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.