These brain regions are all parts of the limbic system, which is heavily involved in emotion and memory. KS involves neuronal loss, that is, damage to neurons; gliosis, which is a result of damage to supporting cells of the central nervous system, and bleeding also occurs in mammillary bodies. Damage to the medial dorsal nucleus or anterior nuclei of the thalamus (limbic-specific nuclei) is also associated with this disorder. Cortical dysfunction may have arisen from thiamine deficiency, alcohol neurotoxicity, and/or structural damage in the diencephalon.Originally, it was thought that a lack of initiative and a flat affect were important characteristics of emotional presentation in those affected. Studies have questioned this, proposing that neither is necessarily a symptom of KS. Research suggesting that people with Korsakoff syndrome are emotionally unimpaired has made this a controversial topic. It can be argued that apathy, which is a usual characteristic, reflects a deficit of emotional expressions, without affecting the experience or perception of emotion.KS causes deficits in declarative memory in most people, but leaves implicit spatial, verbal, and procedural memory functioning intact. People with KS have deficits in the processing of contextual information. Context memories refers to the where and when of experiences, and is an essential part of recollection. The ability to store and retrieve this information, such as spatial location or temporal order information, is impaired. Research has also suggested that people with Korsakoff syndrome have impaired executive functions, which can lead to behavioral problems and interfere with daily activities.
It is unclear, however, which executive functions are affected most. Nonetheless, IQ is usually not affected by the brain damage associated with Korsakoffs syndrome.At first it was thought that those with KS used confabulation to fill in memory gaps. However, it has been found that confabulation and amnesia do not necessarily co-occur. Studies have shown that there is dissociation between provoked confabulation, spontaneous confabulation (which is unprovoked), and false memories. That is, people affected could be led to believe certain things had happened which actually had not, but so could people without Korsakoff syndrome. Causes
Conditions resulting in thiamine deficiency and its effects include chronic alcoholism and severe malnutrition. Alcoholism may co-occur with poor nutrition, which in addition to inflammation of the stomach lining, causes thiamine deficiency. Other causes include dietary deficiencies, prolonged vomiting, eating disorders, and the effects of chemotherapy. It can also occur in pregnant women who have a form of extreme morning sickness known as hyperemesis gravidarum. Mercury poisoning can also lead to Korsakoff syndrome. Though it does not always co-occur, this disorder can emerge frequently as a consequential result of Wernickes encephalopathy.PET scans show that there is a decrease of glucose metabolism in the frontal, parietal and cingulated regions of the brain in those with Korsakoff syndrome. This may contribute to memory loss and amnesia. Structural neuroimaging has also shown the presence of midline diencephalic lesions and cortical atrophy.Structural lesions of the central nervous system, though rare, can also contribute to symptoms of KS.