Direct Electrophysiological Correlates of Body Ownership in Human Cerebral Cortex

Abstract

Over the past decade, numerous neuroimaging studies based on hemodynamic markers of brain activity have examined the feeling of body ownership using perceptual body-illusions in humans. However, the direct electrophysiological correlates of body ownership at the cortical level remain unexplored. To address this, we studied the rubber hand illusion in 5 patients (3 males and 2 females) implanted with intracranial electrodes measuring cortical surface potentials. Increased high-γ (70–200 Hz) activity, an index of neuronal firing rate, in premotor and intraparietal cortices reflected the feeling of ownership. In both areas, high-γ increases were intimately coupled with the subjective illusion onset and sustained both during and in-between touches. However, intraparietal activity was modulated by tactile stimulation to a higher degree than the premotor cortex through effective connectivity with the hand-somatosensory cortex, which suggests different functional roles. These findings constitute the first intracranial electrophysiological characterization of the rubber hand illusion and extend our understanding of the dynamic mechanisms of body ownership.

Which hand is mine? Discriminating body ownership perception in a two-alternative forced-choice task

“…It should also be noted that the present behavioral results are consistent with neuroimaging studies that have demonstrated activity in frontal and parietal areas related to the integration of visual, tactile, and proprioceptive signals (Gentile, Guterstam, Brozzoli, & Ehrsson, 2013;Limanowski & Blankenburg, 2016) during the RHI (Ehrsson et al, 2004;Guterstam et al, 2019) and that the strength of this activation correlates with the strength of hand ownership as rated in questionnaires (Ehrsson et al, 2004;Gentile et al, 2013;Guterstam et al, 2013). Future fMRI studies could use the current psychophysical approach to examine whether the activity in these areas follows the same psychometric curves as the behavioral discriminations, and future transcranial magnetic stimulation studies could use the current approach as a sensitive method to test whether transient perturbation of the neural processing in these areas affects the perceptual ownership discriminations.…”

Statistical inference of body representation in the macaque brain

“…Our results are also consistent with a human electrocorticogram study, that showed sustained high-γ activity in the premotor cortex reflected the feeling of ownership during the rubber-hand illusion. Instead, high-γ activity locked to the tactile stimulus (but not to the illusion itself) was more closely localized to the posterior cortex (31).…”

Virtual reality alters cortical oscillations related to visuo-tactile integration during rubber hand illusion

“…In particular, the upper limit of the gamma band frequency was decided based on the finding that the high frequency band (> 60 Hz) activity was functionally differentiated from the low (30–60 Hz) gamma 38 . Although higher gamma power has been observed in intracranial EEG recordings during the RHI 39 , we focused on the lower gamma band because the scalp EEGs with HMD are susceptible to noise. For each target component, we averaged all values across time and frequency points and obtained one value for each condition and participant.…”