EN
Ventral tegmental area (VTA) is thought to be an important component in the mesocorticolimbic system involved in the regulation of theta rhythm in the hippocampus. In this study we investigated the effect of pharmacological inactivation of the VTA on theta rhythm parameters in fear conditioned rats. Animals were implanted with bilateral recording electrodes into the dorsal hippocampus and bilateral injection cannula into the VTA. Hippocampal LFP was recorded throughout the experiment, in pre- and post-injection condition during freezing behavior and active locomotion (avoidance). We found that intra-VTA injection of procaine temporary suppressed avoidance response and decreased the power of hippocampal theta rhythm during freezing in comparison to control (water). Our results indicate that inactivation of neuronal activity in the VTA reduces hippocampal theta rhythm as well as avoidance response in fear conditioned animal. Supported by MNiSW Grant IP2011 034371.