Updating counterstriek 1 5 1 6
Here, we show that in rats, the dorsal striatum and basal amygdala belong to a common functional network underlying temporal expectancy and learning of a CS–US interval.Importantly, changes in coherence between striatum and amygdala local field potentials (LFPs) were found to couple these structures during interval estimation within the lower range of the theta rhythm (3–6 Hz).Thus, the shift of peak time was accompanied by a corresponding change in the width of the suppression curves, in agreement with the scalar property.Therefore, our protocol allows us to assess the scalar property for potential neural correlates, as well as to assess whether plasticity mechanisms underlie fast learning of a new CS–US interval once all the other contingencies have been learned.(a) Graphical representation of the paradigm used to investigate correlates of interval timing.Hence, whether and how the amygdala is involved in interval timing remains unknown.Interestingly, there are direct amygdala projections to the striatum, providing an anatomical substrate for functional interactions for processing the CS–US interval.
To assess the scalar property without the confound of peak rate differences, both curves were also normalized to their respective maximal values.
Neuroimaging investigations of interval timing in humans and studies in animals have implicated multiple brain regions, and in particular the dorsal striatum and prefrontal cortex.
Although such observations suggest that the amygdala plays a role in temporal expectancy of the aversive event, the protocols used in the latter investigations were not designed to address the timing processes per se and thus do not rule out other potential causes of changes in neuronal activity such as motor activity or the associative component of learning.
In the current study, we asked whether the dorsal striatum forms, with the amygdala, a functional network that is at play in temporal expectancy of an aversive US and whether these structures undergo neural changes when the animal learns a new CS–US interval.
To do so, we developed an experimental paradigm using auditory aversive conditioning in which the time from CS onset is the only predictor of the US arrival.