The effect of rTMS on neural correlates of time perception

The parietal lobe plays a crucial role in the attentional networks that help shape our perception, including our perception of time. Based on neuropsychological and neurophysiological evidence, a “when” pathway including the right parietal lobe has been proposed as the critical cortical site for the discrimination of objects across time. Consistent with the view of time perception as a meta-percept arising from multisensory integration (Ivry & Schlerf, 2008; Mauk & Buonomano, 2004), temporal distortions often reflect dynamic interactions between sensory input and attentional modulation. One compelling example of temporal distortion is the "oddball effect," where an unexpected or deviant stimulus embedded within a stream of identical standards is perceived as lasting longer than its actual duration. While attentional capture plays a major role in this subjective expansion of time, the cortical mechanism responsible for this effect remains unclear. We therefore set to investigate the direct role of parietal brain areas in time perception using combined repetitive transcranial magnetic stimulation (rTMS) and electroencephalography (EEG). Participants judged the duration of oddball stimuli before and after 1-Hz rTMS applied to the right inferior parietal lobule (rIPL), right intraparietal sulcus (rIPS), or occipital cortex (control). Stimulation of rIPL selectively reduced the oddball illusion, aligning subjective reports more closely with objective duration. No significant behavioral changes were observed after stimulation to rIPS or occipital cortex. EEG data revealed robust ERP differences between standard and oddball stimuli, particularly in the P3b time window (300–400 ms), consistent with attentional updating. These findings highlight the rIPL's specific contribution to time perception and provide new insights into the cortical mechanisms governing temporal attention.