Temporally Coordinated Deep Brain Stimulation in the Dorsal and Ventral Striatum Synergistically Enhances Associative Learning.

Husam A Katnani,Samer Abdel-Aziz,Churl-Su Kwon,John T Gale,Shaun R Patel,Emad N Eskandar

doi:10.1038/srep18806

Husam A Katnani, Samer Abdel-Aziz + Show 4 more

Open Access

https://doi.org/10.1038/srep18806

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Abstract

The primate brain has the remarkable ability of mapping sensory stimuli into motor behaviors that can lead to positive outcomes. We have previously shown that during the reinforcement of visual-motor behavior, activity in the caudate nucleus is correlated with the rate of learning. Moreover, phasic microstimulation in the caudate during the reinforcement period was shown to enhance associative learning, demonstrating the importance of temporal specificity to manipulate learning related changes. Here we present evidence that extends upon our previous finding by demonstrating that temporally coordinated phasic deep brain stimulation across both the nucleus accumbens and caudate can further enhance associative learning. Monkeys performed a visual-motor associative learning task and received stimulation at time points critical to learning related changes. Resulting performance revealed an enhancement in the rate, ceiling, and reaction times of learning. Stimulation of each brain region alone or at different time points did not generate the same effect.

Highlights

Similar to a previous finding by Williams et al (2006) we show that the animals have a significant increase in the rate of rise for learning performance when receiving stimulation in the Cd during the feedback epoch as compared with the No Stim condition learning curve (Figs 2B and 3A, thick green trace)
Previous findings from neurophysiological studies in non-human primates have suggested that the Cd and NAc are integrally involved in associative learning[10,11], but at distinct task-epochs[4,12]
We posited that the application of coordinated electrical stimulation following the observed temporal specificity could multiplicatively enhance learning

Summary

Introduction

We observed a trend that followed a logistic function, in which the mean start performance for each condition on trial 1 was ~25% (Fig. 2A, inset) with the ceiling for learning at ~79% for the No Stim, NAc Stim and Cd Stim blocks, and the ceiling for NAc → Cd Stim block at ~95%.

Results

Conclusion