Inhibition of prefrontal protein synthesis following recall does not disrupt memory for trace fear conditioning

Targeted intra-mPFC infusions of anisomycin or vehicle were performed immediately following recall of trace fear memory at 24 hours, or at 30 days, following training in a one-day or a two-day protocol. The present study demonstrates three key findings: 1) trace fear memory does not undergo protein synthesis dependent reconsolidation in the PFC, regardless of the intensity of the training, and 2) regardless of whether the memory is recent or remote, and 3) intra-mPFC inhibition of protein synthesis immediately following training impaired remote (30 days) memory.These results suggest that not all structures that participate in memory storage are involved in reconsolidation. Alternatively, certain types of memory-related information may reconsolidate, while other components of memory may not.Protein synthesis dependency around the time of training is a hallmark of long-term memory consolidation [1]. This has been repeatedly demonstrated across species and types of new information learned [2]. Reactivation of information already committed to long-term memory may induce an additional protein synthesis dependent period, during which the original memory can be disturbed by administration of protein synthesis inhibitors, suggestive of a reconsolidation process [3], although alternative interpretations have been suggested [4]. While protein synthesis dependencies have been observed for both consolidation and reconsolidation, evidence suggests that consolidation and reconsolidation differ in several key aspects (for review see [5])[6]. For example, a protein synthesis-dependent period follows every training paradigm (consolidation), whereas not every reactivation of memory results in a re-dependency on protein synthesis (reconsolidation). Whether a reactivated memory undergoes reconsolidation appears to depend on several factors, including the age of the memory and training intensity [7,8] For example, a conditioned taste aversion (CTA) memory resulting from a more intense,