Post-traumatic stress disorderPost-traumatic stress disorder (PTSD) is a mental and behavioral disorder that develops from experiencing a traumatic event, such as sexual assault, warfare, traffic collisions, child abuse, domestic violence, or other threats on a person's life or well-being. Symptoms may include disturbing thoughts, feelings, or dreams related to the events, mental or physical distress to trauma-related cues, attempts to avoid trauma-related cues, alterations in the way a person thinks and feels, and an increase in the fight-or-flight response.
Rapid eye movement sleepRapid eye movement sleep (REM sleep or REMS) is a unique phase of sleep in humans, mammals and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream vividly. The REM phase is also known as paradoxical sleep (PS) and sometimes desynchronized sleep or dreamy sleep, because of physiological similarities to waking states including rapid, low-voltage desynchronized brain waves.
FearFear is an intensely unpleasant emotion in response to perceiving or recognizing a danger or threat. Fear causes physiological changes that may produce behavioral reactions such as mounting an aggressive response or fleeing the threat. Fear in human beings may occur in response to a certain stimulus occurring in the present, or in anticipation or expectation of a future threat perceived as a risk to oneself.
Complex post-traumatic stress disorderComplex post-traumatic stress disorder (CPTSD) is a stress-related mental disorder generally occurring in response to complex traumas, i.e. commonly prolonged or repetitive exposures to a series of traumatic events, within which individuals perceive little or no chance to escape. In the ICD-11 classification, CPTSD is a category of post-traumatic stress disorder (PTSD) with three additional clusters of significant symptoms: emotional dysregulations, negative self-beliefs (e.g.
HippocampusThe hippocampus (via Latin from Greek ἱππόκαμπος, 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. The hippocampus is located in the allocortex, with neural projections into the neocortex in humans, as well as primates.
GlucocorticoidGlucocorticoids (or, less commonly, glucocorticosteroids) are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every vertebrate animal cell. The name "glucocorticoid" is a portmanteau (glucose + cortex + steroid) and is composed from its role in regulation of glucose metabolism, synthesis in the adrenal cortex, and its steroidal structure (see structure below).
Sleep disorderA sleep disorder, or somnipathy, is a medical disorder of an individual's sleep patterns. Some sleep disorders are severe enough to interfere with normal physical, mental, social and emotional functioning. Polysomnography and actigraphy are tests commonly ordered for diagnosing sleep disorders. Sleep disorders are broadly classified into dyssomnias, parasomnias, circadian rhythm sleep disorders involving the timing of sleep, and other disorders including ones caused by medical or psychological conditions.
Neuroscience of sleepThe neuroscience of sleep is the study of the neuroscientific and physiological basis of the nature of sleep and its functions. Traditionally, sleep has been studied as part of psychology and medicine. The study of sleep from a neuroscience perspective grew to prominence with advances in technology and the proliferation of neuroscience research from the second half of the twentieth century. The importance of sleep is demonstrated by the fact that organisms daily spend hours of their time in sleep, and that sleep deprivation can have disastrous effects ultimately leading to death in animals.
Fear of flyingFear of flying is a fear of being on an airplane, or other flying vehicle, such as a helicopter, while in flight. It is also referred to as flying anxiety, flying phobia, flight phobia, aviophobia, aerophobia, or pteromerhanophobia (although aerophobia also means a fear of drafts or of fresh air). Acute anxiety caused by flying can be treated with anti-anxiety medication. The condition can be treated with exposure therapy, which works better when combined with cognitive behavioral therapy.
Extinction (psychology)Extinction is a behavioral phenomenon observed in both operantly conditioned and classically conditioned behavior, which manifests itself by fading of non-reinforced conditioned response over time. When operant behavior that has been previously reinforced no longer produces reinforcing consequences the behavior gradually stops occurring. In classical conditioning, when a conditioned stimulus is presented alone, so that it no longer predicts the coming of the unconditioned stimulus, conditioned responding gradually stops.
