Interareal phase coherence as a mechanism for attention-dependent neuronal signal routing: A model-guided causal analysis using new, multi-contact floating silicon probes for intracortical chronic stimulation and recording in primates

点击翻译按钮获取中文摘要

The brain consists of large neuronal networks that are densely inter-connected. Depending on context and task, sub-networks become selected such that specific computations are performed, which ultimately lead to the appropriate behavioural output. Thereby sensory signals become selectively channelled through the brain. The latter is particularly evident in the visual system during selective attention: In higher areas of visual cortex such as V4, the responses of neurons with several stimuli in their receptive fields were shown to be similar as if only the attended stimulus would be present. In previous experiments, we showed that neuronal activity synchronizes specifically between neurons in visual area V4 and those input neurons which provide the signals for the attended stimulus. Most importantly, we could show in recent experiments that attention-dependent synchronization is causally responsible for attention-dependent signal routing.These findings raise the question how attention controls interareal synchronization mechanisms. Still there is no model available that captures and integrates the relevant experimental results in unifying framework; and methods to acquire data from high numbers of neurons in parallel and to influence them with high temporal and spatial resolution in the primate brain are still in their infancy. In this project we join as neurobiologists, theorists and engineers to attack these questions. To improve experimental access to, and control of the networks under investigation we already developed together fully implantable, virtually force-free floating multi-contact electrodes for chronic intracortical recording and stimulation in the primate cortex. Using such electrodes will allow us to use high resolution electric stimulation as a causal instruments to directly manipulate the mechanisms putatively underlying attentional control of selective signal and information routing. We will improve our new tools to allow implantation of entire arrays of multi-contact electrodes with increased longevity and stimulation capabilities to directly influence different aspects of the dynamics of the cortical networks. Furthermore, the results will serve to characterize the fundamental properties of the network's dynamic properties and will be used to build realistic models for control mechanisms of attention-dependent signal routing.