Behavioral Neuroscience: Sleep, Metabolism, Learning, and Memory

Comprehensive vocabulary flashcards covering sleep physiology, sleep disorders, neuropharmacology, appetite peptides, metabolism, conditioning mechanisms, visual pathways, and memory neurobiology.

Electroencephalogram (EEG)

A psychophysiological measure utilizing electrodes on the scalp to detect brain electrical activity; distinguishes Stage 3 sleep by high-amplitude, low-frequency delta waves ($< 3.5\,\text{Hz}$) and REM sleep by desynchronized beta/theta activity.

Electrooculogram (EOG)

A psychophysiological measure recorded via electrodes placed around the eyes to monitor ocular movements; indicates little or no movement during Stage 3 sleep and rapid eye movements during REM sleep.

Electromyogram (EMG)

A psychophysiological measure utilizing electrodes placed on facial muscles to monitor muscle activity and tone; reflects low muscle tone during Stage 3 sleep and complete muscle paralysis with occasional twitches during REM sleep.

Extrastriate Cortex (in REM Sleep)

Visual association cortex that exhibits increased cerebral blood flow during REM sleep, supporting vivid dream imagery.

Striate Visual Cortex (in REM Sleep)

The primary visual cortex, which exhibits decreased blood flow during REM sleep due to the absence of external visual input while the eyes remain closed.

Primary Insomnia

Difficulty falling or staying asleep that is not attributable to another medical or psychiatric condition, affecting approximately $1\text{--}10\%$ of individuals.

Secondary Insomnia

Difficulty initiating or maintaining sleep resulting from an underlying medical condition (e.g., chronic pain, depression, sleep apnea) or iatrogenic factors (e.g., sedative drug dependence), affecting about $30\text{--}40\%$ of people at some point.

Fatal Familial Insomnia

An inherited prion disease characterized by misfolded proteins that causes progressive, unremitting insomnia and eventual death.

Obstructive Sleep Apnea

A sleep disorder caused by relaxation of throat muscles that leads to physical collapse and blockage of the upper airway during sleep.

Central Sleep Apnea

A sleep disorder occurring when the brainstem fails to transmit appropriate respiratory signals to the breathing muscles.

Benzodiazepines

Prescription sleep medications (e.g., alprazolam, clonazepam) that act as positive allosteric modulators (indirect agonists) of $GABA_A$ receptors to enhance neural inhibition, promote non-REM sleep, and suppress slow-wave and REM sleep.

Orexin Receptor Antagonists

A class of sleep aids (e.g., suvorexant) that block orexin receptors to diminish wake-promoting neurochemical signals and assist with sleep onset and maintenance.

Sodium Oxybate (GHB)

A prescription medication used in the management of narcolepsy that specifically targets and reduces cataplexy.

Adenosine

A neuromodulator produced as glycogen stores deplete during wakefulness; it accumulates in extracellular space, binds neuronal receptors to inhibit activity, and generates sleep pressure.

Suprachiasmatic Nucleus (SCN)

The hypothalamic nucleus that serves as the master biological clock regulating circadian rhythms; it receives direct photic input from melanopsin-containing retinal ganglion cells ($\text{mRGCs}$) to entrain the sleep–wake cycle.

Locus Coeruleus

A noradrenergic pontine structure involved in vigilance and arousal; its neurons exhibit peak firing during wakefulness, reduced firing in slow-wave sleep, and near silence during REM sleep.

Raphe Nuclei

Brainstem nuclei containing serotonin-synthesizing neurons that promote wakefulness; they show moderate activity in slow-wave sleep and their lowest firing rates during REM sleep.

Tuberomammillary Nucleus

A hypothalamic structure containing histaminergic neurons that sustain cortical arousal; it displays high activity during wakefulness and low activity across both slow-wave and REM sleep.

Melanin-Concentrating Hormone (MCH)

An orexigenic peptide synthesized by neurons in the lateral hypothalamus with widespread central projections; it stimulates food consumption and decreases metabolic rate.

Neuropeptide Y (NPY)

A peptide produced in the arcuate nucleus that projects to the paraventricular nucleus ($\text{PVN}$), MCH, and orexin neurons of the lateral hypothalamus to stimulate eating and decrease metabolic expenditure.

