Biological Basis of Behavior, States of Consciousness, and Sensation

Flashcards containing key vocabulary definitions grounded in the Unit 1 lecture transcript covering biological bases of behavior, states of consciousness, and sensation.

Nature

The view that behaviors and mental processes are inborn, innate, and shaped by biological, genetic influences and natural selection.

Nurture

The view that behaviors and mental processes result from an individual's environment, experiences, learned behaviors, and social interactions.

Evolutionary Psychology

The study of how behaviors and mental processes present in species today exist because of natural selection.

Behavioral Genetics

The study of the relative power and limits of genetic and environmental influences on behavior.

Neuron

The smallest unit in the nervous system (over 100 billion in the human brain) that transmits and receives information throughout the body.

Glial Cells

Cells in the nervous system that nourish and protect neurons.

Dendrites

Branching neuron structures that receive incoming messages from other cells.

Axon

A neuron extension that passes electrical messages away from the cell body to other neurons, muscles, or glands.

Myelin Sheath

A fatty tissue layer covering the axon of some neurons that helps speed up neural impulses.

Synapse

The structure created by the terminal button of one neuron, the synaptic gap (cleft), and the dendrite of another neuron.

Reuptake

The process of a presynaptic neuron reabsorbing excess neurotransmitters from the synaptic gap.

Threshold

The specific level of stimulation an impulse must exceed for a neuron to fire.

All or None Law

The principle stating that a neuron fires completely all the way through or does not fire at all.

Resting Potential

The electrical charge across a resting neuron membrane (polarization), characterized by positive ions outside and negative ions inside.

Action Potential

A brief electrical neural impulse triggered by depolarization, during which positive ions rush inside and negative ions rush outside along the neuron.

Absolute Refractory Period (ARP)

A brief period lasting a few thousandths of a second immediately after firing, during which a neuron cannot fire again regardless of stimulus strength.

Relative Refractory Period (RRP)

The phase following the absolute refractory period during which a neuron can fire only if the incoming stimulus is stronger than normal.

Sensory (Afferent) Neurons

Neurons that carry incoming information from sense organs to the Central Nervous System (CNS).

Motor (Efferent) Neurons

Neurons that carry outgoing information from the Central Nervous System (CNS) to muscles and glands.

Interneurons

Neurons within the Central Nervous System that communicate internally and carry messages between sensory and motor neurons.

Multiple Sclerosis

An autoimmune disorder causing the body's immune system to attack the myelin sheath, leading to numbness, speech impairment, and motor coordination issues.

Myasthenia Gravis

An autoimmune disorder causing weakness in the voluntary muscles due to the destruction of neuromuscular connections.

Agonist

A drug or molecule that increases a neurotransmitter's action by binding to receptor sites and triggering a response.

Antagonist

A drug or molecule that blocks a neurotransmitter's action by occupying receptor sites without activating them.

Neuroplasticity

The brain's ability to change and adapt in response to experiences, learning, or to compensate for tissue loss following injury or disease.

Somatic System

A subdivision of the Peripheral Nervous System containing afferent and efferent neurons that controls voluntary muscle movements and sensory inputs.

Autonomic System

A subdivision of the Peripheral Nervous System that connects the CNS to internal organs and glands, regulating involuntary actions and fight-or-flight responses.

Sympathetic System

The division of the autonomic nervous system that arouses the body and mobilizes its energy during stress ("Flight, Fright, or Freeze").

Parasympathetic System

The division of the autonomic nervous system that calms the body and conserves its energy.

Endocrine System

The body's slower chemical communication system consisting of glands that secrete hormones into the bloodstream.

Electroencephalogram (EEG)

A diagnostic technique using macroelectrodes to measure brain wave activity and record sleep patterns.

Cerebellum

A structure located in the central core of the brain responsible for balance and coordinating voluntary body movements.

Reticular Activating System (RAS)

A brain stem formation vital for attention and arousal that sends alert signals to higher brain centers; damage can result in a coma.

Medulla

The base of the brain stem that controls autonomic survival functions like breathing, heart rate, and blood pressure.

Pons

A structure in the brain stem that regulates the sleep/wake cycle.

Thalamus

The brain's sensory relay station located deep in the limbic system that routes sensory input (except smell) to high cerebral regions.

Hypothalamus

A limbic system structure below the thalamus regulating hunger, thirst, sexual arousal, emotions, and body temperature.

Amygdala

A limbic system structure linked to self-preservation emotions such as fear and aggression.

Hippocampus

A structure in the limbic system essential for processing and forming new memories.

Cerebral Cortex

The intricate outer layer of interconnected neural cells covering the cerebral hemispheres, responsible for higher mental processes, weighing 80% of brain weight and housing 70% of CNS neurons.

Frontal Lobes

Portions of the cerebral cortex located behind the forehead involved in speaking, voluntary muscle movements (motor cortex), higher-order thinking, judgement, decision-making, and personality.

Parietal Lobes

Portions of the cerebral cortex receiving sensory input for touch (somatosensory cortex), body position, and spatial awareness.

Temporal Lobes

Portions of the cerebral cortex lying above the ears containing the auditory cortex, involved in hearing and complex visual tasks.

Occipital Lobes

Portions of the cerebral cortex at the back of the head containing the visual cortex responsible for processing visual input from the eyes.

