Biological Psychology, Sensation, and Perception

Comprehensive vocabulary flashcards covering neuroanatomy, neural transmission, neuroimaging techniques, psychophysics, sensory systems, and perceptual organization from Chapters 3 and 4.

Sensation

The detection of physical energy from the environment by our sense organs.

Perception

The brain's interpretation and organization of raw sensory inputs into meaningful information.

Transduction

The cellular process by which external physical stimuli are converted into neural electrical activity by specialized sense receptors.

Sensory Adaptation

The reduction in sensitivity and activation of a sense receptor following initial detection when the stimulus remains constant.

Absolute Threshold

The lowest intensity level of a stimulus needed for a person to detect it at above-chance performance (greater than $50\%$ of the time).

Just Noticeable Difference (JND)

The smallest amount of change in stimulus intensity that humans can reliably detect.

Weber's Law

The psychophysical principle stating that there is a constant proportional relationship between the just noticeable difference (JND) and the original stimulus intensity.

Signal Detection Theory

A theoretical framework describing how stimuli are detected under conditions of uncertainty, categorizing responses into True Positives, False Negatives, False Positives, and True Negatives.

Synesthesia

A rare neurological condition marked by cross-modal sensations, wherein stimulation of one sensory pathway leads to involuntary, automatic experiences in a second sensory pathway.

Selective Attention

The cognitive process of focusing on one specific sensory channel while ignoring or minimizing competing sensory inputs, demonstrated by the cocktail party effect.

Inattentional Blindness

The failure to detect unexpected stimuli that are in plain sight because attentional resources are focused elsewhere.

Change Blindness

The inability of an observer to detect noticeable visual changes occurring within their visual environment.

Binding Problem

The unresolved psychological question of how the brain seamlessly integrates disparate sensory inputs processed across separate cortical regions into a single, unified perception.

Cornea

The curved, transparent dome of cells covering the front of the eye that bends incoming light waves to focus them on the retina.

Lens

The transparent structure in the eye that changes its curvature through accommodation to fine-tune the focus of light onto the retina for objects at varying distances.

Retina

The innermost, light-sensitive membrane lining the back of the eyeball where incoming photons are converted into neural impulses by photoreceptors.

Fovea

The central focal region of the retina containing the highest density of cones, responsible for visual acuity and sharp central vision.

Rods

Retinal photoreceptors specialized for low-light vision and dark adaptation that are completely absent in the fovea.

Cones

Retinal photoreceptor cells that require high levels of light and are responsible for high-resolution visual detail and colour vision.

Blind Spot

The region of the visual field corresponding to the optic disc where the optic nerve leaves the back of the eye, which contains no photoreceptor cells.

Trichromatic Theory

A colour perception theory proposing that visual colour is based on the differential activation of three distinct cone types maximally sensitive to blue, green, and red light.

Opponent Process Theory

A theory stating that colour vision is mediated by three pairs of antagonistic, complementary colour channels: red versus green, blue versus yellow, and black versus white.

Visual Agnosia

A severe object recognition impairment resulting from damage to higher visual cortical association areas, despite intact primary visual sensation.

Blindsight

A condition in which cortically blind individuals with damage to primary visual cortex ($\text{V1}$) demonstrate above-chance visual accuracy for stimuli they claim not to consciously see.

Place Theory

A theory of pitch perception proposing that different frequencies stimulate specific physical locations along the basilar membrane, accounting primarily for the perception of high tones.

Frequency Theory

A pitch perception theory stating that the rate of action potentials firing down the auditory nerve matches the exact frequency of a sound wave, explaining the perception of low tones.

Gate Control Model

A model positing that neural mechanisms in the spinal cord act as a gate that opens or closes to regulate whether pain signals reach conscious awareness in the brain.

Phantom Pain

Persistent pain sensations perceived as originating from an amputated limb, often treatable using mirror therapy.

Perceptual Set

A cognitive predisposition or mental expectation that influences and shapes the way sensory information is perceived.

