Relaying in the brain: a novel approach for the feature binding problem

The brain is a highly distributed system in which numerous operations are executed in parallel. This raises the questions of how the computations occurring simultaneously in spatially segregated processing areas are coordinated and bound together to give rise to coherent percepts and actions. Multi-electrode recordings have unveiled observations of zero
time-lag synchronization among some remote cerebral cortical areas during the last 20 years. However, the transmission delays associated with axonal conduction among such distant regions can amount to several tens of milliseconds. It is still unclear which mechanism is giving rise to isochronous discharge of widely distributed neurons, despite of such latencies. Here we propose a simple, but robust, network motif densely embedded within the cortico-thalamic circuitry and found that, even in the presence of large axonal conduction delays, distant neuronal populations self-organize into lag-free oscillations. According to our results the relaying of cortical activity provided by the associative nuclei of the thalamus represents an ideal circuit to circumvent the phase-shifts and time-lags associated with transmission delays and gives an alternative and novel explanation for the feature binding problem.