Broca's Area

A region in the left frontal lobe that controls language expression and directs muscle movements involved in speech.

Wernicke's Area

A region in the left temporal lobe involved in language comprehension and understanding.

Aphasia

An impairment of language usually caused by left hemisphere damage to Broca's area (impairing speaking) or Wernicke's area (impairing understanding).

Corpus Callosum

A thick band of neural fibers connecting the right and left cerebral hemispheres that enables them to communicate.

Circadian Rhythm

An internal biological clock roughly adapted to 24-hour solar cycles regulating sleep-wake patterns, temperature, digestion, and hormone levels.

NREM Sleep

Non-rapid eye movement sleep encompassing all sleep stages (NREM-1, NREM-2, NREM-3) except REM sleep.

REM Sleep

A recurring paradoxical sleep stage characterized by rapid eye movement, vivid dreaming, elevated heart rate, and muscle paralysis.

Insomnia

A sleep disorder characterized by persistent difficulty falling or staying asleep occurring over about 3 months.

Narcolepsy

A sleep disorder characterized by sudden attacks of overwhelming sleepiness that directly trigger REM sleep during waking hours.

Sleep Apnea

A sleep disorder characterized by repeatedly stopping breathing briefly throughout sleep.

Activation Synthesis Theory

The theory that dreams are meaningless side effects of random neural misfiring, created when the brain synthesizes activity from an active limbic system while frontal lobes are inactive.

Consolidation Theory

The theory proposing that dreams function to reprocess daily information to help sort, consolidate, and store memories into long-term storage.

Depressants

Psychoactive drugs that reduce neural activity and slow down body functions (e.g., alcohol, barbiturates).

Opioids

Drugs that block pain receptor cells between the brain and body and act as endorphin agonists (e.g., heroin, morphine, fentanyl).

Stimulants

Psychoactive drugs that excite neural activity and speed up bodily functions (e.g., caffeine, nicotine, cocaine, amphetamines).

Hallucinogens

Psychoactive drugs that distort perceptions and evoke sensory imagery without external sensory input (e.g., LSD, marijuana, shrooms).

Sensation

The process by which sensory receptor cells and the nervous system receive physical stimulus energy from the environment and convert it into neural signals.

Transduction

The conversion of one form of physical energy (stimulus) into neural impulses that the brain can process.

Perception

The brain's process of organizing and interpreting sensory information to recognize meaningful objects and events.

Synesthesia

A sensory condition described as "joined perception" where stimulation of one sense automatically triggers an involuntary sensation in another sense.

Bottom-Up Processing

Perceptual analysis that begins with raw sensory receptors and works up to the brain to build a complete perception.

Top-Down Processing

Information processing guided by higher-level mental processes, experience, and expectations.

Absolute Threshold

The minimum stimulus intensity needed to detect a specific stimulus $50\%$ of the time.

Difference Threshold

The minimum difference between two stimuli required for detection $50\%$ of the time (Just Noticeable Difference).

Weber's Law

The principle stating that to be perceived as different, two stimuli must differ by a constant minimum percentage rather than a constant amount.

Sensory Adaptation

Diminished sensitivity resulting from constant exposure to an unchanging stimulus due to less frequent nerve firing.

Rods

Visual receptor cells (approximately 120 million per eye) located outside the fovea that detect black, white, and gray, functioning in dark adaptation and peripheral vision.

Cones

Visual receptor cells (approximately 8 million per eye) concentrated near the center of the fovea that detect fine detail and color.

Prosopagnosia

A neurological condition (face blindness) caused by occipital lobe damage, resulting in an inability to perceive or recognize faces despite functional retinas.

Trichromatic Theory

The theory proposing that the fovea contains three distinct cone types (red, green, blue) that combine stimulation to produce any perceived color.

Opponent Process Theory

The theory proposing that color vision depends on ganglion cells operating in three opposing pairs: yellow-blue, red-green, and black-white.

Place Theory

The pitch perception theory asserting that pitch links to the exact location along the cochlea's basilar membrane that is stimulated; best explains high pitches.

Frequency Theory

The pitch perception theory stating that pitch corresponds to the rate or frequency of cilia firing along the basilar membrane; best explains low pitches.

Conduction Deafness

Hearing loss caused by mechanical damage to the eardrum or the ossicles (hammer, anvil, stirrup).

Sensorineural Deafness

Hearing loss caused by damage to the cochlea's receptor hair cells or the auditory nerve.

Olfaction

The anatomical sense of smell.

Pheromones

Chemical signals used for species communication processed via the vomeronasal organ (VNO), olfactory bulb, amygdala, and hypothalamus.

Gustation

The sense of taste, comprised of six primary taste sensations: sweet, salty, sour, bitter, umami, and oleogustus.

Gate Control Theory

The theory stating that a neurological gate in the spinal cord, controlled by higher cerebral cortex signals, opens or blocks pain signals.

Kinesthetic Sense

The system for sensing the position, speed, and direction of movement of individual body parts via stretch receptors in muscles and Golgi tendon organs.

Vestibular Sense

The sense of body movement, orientation, and balance mediated by fluid-filled semicircular canals and vestibular sacs in the inner ear.

action potentials

neural impulses that move down axon

sodium channels

allows sodium ions to flow into the axon

potassium channels

allows potassium ions to flow out of the axon

sodium-potassium pumps

restore proper ion concentrations