State of belief, subjective certainty and bliss as a product of cortical dysfunction

[Insular lobe epilepsy. Part 1: semiology]

The insula is often referred to as "the fifth lobe" of the brain, and its accessibility used to be very limited due to the deep location under the opercula as well as the sylvian vasculature. It was not until the availability of modern stereo-electroencephalography (SEEG) technique that the intracranial electrodes could be safely and chronically implanted within the insula, thereby enabling anatomo-electro-clinical correlations in seizures of this deep origin. Since the first report of SEEG-recorded insular seizures in late 1990s, the knowledge of insular lobe epilepsy (ILE) has rapidly expanded. Being on the frontline for the diagnosis and management of epilepsy, neurologists should have a precise understanding of ILE to differentiate it from epilepsies of other lobes or non-epileptic conditions. Owing to the multimodal nature and rich anatomo-functional connections of the insula, ILE has a wide range of clinical presentations. The following symptoms should heighten the suspicion of ILE: somatosensory symptoms involving a large/bilateral cutaneous territory or taking on thermal/painful character, and cervico-laryngeal discomfort. The latter ranges from slight dyspnea to a strong sensation of strangulation (laryngeal constriction). Other symptoms include epigastric discomfort/nausea, hypersalivation, auditory, vestibular, gustatory, and aphasic symptoms. However, most of these insulo-opercular symptoms can easily be masked by those of extra-insular seizure propagation. Indeed, sleep-related hyperkinetic (hypermotor) epilepsy (SHE) is a common clinical presentation of ILE, which shows predominant hyperkinetic and/or tonic-dystonic features that are often indistinguishable from those of fronto-mesial seizures. Subtle objective signs, such as constrictive throat noise (i.e., laryngeal constriction) or aversive behavior (e.g., facial grimacing suggesting pain), are often the sole clue in diagnosing insular SHE. Insular-origin seizures should also be considered in temporal-like seizures without frank anatomo-electro-clinical correlations. All in all, ILE is not the epilepsy of an isolated island but rather of a crucial hub involved in the multifaceted roles of the brain.

[Insular lobe epilepsy. Part 2: presurgical evaluation & surgical interventions with stereo-electroencephalography]

Identification of insular lobe epilepsy (ILE) presents a major clinical challenge in the diagnosis and treatment of drug-resistant focal epilepsies. ILE has diverse clinical presentations due to the multifaceted functions of the insula. Surface EEG findings do not provide straightforward information to predict this deeply-situated origin of seizures; they are even misleading, masquerading as those of other focal epilepsies, such as temporal and frontal ones. Non-invasive imagings may disclose insular abnormalities, but extra-insular abnormalities can coexist or even stand out. Careful reading and a second-look guided by other clinical information are crucial in order not to miss subtle insulo-opercular abnormalities. Furthermore, a possible insular origin of seizures should be considered in MRI-negative frontal/temporal/parietal epilepsies. Therefore, exploration/exclusion of insular-origin seizures is necessary for a great majority of surgical candidates. As for the stereo-electroencephalography, considered as the gold standard method for intra-cranial EEG investigations with suspicion of ILE, planning of electrode positions/trajectories require sufficient knowledge of the functional localization and anatomo-functional connectivity of the insula. Dense sampling within the insula is required in patients with probable ILE, because the seizure-onset zone can be restricted to a single insular gyrus or even a part of it. It is also crucial to explore extra-insular regions on the basis of non-invasive investigation results while considering their anatomo-functional relationships with the insula. From a surgical perspective, differentiating seizures strictly confined to the insula from those extending to the opercula is of particular importance. Pure insular seizures can be treated with less invasive measures, such as radiofrequency thermocoagulation. To conclude, close attention must be paid to the possibility of ILE throughout the diagnostic workup. The precise identification/exclusion of ILE is a prerequisite to provide appropriate and effective surgical treatment in pharmaco-resistant focal epilepsies.

