Volatility of subliminal haptic feedback alters the feeling of control in schizophrenia.

Abstract

It has been proposed that agency disorders found in schizophrenia rely on aberrant processing of prediction error. Overreactivity to nonpertinent prediction errors may lead to the attribution of one's own actions to an external source. When applied to perception, this could explain hallucinations. However, experiments in motor control or perception have mainly suggested deficient prediction errors. Using a novel approach based on the manipulation of temporal delays, 23 patients with schizophrenia, 18 patients with bipolar disorder, and 22 healthy participants performed a pointing task with a haptic device that provided haptic feedback without or with delays, which were processed consciously (65 ms) or unconsciously (15 ms). The processing of prediction errors was measured via the adaptation of the hand trajectory, that is, the deceleration in anticipation of the surface, and its modulation as a function of recent history (stable or unstable sensory feedback). Agency was evaluated by measuring the participants' feeling of controlling the device. Only patients with schizophrenia reported a decrease in the feeling of control following subliminally delayed haptic feedback and adapted deceleration durations following subliminally delayed haptic feedback. This effect was correlated with positive symptoms. The overreactivity to subliminal delays was present only when delays occurred repeatedly in an unpredictable way, that is, with a volatile distribution. The results suggest that small temporal uncertainties that should be held as negligible, trigger an aberrant overreactivity which could account for hallucinations and alterations of the patients' conscious feeling of control. General Scientific SummaryInsignificantly small temporal uncertainties in the perceptual and motor domains are typically ignored. This study reveals that patients with schizophrenia, but not bipolar disorders, overreact to delays of a few milliseconds in the haptic feedback. They inadequately adapt their movements to delays and their feeling of control decreases. These effects correlate with positive symptoms, suggesting that negligible prediction errors may become salient in an aberrant way and may thus disturb agency.

Spontaneous Necker-Cube Reversals are not that Spontaneous

“…These deviating perceptual dynamics in patients may indicate an underlying imbalance between stable and unstable brain states. Deviating patterns of EEG variability and other stability measures of brain activity further confirm these observations (Foerster et al, 2021;Hecker et al, 2022;Huang et al, 2022;Koshiyama et al, 2018;Marques-Carneiro et al, 2021). In summary, the present paradigm together with the identified physiological effects are a perfect starting point for further research about stability features of brain activity comparing patients with healthy controls.…”

Spontaneous Necker-cube reversals may not be that spontaneous

“…These deviating perceptual dynamics in patients may indicate an underlying imbalance between stable and unstable brain states. Deviating patterns of EEG variability and other stability measures of brain activity further confirm these observations (Koshiyama et al, 2018;Foerster et al, 2021;Marques-Carneiro et al, 2021;Hecker et al, 2022;Huang et al, 2022). In summary, the present paradigm together with the identified physiological effects are a good starting point for further research about stability features of brain activity comparing patients with healthy controls.…”

The Blursday database as a resource to study subjective temporalities during COVID-19

“…Phenomenological approaches have related time with self since as early as the twentieth century 98 , leading psychiatrists to link time with disorders of the self in psychosis [99][100][101] . Such a link has been evidenced experimentally 102,103 . In addition to the PQ-16 questionnaire exploring attenuated psychosis, the self-preference task was added to provide an objective self-related measure.…”