Neuroscience

Biological rhythms

A regular fluctuation in any living process, such as hormone levels, body temperature, and drug sensitivity.

Circadian rhythms

A pattern of behavior, biochemical, or physiological fluctuation that has a 24-hour period.

Ultradian rhythms

rhythmic biological events that last shorter than a day, such as bouts of activity, feeding, and hormone release

Infradian rhythms

rhythmic biological events that last longer than a day, such as menstrual cycles, and behavioral disorders

Free-running

referring to a rhythm of behavior shown by an animal deprived of external cues about time of day

Suprachiasmatic Nucleus (SCN)

A region located above the optic chiasm in the hypothalamus that houses the circadian clock.

Retinohypothalamic pathway

The route by which specialized retinal ganglion cells send their axons to the SCN to convey information about light.

melanopsin

a photopigment found in retinal ganglion cells that project light stimuli to the SCN

Electroencephalography (EEG)

the recording of gross electrical activity of the brain via large electrodes placed on the scalp; provides a way to define, describe, & classify levels of arousal & states of sleep

REM sleep

Paradoxical sleep; A stage of sleep characterized by small-amplitude, fast EEG waves, no postural tension, and rapid eye movements.

Non-REM sleep

Sleep divided into stages 1-3, defined by distinctive EEG activity different from that seen in REM sleep.

Beta waves

Desynchronized EEG; low-amplitude waves with many relatively fast frequencies; >15-20 Hz; awake & alert adult

Alpha waves

8-12 Hz; relaxed adult with eyes-closed

Stage 1 Sleep

the initial stage of non-REM sleep, which is characterized by vertex spikes, slow heart rate, & reduced muscle tension; usually lasts several minutes

Stage 2 Sleep

a stage of non-REM sleep that is defined by sleep spindles & K complexes; if woken people will deny being asleep

Stage 3 Sleep

Slow Wave Sleep (SWS); a stage of non-REM sleep that is defined by the presence of large amplitude, slow delta waves

Sleep recovery

The process of sleeping more than normally after a period of sleep deprivation, compensating for lost sleep.

Orexin

A neuropeptide produced in the hypothalamus that is involved in switching between sleep states.

Night terrors

Sudden arousal from stage 3 sleep marked by intense fear and autonomic activation, typically affecting children.

Sleep apnea

A sleep disorder where respiration slows or stops periodically, resulting in excessive daytime sleepiness.

Emotion

A subjective mental state usually accompanied by distinctive cognition, behaviors, and physiological changes.

Sympathetic nervous system

Part of the autonomic nervous system that acts as the fight-or-flight system, preparing the body for action.

Parasympathetic nervous system

Part of the autonomic nervous system that generally prepares the body to relax and recuperate.

James-Lange theory

The theory that bodily responses cause emotional experiences; autonomic reactions trigger feelings.

Cannon-Bard theory

The theory that the brain interprets a situation to decide which emotion is appropriate, resulting in simultaneous emotional experience and autonomic reaction.

Folk psychology

The notion that feelings trigger autonomic reactions.

Schachter & Singer theory

The theory suggesting that individuals cognitively attribute specific emotions to arousal based on context.

Basic emotions

Proposed by Plutchik, these are eight core emotions grouped in four pairs of opposites: joy/sadness, affection/disgust, anger/fear, expectation/surprise.

Facial expressions

Distinctive expressions that convey emotions such as anger, sadness, happiness, fear, disgust, surprise, and contempt, as suggested by Ekman

Brain self-stimulation

The process where animals work to provide electrical stimulation to particular brain sites, presumably because the experience is rewarding.

Medial Forebrain Bundle

A collection of axons traveling in the midline region of the forebrain that is concentrated with brain sites supporting self-stimulation responses.

Decorticate rage

Sudden intense rage characterized by actions lacking clear direction that occurs after the cortex is removed from dogs.

Limbic system

A network of brain nuclei implicated in emotions, including the amygdala, which is crucial for emotional learning.

Fear conditioning

A form of classical conditioning where a previously neutral stimulus elicits responses of fear after being paired with an unpleasant stimulus.

Amygdala

A group of nuclei in the medial part of the temporal lobe that is crucial for adverse conditioning and appetitive learning.

Low road pathway

A direct neural route from the thalamus to the amygdala that allows for immediate emotional reactions to stimuli.

High road pathway

A neural pathway that routes information through the sensory cortex for conscious and fine-grained emotional processing.

Cingulate cortex

A brain region whose activity is altered in different emotions like sadness, happiness, and anger.

Aggression

Behavior that is intended to cause pain or harm to others, whether physical, emotional, or mental.

Intermale aggression

Aggression observed between males of the same species.

Medial amygdala

A portion of the amygdala that receives olfactory and pheronomonal information.

Ventromedial hypothalamus (VMH)

A region of the hypothalamus involved in sexual behaviors, eating, and aggression, and serves as a trigger to activate aggressive behavior.

Maternal aggression

Aggressive behavior of a mother defending her nest or offspring, controlled by circuits in the VMH and other regions.

Psychopath

An individual incapable of experiencing remorse, often intelligent and charming but with poor self-control and grandiose self-worth.

Stress

Any circumstance that upsets homeostatic balance.

Stress Response Stages

Progresses through alarm system activation, fight-or-flight response, and HPA axis activation.

Epinephrine

A compound that acts both as a hormone and a synaptic transmitter, involved in the fight-or-flight response.

Norepinephrine

A neurotransmitter produced by sympathetic postganglionic neurons to accelerate organ activity.

Cortisol

A glucocorticoid stress hormone secreted by the adrenal cortex, involved in the stress response.

Childhood Stress

Has an enduring impact on health in later life, affecting neural development and emotional regulation.

Stress Immunization

A hypothesis suggesting early stress can enhance resilience to later stress, given proper parental comfort.

Maternal Deprivation

Causes long-lasting changes in epigenetic regulation, affecting responses to stress.

Psychosomatic Medicine

Study emphasizing the role of psychological factors in disease.

Health Psychology

Focuses on psychological influences on health-related processes.

Psychoneuroimmunology

The study of the immune system and its interaction with the nervous system and behavior.

Chronic Stress Effects

Long-lasting stress has pronounced suppressive effects on the immune system.

Relaxation Training

Focusing on calming thoughts and muscle relaxation to reduce stress.

Mindfulness-Based Stress Reduction (MBSR)

Pairs relaxation with present-moment awareness, reducing anxiety and preventing relapses.