Regulation of hippocampal memory traces by neurogenesis.
The hippocampus has long been known as a brain structure fundamental for memory formation and retrieval. Recent technological advances of cellular tracing techniques and optogenetic manipulation strategies have allowed to unravel important aspects of the cellular origin of memory, and have started to shed new light on the neuronal networks involved in encoding, consolidation and retrieval of memory in the hippocampus. In particular, memory traces, or engrams, that are formed during encoding in the dentate gyrus and CA3 region are crucial for memory retrieval and amenable to modulation by neuroplastic mechanisms, including adult hippocampal neurogenesis. Here, we will discuss how memory traces are being encoded at the cellular level, how they may contribute to pattern separation and pattern completion in the hippocampus, and how they can be associated with different experiences to express memories of opposite valence. We propose a mechanism by which adult hippocampal neurogenesis may contribute to the formation of engrams, which may be relevant not only for the encoding of contextual information, but also for mood abnormalities, such as anxiety and depression.
Department of Psychiatry; Columbia University; New York, NY USA; Division of Integrative Neuroscience, New York State Psychiatric Institute/Research Foundation for Mental Hygiene; Inc. ; New York, NY USA.
Christoph
C
Anacker
Department of Psychiatry; Columbia University; New York, NY USA; Division of Integrative Neuroscience, New York State Psychiatric Institute/Research Foundation for Mental Hygiene; Inc. ; New York, NY USA.
Christine Ann
CA
Denny
Department of Neuroscience; Columbia University; New York, NY USA; Department of Pharmacology; Columbia University; New York, NY USA; Department of Psychiatry; Columbia University; New York, NY USA; Division of Integrative Neuroscience; New York State Psychiatric Institute ; New York, NY USA.
René
R
Hen
BDNF; amygdala; dentate gyrus; entorhinal cortex; fear conditioning; immediate early genes; optogenetics; stem cells; stress