Fig. 8: Model for how Syngap1 expression shapes tactile sensitivity and perceptual behaviors through regulation of cortical SMI circuitry.

a When a Syngap1+/− animals explore objects with whiskers, touch information is poorly encoded in cortex, which prevents attentional processes from engaging a state-switch, which leads to reduced exploration times. Reduced exploration time will overtly decrease the opportunity for whiskers to code tactile signals required to compute object features. This will impact the strength of a tactile percept, which will impair perceptual learning and associated adaptive behaviors. b In these mice, the touch signals that arrive in the cortex during the shortened object exploration are weakly encoded. In L5 somatosensory cortex, these weak touch signals are integrated with overly strong whisker motion (motor) signals, a signal-to-noise ratio (SNR) deficit that will degrade the ability of circuits to compute touch and texture features. Indeed, whisker motion and whisker touch generate two distinct streams of information at the level of the whisker follicle. The motor stream carries real-time whisker location information, while the touch stream contains a code for when touch occurred and how strong it was (through whisker curvature). These streams of information are integrated in barrel cortex L5 neurons, which enables an understanding of where the object rests relative to the head. This model can explain how Syngap1 mice learn so poorly within the tactile domain. It is important to note that we also demonstrate that perceptual behaviors are disrupted when the task is biased toward whisker touch, but perception is intact for similar tasks when multisensory processes are available to the Syngap1 animal.