An investigation on the effects of single pulse transcranial magnetic stimulation in a modified maximum entropy auditory stimulation paradigm

In this paper, we intend to investigate further the effects of single pulse TMS (sTMS) on auditory attention through an experimental design that combines a modified version of maximum entropy stimulation paradigm. Single pulses of TMS with 4.4s inter-stimulus interval (ISI) were applied to the left temporal lobe of subjects while three randomized auditory stimuli with constant ISI of 1.1s were delivered to the contralateral side within the TMS stimulation duration. Our main focus was to examine the time course of the auditory late responses (ALRs) due to TMS stimulation by a phase clustering on the unit circle measure and an adaptive shift- invariant feature extraction method. In the attention scheme, a significant difference in the phase stability between TMS and no-TMS was found in the range of the N1 wave of ALRs. However, the difference occurs only for the data after 1.1s. Furthermore, there is an absence of differences in the amplitude of the ALR. In addition, the effects of TMS and attention can also be discriminated very well and illuminate the effects of TMS in auditory attention. It is concluded that even sTMS might have the potential to alter the attentional states and the effects can last about 1s, at least when considering the large- scale neural correlates of attention in ALR sequences.