Habits are notoriously difficult to break and, if broken, are usually replaced by new routines. To examine the neural basis of these characteristics, the authors recorded spike activity in cortical and striatal “habit sites” as rats learned maze tasks. They found that striatal habit-related activity patterning emerged early and was outcome insensitive. Prefrontal cortical habit-related patterning emerged late and was flexible. Prefrontal activity was required for overtraining to yield a crystallized habit. Selective optogenetic disruption of infralimbic activity during overtraining prevented habit formation. They suggest that learning-related spiking dynamics of both striatum and neocortex are necessary for habit crystallization and show how manipulation of selective pathways may alter habit formation.
Smith KS and Graybiel AM: A dual operator view of habitual behavior reflecting cortical and striatal dynamics. Neuron 79(2): 361-374 (2013).
