Memory

Procedural memory is a part of the long-term memory that is responsible for knowing how to do things, also known as motor skills. As the name implies, procedural memory stores information on how to perform certain procedures, such as walking, talking and riding a bike.  Procedural memory is sometimes referred to as implicit memory, because previous experiences aid in the performance of a task without explicit and conscious awareness of these previous experiences, although it is more properly a subset of implicit memory.

Declarative memory (“knowing what”) is memory of facts and events, and refers to those memories that can be consciously recalled (or "declared"). It is sometimes called explicit memory, since it consists of information that is explicitly stored and retrieved, although it is more properly a subset of explicit memory. Declarative memory can be further sub-divided into episodic memory and semantic memory.

Episodic memory is the memory of autobiographical events (times, places, associated emotions, and other contextual who, what, when, where, why knowledge) that can be explicitly stated. It is the collection of past personal experiences that occurred at a particular time and place.

Neurological Laws

Alexander's law refers to the phenomenon in which the spontaneous nystagmus of a patient with a vestibular lesion is more intense when the patient looks in the quick-phase than in the slow-phase direction. 

Forearm ischemic exercise screening test

There is evidence that ischemic exercise test can be harmful in patients with myopathies. Therefore recently non-ischemic forearm exercise test has been suggested. However in view of the long tradition of ischemic testing and the lack of sensitivity in mitochondrial myopathy the protocol for ischemic testing is given.

While the patient is at rest, blood samples are taken for baseline levels of lactate and ammonia. A blood pressure cuff is then placed over the upper arm and inflated to a pressure higher than systolic, rendering the forearm ischemic. The patient begins immediately repetitive, rapid grip exercises. Normal individuals are able to tolerate ischemic exercise for as long as 180 seconds before pain and fatigue ensues. Patients with glycogen metabolism disorders seldom exercise more than 60 seconds.

When the patient fatigues, the blood pressure cuff is released and 1 minute later blood is drawn from the exercised arm. Similar samples are taken again at 2,4,6,10,and 14 minutes following the end of the exercise.

Normal subjects exhibit a 3 to 5 fold rise in lactate and ammonia levels within 5 minutes after the end of the exercise, with a full return to baseline level about 10-15 minutes after cessation of the test. Failed lactate production suggest a metabolic block (myophosphorylase deficiency (McArdle disease)). The venous level of ammonia also rises during the test. Failure of the lactate and ammonia to rise suggests an inadequate test. Normal lactate but impaired ammonia production suggests myoadenylate deaminase deficiency or a related disorder of purine nucleotide metabolism.

Charcot-Bouchard aneurysms

Charcot-Bouchard aneurysms are a common cause of stroke. If a Charcot-Bouchard aneurysm ruptures, it will lead to an intracerebral hemorrhage.

• French physicians Jean-Martin Charcot and Charles-Joseph Bouchard described it. Bouchard discovered these aneurysms.
• Charcot-Bouchard aneurysms are associated with chronic hypertension.
• They are usually occur due to involvement of small penetrating (<300 µm) lenticulostriate branch of middle cerebral artery in the basal ganglia, brainstem and midbrain.

They are the reason why hypertensive bleed is most common in Basal Ganglia

Stiff Person Syndrome- Antibodies

The most common pathologic correlate is anti–glutamic acid decarboxylase (GAD) antibodies (It has been associated with a wide range of neurologic diseases). 

Additional possible pathophysiologic etiologies in patients negative for GAD antibody include postsynaptic elements such as synaptophysin, amphiphysin, gephyrin, and GABA-transaminase. 

It is also associated with a number of non-neurologic diseases, including diabetes mellitus and thyroiditis.

NOS

A dissociate disorder NOS (Not Otherwise Specified) is a disorder that includes a dissociative symptom (i.e., a disruption in the usually integrated functions of consciousness, memory, identity, or perception of the environment) that does not meet the criteria for any specific Dissociative Disorder. This disorder is no longer recognized in the 2013 DSM-5 and exists now for informational/historical purposes.

Examples-

• Presentations in which a) there are not two or more distinct personality states, or b) amnesia for important personal information does not occur.
• Derealization unaccompanied by depersonalization in adults.
• States of dissociation that occur in individuals who have been subjected to periods of prolonged and intense coercive persuasion (e.g., brainwashing, thought reform, or indoctrination while captive).
• Dissociative trance disorder: single or episodic disturbances in the state of consciousness, identity, or memory that are indigenous to particular locations and cultures. Dissociative trance involves narrowing of awareness of immediate surroundings or stereotyped behaviors or movements that are experienced as being beyond one’s control. Possession trance involves replacement of the customary sense of personal identity by a new identity, attributed to the influence of a spirit, power, deity, or other person, and associated with stereotyped “involuntary” movements or amnesia. Examples include amok (Indonesia), bebainan (Indonesia), latah (Malaysia), pibloktoq (Arctic), ataque de nervios (Latin America), and possession (India). The dissociative or trance disorder is not a normal part of a broadly accepted collective cultural or religious practice. 
• Loss of consciousness, stupor, or coma not attributable to a general medical condition.
• Ganser syndrome: the giving of approximate answers to questions (e.g., “2 plus 2 equals 5″) when not associated with Dissociative Amnesia or Dissociative Fugue.