Topic: trial-by-trial variability

The striatum is crucial for motor control and reinforcement learning. The striatum has only 1% fast-spiking interneurons (FSI) which constitute feedforward inhibition (FFI). Therefore, striatal neurons receive a high degree of shared FFI, which makes the striatum a unique network in the brain. Here we ask, what role such high shared FFI may play in striatal function besides inducing synchrony. We found that with highly shared connectivity FSIs increase the trial-by-trial variability of striatal responses. Moreover, when the striatum is driven by correlated inputs, FSIs decorrelate the response

In the mouse visual cortex, neural representations of stimuli fluctuate across repetitions (Schölvinck et al. 2015, Deitch et al. 2021). The single-trial dynamics, often termed as representational drift, were also found in other cortical structures (Rokni et al. 2007, Low et al. 2021, Schoonover et al. 2021). However, most of these studies focused on slow drift over days. Here, we demonstrated that representational drift occurs at a fast timescale of several minutes and is prevalent regardless of stimulus type and independent of behavioral state. Within sessions of the same day, repeats of the