ABSTRACT
The mesolimbic dopaminergic system that projects from the ventral tegmental area [VTA] to the nucleus accumbens [NAc] is critical for initiation of opioid reinforcement and reward-related effects of drugs of abuse. In the present study, the effects of reversible inactivation of VTA on firing rate of nucleus accumbens neurons and on acquisition and expression of morphine-induced conditioned place preference [CPP] were investigated in rats. Adult male Wistar rats were used in these experiments. In behavioral study, the reversible inactivation of VTA was done through bilateral intra-VTA microinjection of 2% lidocaine during the acquisition and expression of morphine [5 mg/kg; s.c.]-induced CPP and in electrophysiology section, it was done through unilateral intra-VTA microinjection of 2% lidocaine during single unit recording from the NAc neurons. Conditioning score and locomotor activity were recorded by Ethovision software. Firing rate of neurons was recorded by single unit recording technique. The results showed that bilateral intra-VTA administration of lidocaine significantly decreases the acquisition [P<0.01] and expression [P<0.05] of morphine-induced CPP compared to their respective saline-microinjected groups. Moreover, intra-VTA administration of lidocaine had no effect on locomotor activity in these experiments. Also, unilateral intra-VTA administration of lidocaine significantly increased the firing rate of nucleus accumbens neurons. Our results further support the idea that VTA may play an important role in the acquisition and expression of morphine-induced CPP
ABSTRACT
Spike sorting is a class of techniques used in the analysis of electrophysiological data. Studying the dynamics of neural activity via electrical recording relies on the ability to detect and sort neural spikes recorded from a number of neurons by the same electrode. This article reviews methods for detecting and classifying action potentials, a problem commonly referred to as spike sorting