The forgotten insular cortex: Its role on recognition memory formation

For a long time, the insular cortex (IC) has been related with taste physiology and taste memory processes in animal studies. Recently, the role of the IC has been highlighted by findings involving the IC in non-taste memory formation in both human and animal studies. Recognition memory is based on the ability to assess the familiarity of a previously encountered stimulus, and it is considered a form of declarative memory. In this work, I am proposing that the IC and its related circuitry are highly involved in the conversion of novel to familiar stimulus for both object and taste recognition memory. In addition, I will review some of the molecular mechanisms involved in the modification of novelty to familiarity memory processes, including the role of epigenetic mechanisms on the consolidation of recognition memory within the IC. In the second part of the paper, I will review some of the possible mechanisms to transform a novel taste into a familiar aversive taste by a functional interaction between the IC and the amygdala. In summary, the IC is an important area that will open a new avenue for the study of the mechanisms involved in the neurobiology of learning and memory in the near future.