Effects of Heating Hypothalamus of Dogs by Diathermy

Septal and Hypothalamic Stimulation of Unanesthetized Cats

“…Less vigorous shivering, with a greater latency of onset, was produced during stimulation of the lateral septal region of the forebrain. When stimulating anesthetized cats to suppress shivering, a greater stimulus intensity was necessary for the medial septum than for the dorso-lateral boundary of the anterior hypothalamus and preoptic region, an area shown by others (Magoun et al, 1938;Hemingway et al, 1940;Andersson et al, 1956) to integrate heat loss mechanisms. Cold-induced shivering was abolished, or markedly reduced, in unanesthetized cats with lesions in the dorso-medial posterior hypothalamus.…”

Effects of septal and hypothalamic lesions on shivering☆

“…Shivering, long known to be suppressed during localized warming of the pre-optic anterior hypothalamic region (Hemingway et al, 1940;Magoun et al, 1938), has recently been evoked by cooling the same region with little or no fall in skin temperature (Andersson and Larsson, 1961;Chatonnet, 1961;Hammel et al, 1960). This suggests but, in the absence of sufficient microelectrode experimentation, not altogether proves that brain temperature is "sensed" in this discrete prosencephalic region and that shivering can be evoked by its thermal activation without the support of a peripheral input from cudtaneous "cold" fibers.…”

Activation and suppression of shivering during septal and hypothalamic stimulation

“…Although there are some fornical fibers that project through both the septum and hypothalamus to make direct connections with the midbrain (Nauta, 1958;Sprague and Meyer, 1950), neither these fibers nor those septal projections to the thalamus could produce shivering, since the thalamus and also the hippocampus, from which the fornical fibers arise, can be ablated without affecting the production of shivering. Anterior hypothalamic stimulation, either thermal (Hemingway et al, 1940;Magoun et al, 1938) or electrical (Andersson et al, 1956;Hemingway et al, 1954), is known to suppress shivering. There are septal projections to both anterior and posterior hypothalamic regions.…”