Many attempts have been made to localize the physical trace of a memory, or engram, in the
brain. However, until recently, engrams have remained largely elusive. In this Review, we …

The adaptive regulation of fear memories is a crucial neural function that prevents
inappropriate fear expression. Fear memories can be acquired through contextual fear …

We often assume that the variables of functional and structural brain parameters—such as
synaptic weights, the firing rates of individual neurons, the synchronous discharge of neural …

Single-cell sequencing methods have emerged as powerful tools for identification of
heterogeneous cell types within defined brain regions. Application of single-cell techniques …

Memory retrieval involves the interaction between external sensory or internally generated
cues and stored memory traces (or engrams) in a process termed 'ecphory'. While ecphory …

Hippocampal place cells take part in sequenced patterns of reactivation after behavioral
experience, known as replay. Since replay was first reported, nearly 20 years ago, many …

In the brain, neuronal gene expression is dynamically changed in response to neuronal
activity. In particular, the expression of immediate-early genes (IEGs) such as egr-1, c-fos …

Memory traces are believed to be ensembles of cells used to store memories. To visualize
memory traces, we created a transgenic line that allows for the comparison between cells …

The synaptic plasticity and memory hypothesis asserts that activity-dependent synaptic
plasticity is induced at appropriate synapses during memory formation and is both …

Memories can be unreliable. We created a false memory in mice by optogenetically
manipulating memory engram–bearing cells in the hippocampus. Dentate gyrus (DG) or …