Short-Term Plasticity in the Ventral Striatum a Comparision between in Vivo and in Vitro Measurements

Abstract

In order to understand how information from the subiculum is mediated by way of the nucleus accumbens (Acb) to more caudally lying areas, it is of importance to know how the limbic inputs affect Acb output neurons. Here we report experiments using electrophysiological recording techniques and stimulation of the subiculum-accumbens pathways (i.e. the fornix) under various conditions to address this question. De France et al. (1985a) investigated a possible interaction between successive responses using paired pulse stimulation with intervals in the range of 10–40 ms. They showed that the response to the second, or test stimulus was suppressed at intervals below 30 ms. In a separate paper (De France et al. 1985b) these authors reported a suppressive effect of dopamine on the responses when the input fibers were stimulated once every 1–2 s. For stimulation with a rate of 6 pulses/s (intervals 167 ms) no such effect was found. The subiculum is a part of the hippocampal formation, that is known to have EEG activity predominantly in the theta range (4–12 Hz). Therefore, the transmission of the signals in the subiculum-accumbens pathways may be frequency-dependent.