Ecstatic or Mystical Experience through Epilepsy

Ecstatic epilepsy is a rare form of focal epilepsy, so named because the seizures' first symptoms consist of an ecstatic/mystical experience, including feelings of increased self-awareness, mental clarity, and "unity with everything that exists," accompanied by a sense of bliss and physical well-being. In this perspective article, we first describe the phenomenology of ecstatic seizures, address their historical context, and describe the primary brain structure involved in the genesis of these peculiar epileptic seizures, the anterior insula. In the second part of the article, we move onto the possible neurocognitive underpinnings of ecstatic seizures. We first remind the reader of the insula's role in interoceptive processing and consciously experienced feelings, contextualized by the theory of predictive coding. This leads us to hypothesize that temporary disruptions to activity in the anterior insula could interrupt the generation of interoceptive prediction errors, and cause one to experience the absence of uncertainty, and thereby, a sense of bliss. The absence of interoceptive prediction errors would in fact mimic perfect prediction of the body's physiological state. This sudden clarity of bodily perception could explain the ecstatic quality of the experience, as the interoceptive system forms the basis for unified conscious experience. Our alternative hypothesis is that the anterior insula plays an overarching role in the processing of surprise and that the dysfunction caused by the epileptic discharge could interrupt any surprise exceeding expectations, resulting in a sense of complete control and oneness with the environment.

Retrograde amnesia abolishes the self-reference effect in anterograde memory

Is retrograde amnesia associated with an ability to know who we are and imagine what we will be like in the future? To answer this question, we had S.G., a patient with focal retrograde amnesia following hypoxia, two brain-damaged (control) patients with no retrograde memory deficits, and healthy controls judge whether each of a series of trait adjectives was descriptive of their present self, future self, another person, and that person in the future, and later recognize studied traits among distractors. Healthy controls and control patients were more accurate in recognizing self-related compared to other-related traits, a phenomenon known as the self-reference effect (SRE). This held for both present and future self-views. By contrast, no evidence of (present or future) SRE was observed in SG, who concomitantly showed reduced certainty about his personality traits. These findings indicate that retrograde amnesia can weaken the self-schema and preclude its instantiation during self-related processing.

Epistemic Feelings are Affective Experiences

This paper develops the claim that epistemic feelings are affective experiences. To establish some diagnostic criteria, characteristic features of affective experiences are outlined: valence and arousal. Then, in order to pave the way for showing that epistemic feelings have said features, an initial challenge coming from introspection is addressed. Next, the paper turns to empirical findings showing that we can observe physiological and behavioural proxies for valence and arousal in epistemic tasks that typically rely on epistemic feelings. Finally, it is argued that the affective properties do not only correlate with epistemic feelings but that we, in fact, capitalise on these affective properties to perform the epistemic tasks. In other words: the affective properties in question constitute epistemic feelings.

Precentral gyrus and insula responses to stress vary with duration to diagnosis in functional seizures

OBJECTIVE

This study was undertaken to determine whether undiagnosed illness duration (time between functional seizures [FS] onset and diagnosis) is linked to differences in neural response and functional connectivity during processing of stressful experiences.

METHODS

Forty-nine participants with traumatic brain injury preceding the onset of FS confirmed by video-electroencephalography were recruited prospectively. Participants completed psychiatric symptom assessments before undergoing functional magnetic resonance imaging (fMRI) with an acute psychosocial stress task. Linear mixed effects (LME) analyses identified significant interactions between the factors of group (early vs. delayed diagnosis) and time lag to diagnosis on neural responses to stressful math performance and auditory feedback (corrected α = .05). Functional connectivity analysis utilized clusters from initial LME analyses as seed regions to determine significant interactions between these factors on network functional connectivity.

RESULTS

Demographic and psychiatric symptom measures were similar between early (n = 25) and delayed (n = 24) groups. Responses to stressful math performance within the left anterior insula and functional connectivity between the anterior insula seed region and a precentral gyrus cluster were significantly negatively correlated with time lag to diagnosis for the early but not the delayed FS diagnosis group. There was no correlation between fMRI findings and psychiatric symptoms.

SIGNIFICANCE

This study indicates that aberrant left anterior insula activation and its functional connectivity to the precentral gyrus underlie differences in processing of stressful experiences in patients with delayed FS diagnosis. Follow-up comparisons suggest changes are associated with undiagnosed illness duration rather than psychiatric comorbidities and indicate a potential mechanistic association between neuropathophysiology, response to stressful experiences, and functional neuroanatomy in FS.

