Figure 1.

Panel (A) (adapted from Matell et al., 2003) displays the activity pattern of a representative striatal neuron showing differential activity at two times associated with possible reinforcement (10 and 40 s), indicating sensitivity to specific temporal interval(s). Importantly, the behavioral response rate was equivalent at these two times, thereby ruling out a simple motor coding role of the striatum. The peak in firing at 10 s and the secondary increase in firing at 40 s could result from two processes. (B) Represents a temporally modulated motor coding scheme in which the neural activity is directly tied to the motor behavior of the rat, but firing is enhanced at 10 s, and/or diminished at 40 s, thereby demonstrating temporal expectation. (C) Represents an “abstract” temporal coding scheme, such that both 10 and 40 s are represented by the neuron, and the smaller magnitude at 40 s reflects scalar variability. In this latter coding scenario, the motor behavior of the rat is a “downstream” effect and does not contribute to striatal firing rates.