Abstract
People get accustomed to the experience of time. An almost constant movement from the past towards the future appears psychologically inevitable and similar to gravitation, which physically and inevitably appears to pull us towards the center of the earth. This contribution describes conditions which change the perception of time; Alzheimer's disease, which eliminates the recent past; frontotemporal dementia, which diminishes curiosity, fear, and further future concerns; and delirium with a loss of a laminar stream of consciousness or time. It may be a coincidence that brain structures primarily dealing with the past rest in the back of the head, while structures considering future prospects sit in the frontal lobe, and a laminar processing of the present relies on an intact central brain structure. Even though physical time may continue as usual, its perception and validation is subject to cerebral distortions.
Keywords: Time, neurobiology, neurodegeneration, confusional state, dementia, frontotemporal lobar degeneration, dementia with lewy bodies, pick, alzheimer.