Perceptual Constancy

The cognitive ability to perceive objects as having stable size, shape, and colour despite dramatic physical variations in the sensory signals received by our receptors.

Checker-Shadow Illusion

A visual illusion demonstrating that perceived brightness depends strongly on surrounding context and perceived illumination rather than raw reflected light alone.

Gestalt Principles

A set of perceptual organizing rules (including proximity, similarity, continuity, closure, symmetry, and figure-ground) describing how humans perceive visual scenes as holistic structures.

Visual Cliff

An elevated glass platform apparatus used to assess infant depth perception, showing that hesitation emerges as young as $6\text{ months}$ of age through a mix of innate mechanisms and experience.

Additive Colour Mixing

The process of combining different wavelengths of emitted light, where overlapping spectral components combine to produce white light.

Subtractive Colour Mixing

The process of mixing physical pigments or dyes, where overlapping substances absorb wavelengths of light and combine toward black.

Phrenology

An early, discredited 19th-century brain-mapping method that claimed the shape and bumps on an individual's skull reflected brain organ size and localized cognitive faculties.

Electroencephalograph (EEG)

A non-invasive technique that records electrical brain activity through scalp electrodes, providing high temporal resolution in the millisecond range.

Computed Tomography (CT)

A structural neuroimaging method utilizing multiple cross-sectional $X\text{-ray}$ scans assembled by a computer to construct three-dimensional anatomical images.

Magnetic Resonance Imaging (MRI)

A brain-imaging technique that uses powerful magnetic fields to indirectly produce high-resolution structural pictures of the brain.

Functional MRI (fMRI)

A brain-imaging technique that monitors blood oxygenation changes using magnetic fields to measure neural activity and structure simultaneously.

Positron Emission Tomography (PET)

A functional imaging method that tracks the consumption of injected, radioactive glucose-like molecules to visualize active brain regions.

Magnetoencephalography (MEG)

A neuroimaging technology that detects tiny magnetic fields generated by neuronal electrical activity, providing simultaneous high spatial and temporal resolution.

Deep Brain Stimulation (DBS)

A neurosurgical technique involving the implantation of electrodes to deliver electrical currents directly into specific brain targets, used to treat Parkinson's disease and depression.

Transcranial Magnetic Stimulation (TMS)

A procedure applying strong, rapid magnetic fields to the surface of the skull to temporarily enhance or interrupt localized cortical function.

Dendrites

Branchlike extensions extending outward from a neuron's soma that serve as specialized receivers of incoming chemical and electrical messages.

Axon

The elongated, tail-like projection of a neuron that conducts electrical impulses away from the cell body toward axon terminals.

Synapse

The microscopic, fluid-filled gap (synaptic cleft) separating the presynaptic axon terminal and the postsynaptic receptor membrane.

Glial Cells

Non-neuronal brain cells that exist in an approximate $1:1$ ratio with neurons, providing structural support, insulation, and metabolic maintenance.

Resting Potential

The baseline electrical charge across a neuronal membrane when it is neither receiving nor transmitting signals, typically measured between $-60\,\text{mV}$ and $-70\,\text{mV}$.

Action Potential

An abrupt, all-or-none electrical wave of depolarization that originates near the cell body and propagates down the axon to trigger neurotransmitter release.

Absolute Refractory Period

The brief recovery window immediately following an action potential during which a neuron cannot fire again regardless of stimulus strength.

Reuptake

The active recycling mechanism wherein released neurotransmitters in the synaptic cleft are drawn back into the presynaptic terminal, terminating synaptic transmission.

Glutamate

The primary excitatory neurotransmitter in the central nervous system, vital for learning and synaptic plasticity, but toxic to neurons in excessive amounts.

GABA (Gamma-Aminobutyric Acid)

The primary inhibitory neurotransmitter in the central nervous system, responsible for dampening overall neural excitation and facilitating learning and memory.

