Rats can learn a temporal task in a single session

Abstract

Fixed interval, peak interval, and temporal bisection procedures have been used to assess cognitive functions and address questions such as how animals perceive, represent, and reproduce time intervals. They have also been extensively used to test the effects of drugs on behavior, and to describe the neural correlates of interval timing.However, those procedures usually require several weeks of training for behavior to stabilize. Here, we compared three types of training protocols and reported a procedure in which performance by the end of the very first session nearly matches the performance of long-term training. We also discuss this fast-learning protocol in terms of an information-theory approach. This one-day training protocol can be used to investigate temporal learning and may be especially useful to electrophysiological and neuropharmacological studies.

Low-cost open hardware system for behavioural experiments simultaneously with electrophysiological recordings

“…The proportion of short responses decreases over responses around the criterion (1.5 s). Our data show that a small number of training days elicited a significant change in behavior, corroborating with Reyes et al [24] .

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“…The differential reinforcement of response duration (DRRD) task requires that the rat sustains a behavioral response for a minimum amount of time (criterion) [23] , [24] . The trial was initiated when the animal pressed the lever.…”

“…If it kept the bar pressed for a period longer than the criteria, the Arduino released the reward initiating the stepper motor that rotates the carousel until a sugar pellet drops. More details about this task can be found in Reyes et al [24] under the name of “Fixed” protocol. We used three TTL signals to encode the following events in the SRT experiments: 1) Bar state; 2) Food delivery/Success trial; 3: Fail trial.…”

Time encoding migrates from prefrontal cortex to dorsal striatum during learning of a self-timed response duration task

“…We conceived a novel experimental design in which rats improve their timing in a single session ( Reyes et al, 2020 ), allowing us to track the activity of individual neurons during learning ( Figure 1 ). Animals had to remain in a nose poke for at least 1.5 s to receive access to the sucrose solution, limited to three licks, after which the access gate closes ( Figure 1A ).…”

“…To further investigate the underlying changes induced by the mPFC inactivation, we fitted the distributions of response durations with a double Gaussian function ( Figure 4D ). The distributions became bimodal during learning, and it has been shown ( Reyes et al, 2020 ) that such a phenomenon happens not only at the group level—what could suggest an artifact of group averaging—but also at the individual level. Even well-trained animals display bimodal distributions, suggesting that rats alternate between responses of two classes: premature (short) and time-controlled (long, Figure 4D ).…”