There is strong evidence for a correlation between the spiking activity of individual neurons relative to the average activity of the neighboring neural network in which they are embedded (reflected in local field potential, or LFP). To improve the representation of attended stimulus and consequently behavioral performance, selective attention modulates 1) this correlation of sensory neurons’ with their neighboring population activity as well as 2) the neurons’ stimulus response. Here we show evidence for an encoding strategy in the visual cortex, which enables a selective routing of the behaviorally relevant information to downstream areas by aligning the spiking activity to a specific phase. To eva‎luate our hypothesis, we used recorded spiking activity and LFP for 90 well-isolated neurons in the medial superior temporal (MST) cortex of monkeys performing an attention (spatial or feature-based) task. Our results show that MST neurons tend to fire spikes at a specific phase of ongoing population beta oscillations (~20 Hz). Interestingly, this preferred spiking phase shifts significantly depending on the behavioral relevance. We show when the animal attends toward the receptive field, the neuron fires spikes at a later phase compared to when attention is shifted away from the receptive field (0.77 rad for neurons with at least 10 percent of attentional modulation in their spike rate). Importantly, the attentional shift of preferred spiking phase is significantly correlated with the animal’s behavioral performance in detecting the visual change. Furthermore, our computational modelling suggests that neural networks can manipulate the preferred phase of coupling by imposing differential synaptic delays on postsynaptic potentials. We propose that this systematic change in preferred spiking phase may lead to better readout of relevant visual information by making neurons which represent the attended/unattended locations relay their information at distinct phases linked to periods of better/worse perceptual sensitivity for the higher-level cortical areas. This strategy limits perception selectively to relevant visual sensory inputs and allows sensory events to lead better-matching behavioral outcomes.

فرهاد شهبازي، معين اسقايي

وحيد سالاري

كيوان آقابابائي ساماني، جلال ذهبي