Auditory streaming is the process by which environmental sound is segregated into
discrete perceptual objects. The auditory system has a remarkable capability in this
regard as revealed in psychophysical experiments in humans and other primates.
However, little is known about the underlying neuronal mechanisms, in part because
of the lack of suitable behavioural paradigms in non-primate species. The mouse is an
increasingly popular model for studying the neural mechanisms of perception and action
because of the range of molecular tools enabling precise manipulation of neural circuitry.
Here we present a novel behavioural task that can be used to assess perceptual aspects
of auditory streaming in head-fixed mice. Animals were trained to detect a target sound
in a one of two simultaneously presented, isochronous pure tone sequences. Temporal
expectation was manipulated by presenting the target sound in a particular stream either
early (∼2 s) or late (∼4 s) with respect to trial onset in blocks of 25–30 trials. Animals
reached high performance on this task (d’ > 1 overall), and notably their false alarms
were very instructive of their behavioural state. Indeed, false alarm timing was markedly
delayed for late blocks compared to early ones, indicating that the animals associated a
different context to an otherwise identical stimulus. More finely, we observed that the false
alarms were timed to the onset of the sounds present in the target stream. This suggests
that the animals could selectively follow the target stream despite the presence of a
distractor stream. Extracellular electrophysiological recordings during the task revealed
that sound processing is flexibly modulated in a manner consistent with the optimisation
of behavioural outcome. Together, these results indicate that the perceptual streaming
can be inferred via the timing of false alarms in mice, and provide a new paradigm with
which to investigate neuronal mechanisms of selective attention.