Memory and its disorders

Memory is the organism's ability to receive, store and recall previous experiences.
 * It enables the preservation of past experience, it is a necessary condition for adaptation.
 * Memory is one of the functional systems of the brain (such as emotions, motor skills, …).
 * There are two main types of memory – phylogenetic and ontogenetic.

Phylogenetic Memory

 * Unconditioned reflexes
 * Instincts

Ontogenetic memory

 * Ontogenetic memory can be divided in different ways:
 * 1) declarative memory – conscious, explicit, verbal (statements), non-verbal (ideas);
 * 2) semantic component – ​​information obtained through certain specific experiences;
 * 3) episodic component – ​​contextual, memories of events.
 * 4) non- declarative memory –  procedural memory – implicit, not clearly aware, developmentally old memory, memory contents contained in various skills.
 * Clinical division:
 * 1) immediate – within 30 s;
 * 2) recent – ​​several months;
 * for remote events.


 * Division according to the retention time of the memory trace:
 * 1) short term;
 * 2) long term.


 * Division according to experimental physiology:
 * 1) working memory – processes in the short term;
 * 2) operational memory;
 * 3) stock.

Basic memory skills:
 * Ability to store (implantability, impregnation).
 * Ability to keep, fix (retention).
 * The ability not to change, to have stored without changes (conservation)
 * Ability to recall (reproduction).

Ultra short memory

 * The sensory register, lasting fractions of seconds to a second, is closely related to attention.

Short-term memory

 * It is based on  reverberation circuits (short-term temporary connection of neural networks along which the excitation circulates).
 * It lasts on the order of seconds, in the event of a malfunction, the ability to absorb is damaged (disorder of the reticular formation, frontal lobes).

Consolidation phase of memory - medium-term memory

 * Some circuits disappear in the short term, others persist, the emotional component, and the  principle of reward and punishment is important.
 * The limbic system and thehypothalamus, are mainly involved in emotional remembering.
 * The consolidation phase is the transition to long-term memory, it includes the creation of memory traces.
 * The limbic system is activated by reward and punishment, it strengthens the influence of appropriate stimuli.
 * Electrochemical changes occur - pharmacologically influenceable.
 * Acetylcholine is of great importance for this kind of memory.

Long-term memory

 * Long-term memory has a structural, morphological basis, the number of dendrites increases; in old age, due to toxins, their number decreases, during intensive learning, the number of dendrites increases; this process appears to underlie memory.
 * The mechanism of activation of spines in the hippocampus – AP activates the enzyme calpain I, thereby creating the substance fodrin, which is contained in the neuronal cytoskeleton, degrades and exposes excitatory AMK receptors.
 * The issue of localization is highly controversial.
 * A prerequisite for conscious memorization is a motive.
 * Determinants – the strength of the stimulus, emotional coloring, ability to concentrate, and emotional tuning.
 * Everyone has different dispositions, someone has a better visual, ...
 * Memory is impaired by fatigue and passivity.

Hypomnesia

 * Decreased memory performance, either globally or selectively.
 * Most often with organic impairment, as part of the dementia syndrome.
 * When tired, due to drugs, toxins.
 * In dementia, inculpability is mainly impaired.
 * Confabulation – the affected person answers the questions closely but factually incorrectly, but he is nevertheless convinced that he is right, and in a moment he can answer the same question differently.
 * Amnestic disorientation – a total implantable disorder.

Korczak syndrome

 * Impulsivity disorder, confabulation, amnestic disorientation.
 * Alcohol dementia, Alzheimer's disease.

Amnesia

 * Complete memory loss, usually limited in time, full or selective.
 * Retrograde, anterograde.
 * Common in quantitative disorders of consciousness, after injury.
 * Continuous or island-like (delirium, alcohol intoxication - e.g. window -palimpsest).
 * Selective amnesia – in hysterical persons, it displaces unpleasant memories.

Transient global amnesia

 * Amnestic stroke: a sudden memory disorder, mainly organic, caused by a strong stressor, starts suddenly, ends suddenly.
 * Psychogenic amnesia
 * Dissociative amnesia: dissociative fugues (wandering), influenced by hypnosis.

Hypermnesia

 * Excessive, disproportionate memorization of certain selective material.
 * Usually part of paranoid psychoses (remembers associations related to delusion).
 * In neuroses, mania.

Paramnesia

 * Distortion of the stored content, but the person has a sense of accuracy.

Memory Delusion

 * In pathic paramnesia, the bearer is irresistibly convinced of the reality of a certain idea, typical ofpsychosis and personality disorders.

Ecmnesis

 * Inaccurate temporal localization of the correct memory

Cryptomnesia

 * In unintentional plagiarism, the patient is convinced of the authorship of something that he did not invent himself, but read or heard somewhere.

Pseudologia phantastica

 * "Baron Prasil's Syndrome“, is a fabulous lie - it is not a true memory disorder, typical of hysteria, even in children.

Attention (prosexy)

 * Attention is a mental function, it can be described as focused perception.
 * It is the ability to purposefully select certain perceptions from a complex of perceived stimuli.

Characteristics of attention:
 * 1) concentration – the intensity of focus;
 * 2) capacity – an indicator of the extent of attention, the number of perceptions that we can simultaneously monitor;
 * 3) tenacity - constancy, perseverance;
 * 4) irritability – threshold of intensity of stimuli capable of binding attention;
 * 5) vigilance - the ability to distribute it.

Dividing attention
 * 1) active;
 * 2) passive (unintentional).


 * A certain level of alertness (ARAS) and sufficient motivation are needed to maintain attention.

Hypoprosexia

 * Decreased attention span.
 * General or selective.
 * Overall, mainly in dementia, and severe depression.
 * Oligophrenia, including neuroses, pharmaceuticals (barbiturates, neuroleptics).

Hyperprosexy

 * More often selective.
 * Manic syndrome – increased irritability, tenacity, and distribution, but attention tends to be unstable and oscillates.

Paraprosexy

 * The incorrect focus of attention.
 * For example,schizophrenia – excessive focus on delusions.

Related Articles

 * Amnestic syndrome