PSYC 201: Sensation, Perception, Psychopharmacology, and Sleep

Vocabulary practice flashcards covering sensory systems, visual and auditory pathways, chemical and somatosensory mechanisms, psychopharmacology drug classes, dimensions of consciousness, and sleep architecture.

Sensory Transduction

The biological process in which sensory organs convert a physical stimulus from the environment into neural signals for propagation throughout the nervous system.

Rod and Cone Photoreceptors

The specialized visual receptor cells in the retina of the eye that perform sensory transduction; cones (comprising S, M, and L types) mediate colour perception, whereas rods detect lower levels of visible light.

Lateral Geniculate Nucleus (LGN)

A subcortical nucleus in the thalamus that receives visual information from retinal ganglion cells via the optic nerve and chiasm before projecting it to the visual cortex in the occipital lobe.

Primary Auditory Cortex (A1)

The region located in the temporal lobe responsible for auditory perception, receiving biaural input routed from the cochlea via the vestibulocochlear nerve, brain stem, and thalamus.

Sound Intensity / Amplitude

The physical property of sound reflecting the amount of energy in a wave; human hearing limits span from 0\text{ to }\raisebox{0.5ex}{\texttildelow}120\text{ dB(SPL)}.

Sound Frequency

The number of sound waves per second, measured in $\text{Hz}$; human auditory perception detects frequencies ranging from 20\text{ to }\raisebox{0.5ex}{\texttildelow}20{,}000\text{ Hz}.

Sound Complexity / Purity

The physical property resulting from the summation of different frequencies, which produces the perceived timbre or quality of a sound.

Basilar Membrane

A structure within the cochlea responsible for auditory transduction; its narrow, stiff end near the oval window detects high frequencies (\raisebox{0.5ex}{\texttildelow}20{,}000\text{ Hz}), while its wide, flexible end responds to low frequencies (\raisebox{0.5ex}{\texttildelow}20\text{ Hz}).

Primary Olfactory Cortex

The cortical complex located in the temporal lobe that processes smell sensations, receiving direct input from olfactory neurons in the olfactory bulb via the olfactory nerve while bypassing the thalamus.

Primary Gustatory Cortex

The region within the frontal and insular lobes responsible for processing taste information transmitted through three separate cranial nerves by way of the brain stem and thalamus.

Umami

One of the fundamental taste qualities, transduced in taste buds by receptors that detect glutamate, inosinate, and guanylate in foods such as tomatoes, cheese, meat, fish, and dried shiitake mushrooms.

Mechanoreceptors

Specialized sensory receptors located in the skin that transduce physical force (including its presence, rate of change, amount, and movement) into action potentials sent to the spinal cord.

Primary Somatosensory Cortex

The area in the parietal lobe that receives ascending somatosensory fibres from the spinal cord via the brain stem and thalamus, processing touch and bodily sensations.

Nociception

The fundamental sensory process of detecting noxious stimuli (stimuli harmful to the body) through specialized chemical, mechanical, or temperature-sensitive nociceptors.

Nociceptive Pain

The conscious perception resulting from the detection of noxious, tissue-damaging stimuli.

Inflammatory Pain

A form of pain that arises following tissue injury to signal the need for healing and behavioural prevention of further damage.

Neuropathic Pain

Pain that occurs in the absence of an external noxious stimulus, often categorized as psychogenic or psychosomatic.

Agonist

A psychoactive chemical or drug that binds to a neurotransmitter receptor and mimics or enhances the effect of that neurotransmitter.

Antagonist

A psychoactive chemical or drug that binds to a receptor and prevents or blocks the endogenous neurotransmitter from functioning.

Anxiolytics / Sedative Hypnotics

A functional class of psychoactive drugs (such as alcohol, barbiturates, and benzodiazepines) that depress brain activity primarily by acting as agonists for GABA, the primary inhibitory neurotransmitter.

Antipsychotics

A class of drugs (including phenothiazines such as thorazine) designed to relieve psychosis by modulating multiple neural pathways, notably dopamine transmission.

Selective Serotonin Reuptake Inhibitors (SSRIs)

A class of antidepressant drugs (such as Prozac) that elevate mood and increase activity by acting as agonists on the serotonin ($5\text{-HT}$) pathway.

Opioid Analgesics

Compounds derived from the opium poppy (including morphine, heroin, oxycontin, and fentanyl) that act as agonists on endogenous opioid receptors to produce pain relief, relaxation, and euphoria.

Psychotropics / Hallucinogens

A category of substances (such as marijuana and LSD) that act on various neurotransmitter systems (such as cannabinoid and serotonin receptors) to distort the perception of reality and generate hallucinations.

Stimulants

Psychoactive substances (such as caffeine, nicotine, and amphetamines) that activate the nervous system to produce arousal, reduce fatigue, elevate alertness, and enhance exhilaration or irritability.

Dimensions of Consciousness

The two objective metrics used to characterize conscious states: wakefulness (the level of consciousness) and awareness (the content of consciousness).

Glasgow Scale

A clinical assessment tool used to measure an individual's level of consciousness and assess the depth of a coma.

Reticular Formation

A brain stem network that, together with the thalamus, enables consciousness and arousal, whereas the cerebral cortex provides the content of consciousness.

Inattentive Blindness

A cognitive phenomenon wherein an individual fails to perceive fully visible objects or events because their attention is focused on a specific context or purpose.

Fatal Familial Insomnia

A rare prion disease characterized by progressive, total sleep deprivation that leads to death after approximately $6\text{ months}$.

Circadian Rhythm

A daily biological cycle of approximately $24\text{ h}$ that free-runs at roughly $26\text{ h}$ without environmental cues and is entrained by environmental light.

Suprachiasmatic Nucleus (SCN)

A nucleus situated within the hypothalamus that maintains the body's circadian rhythms by receiving direct light information from the retina.

Ultradian Rhythm

Recurrent physiological or neural cycles that repeat multiple times within a single day, such as infra-low frequency brain oscillations.

Beta ($\beta$) Waves

High-frequency, low-amplitude EEG waveforms operating between $13\text{ to }30\text{ Hz}$, characteristic of conscious wakefulness and REM sleep.

Alpha ($\alpha$) Waves

Synchronized EEG waveforms with frequencies ranging from $7\text{ to }13\text{ Hz}$, typically observed during relaxed wakefulness.

Theta ($\theta$) Waves

EEG neural oscillations between $3.5\text{ to }7\text{ Hz}$ that predominate during Stage 1 (N1) and Stage 2 (N2) sleep.

Delta ($\delta$) Waves

High-amplitude, low-frequency EEG waves measuring $0.5\text{ to }3.5\text{ Hz}$, which characterize deep slow-wave sleep (Stage 3 and Stage 4).

Rapid Eye Movement (REM) Sleep

A stage of sleep characterized by beta-like EEG activity, dreaming, and vivid neural processing, which accounts for approximately $50\%$ of daily sleep in infants and decreases to about $19\text{--}20\%$ in older adults.

Threat Simulation Hypothesis

An evolutionary theory proposing that dreaming maintains continuity with waking life and provides an adaptive virtual environment to practice escaping threats and resolving survival challenges.

Activation-Synthesis Model

A neurobiological model suggesting that dreams are the cerebral cortex's attempt to synthesize and make sense of random neural activation required for the maintenance of long-term memory.

Sleepwalking (Somnambulism)

A sleep disorder involving the execution of practiced motor routines that occurs specifically during non-REM sleep stages.