Magnetoencephalography in a human subject performing a visual binding task reveals coherent oscillations at approximately 40 Hz synchronised across widely separated cortical areas. This rhythm is thought to subserve which function?

• A Synchronisation of cortical slow waves during stage N3
• B Generation of sleep spindles during stage N2
• C Maintenance of hippocampal theta during exploration
• D Binding of distributed sensory features into a unified conscious percept ✓

Explanation

Gamma oscillations, roughly 30 to 80 Hz, are recorded during attentive waking states and are proposed to bind features processed in separate cortical regions into a single percept, a concept popularised by studies of 40 Hz activity. Sleep spindles are 12 to 14 Hz thalamic rhythms, hippocampal theta is 4 to 7 Hz, and slow waves are below 4 Hz, so none of these frequency bands matches the observed 40 Hz signal.

Reference: Principles of Neural Science, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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