On the other hand, the quantification of motor circuit abnormality makes it possible to further investigate how specifically motor dysfunction interacts with cognitive burdens during freezing, therefore extending the classical ‘interference model’ of FOG. By showing that dual tasking did not directly impact the strength of PAC in M1, while only trials with low PAC could resist freezing when performing extra concurrent tasks, we reveal that motor and cognitive processing are actually competing for finite computational capacity. Both walking and dual tasking require cortical processing resources, while the elevation of PAC due to the parkinsonian state makes walking take more resources. This leads to a corresponding decrease of available resources for cognitive processing, increases the probability of ‘information overload’ and ultimately causes FOG.
