Limbic regions involved in emotion and mood. A Limbic regions involved in emotion and mood. A. A ring of tissue (limbus) composed of the hippocampus and amygdala as well as the cingulate and parahippocampal gyri encircles the upper brainstem. It consists of evolutionarily older forms of cortex than the six-layered neocortex. This ring has been called the limbic system, but is no longer thought to represent a single-purpose system involved in emotion. Rather “limbic” structures play important roles in diverse circuits that interact with the prefrontal cortex and the hypothalamus. B. Multiple views of the prefrontal cortex and related areas. Panel 1: View from the bottom of the brain showing the ventromedial (pink) and orbital (green) prefrontal cortex. Panel 2: Dorsolateral prefrontal cortex (purple). Panel 3: Hippocampus (bottom, pink) and amygdala (top, stippled pink). Panel 4: Anterior cingulate gyrus (yellow), a region of medial prefrontal cortex. Brodmann area 25, a target for deep brain stimulation, is shown. (Reproduced with permission from Davidson RJ, Pizzigalli D, Nitschke JB, Putnam K. Depression: perspectives from affective neuroscience. Annu Rev Psychol. 2002;53:545–574.) Source: Mood and Emotion, Molecular Neuropharmacology: A Foundation for Clinical Neuroscience, 3e Citation: Nestler EJ, Hyman SE, Holtzman DM, Malenka RC. Molecular Neuropharmacology: A Foundation for Clinical Neuroscience, 3e; 2015 Available at: http://neurology.mhmedical.com/DownloadImage.aspx?image=/data/books/1204/nes003_fig_15-01b.png&sec=72650367&BookID=1204&ChapterSecID=72650358&imagename= Accessed: October 24, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved