Local and regional heterogeneity underlying hippocampal modulation of cognition and mood

Abstract

While the hippocampus has been classically studied for its role in learning and memory, there is significant support for a role of the HPC in regulating emotional behavior. Emerging research suggests these functions may be segregated along the dorsoventral axis of the HPC. In addition to this regional heterogeneity, within the HPC, the dentate gyrus is one of two areas in the adult brain where stem cells continuously give rise to new neurons. This process can influence and be modulated by the emotional state of the animal, suggesting that adult neurogenesis within the DG may contribute to psychiatric disorders and cognitive abilities. Yet, the exact mechanism by which these newborn neurons influence behavior remains unknown. Here, we will examine the contribution of hippocampal neurogenesis to the output of the HPC, and suggest that the role of neurogenesis may vary along the DV axis. Next, we will review literature indicating that anatomical connectivity varies along the DV axis of the HPC, and that this underlies the functional segregation along this axis. This analysis will allow us to synthesize novel hypotheses for the differential contribution of the HPC to cognition and mood.

Impact of neonatal anoxia on adult rat hippocampal volume, neurogenesis and behavior

“…Dorsal hippocampus has a preferential role in spatial learning and memory, while ventral hippocampus is associated with anxiety-related behaviors (Bannerman, Rawlins et al 2004;Tannenholz, Jimenez et al 2014). Hippocampal neurogenesis can influence and be modulated by the emotional state of the animal, suggesting that adult neurogenesis within the dentate gyrus may contribute to psychiatric disorders and cognitive abilities (Tannenholz, Jimenez et al 2014).…”

“…Hippocampal neurogenesis can influence and be modulated by the emotional state of the animal, suggesting that adult neurogenesis within the dentate gyrus may contribute to psychiatric disorders and cognitive abilities (Tannenholz, Jimenez et al 2014). …”

Adult Hippocampal Neurogenesis, Fear Generalization, and Stress

“…The ventral hippocampus is known to control HPA axis responses through distinct pathways linking the subiculum and CA1 with hypothalamic nuclei and mammillary bodies (Tannenholz et al, 2014) as well as the lateral septum (Anthony et al, 2014;Strange et al, 2014). However, a role for adult hippocampal neurogenesis in regulation of the HPA axis is debated.…”

Adult Neurogenesis and Psychiatric Disorders

“…Behavioral analyses using different approaches for ablation of adult hippocampal neurogenesis have suggested a connection between neurogenesis and cognitive functions, such as spatial and temporal encoding and contextual discrimination (Aimone et al 2014). Ventral hippocampus has been associated with modulation of affective behaviors and emotionally salient memories (Kheirbek and Hen 2011;Kheirbek et al 2013;Tannenholz et al 2014;Wu and Hen 2014). The relationship between adult hippocampal neurogenesis and mood regulation is complex.…”