During EEG, which rhythm is characterized by a cortical block during motor activity?

The mu rhythm is specifically associated with the motor cortex and is often observed during periods of motor activity or preparation for movement. When the individual engages in motor actions, the mu rhythm exhibits a pattern of electrical activity that shows a cortical block, meaning that there is a decrease in the amplitude of this rhythm. This phenomenon is reflective of the brain's ability to suppress certain electrical activities in anticipation of or during actual movement, which plays a crucial role in motor control and execution.

The mu rhythm typically ranges from 8 to 13 Hz and is particularly prominent over the central regions of the scalp. It is noteworthy that this rhythm can also be influenced by the observation of others' movements, further connecting it to both motor execution and the mirror neuron system.

In contrast, the other rhythms mentioned do not share this specific cortical block characteristic during motor activity. Delta rhythm is more commonly associated with deep sleep, theta rhythm is linked with tasks requiring cognitive engagement or states of drowsiness, and alpha rhythm generally represents a relaxed state when the eyes are closed, indicating an absence of visual stimuli.

Understanding these distinctive attributes of the mu rhythm helps clarify its role in motor activities and its significance in interpreting EEG results related to motor functions.