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Perisynaptic activity in the prefrontal cortex reflects spontaneous transitions in conscious visual perception
{In binocular rivalry, our perception alternates spontaneously between mutually exclusive or mixed interpretations, although the physical stimulus remains constant. This enables us to study visual consciousness, as it allows for a dissociation between sensory processing and conscious perception [1]. Previous imaging studies in humans have implicated the role of the fronto-parietal network in mediating perceptual alternations [2]. However, whether this frontal activation is indeed related to the percept, or, rather is confounded by, or reflects the consequences of perception viz. decision-making, introspection or motor-output, is still a matter of debate [3, 4]. Moreover, the degree of modulation in the frontal regions at the spiking and perisynaptic activity timescales is yet unclear. Because of the above-mentioned considerations, two male macaques were trained to maintain fixation within a window and follow the motion of the stimulus for up to 12 seconds in a specifically designed no-report paradigm. They were implanted with Utah Arrays (10 $\times$ 10) in the ventro-lateral prefrontal cortex. Spontaneous switches in the percept were identified from the Optokinetic Nystagmus traces. Trials where the stimulus was experimentally switched acted as a control. Sites on the array were sorted according to their preference for either an upwardmoving or a downward-moving stimulus based on the spiking activity. In the high-frequency regime, i.e. the Gamma band (80\textendash150 Hz), the power followed the pattern of selectivity displayed by the neural discharges including adaptation as reported previously [4]. Activity preceding a spontaneous switch revealed epochs of power modulations in the low-frequencies, i.e. the Delta Band (1\textendash4 Hz) and the Theta Band (4\textendash8 Hz), whereas this activity manifested itself strongly post-switch during physical alternation, pointing towards a role of slow cortical states in refreshing the content of conscious visual perception. Moreover, this burst-like activity was stronger when a preferred stimulus switched to a non-preferred stimulus implicating these slow cortical states in specifically overcoming an energy barrier required to transition from a preferred to a non-preferred stimulus. Taken together, these results strongly suggest that oscillatory activity in the prefrontal cortex plays a central role in the spontaneous transitions in conscious visual perception.}
@misc{item_2608061, title = {{Perisynaptic activity in the prefrontal cortex reflects spontaneous transitions in conscious visual perception}}, booktitle = {{AREADNE 2018: Research in Encoding And Decoding of Neural Ensembles}}, abstract = {{In binocular rivalry, our perception alternates spontaneously between mutually exclusive or mixed interpretations, although the physical stimulus remains constant. This enables us to study visual consciousness, as it allows for a dissociation between sensory processing and conscious perception [1]. Previous imaging studies in humans have implicated the role of the fronto-parietal network in mediating perceptual alternations [2]. However, whether this frontal activation is indeed related to the percept, or, rather is confounded by, or reflects the consequences of perception viz. decision-making, introspection or motor-output, is still a matter of debate [3, 4]. Moreover, the degree of modulation in the frontal regions at the spiking and perisynaptic activity timescales is yet unclear. Because of the above-mentioned considerations, two male macaques were trained to maintain fixation within a window and follow the motion of the stimulus for up to 12 seconds in a specifically designed no-report paradigm. They were implanted with Utah Arrays (10 $\times$ 10) in the ventro-lateral prefrontal cortex. Spontaneous switches in the percept were identified from the Optokinetic Nystagmus traces. Trials where the stimulus was experimentally switched acted as a control. Sites on the array were sorted according to their preference for either an upwardmoving or a downward-moving stimulus based on the spiking activity. In the high-frequency regime, i.e. the Gamma band (80\textendash150 Hz), the power followed the pattern of selectivity displayed by the neural discharges including adaptation as reported previously [4]. Activity preceding a spontaneous switch revealed epochs of power modulations in the low-frequencies, i.e. the Delta Band (1\textendash4 Hz) and the Theta Band (4\textendash8 Hz), whereas this activity manifested itself strongly post-switch during physical alternation, pointing towards a role of slow cortical states in refreshing the content of conscious visual perception. Moreover, this burst-like activity was stronger when a preferred stimulus switched to a non-preferred stimulus implicating these slow cortical states in specifically overcoming an energy barrier required to transition from a preferred to a non-preferred stimulus. Taken together, these results strongly suggest that oscillatory activity in the prefrontal cortex plays a central role in the spontaneous transitions in conscious visual perception.}}, pages = {58}, publisher = {AREADNE Foundation}, address = {Cambridge, MA, USA}, year = {2018}, slug = {item_2608061}, author = {Dwarakanath, A and Kapoor, V and Safavi, S and Logothetis, NK and Eschenko, O} }