Activity Detail
Seminar
Interoceptive information onto orexin neurons by insulin-like growth factor I
SEMINAR Prof. Ignacio Torres Aleman
The brain receives external (sensory) and internal (interoceptive) information and computes it to produce behavioral outputs accordingly. Internal bodily states are transmitted to the brain through interoceptive pathways comprising humoral factors and the peripheral nervous system. During the last decades we have been analyzing the role of circulating IGF-I as a neuroactive signal participating in a striking variety of processes. Although IGF-I receptors are widely distributed in the brain, we explore the possibility that IGF-I modulates functional hubs in the brain that could help explain its wide spectrum of actions. We focused on orexin neurons of the lateral hypothalamus, an ancient “governing” hub displaying a large variety of roles, including regulation of mood and cognition, energy partitioning, and circadian activity. Since orexin neurons express IGF-I receptors and are activated by this growth factor, we down-regulated its receptors using Cre/Lox genetics and viral transduction and found that IGF-I modulates the sleep-wake cycle, energy expenditure and coping strategies, among other important functions. The latter led us to explore novel pathways for treatment of post-traumatic stress disorders. Therefore, the functional link between serum IGF-I and hypothalamic orexin neurons helps to explain the multi-tasking actions of this growth factor in the brain.