Depersonalization-derealization disorderDepersonalization-derealization disorder (DPDR, DPD) is a mental disorder in which the person has persistent or recurrent feelings of depersonalization and/or derealization. Depersonalization is described as feeling disconnected or detached from one's self. Individuals may report feeling as if they are an outside observer of their own thoughts or body, and often report feeling a loss of control over their thoughts or actions. Derealization is described as detachment from one's surroundings.
PhobiaA phobia is an anxiety disorder, defined by a persistent and excessive fear of an object or situation. Phobias typically result in a rapid onset of fear and are usually present for more than six months. Those affected go to great lengths to avoid the situation or object, to a degree greater than the actual danger posed. If the object or situation cannot be avoided, they experience significant distress. Other symptoms can include fainting, which may occur in blood or injury phobia, and panic attacks, often found in agoraphobia and emetophobia.
Sleep cycleThe sleep cycle is an oscillation between the slow-wave and REM (paradoxical) phases of sleep. It is sometimes called the ultradian sleep cycle, sleep–dream cycle, or REM-NREM cycle, to distinguish it from the circadian alternation between sleep and wakefulness. In humans, this cycle takes 70 to 110 minutes (90 ± 20 minutes). Electroencephalography shows the timing of sleep cycles by virtue of the marked distinction in brainwaves manifested during REM and non-REM sleep.
Rapid eye movement sleep behavior disorderRapid eye movement sleep behavior disorder or REM behavior disorder (RBD) is a sleep disorder in which people act out their dreams. It involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. The major feature of RBD is loss of muscle atonia (i.e., the loss of paralysis) during otherwise intact REM sleep (during which paralysis is not only normal but necessary). The loss of motor inhibition leads to sleep behaviors ranging from simple limb twitches to more complex integrated movements that can be violent or result in injury to either the individual or their bedmates.
Ventromedial prefrontal cortexThe ventromedial prefrontal cortex (vmPFC) is a part of the prefrontal cortex in the mammalian brain. The ventral medial prefrontal is located in the frontal lobe at the bottom of the cerebral hemispheres and is implicated in the processing of risk and fear, as it is critical in the regulation of amygdala activity in humans. It also plays a role in the inhibition of emotional responses, and in the process of decision-making and self-control. It is also involved in the cognitive evaluation of morality.
SleepSleep is a state of reduced mental and physical activity in which consciousness is altered and sensory activity is inhibited to a certain extent. During sleep, there is a decrease in muscle activity, and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli, it still involves active brain patterns, making it more reactive than a coma or disorders of consciousness. Sleep occurs in repeating periods, during which the body alternates between two distinct modes: REM and non-REM sleep.
Memory consolidationMemory consolidation is a category of processes that stabilize a memory trace after its initial acquisition. A memory trace is a change in the nervous system caused by memorizing something. Consolidation is distinguished into two specific processes. The first, synaptic consolidation, which is thought to correspond to late-phase long-term potentiation, occurs on a small scale in the synaptic connections and neural circuits within the first few hours after learning.
Sleep paralysisSleep paralysis is a state, during waking up or falling asleep, in which one is conscious but is unable to move or speak. During an episode, one may hallucinate (hear, feel, or see things that are not there), which often results in fear. Episodes generally last no more than a few minutes. It can recur multiple times or occur as a single episode. The condition may occur in those who are otherwise healthy or those with narcolepsy, or it may run in families as a result of specific genetic changes.
Classical conditioningClassical conditioning (also respondent conditioning and Pavlovian conditioning) is a behavioral procedure in which a biologically potent physiological stimulus (e.g. food) is paired with a neutral stimulus (e.g. the sound of a musical triangle). The term classical conditioning refers to the process of an automatic, conditioned response that is paired with a specific stimulus. The Russian physiologist Ivan Pavlov studied classical conditioning with detailed experiments with dogs, and published the experimental results in 1897.
Exposure therapyExposure therapy is a technique in behavior therapy to treat anxiety disorders. Exposure therapy involves exposing the target patient to the anxiety source or its context without the intention to cause any danger (desensitization). Doing so is thought to help them overcome their anxiety or distress. Procedurally, it is similar to the fear extinction paradigm developed for studying laboratory rodents.