Insular Stimulation Produces Mental Clarity and Bliss

For the first time, an ecstatic aura has been evoked through the electrical stimulation of the dorsal anterior insula during presurgical invasive intracerebral monitoring in a patient who did not suffer from an ecstatic form of epilepsy. This case provides more evidence that the anterior insula is the major generator of such a mystical‐type experience even in individuals with no underlying brain network changes related to a preexisting ecstatic epilepsy. ANN NEUROL 2022;91:289–292

Epilepsy and Ecstatic Experiences: The Role of the Insula

Ecstatic epilepsy is a rare form of focal epilepsy in which the aura (beginning of the seizures) consists of a blissful state of mental clarity/feeling of certainty. Such a state has also been described as a “religious” or mystical experience. While this form of epilepsy has long been recognized as a temporal lobe epilepsy, we have accumulated evidence converging toward the location of the symptomatogenic zone in the dorsal anterior insula during the 10 last years. The neurocognitive hypothesis for the genesis of a mental clarity is the suppression of the interoceptive prediction errors and of the unexpected surprise associated with any incoming internal or external signal, usually processed by the dorsal anterior insula. This mimics a perfect prediction of the world and induces a feeling of certainty. The ecstatic epilepsy is thus an amazing model for the role of anterior insula in uncertainty and surprise.

Neurocircuitry of Contingency Awareness in Pavlovian Fear Conditioning

In Pavlovian fear conditioning, contingency awareness provides an indicator of explicit fear learning. A less studied aspect of fear-based psychopathologies and their treatment, awareness of learned fear is a common cause of distress in persons with such conditions and is a focus of their treatment. The present work is a substudy of a broader fear-conditioning fMRI study. Following fear conditioning, we identified a subset of individuals who did not exhibit explicit awareness of the CS-US contingency. This prompted an exploratory analysis of differences in "aware" versus "unaware" individuals after fear conditioning. Self-reported expectancies of the CS-US contingency obtained immediately following fear conditioning were used to differentiate the two groups. Results corrected for multiple comparisons indicated significantly greater BOLD signal in the bilateral dlPFC, right vmPFC, bilateral vlPFC, left insula, left hippocampus, and bilateral amygdala for the CS+>CS- contrast in the aware group compared with the unaware group (all p values ≤ 0.004). PPI analysis with a left hippocampal seed indicated stronger coupling with the dlPFC and vmPFC in the aware group compared with the unaware group (all p values ≤ 0.002). Our findings add to our current knowledge of the networks involved in explicit learning and awareness of conditioned fear, with important clinical implications.

Ecstatic and gelastic seizures related to the hypothalamus

Ecstatic seizures constitute a rare form of epilepsy, and the semiology is diverse. Previously, brain areas including the temporal lobe and the insula have been identified to be involved in clinical expression. The aim of this report is to review changes in ecstatic seizures in a patient before and after operation for a hypothalamic hamartoma, and to scrutinize the relation to gelastic seizures. In this case, the ecstatic seizures disappeared after surgery of the hamartoma but reappeared eleven years later. Clinical information was retrospectively obtained from medical records, interviews, and a questionnaire covering seizure semiology that pertained to ecstatic and gelastic seizures. Our findings imply a possible connection between gelastic and ecstatic seizures, originating from a hypothalamic hamartoma. To our knowledge, this location has not previously been described in ecstatic seizures. Gelastic seizures may in this case be associated with ecstatic seizures. We speculate that patients with ecstatic seizures may have an ictal activation of neuronal networks that involve the insula. Our case may add information to the knowledge concerning ecstatic seizures.

