Biological Bases of Behavior
6. Drugs and Consciousness
Psychoactive drugs: Chemical substances that alter perceptions and moods.
Agonists: Molecules that increase a neurotransmitter's action (by mimicking it or blocking reuptake).
Antagonists: Molecules that inhibit or block a neurotransmitter's action.
Reuptake inhibitors: Drugs that interfere with the reabsorption of neurotransmitters, leaving more in the synapse (e.g., SSRIs).
Stimulants: Drugs (like Caffeine and Cocaine) that excite neural activity and speed up body functions.
Depressants: Drugs (like Alcohol) that reduce neural activity and slow body functions.
Hallucinogens: Psychedelic drugs (like Marijuana—specifically THC) that distort perceptions and evoke sensory images in the absence of sensory input.
Opioids: Drugs (like Heroin) derived from opium that depress neural activity, temporarily lessening pain and anxiety.
Tolerance: The diminishing effect with regular use of the same dose of a drug.
Addiction: Compulsive craving of drugs or certain behaviors despite known adverse consequences.
Withdrawal: The discomfort and distress that follow discontinuing an addictive drug or behavior.
7. Brain Structures and Functions
Brain stem: The oldest part and central core of the brain, responsible for automatic survival functions.
Medulla: The base of the brainstem; controls heartbeat and breathing.
Reticular activating system (RAS): A nerve network in the brainstem that plays an important role in controlling arousal/alertness.
Cerebellum: The "little brain" at the rear of the brainstem; processes sensory input, coordinates movement, and balance.
Cerebral cortex: The intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.
Limbic system: Neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.
Thalamus: The brain's sensory control center; directs messages to the sensory receiving areas in the cortex.
Hypothalamus: Directs maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the Pituitary gland (the "master gland"), and is linked to emotion and reward.
Hippocampus: A neural center in the limbic system that helps process explicit (conscious) memories.
Amygdala: Two lima-bean-sized neural clusters in the limbic system linked to emotion (specifically fear and aggression).
Corpus callosum: The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.
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8. Lobes and Specialization
Occipital lobes: At the back of the head; includes areas that receive information from the visual fields.
Temporal lobes: Roughly above the ears; includes auditory areas.
Parietal lobes: At the top/rear; receives sensory input for touch and body position.
Frontal lobes: Behind the forehead; involved in speaking, muscle movements, and making plans/judgments.
Association areas: Areas of the cerebral cortex not involved in primary motor or sensory functions; involved in Higher-order thinking and Linguistic processing.
Executive functioning: High-level cognitive processes (planning, decision making) primarily managed by the Prefrontal cortex.
Somatosensory cortex: Area at the front of the parietal lobes that registers and processes body touch and movement sensations.
Motor cortex: Area at the rear of the frontal lobes that controls voluntary movements.
Hemispheric specialization: The tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other.
Split brain research: Studies of patients whose corpus callosum has been severed, revealing the independent functions of the two hemispheres.
Broca’s area: Controls language expression; an area of the left frontal lobe that directs muscle movements involved in speech.
Wernicke’s area: Controls language reception; a brain area (usually left temporal lobe) involved in language comprehension.
Aphasia: Impairment of language. Broca's aphasia results in difficulty speaking; Wernicke's aphasia results in difficulty understanding or producing meaningful speech.
Contralateral hemispheric organization: The setup where the left side of the brain controls the right side of the body, and vice versa.
Plasticity: The brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.
9. Tools of Discovery
EEG (Electroencephalogram): An amplified recording of the waves of electrical activity sweeping across the brain's surface.
fMRI (Functional MRI): A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans.
Lesioning: Purposefully destroying tiny clusters of normal or defective brain cells to observe the effects on behavior.
10. Sleep and Consciousness
Consciousness: Our subjective awareness of ourselves and our environment.
Circadian rhythm: Our biological clock; regular bodily rhythms (e.g., temperature and wakefulness) that occur on a 24-hour cycle.
Jet lag: A temporary sleep disorder caused by traveling across time zones, disrupting the circadian rhythm.
Shift work: Work schedules outside the standard 9-to-5, which can disrupt sleep patterns.
NREM stage 1: The transition from wakefulness to sleep; may involve Hypnogogic sensations (vivid dreams/hallucinations like falling).
NREM stage 2: Characterized by sleep spindles (bursts of rapid brain activity).
NREM stage 3: Deep sleep with slow delta waves.
REM sleep: Rapid Eye Movement sleep; a recurring sleep stage during which vivid dreams commonly occur (also called paradoxical sleep).
REM rebound: The tendency for REM sleep to increase following REM sleep deprivation.
Activation-synthesis theory: The theory that dreams are the brain's attempt to synthesize random neural activity.
Consolidation theory / Memory consolidation: The idea that sleep helps sift, sort, and fix the day’s experiences into long-term memory.
Restoration of resources: Theory that sleep allows the body and brain to repair and replenish chemical and physical resources.
11. Sleep Disorders
Insomnia: Persistent problems in falling or staying asleep.
Narcolepsy: A sleep disorder characterized by uncontrollable sleep attacks.
REM sleep behavior disorder: A condition where the paralysis normally associated with REM sleep is absent, causing the person to act out their dreams.
Sleep apnea: A disorder in which the person stops breathing for brief periods while asleep.
Somnambulism: Sleepwalking; occurs during NREM-3 deep sleep.