Neural Circuits and Some New Factors Involved in Hippocampal Memory

Abstract

Humans and other primates have memory, and the hippocampus plays a critical role in this process. The neural circuitry is one of the structural foundations for the hippocampus in exerting memory function. To understand the relationship between the hippocampus and memory, we need to understand neural circuits. Past research has identified several classical neural circuits involved in memory. Although there are challenges with the study of hippocampal neural circuits, research on this topic has continued, and some progress has been made. Here, we discuss recent advances in our understanding of hippocampal neural circuit mechanisms and some of the newly discovered factors that affect memory. Substantial progress has been made regarding hippocampal memory circuits and Alzheimer’s disease. However, it is unclear whether these novel findings regarding hippocampal memory circuits hold promise for human memory studies. Additional research on this topic is needed.

Characterizing BOLD activation patterns in the human hippocampus with laminar fMRI

“…Furthermore, animal research has shown that in stark difference to the classical canonical microcircuits in the neocortex, differentiating feedforward and feedback pathways 2 , the hippocampal projections are primarily feedforward. Nevertheless, inputs to hippocampal pyramidal cells can be differentiated based on their position along the dendritic tree (a schematic depiction is given in supplementary figure S1): While synaptic connections along the "trisynaptic pathway" [3][4][5] (entorhinal cortex (EC) → DG → CA3 → CA1) terminate at perisomatic CA3 and CA1 layers (i.e., St. pyramidale and St. radiatum), direct EC projections terminate at distal apical dendrites (in St. lacunosum-moleculare) of CA1 and CA3; CA3 receives additional input to proximal apical dendrites via its abundant recurrent collaterals 6 .…”