The demystification of autoscopic phenomena: experimental propositions

Breathing control, brain, and bodily self-consciousness: Toward immersive digiceuticals to alleviate respiratory suffering

Breathing is peculiar among autonomic functions through several characteristics. It generates a very rich afferent traffic from an array of structures belonging to the respiratory system to various areas of the brain. It is intimately associated with bodily movements. It bears particular relationships with consciousness as its efferent motor control can be automatic or voluntary. In this review within the scope of "respiratory neurophysiology" or "respiratory neuroscience", we describe the physiological organisation of breathing control. We then review findings linking breathing and bodily self-consciousness through respiratory manipulations using virtual reality (VR). After discussing the currently admitted neurophysiological model for dyspnea, as well as a new Bayesian model applied to breathing control, we propose that visuo-respiratory paradigms -as developed in cognitive neuroscience- will foster insights into some of the basic mechanisms of the human respiratory system and will also lead to the development of immersive VR-based digital health tools (i.e. digiceuticals).

Cases with parietal and occipital lobe epilepsies

Background

For seizures emerging from the posterior cortex it can be a challenge to differentiate if they belong to temporal, parietal or occipital epilepsies. Sensoric auras like visual phenomena may occur in all of these focal epilepsies. Ictal signs may mimic non- epileptic seizures.

Case presentations

Case 1: Patient suffering from a pharmacoresistent focal epilepsy. Focal seizures with sudden visual disturbance, later during the seizure epigastric aura, vertigo-nausea, involvement to bilateral tonic-clonic seizures. MEG detected interictal spikes, source localization indicated focal epileptic activity parietal right.

Case 2: Patient with focal pharmacoresistent epilepsy, semiology with focal unaware seizures, feeling that something like a coat is imposed from behind on him, then feeling cold over the whole body, goose bumbs from both arms to head, then block of motoric activity, later focal unaware seizures with stare gaze, blinking of eyes, clouding of consciousness, elevation of arms and legs, sometimes tonic-clonic convulsions. EEG/MEG source localization and MRI detected an epileptogenic lesion parietal left.

Case 3: Patient with pharmacoresistent focal epilepsy, focal aware seizures, a dark spot occurring in the left visual field, sometimes anxiety during seizures (leading to the suspicion of non-epileptic psychogenic pseudo seizures). MRI demonstrated an atrophy occipito-temporal right after sinus vein thrombosis. Ictal video-EEG showed a focal seizure onset occipital right.

Conclusion

Contribution of noninvasive and/or invasive confirmation of the localization of the underlying focal epileptic activity in posterior cortex is illustrated. Characteristics of posterior cortex epilepsies are ventilated.

A structural MRI study of cortical thickness in depersonalisation disorder

Depersonalisation disorder (DPD) is characterised by a sense of unreality about the self and the world. Research suggests altered autonomic responsivity and dysfunction in prefrontal and temporal lobe areas in this condition. We report the first structural magnetic resonance imaging study of 20 patients with DPD and 21 controls using the FreeSurfer analysis tool employing both region-of-interest and vertex-based methods. DPD patients showed significantly lower cortical thickness in the right middle temporal region according to both methods of analysis. The vertex-based method revealed additional differences in bilateral temporal lobes, inferior frontal regions, the right posterior cingulate, and increased thickness in the right gyrus rectus and left precuneus. Clinical severity scores were negatively correlated with cortical thickness in middle and right inferior frontal regions. In sum, grey matter changes in the frontal, temporal, and parietal lobes are associated with DPD. Further research is required to specify the functional significance of the findings and whether they are vulnerability or disease markers.

Signs of increased cortical hyperexcitability selectively associated with spontaneous anomalous bodily experiences in a nonclinical population

INTRODUCTION

The current study examined the presence of cortical hyperexcitability, in nonclinical hallucinators, reporting different forms of anomalous bodily experiences (ABEs). Groups reporting visual out-of-body experiences and nonvisual sensed-presence experiences were examined. It was hypothesised that only those hallucinators whose experiences contained visual elements would show increased signs of visual cortical hyperexcitability.

METHODS

One hundred and eighty-two participants completed the "Pattern-glare task" (involving the viewing of striped gratings with spatial frequencies irritable to visual cortex)-a task known to reflect degrees of cortical hyperexcitability associated with hallucinatory/aura experiences in neurological samples. Participants also completed questionnaire measures of anomalous "temporal-lobe experience" and predisposition to anomalous visual experiences.

