Their oscillations are tightly linked to attention in both low and high frequencies 18, 25– 29. LFPs represent synaptic activities of local cortical neuronal populations 24. Covertly directing attention towards the receptive field of a neuron in visual cortex enhances the neural responses even in the absence of visual stimulation 5, 6, alters the shape and profile of receptive fields 7– 9, modulates the variability and temporal structure of the neuron’s firing patterns 10, 11, modulates inter-neuronal correlations to increase neural discriminability 12, 13 and synchronizes neighboring neurons, presumably to better propagate information to downstream areas 14– 16.Īttention has been suggested to exploit oscillatory neural activities, as well as oscillatory components of local field potentials (LFP), to enhance the efficacy of cortical processing 17– 23. Attentional influences on neural responses in sensory cortex have been extensively documented effects which reflect a multitude of aspects of cortical information processing 1– 4. This allows the brain to make the most efficient use of its limited neural resources and to create appropriate behavioral responses quickly 1. Attention selectively routes the most behaviorally relevant information from the stream of sensory inputs through the hierarchy of cortical areas. One of the most important cognitive functions of the mammalian brain is selective attention. These results suggest a functional utilization of intrinsic neural oscillatory activities for an enhanced processing of upcoming stimuli. We further show that the attentional enhancement of phase coherence is positively correlated with the modulation of the stimulus-induced firing rate, and importantly, a higher phase coherence is associated with a faster behavioral response. Our data reveal that phase coherence increases following a spatial cue deploying attention towards the receptive field of the recorded neural population. We document an attentional modulation of pre-stimulus inter-trial phase coherence (a measure of deviation between instantaneous phases of trials) of low frequency local field potentials (LFP) in visual area MT of macaque monkeys. Here, we hypothesize that selective attention controls the phase of oscillatory neural activities to efficiently process relevant information. These studies mainly focused on the stimulus presentation period, rather than the pre-stimulus period. Previous studies have shown that visual attention depends on the phase of oscillatory brain activities.

Global phase coherence matlab