrating sensory processes (such vision and hearing). It contains a system of dopamine-releasing neurons that is involved in the performance of voluntary movements.

Corpus Callosum

The structure that connects the 2 cerebral hemispheres.

Terminal Buttons

They are small knobs at the end of the axon that secrete chemicals called neurotransmitters.

Monozygotic

Twins emerge from one zygote that splits for unknown reasons (Identical twins).

Heterozygous

Two genes in a specific pair are different (parents contribute different genes.)

Homozygous

Two genes in a specific pair are the same (both parents contribute same).

Magnetic Resonance Imaging (MRI)

Uses magnetic fields, radio waves, and computerized enhancement to map out brain structure (3-D unlike CT Scans). The new fMRI also identifies area of high brain activity.

Synaptic Transmission

the process of transferring information at a synapse - see neurotransmitter.