Unit 3: Biological Bases of Behavior: 3B – The Brain

Lesion
Tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue.

Electroencephalogram (EEG)
An amplified recording of the waves of electrical activity that sweep across the brain’s surface. These waves are measured by electrodes placed on the scalp.

CT (Computed Tomography) Scan
A series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body. Also called CAT scan.

PET (Positron Emission Tomography) Scan
A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.

MRI (Magnetic Resonance Imaging)
A technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy.

fMRI (functional MRI)
A technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function.

Brainstem
The oldest part and 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 base of the brainstem; controls heartbeat and breathing.

Reticular Formation
A nerve network in the brainstem that plays an important role in controlling arousal.

Thalamus
The brain’s sensory switchboard, located on top of the brainstem; it directs messages to the sensory recieving areas in the cortex and transmits replies to the cerebellum and medulla.

Cerebellum
The “little brain” at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance.

Limbic System
Doughnut-shaped neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

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

Hypothalamus
A neural structure lying below (hypo) 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.

Cerebral Cortex
The intricate fabric of interconnected neural cellscovering the cerebral hemispheres; the body’s ultimate control and information-processing center.

Glial Cells (Glia)
Cells in the nervous system that support, nourish, and protect neurons.

Frontal Lobes
Portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgements.

Parietal Lobes
Portion of the cerebral cortex lying at the top of the head and toward the rear; recieves sensory input for touch and body position.

Occipital Lobes
Portion of the cerebral cortex lying at the back of the head; includes areas that recieve information from the visual fields.

Temporal Lobes
Portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each recieving information primarily from the opposite ear.

Motor Cortex
An area at the rear of the frontal lobes that controls voluntary movements.

Sensory Cortex
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.

Aphasia
Impairment of language, usually caused by left hemisphere damage either to Broca’s area (impairing speaking) or to Wernicke’s area (impairing understanding).

Broca’s Area
Controls language expression–an area, usually in the left frontal lobe, that directs the muscle movements involved in speech.

Wernicke’s Area
Controls language reception–a brain area involved in language comprehension and expression; usually in the left temporal lobe.

Plasticity
The 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 (mainly those of the corpus callosum) connecting them.

Consciousness
Our 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.