|MadSci Network: Neuroscience|
Jennifer, You have already answered your own question! As you already know, fear and temperature both have strong effects on piloerection (goosebumps) through autonomic nervous systems feedback systems. These are mediated like other emotion-linked autonomic reflexes by routing through the limbic system. These other emotion-linked autonomic reflexes include blushing, blanching, butterflies in the stomach. The limbic system is the site of primitive drives: sex, fear, rage, aggression and hunger. Anatomical sites for the limbic system include amygdala, parahippocampal gyrus, uncus, subcallosal gyrus, cingulate gyrus, fornix, dentate gyrus, hypothalamus and hippocampus. These are found around a major structure called the thalamus which receives virtually all sensory input. The medial forebrain bundle is a bidirectional communication with the brainstem which then directly mediates autonomic reflexes. A second method of invoking the autonomic reflexes is through the hypothalamus which also sends nerve projections to the brainstem. Specifically, direct stimulation of the amygdala and hypothalamus evokes the piloerection pathway. It's in these physical structures that emotional stimulation by music or the reading of poetry, etc. can result in piloerection. BTW, the hippocampus is also involved in learning and memory, suggesting the importance of emotions on learning and the reason why background music can help with learning. Hope that helps answer your questions! Dr. Dave
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