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Hyperadrenergic orthostatic hypotension refers to an orthostatic drop in blood pressure despite high levels of sympathetic adrenergic response. This occurs when a person with normal physiology is unable to compensate for >20% loss in intravascular volume. [26] This may be due to blood loss, dehydration or third-spacing. On standing the person ...
Alcohol acts as a general central nervous system depressant, but it also affects some specific areas of the brain to a greater extent than others. Memory impairment caused by alcohol has been linked to the disruption of hippocampal function—particularly affecting gamma-Aminobutyric acid (GABA) and N-methyl-D-aspartate (NMDA) neurotransmission which negatively impacts long-term potentiation ...
Episodes of vasovagal syncope are typically recurrent and usually occur when the predisposed person is exposed to a specific trigger. Before losing consciousness, the individual frequently experiences early signs or symptoms such as lightheadedness, nausea, the feeling of being extremely hot or cold (accompanied by sweating), ringing in the ears, an uncomfortable feeling in the heart, fuzzy ...
In addition, reduced glutamate release in the dorsal hippocampus has been linked to spatial memory loss. Chronic alcohol users experience an upregulation of NMDA receptors because the brain is attempting to reestablish homeostasis. When a chronic alcohol user stops drinking for more than 10 hours, apoptosis can occur due to excitotoxicity. The ...
Amnesic patients with damage to the hippocampus are able to demonstrate some degree of unimpaired semantic memory, despite a loss of episodic memory, due to spared parahippocampal cortex. [38] In other words, retrograde amnesics "know" about information or skill, but cannot "remember" how they do.
These molecular abnormalities damage the cerebellum and hippocampus, which results in deficiencies in long-term memory functions and spatial working memory. Chronic sleep deprivation also raises the brain's amyloid-beta aggregation, which is linked to neurodegenerative diseases like Alzheimer's.
The attack was witnessed by a capable observer and reported as being a definite loss of recent memory (anterograde amnesia). There was an absence of clouding of consciousness or other cognitive impairment other than amnesia. There were no focal neurological signs or deficits during or after the attack.
In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of the brain to suffer damage; short-term memory loss and disorientation are included among the early symptoms. Damage to the hippocampus can also result from oxygen starvation , encephalitis, or medial temporal lobe epilepsy.