[The effect of the hypothalamic motivational centers on the function of the cortical visual area of the hemispheres].
Chronic experiments were carried out in waking rabbits. A single stimulation of the middle hypothalamus (the ventromedial, VMN, and the lateral, LN, nuclei) was shown to induce the phasic action on a formation of the primary response (PR) of the visual cortex (VC) to the testing light flash. At the first phase (1-43 ms for the VMN and 1-10 ms for the LN) the hypothalamic-cortical responses completely inhibited the formation of the VC response to the light stimulus. At the second phase (43-130 ms for the VMN and 10-150 ms for the LN) they selectively and rather significantly facilitated the formation of the positive PR component the negative one being suppressed. This suppression was stronger and longer during the stimulation of the VMN, than that of the LN (140 and 50 ms correspondingly). The data obtained suggested the existence of a highly organized apparatus of the phasic (both by the VMN and LN) control of the VC function being realized both by means of facilitatory axo-somatic mechanisms at the level of the basal dendrites of the layer IV cortical neurons, and by means of the inhibitory mechanisms at the level of the apical dendrites of the superficial cortical layers.
Gadzhieva
N A
NA
Dmitrenko
A I
AI
D000818:Animals; D004558:Electric Stimulation / Q000379:methods; D004567:Electrodes, Implanted; D005074:Evoked Potentials, Visual / Q000502:physiology; D007033:Hypothalamus, Middle / Q000502:physiology*; D008297:Male; D009042:Motivation; D010775:Photic Stimulation / Q000379:methods; D011817:Rabbits; D014793:Visual Cortex / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology