The Insula and Taste Learning

• Published in: Frontiers in molecular neuroscience Vol. 10; p. 335
• Main Authors: Yiannakas, Adonis, Rosenblum, Kobi
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 03-11-2017; Frontiers Media S.A
• Subjects: Acetylcholine receptors (muscarinic); Amygdala; Associative learning; c-Fos protein; Ca2+/calmodulin-dependent protein kinase II; Cognitive ability; Cortex (insular); Cortex (somatosensory); Cyclic AMP response element-binding protein; Dopamine receptors; ERK-MAPK; Extracellular signal-regulated kinase; Genetic markers; Glutamatergic transmission; Immediate-early proteins; insula; insular cortex; Kinases; Neuroimaging; Neuroscience; Neurotransmission; Prefrontal cortex; Protein biosynthesis; Synaptic plasticity; taste; Taste aversion learning; taste circuit; Transcription factors; translation regulation; γ-Aminobutyric acid; taste circuit; ERK-MAPK; immediate early genes; taste; translation regulation; insular cortex; insula
• ISSN: 1662-5099; 1662-5099
• DOI: 10.3389/fnmol.2017.00335

The sense of taste is a key component of the sensory machinery, enabling the evaluation of both the safety as well as forming associations regarding the nutritional value of ingestible substances. Indicative of the salience of the modality, taste conditioning can be achieved in rodents upon a single pairing of a tastant with a chemical stimulus inducing malaise. This robust associative learning paradigm has been heavily linked with activity within the insular cortex (IC), among other regions, such as the amygdala and medial prefrontal cortex. A number of studies have demonstrated taste memory formation to be dependent on protein synthesis at the IC and to correlate with the induction of signaling cascades involved in synaptic plasticity. Taste learning has been shown to require the differential involvement of dopaminergic GABAergic, glutamatergic, muscarinic neurotransmission across an extended taste learning circuit. The subsequent activation of downstream protein kinases (ERK, CaMKII), transcription factors (CREB, Elk-1) and immediate early genes (c-fos, Arc), has been implicated in the regulation of the different phases of taste learning. This review discusses the relevant neurotransmission, molecular signaling pathways and genetic markers involved in novel and aversive taste learning, with a particular focus on the IC. Imaging and other studies in humans have implicated the IC in the pathophysiology of a number of cognitive disorders. We conclude that the IC participates in circuit-wide computations that modulate the interception and encoding of sensory information, as well as the formation of subjective internal representations that control the expression of motivated behaviors.