Behavioral Neuroscience - Circadian Rhythms

This set of flashcards covers key vocabulary and concepts related to circadian rhythms and their biological significance as studied in Behavioral Neuroscience.

Circadian Rhythms

Biological processes that display a rhythm of about 24 hours.

Diurnal

Active during the light, as seen in humans and dogs.

Nocturnal

Active during the dark, as seen in bats and skunks.

Crepuscular

Active during twilight, shortly before sunrise and after sunset, as seen in house cats and rabbits.

Endogenous Clock

The internal mechanism that generates circadian rhythms.

Zeitgeber

A cue, such as light, that synchronizes the endogenous clock.

Free Running

When organisms are not exposed to external cues, they rely solely on their internal clock.

Suprachiasmatic Nucleus (SCN)

The main biological clock, located above the optic chiasm in the hypothalamus.

Frankenhamsters

Hamsters used to study the effects of genetic mutations on circadian rhythms.

Melanopsin

A photopigment found in intrinsically photosensitive retinal ganglion cells.

Intrinsic Photosensitive Retinal Ganglion Cells (ipRGCs)

Retinal cells that help transmit light information to the SCN.

Pupillary Light Reflex (PLR)

A rapid constriction of the pupil in response to intense light.

Molecular Clock

The process in the SCN that regulates circadian rhythms through protein production and degradation.

PER and CRY proteins

Proteins that are part of the feedback loop controlling circadian rhythms.

Chronotype

An individual's natural preference for sleep and wake times.

Infradian Rhythms

Biological rhythms longer than a day, such as reproductive cycles.

Ultradian Rhythms

Biological rhythms shorter than a day, such as feeding or hormone release.

Circannual Rhythm

Biological rhythms that cycle approximately once a year.

Melatonin

A hormone released by the pineal gland, affected by light exposure.

Blue Light

A type of light that significantly suppresses melatonin secretion.

Retinohypothalamic Pathway

The pathway through which light information travels from the retina to the SCN.

Light-Dark Cycle

The daily cycle of light and darkness that influences circadian rhythms.

Phase Shift

A change in the timing of the biological clock in response to external cues.

Light Conditions

The external environmental factors that can influence circadian rhythms.

Melatonin Secretion

The release of melatonin which is inhibited by light.

Pineal Gland

The gland that secretes melatonin in response to darkness.

Ganglion Cells

Retinal cells that transmit signals to the SCN and contain melanopsin.

Photopigment

A light-sensitive protein found in certain cells.

Activity Plots

Graphs that record the activity patterns of organisms over time.

SCN Lesions

Damage to the suprachiasmatic nucleus that disrupts circadian rhythms.

Behavioral Synchronization

The alignment of an organism's behavior with environmental cycles.

Optic Chiasm

The part of the brain where optic nerves cross; located near the SCN.

Daily Cycle

The regular cycle of day and night impacting biological processes.

Environmental Cues

External signals that influence biological rhythms.

Genetic Mutation

A change in DNA that can affect circadian rhythms, as seen in tau mutants.

Seasonal Mating Behavior

Reproductive activities in animals that can be influenced by a circannual clock.

Hamster Wheel Activity

Observed behavior in hamsters used to study circadian rhythms.

Dim Light Conditions

Light levels that can still influence circadian rhythms within a certain spectrum.

Physiological Changes

Alterations in physical and biochemical processes dependent on circadian rhythms.

Dimerization

The process of two proteins binding together, significant in clock function.

Glutamate

A neurotransmitter released by ipRGCs that promotes circadian rhythm alignment.

Night Owls

Individuals who prefer to sleep late and wake later.

Morningness–Eveningness Questionnaire (MEQ)

A tool used to assess an individual's chronotype.

Evening-Type (E-Type)

Another term for night owls, reflecting their sleep patterns.

Morning-Type (M-Type)

Individuals who prefer to wake early and sleep early.

Activity Bouts

Periods of heightened activity, part of ultradian rhythms.

Hormone Release Patterns

Variations in hormone secretions in accordance with biological rhythms.

External Environment

The surroundings that can affect biological rhythms.

Behavioral Patterns

Repeated ways in which organisms respond to environmental cues.

Psychological Impacts

Effects of circadian rhythms on mental states and behavior.

Synchronized Behavior

Timing of biological functions in accordance with environmental changes.

Light Exposure Duration

The length of time an organism is exposed to light in a cycle.

Environmental Synchronization

The alignment of internal clocks to external time cues.

Molecular Feedback Loop

The cycle through which proteins regulate circadian rhythms and gene expression.

Endogenous Circannual Clock

An internal clock that regulates annual biological rhythms.

Long Nights Effect

Increased melatonin production during extended dark periods in winter.

Seasonal Changes

Alterations in behavior and physiology with the changing seasons.

Genetic Influence

How genes affect circadian rhythms and individual differences in sleep patterns.

Protein Cycle

The regular pattern of production and degradation of proteins in circadian processes.

Ganglion Cell Types

Different types of cells in the retina contributing to circadian light signaling.

Anticipation of Events

The ability to predict environmental changes based on circadian rhythms.

Sleep-Wake Cycle

The regular pattern of sleeping and waking as influenced by circadian rhythms.

Biological Processes

Functions performed by living organisms that are time-dependent.

Retinal Pathways

The connections that relay light signals to the brain.

Circadian Alignment

The synchronization of behavior to the natural light-dark cycle.

Adaptive Mechanisms

The strategies organisms develop to optimize functioning based on circadian rhythms.

Behavioral Neuroscience

The study of the relationship between behavior and biological processes.

Hamster Activity Rhythm

The daily pattern of activity observed in hamsters related to light cycles.

Free-Running Periods

Cycles of activity when organisms are isolated from light cues.

Shortened Sleep Duration

Less sleep time associated with phase shifts and environmental changes.

Light Manipulation

The method of altering light exposure to study effects on circadian rhythms.

Biological Wiring

The connections in the brain regulating circadian rhythms.

Behavioral Research

The investigation of how biological processes impact behavior.

Chronobiology

The science of biological rhythms and their effects on life.

Functional Anatomy

The relationship between the structures of the SCN and their functions.

Mammalian Adaptations

Changes in mammals’ biological systems due to environmental influences.

Experimental Studies

Research designs testing hypotheses regarding biological rhythms.

Light Sensitivity

The degree to which cells like ipRGCs react to different light conditions.

Physiological Adaptations

Changes in body functions influenced by circadian rhythms.