Several key regions of the forebrain are involved in regulation of autonomic functions. These areas include the several areas within the hypothalamus (viz., paraventricular hypothalamic nucleus, lateral hypothalamic area, posterior periventricular area, and zona incerta), the basal forebrain (viz., central nucleus of the amygdala and bed nucleus of the stria terminalis), and the cerebral cortex (viz., insular and medial prefrontal cortex). All these areas have been implicated on anatomical grounds to be part of a central autonomic network involving multiple interconnecting circuits. Apart from these complex interconnections, most of these areas project to the lower brain stem where they are capable of influencing the cell groups which innervate the vagal and sympathetic preganglionic neurons or in some cases, like the paraventricular hypothalamic nucleus and the lateral hypothalamic area, provide direct projections to these neurons.