Unit 1: Biological Bases of Behavior

Paul Broca

Performed an autopsy revealing that damage to Broca’s area in the left hemisphere leads to expressive aphasia.

Broca’s area

Part of the left frontal lobe associated with the loss of the ability to speak.

Expressive aphasia

The loss of the ability to speak due to damage to Broca’s area.

Carl Wernicke

Identified Wernicke’s area responsible for understanding language in the left temporal lobe.

Wernicke’s area

Area in the left temporal lobe that, when damaged, results in receptive aphasia.

Receptive aphasia

Loss of the ability to comprehend written and spoken language due to damage to Wernicke’s area.

Lesions

Precise destruction of brain tissue that allows systematic study of function loss.

PET scan

Produces color graphics based on metabolic activity in brain regions.

Functional MRI (fMRI)

Shows brain activity by measuring changes in blood oxygen levels.

Central nervous system

Comprises the brain and spinal cord.

Peripheral nervous system

Includes the somatic and autonomic nervous systems, carrying information to and from the CNS.

Somatic nervous system

Controls voluntary muscle movements.

Autonomic nervous system

Controls involuntary processes, subdivided into sympathetic and parasympathetic systems.

Sympathetic nervous system

Prepares the body for stressful situations, stimulating fight or flight responses.

Parasympathetic nervous system

Calms the body after stress, restoring normal bodily functions.

Thalamus

Relays sensory information to appropriate areas of the cerebral cortex.

Hippocampus

Critical for the formation of new long-term memories.

Neurotransmitters

Chemicals that transmit signals across synapses from one neuron to another.

Dopamine

A neurotransmitter associated with alertness and movement.

Action potential

A rapid change in the membrane potential of a neuron, leading to neural firing.

Saltatory conduction

Increased speed of neural impulses due to myelin sheath covering the axon.

Reflex arc

The path of impulse conduction involving sensory, interneurons, and motor neurons.

Endocrine system

Glands that secrete hormones into the bloodstream to regulate various bodily functions.

Circadian rhythm

The natural, internal process that regulates the sleep-wake cycle, repeated roughly every 24 hours.

Insomnia

The inability to fall asleep or stay asleep.

Hypnosis

An altered state of consciousness characterized by deep relaxation and heightened suggestibility.

Meditation

Techniques used to focus concentration away from thoughts to cultivate calmness and tranquility.

Psychoactive drugs

Chemicals that alter perception, thinking, behavior, and mood by affecting the brain.

Depressants

Psychoactive drugs that reduce CNS activity and induce relaxation.

Hallucinogens

Psychoactive drugs that alter moods and distort perceptions.