Elicited intrusive thoughts

Irina Popa, Cristian Donos, Andrei Barborica, Ioan Opris, Mihai Dragoş Mălîia, Mirela Ene, Jean Ciurea ,Ioana Mîndruţă.  Intrusive thoughts elicited by direct electrical stimulation during stereo-electroencephalography.  Front. Neurol., 18 July 2016

Cortical direct electrical stimulation (DES) is a method of brain mapping used during invasive presurgical evaluation of patients with intractable epilepsy. Intellectual auras like intrusive thoughts, also known as forced thinking (FT), have been reported during frontal seizures. However, there are few reports on FT obtained during DES in frontal cortex. We report three cases in which we obtained intrusive thoughts while stimulating the dorsolateral prefrontal cortex and the white matter in the prefrontal region. In order to highlight the effective connectivity that might explain this clinical response, we have analyzed cortico-cortical potentials evoked by single pulse electrical stimulation….

Intrusive thoughts are a psychological phenomenon present in different neurological and psychiatric disorders. Understanding the structure and physiology of the brain networks eliciting this response will create new diagnostic and therapeutic opportunities for disorders such as schizophrenia, obsessive–compulsive disorder, or post-traumatic stress disorder.

The term forced thinking (FT) was first used by Penfield and Jasper, and it describes a rare ictal manifestation of frontal seizures. Since then, we found only a few reports where the authors have elicited “a little familiar thought” probably similar to a déjà vu state while stimulating the temporo-polar cortex . Given the scarcity of literature data on FT during direct electrical stimulation (DES), the network involved is still a matter of research…

Patient reported that “the stimulation induces the disappearance of the word in my mind and replaces it with something else.” She was not able to remember what that thought was. The effect lasted for 5 s, as long as the electrical stimulation was applied. Moreover, at an intensity of 3 mA, while performing a mental task (word generation in a semantic field), the patients stopped performing the task and reported again that “the stimulation induces the disappearance of the word in my mind and replaces it with the idea of leaving.” No afterdischarges were recorded, and the patient could restart the activity after the stimulation. This time, she also presented right head and eye version…

The patient reported that he had “a though that seems to come from nowhere.” In other trials of stimulation (Y′03-04, 3 mA), the patient reported a thought that he could not remember, but “could be something embarrassing if said out loud.”…

Patient reported: “I feel like someone erases all my thoughts and replaces them with something else that is capturing all my attention.” These intrusive thoughts impair the stream of thinking; therefore, the patient ceases the word generation task…

Consistent with the current knowledge, during frontal lobe stimulation, we were able to elicit intrusive thoughts invading patients’ mind and pushing away their own thoughts, with no emotional involvement. The responses were clearly different from auditory hallucinations or the inner speech phenomena described as verbal thinking. The stimulation was performed in DLPFC in P1 and in the white matter underlying the PFC mantle in P2 and P3…

Our results demonstrate that FT can be initiated by stimulating very well-defined regions of the PFC. A larger network, as evidenced by the connectivity analysis using cortico-cortical evoked potentials, may be involved in these behavioral and psychological manifestations.

Courtesy of:  http://journal.frontiersin.org/article/10.3389/fneur.2016.00114/full?utm_source=newsletter&utm_medium=email&utm_campaign=Neurology-w31-2016