Neurobiology of passive avoidance impairment after ischemia.

Fatigue in Multiple Sclerosis

“…The neurobiology is suggested by operant conditioning of hippocampal CAl pyramidal cell bursting at different concentrations of dopamine lateralized to the right hemisphere, showing a sharp peak at 1 mM and falling off abruptly when this optimal concentration of dopamine was either halved or doubled. 2 This hypothesis is supported by profound effects on neuronal integration due to either an increase or a decrease in monoaminergic inputs 3 and by dopamine release in passive avoidance impairment after ischemia. It is also supported by the contribution of articulatory rehearsal to short-term memory 2 guiding the temporal organization of behavior, 3 by optimal response organization at intermediate dopamine tone in a medialfrontal-striatal activation system, by the concept of cellular tone, and by a neurochemical model underlying differences in reaction times between introverts and extroverts.…”

Reply from the author:

“…The neurobiology is suggested by operant conditioning of hippocampal CAl pyramidal cell bursting at different concentrations of dopamine lateralized to the right hemisphere, showing a sharp peak at 1 mM and falling off abruptly when this optimal concentration of dopamine was either halved or doubled. 2 This hypothesis is supported by profound effects on neuronal integration due to either an increase or a decrease in monoaminergic inputs 3 and by dopamine release in passive avoidance impairment after ischemia. It is also supported by the contribution of articulatory rehearsal to short-term memory 2 guiding the temporal organization of behavior, 3 by optimal response organization at intermediate dopamine tone in a medialfrontal-striatal activation system, by the concept of cellular tone, and by a neurochemical model underlying differences in reaction times between introverts and extroverts.…”

“…2 This hypothesis is supported by profound effects on neuronal integration due to either an increase or a decrease in monoaminergic inputs 3 and by dopamine release in passive avoidance impairment after ischemia. It is also supported by the contribution of articulatory rehearsal to short-term memory 2 guiding the temporal organization of behavior, 3 by optimal response organization at intermediate dopamine tone in a medialfrontal-striatal activation system, by the concept of cellular tone, and by a neurochemical model underlying differences in reaction times between introverts and extroverts. The fact that delay-dependent speeding of reaction time, indicating motor readiness, is abolished by depletion of dopamine, prompts the evaluation of the neuromodulation 4 of cortical silent periods 5 in the detection of a missing temporal or "clocking cue" by monitoring temporal features of expressive activity.…”

“…4 This strategy may be implemented by monitoring speech hesitation and switching pauses in emotionally charged dialogues, reflecting properties of neuronal activity and firing. 2 Ernest H. Friedman, M.D.…”