RESULTS

Those reporting increased levels of anomalous bodily experiences provided significantly elevated scores on measures of temporal-lobe experience. Only the visual OBE group reported significantly elevated levels of cortical hyperexcitability as assessed by the pattern-glare task.

CONCLUSIONS

Collectively, the results are consistent with there being an increased degree of background cortical hyperexcitability in the cortices of individuals predisposed to some ABE-type hallucinations, even in the nonclinical population. The present study also establishes the clinical utility of the pattern-glare task for examining signs of aberrant visual connectivity in relation to visual hallucinations.

Unilateral autoscopic phenomena as a lateralizing sign in focal epilepsy

Positive autoscopic phenomena - autoscopy, heautoscopy and out-of-body experience - may occur in a variety of diseases and also in physiological conditions. They are a rare but probably underreported phenomenon in focal epilepsies. Here, we investigate whether ictal lateralized autoscopic phenomena give lateralizing information about the underlying epileptic focus. We present the cases of seven patients from our center who experienced ictal lateralized autoscopic phenomena and analyzed their focus lateralization and localization of the underlying brain lesion. In addition, we reviewed seven cases published in German and English language literature. In the total group of 14 patients with ictal lateralized autoscopic phenomena, 12 (85.7%) of them had a well-defined epileptic focus contralateral to the side of the autoscopic appearance. Therefore, the data point to an association between ictal lateralized autoscopy and contralateral epileptic focus.

Out-of-body experience and auditory and visual hallucinations in a patient with cardiogenic syncope: Crucial role of cardiac event recorder in establishing the diagnosis

Out-of-body experience (OBE) and visual and auditory hallucinations can occur in a variety of medical conditions. We describe a 48-year-old male patient who experienced several paroxysmal events with different combinations of the aforementioned symptoms that could finally be attributed to cardiogenic syncope after subcutaneous implantation of an event recorder and that ceased after implantation of a cardiac pacemaker. Hallucinations and OBE are well-known phenomena in syncope. The special purpose of this report is to highlight the crucial role of implantation of the event recorder in establishing the diagnosis and the additional support of the diagnosis by the cessation after implanting the cardiac pacemaker.

Duration and not strength of activation in temporo-parietal cortex positively correlates with schizotypy

Impaired self- and own body processing in patients with schizophrenia and individuals along the schizophrenia spectrum have been associated with dysfunctional cortical activation at the temporo-parietal junction. Here we investigated whether strength or duration of temporo-parietal junction activation during an own body processing task correlates with level of abnormal self-processing in healthy subjects as measured by the frequency of spontaneously experienced schizotypal body schema alterations (perceptual aberrations) and dissociative experiences. Participants carried out a mental imagery task with respect to their own body. Behavioral data and high density EEG were measured. EEG data were analyzed using evoked potential mapping and electrical neuroimaging. Participants completed two validated self-report questionnaires, one asking about perceptual aberration and one about dissociative experiences. The own body transformation task activated the right temporo-parietal junction at 310-390 ms. Participants' reaction times and duration of activation at the right temporo-parietal junction, but not its strength, were found to correlate positively with perceptual aberration scores. No relationship was found with dissociative experiences scores. Brain activations proceeding and following activation of the right temporo-parietal junction did not correlate with scores on either scale. The positive correlation between performance and right temporo-parietal activation in an own body transformation task with perceptual aberrations scores in our healthy population suggests that disturbances in self- and body processing in individuals along the schizophrenia spectrum might be due to prolonged, rather than stronger activation of the right temporo-parietal junction. We argue that this might reflect local pathology, pathologies in cortico-cortical connections and/or re-entry of top-down processing.

Perceptual aberrations impair mental own-body transformations

Dysfunctional self and bodily processing have been reported from the schizophrenia spectrum. Here, the authors tested 72 students (40 women) to determine whether performance in a mental own-body transformation task relates to self-rated frequency of spontaneously experienced schizotypal body schema alterations (perceptual aberration). Participants provided speeded left-right decisions concerning the body of a visually depicted human figure (front view vs. back view). For men, reaction times to disembodied perspectives increased with increasing scores on a validated perceptual aberration scale. This finding constitutes behavioral evidence for the clinically postulated association between aberrant bodily experiences during everyday life and aberrant processing in a mental own-body transformation task arguably reflecting mild dysfunction at the temporo-parietal junction.