Ecstatic and gelastic seizures relate to the hypothalamus

Ecstatic seizures constitute a rare form of epilepsy, and the semiology is diverse. Previously, brain areas including the temporal lobe and the insula have been identified to be involved in clinical expression. The aim of this report is to review changes in ecstatic seizures in a patient before and after operation of a hypothalamic hamartoma, and to scrutinize the relation to gelastic seizures. In this case, the ecstatic seizures disappeared after surgery of the hamartoma but reappeared eleven years later. Clinical information was retrospectively obtained from medical records, interviews, and a questionnaire covering seizure semiology that pertained to ecstatic and gelastic seizures. Our findings imply a possible connection between gelastic and ecstatic seizures, originating from a hypothalamic hamartoma. To our knowledge, this location has not previously been described in ecstatic seizures. Gelastic seizures may in this case were associated with ecstatic seizures. We speclate patients with ecstatic seizures may have an ictal activation of neuronal networks that involves the insula. Our case may add information to the growing knowledge concerning ecstatic seizures.

Altered cortical development in fetuses with isolated nonsevere ventriculomegaly assessed by neurosonography

OBJECTIVES

To perform a comprehensive assessment of cortical development in fetuses with isolated nonsevere ventriculomegaly (INSVM) by neurosonography.

METHODS

We prospectively included 40 fetuses with INSVM and 40 controls. INSVM was defined as atrial width between 10.0 and 14.9 mm without associated malformation, infection, or chromosomal abnormality. Cortical development was assessed by neurosonography at 26 and 30 weeks of gestation measuring depth of selected sulci and applying a maturation scale from 0 (no appearance) to 5 (maximally developed) of main sulci and areas.

RESULTS

INSVM showed underdeveloped calcarine and parieto-occipital sulci. In addition, significant delayed maturation pattern was also observed in regions distant to ventricular system including Insula depth (controls 30.8 mm [SD 1.7] vs INSVM 31.7 mm [1.8]; P = .04), Sylvian fissure grading (>2 at 26 weeks: controls 87.5% vs INSVM 50%, P = .01), mesial area grading (>2 at 30 weeks: controls 95% vs INSVM 62.5%; P = .03), and cingulate sulcus grading (>2 at 30 weeks: controls 100% vs INSVM 80.5%; P = .01).

CONCLUSIONS

Fetuses with INSVM showed underdeveloped cortical maturation including also regions, where effect of ventricular dilatation is unlikely. These results suggest that in a proportion of fetuses with INSVM, ventricular dilation might be related with altered cortical architecture.

Consciousness as an Inhibited Manifestation and Quantum Physics

The term soul is used in the traditional literature as a synonym for one's true Self and is associated with the subjective essence of one's living. Since, we don't have any means to quantify it, the science has ruled out this idea from its investigations. But, in a recent study, Ceylan et al. (2017) has reintroduced the word soul to scientific literature and examined the possibility of the study of the soul through scientific modalities. The primary focus of their study is to find and understand the scientific analog of the soul as quoted and discussed in the traditional literature. In the present paper, we examine the idea of a soul that uses a novel approach; integrating neuroscience and quantum physics, as proposed in Ceylan et al. (2017). For this purpose, we make use of findings from neuroscientific studies on meditation to understand the concepts of soul and consciousness in terms of inhibition mechanisms. In this context, this paper serves as an attempt to call for more studies to discuss and expand the hypothesis about the soul as uninhibited mental activity.

The possible role of the insula in the epilepsy and the gambling disorder of Fyodor Dostoyevsky

Background The retrospective diagnosis of Fyodor Mikhailovich Dostoyevsky's (1821-1881) neurological and psychiatric disease proves to be particularly interesting. Recent neurobiological data suggest a solution to the questions regarding the writer's retrospective diagnosis, claiming the insular cortex to be the origin of the rare ecstatic seizures. Regarding Dostoyevsky's pathological gambling, this hypothesis is consistent with another finding from recent neuroscience, namely that the malfunction of the insula could be an important underlying pathology in gambling disorder. Case study Literary and scientific overview (1928-2015) on the subjects of Dostoyevsky's epilepsy and gambling disorder. Discussion and conclusion Taking Dostoyevsky's neurological (ecstatic seizures) and psychiatric (pathological gambling) disease and the crossroads into consideration, these two disciplines make regarding the underlying pathology, we would like to suggest a speculative theory that these two disorders have a common insular pathomechanism, namely, the malfunctioning of the risk prediction-risk prediction error coding system. Furthermore, based on Dostoyevsky's case, regarding gambling disorder in general, we would like to hypothesize that the three common gambling-related cognitive distortions (near-miss effect, gambler's fallacy, and the illusion of control) can be all attributed to the impairment of the anterior insular risk prediction-risk prediction error coding system.

