Hyperexcitability inducing factors such as seizure and epilepsy potentiate the synapses and impair learning and memory. Moreover, Dopamine (DA) as a neurotransmitter modulates synaptic plasticity and has an important role in cognitive functions. However, how the modulatory effect of DA on plastic properties of a neuron as well as cognitive functions will change as a consequence of epilepsy is not well understood. In our laboratory, we compared the effect of exogenous DA on synaptic plasticity of both ventral and dorsal hippocampal CA1 region, Stratum Radiatum and Stratum Oriens layers, using field potential recording. Our results demonstrated that DA has a reversal role on LTP in intact and kindled mice such that application of DA prevented LTP induction in intact slices while rescued LTP in kindled slices. Taken together, our results highlight the importance of DAergic modulation in normal and disease conditions.
  Memory deficit following epilepsy has been frequently examined, however, how a neuromodulator such as dopamine can affect LTP and Learning and memory has not been inspected. We have recently demonstrated a deficit in motivation to explore and its link with the poorer spatial memory in PTZ kindled mice. And we showed that DA by improving plastic properties at the synaptic level and novelty driven exploration at behavioural level improves spatial memory. Previously we examined the effect of tonic stimulation of DA neurons on short term memory and exploration using optogenetic stimulation of Ventral Tegmental Area (VTA) dopaminergic neurons. Tonic stimulation significantly improved short term spatial memory and novelty driven exploration in kindled mice. Since, LTP is considered as the basic mechanism of memory formation, therefore it can be concluded that DA has improved spatial memory through increasing the ability of LTP induction in kindled mice.