The Thought From the Machine: Neural Basis of Thoughts With a Coherent and Diminished Sense of Authorship

Abstract

Patients with schizophrenia who experience inserted thoughts report a diminished sense of thought authorship. Based on its elusive neural basis, this functional neuroimaging study used a novel setup to convince healthy participants that a technical device triggers thoughts in their stream of consciousness. Self-reports indicate that participants experienced their thoughts as self-generated when they believed the (fake) device was deactivated, and attributed their thoughts externally when they believed the device was activated—an experience usually only reported by patients diagnosed with schizophrenia. Distinct activations in the medial prefrontal cortex (mPFC) were observed: ventral mPFC activation was linked to a sense of thought authorship and dorsal mPFC activation to a diminished sense of thought authorship. This functional differentiation corresponds to research on self- and other-oriented reflection processes and on patients with schizophrenia who show abnormal mPFC activation. Results thus support the notion that the mPFC might be involved in thought authorship as well as anomalous self-experiences.

Induced feelings of external influence during instructed imaginations in healthy subjects

“…Thus, it is likely that more intense experiences of external influence -as they might be expected in psychotic patients -can still be measured. Klock et al (2021) developed a related paradigm to modulate the authorship of thoughts. In our paradigm we varied the given stimuli using different general and specific categories and additionally varying the emotional valence of the stimuli.…”

“… Klock et al (2021) developed a related paradigm to modulate the authorship of thoughts. In our paradigm we varied the given stimuli using different general and specific categories and additionally varying the emotional valence of the stimuli.…”

“…Only few studies used special experimental designs to directly examine and modulate the feeling of external influence on thoughts [to what extend authorship of thoughts is attributed to an external entity]. Klock et al (2021) instructed healthy participants that transcranial magnetic stimulation (TMS) of the frontal cortex could trigger the thought of an animal (similar to the generation of an involuntary movement stimulating the motor cortex). They informed the participants that they indicate by color, whether the TMS device would be (1) active or (2) not active or (3) in an ambiguous condition the participant was not informed about the activity of the device.…”

“…During the imagination we aimed to modulate the experience of external influence by applying different interventions. It has been shown before that external stimuli and the information given to the participants can modulate the feeling of influence ( Klock et al, 2021 ). Thus, we constructed interventions to examine these two components separately: (1) A physical setup: either very low amplitude (0.4 mA) transcranial direct current stimulation (tDCS), eye contact, skin-to-skin hand touch.…”