Ecstatic Epileptic Seizures: A Glimpse into the Multiple Roles of the Insula

Ecstatic epileptic seizures are a rare but compelling epileptic entity. During the first seconds of these seizures, ecstatic auras provoke feelings of well-being, intense serenity, bliss, and "enhanced self-awareness." They are associated with the impression of time dilation, and can be described as a mystic experience by some patients. The functional neuroanatomy of ecstatic seizures is still debated. During recent years several patients presenting with ecstatic auras have been reported by others and us (in total n = 52); a few of them in the setting of presurgical evaluation including electrical brain stimulation. According to the recently recognized functions of the insula, and the results of nuclear brain imaging and electrical stimulation, the ecstatic symptoms in these patients seem to localize to a functional network centered around the anterior insular cortex, where we thus propose to locate this rare ictal phenomenon. Here we summarize the role of the multiple sensory, autonomic, affective, and cognitive functions of the insular cortex, which are integrated into the creation of self-awareness, and we suggest how this system may become dysfunctional on several levels during ecstatic aura.

Predictions, perception, and a sense of self

In recent years there has been a paradigm shift in theoretical neuroscience in which the brain-as a passive processor of sensory information-is now considered an active organ of inference, generating predictions and hypotheses about the causes of its sensations. In this commentary, we try to convey the basic ideas behind this perspective, describe their neurophysiologic underpinnings, and highlight the potential importance of this formulation for clinical neuroscience. The formalism it provides-and the implementation of active inference in the brain-may have the potential to reveal aspects of functional neuroanatomy that are compromised in conditions ranging from Parkinson disease to schizophrenia. In particular, many neurologic and neuropsychiatric conditions may be understandable in terms of a failure to modulate the postsynaptic gain of neuronal populations reporting prediction errors during action and perception. From the perspective of the predictive brain, this represents a failure to encode the precision of-or confidence in-sensory information. We propose that the predictive or inferential perspective on brain function offers novel insights into brain diseases.

Ictal alterations of consciousness during ecstatic seizures

Patients with ecstatic epileptic seizures report an altered consciousness, which they describe as a sense of heightened perception of themselves – they “feel very present” – and an increased vividness of sensory perceptions. Recently, the anterior insula has been proposed as the region where these seizures originate, based on the results of ictal nuclear imaging in three patients, the first induction of ecstatic auras by electrical stimulation, and the functional characteristics of the anterior insula in neuroimaging literature. Specifically, the anterior insula is thought to play a key role in integrating information from within the body, the external world, as well as the emotional states. In addition, the anterior insula is thought to convert this integrated information into successive global emotional moments, thus enabling both the construct of a sentient self as well as a mechanism for predictive coding. As part of the salience network, this region is also involved in switching from mind wandering toward attentional and executive processing. In this review, we will summarize previous patient reports and recap how insular functioning may be involved in the phenomenon of ecstatic seizures. Furthermore, we will relate these hypotheses to the results from research on meditation and effects of drug abuse.

Anterior insular cortex and emotional awareness

This paper reviews the foundation for a role of the human anterior insular cortex (AIC) in emotional awareness, defined as the conscious experience of emotions. We first introduce the neuroanatomical features of AIC and existing findings on emotional awareness. Using empathy, the awareness and understanding of other people's emotional states, as a test case, we then present evidence to demonstrate: 1) AIC and anterior cingulate cortex (ACC) are commonly coactivated as revealed by a meta-analysis, 2) AIC is functionally dissociable from ACC, 3) AIC integrates stimulus-driven and top-down information, and 4) AIC is necessary for emotional awareness. We propose a model in which AIC serves two major functions: integrating bottom-up interoceptive signals with top-down predictions to generate a current awareness state and providing descending predictions to visceral systems that provide a point of reference for autonomic reflexes. We argue that AIC is critical and necessary for emotional awareness.