Fear- and anxiety-driven behaviors result from interactions in a distributed network of functionally specialized areas of the cortex in which the amygdala plays an essential role by connecting sensory stimuli with their emotional meaning. To avoid detection, mice freeze in place when a looming visual stimulus mimics an approaching object. Alternatively, when detected by a predator the best option for survival may be to escape guided by a cognitive spatial map. Spatial maps are derived from landmark- and path integration-signals accumulated in the cortex from object features and optic flow patterns while navigating through the environment. The cortical network by which this is achieved involves inputs from the visual `where' and `what' streams to the postrhinal area (POR)66 of the parahippocampal cortex, whose output flows through the medial and lateral entorhinal cortex to the hippocampus. Our findings in mice show that POR is the only visual area with strong reciprocal connections with the amygdala, suggesting that POR processes information about emotionally salient objects and guides stimulus-appropriate actions. In direct support for this notion, we have found that POR carries shape, object-motion and self-motion signals. Our results further show that POR contains type 2 muscarinic acetylcholine receptor (M2)-positive and M2-negative modules of which only the M2-negative interpatches receive input from the amygdala. This suggests that interpatches, which in V1 are packed with motion selective cells33, are preferentially tuned by affective inputs from the amygdala. To test this hypothesis we propose to determine the connectional network between POR and the amygdala. Further, we propose to use single unit recordings in POR in awake head-fixed mice, and optogenetic manipulations of inputs from the amygdala, to examine whether the gain of responses to dynamically changing cues and static object features in M2-positive and M2-negative modules is differentially modulated. We expect to find that the amygdala selectively influences responses to object-motion in M2-negative interpatches rather than responses to shape-features represented in M2-postivite patches. If the expectations are confirmed, we will conclude that the amygdala selectively increases the saliency of coherently moving object elements, improves their recognition and optimizes the route13 of escape from of a predator pouncing from a hideout.
Fear- and anxiety-driven behaviors result from communications in a distributed network of functionally specialized cortical areas in which inputs from the amygdala play an essential role by connecting sensory stimuli with their emotional meaning. The goal of this proposal is to test the hypothesis that these influences preferentially affect visual information essential for spatial navigation and the detection of form from motion important for the detection of predators.