Acetylcholine

A neurotransmitter that triggers muscle contraction at neuromuscular junctions and regulates arousal, selective attention, sleep, and memory in the brain.

Dopamine

A monoamine neurotransmitter heavily involved in motor planning, reinforcement, and reward-seeking behavior, implicated in Parkinson's disease and schizophrenia.

Serotonin

A monoamine neurotransmitter responsible for modulating mood, sleep cycles, aggression, and temperature regulation, frequently targeted by antidepressant medications.

Anandamides

Endogenous chemical messengers that influence eating, motivation, memory, and sleep by binding to the same cannabinoid receptors as $\text{THC}$.

Neurotransmitter Agonist

A substance or drug that mimics or enhances the normal pharmacological activity of a neurotransmitter system, such as opiates mimicking endorphins.

Neurotransmitter Antagonist

A drug or compound that binds to receptors and dampens or blocks the normal activity of a neurotransmitter, such as dopamine antagonists used in schizophrenia.

Neural Plasticity

The capacity of the nervous system to alter its structure, synaptic connections, and functional organization in response to development, learning, or injury.

Corpus Callosum

The prominent bundle of myelinated nerve fibers connecting the left and right cerebral hemispheres, enabling interhemispheric communication.

Phineas Gage

An $1848$ railroad foreman who survived a tamping iron blast through his skull that destroyed most of his left prefrontal cortex, leading to dramatic shifts in personality and behavioral inhibition.

Lateralization

The organizational principle describing the specialization of specific cognitive abilities and psychological functions to one cerebral hemisphere over the other.

Basal Ganglia

A cluster of subcortical forebrain nuclei that coordinate voluntary movement, motor planning, and reward-motivated behaviors, impaired in Parkinson's disease.

Thalamus

A limbic system structure acting as the brain's sensory relay station, routing incoming signals from sensory organs to their respective primary sensory cortices.

Hypothalamus

A subcortical forebrain structure that maintains bodily homeostasis, controls the autonomic nervous system, and directs the pituitary gland.

Amygdala

A limbic structure critical for processing emotional memories, regulating arousal, excitement, and triggering conditioned fear responses.

Hippocampus

A curved limbic structure essential for spatial navigation and the consolidation of short-term experiences into lasting memories.

Cerebellum

A hindbrain structure that plays a predominant role in motor coordination, balance, and the execution and acquisition of motor skills.

Pons

A part of the brain stem connecting the cerebral cortex to the cerebellum that plays an instrumental role in triggering dreams.

Medulla

The lowest brainstem structure directly connecting to the spinal cord, responsible for governing vital autonomic reflexes including breathing and heart rate.

Somatic Nervous System

The division of the peripheral nervous system that coordinates voluntary skeletal muscle movements and delivers sensory data to the central nervous system.

Autonomic Nervous System

The division of the peripheral nervous system regulating involuntary vegetative functions of internal organs and glands, split into sympathetic and parasympathetic branches.

Sympathetic Nervous System

The autonomic division that activates during crises or stress to prepare the body for 'fight-or-flight' actions by accelerating heart rate and mobilizing energy.

Parasympathetic Nervous System

The autonomic division responsible for rest and digestion, acting to conserve energy and reduce physiological arousal when threats dissipate.

Pituitary Gland

The master endocrine gland controlled by the hypothalamus, secreting hormones that govern somatic growth, blood pressure, and maternal/social bonding through oxytocin.

Oxytocin

A pituitary hormone involved in reproductive physiology and implicated in parental nurturing and romantic bonding.

Adrenal Glands

Endocrine glands situated above the kidneys that secrete adrenaline and cortisol during states of emotional arousal and physiological emergency.

Heritability

A population-level statistical estimate of the proportion of trait variance across individuals attributable to genetic differences rather than environmental factors.

Epigenetics

The study of stable changes in gene expression and function that occur through environmental exposures and life experience without altering underlying DNA sequences.