Agouti-Related Peptide (AgRP)

An orexigenic peptide synthesized within the arcuate nucleus of the hypothalamus that acts to increase food consumption and decrease metabolic rate.

Cocaine- and Amphetamine-Regulated Transcript (CART)

An anorexigenic peptide produced in the arcuate nucleus that is activated by leptin to suppress feeding behavior and increase metabolic rate.

$\alpha$-Melanocyte-Stimulating Hormone ($\alpha\text{-MSH}$)

A satiety peptide localized in the arcuate nucleus that is stimulated by circulating leptin to inhibit food intake and elevate metabolism.

Leptin

A peripheral protein hormone secreted by adipose tissue that acts as a long-term satiety signal by inhibiting $\text{NPY/AgRP}$ neurons and exciting $\text{CART/}\alpha\text{-MSH}$ neurons in the arcuate nucleus.

Cholecystokinin (CCK)

A peripheral satiety hormone secreted by the duodenum in response to food that acts locally on pyloric sensory neurons.

Peptide YY (PYY)

A gastrointestinal satiety peptide released after food ingestion that signals fullness by inhibiting orexigenic $\text{NPY/AgRP}$ neurons in the arcuate nucleus.

Ghrelin

A peptide hormone secreted by the empty stomach that binds to hypothalamic receptors to stimulate appetite, increase food intake, and elicit vivid food thoughts.

Fasting Phase

The metabolic state occurring when the digestive tract is empty; mediated by glucagon and sympathetic activation to induce hepatic glycogenolysis, triglyceride lipolysis into fatty acids and glycerol, and hepatic gluconeogenesis.

Absorptive Phase

The metabolic period following food ingestion characterized by parasympathetic dominance and insulin secretion, facilitating cellular glucose uptake, glycogenesis in the liver, and fat storage in adipose tissue.

Gut Microbiome

The complex ecosystem of microorganisms (microbiota) inhabiting the gastrointestinal tract, including their structural components, metabolites, genetic material, and surrounding physiological environment.

Stimulus–Response (S-R) Learning

The formation of functional behavioral links between perceptual circuits and motor pathways in response to specific cues, incorporating classical conditioning and operant conditioning.

Hebb's Rule

A foundational neurobiological hypothesis stating that repeated and synchronized activation of a presynaptic neuron and a postsynaptic neuron induces synaptic structural strengthening ('neurons that fire together, wire together').

Relational Learning

A complex form of learning coordinated by the hippocampus that involves forming associations among multiple distinct sensory cues, environmental contexts, spatial relationships, and temporal events.

Ventral Stream

A visual processing pathway projecting from the striate cortex to the inferior temporal cortex responsible for object identification and recognizing 'what' a stimulus is.

Dorsal Stream

A visual pathway extending from the striate cortex to the posterior parietal cortex involved in spatial awareness, motion processing, and recognizing 'where' an object is situated.

Anterograde Amnesia

A memory impairment typically resulting from bilateral medial temporal lobe damage that prevents the consolidation of new long-term declarative memories while sparing immediate memory and nondeclarative learning.

Retrograde Amnesia

The loss of memories acquired prior to brain damage or traumatic insult, typically manifesting with a temporal gradient where recent memories suffer greater disruption than remote memories.

Long-Term Potentiation (LTP)

A long-lasting increase in synaptic transmission efficacy following high-frequency electrical stimulation; characterized postsynaptically by NMDA receptor activation, calcium influx, and the insertion of AMPA receptors.

Targeted Memory Reactivation (TMR)

A cognitive enhancement technique wherein sensory cues paired with information during waking learning are re-exposed during slow-wave sleep to promote memory consolidation and later retrieval.

Morris Water Maze

A behavioral apparatus consisting of a circular pool of opaque water used to assess spatial and relational learning in rodents by measuring escape latency and quadrant preference for a submerged platform.

Radial Arm Maze

An experimental apparatus with several arms radiating from a central platform used to measure rodent spatial learning and working memory via baited vs. unbaited arm entries.

Hippocampal Sharp-Wave Ripples

High-frequency oscillations occurring during slow-wave sleep associated with the accelerated ($5\text{--}20\times$ faster) replay of place cell sequences acquired during prior waking learning.