[Role of dopamine-dependent negative feedback in the hippocampal--basal ganglia--thalamo---hippocampal loop in response decrement].
The mechanism of response decrement in hippocampal and dopaminergic neurons on repeating stimuli based on the dopamine-dependent negative feedback in the hippocampal--basal ganglia--thalamo--hippocampal loop is suggested. Activation of hippocampal neurons caused by new stimulus facilitates occurrence of reaction of dopaminergic cells due to their disinhibition through striatopallidal cells of nucleus accumbens and ventral pallidum. However, increase in dopamine level and activation accumbens and ventral pallidum. However, increase in dopamine level and activation of D2 receptors on the striatopallidal cell, while promoting depression of hippocampal inputs, prevents disinhibition of dopaminergic cells, and their reactions start their decrement. The subsequent decrease in D1 receptor activation leads to reduction of efficiency of neuron excitation in the hippocampal CA1 fields, as well as in striatonigral cells of nucleus accumbens. This leads to a decrease of disinhibition through a direct pathway via the basal ganglia of thalamic nucleus reunions which activates neurons of the CA1 field. This effect causes decrement of reactions of the hippocampal neurons, a subsequent reduction of dopaminergic cell disinhibition, and further decrement of their responses.
Sil'kis
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D000818:Animals; D004298:Dopamine / Q000378:metabolism; D005917:Globus Pallidus / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D013788:Thalamus / Q000502:physiology*
D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D004298:Dopamine