Epilepsy & Behavior 30 (2014) 58–61
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Ictal alterations of consciousness during ecstatic seizures Fabienne Picard a,⁎, Florian Kurth b a b
Department of Neurology, University Hospital and Medical School of Geneva, Switzerland Department of Neurology, UCLA School of Medicine, Los Angeles, USA
a r t i c l e
i n f o
Article history: Received 24 September 2013 Accepted 26 September 2013 Available online 26 October 2013 Keywords: Epilepsy Ecstatic Self-awareness Consciousness Insula Meditation
a b s t r a c t 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. This article is part of a Special Issue entitled Epilepsy and Consciousness. © 2013 Elsevier Inc. All rights reserved.
“The feeling of life, of self-awareness, seemed to grow stronger in such lightening moments.” The ﬁrst description of the state of consciousness observed in ecstatic epileptic seizures was given in the 1860s by Dostoevsky, who described the symptoms of such seizures mainly through the characters in his novels. Prince Mychkine, the main character of “The Idiot”, suffered from such seizures, which were characterized by a sense of bliss. He felt “ﬂashes of lucidity with hyperesthesia of sensory stimuli and of awareness” and “an incredible hitherto unsuspected feeling of bliss and appeasement…”. “My mind grows extraordinarily clear…”. “Such moments represented an incredible effort toward awareness and at the same time the most direct expression of self-awareness.” “Once I returned to normal consciousness, I felt that such illumination, such awareness of a higher consciousness, of a “superior being”, was a kind of illness, a distortion of the normal state. But it was neither mirage nor vain illusions such as those induced by hashish or alcohol that degrade the mind…”. “All my problems, doubts and worries resolved themselves in a limpid subtle Abbreviations: SPECT, single photon emission computed tomography; EEG, electroencephalogram. ⁎ Corresponding author at: Department of Neurology, University Hospital of Geneva, 4 rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland. Fax: +41 22 37 28 340. E-mail address: [email protected]
(F. Picard). 1525-5050/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.yebeh.2013.09.036
peace, with a feeling of understanding and awareness of the ‘Supreme Principle of life’”. While the majority of patients with ecstatic epileptic seizures report similar feelings, they may ﬁnd it more difﬁcult than Dostoevsky to describe these surreal symptoms. Most describe a sense of heightened perception of themselves – they “feel very present” – and an increased vividness of sensory perceptions during their seizures. At an initial stage, these ecstatic epileptic seizures are not accompanied by a loss of consciousness. Thus, they correspond to “simple partial seizures” according to the old ILAE Classiﬁcation of Epilepsies and Epileptic Syndromes , a term now replaced by “focal seizures without impairment of consciousness or awareness” . 2. Patients Seven patients have been described, who all reported a state of heightened self-awareness coupled with feelings of enhanced wellbeing and intense positive emotion. Picard and Craig reported ﬁve patients with ecstatic seizures, whose descriptions of ecstatic auras were very similar to that of Dostoevsky's . Picard later described two more patients . The heightened awareness actually affected both the internal “self-awareness” (feeling of being “more present”) and, according to some of the patients, the awareness of the external world with a more accurate, more acute perception of external stimuli. Among the descriptions of the ictal symptoms in the ﬁrst paper, subject 1 reported: “it is as if I were very, very conscious, more aware, and the sensations, everything, seems bigger, overwhelming me.” Subject 2 used these words: “I feel light inside, but far from being empty. I feel really
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present…. I feel a stronger consciousness of the body and the mind, but I do not forget what is around me”. Subject 4 described: “I feel more conscious of myself, more concentrated on myself… I feel more present from a psychological point of view, with more sensations…”. “Being very conscious of myself, I feel like discharged from anything else, from any worries”. Subject 5 reported: “It is a feeling of total presence, an absolute integration of myself, a feeling of unbelievable harmony of my whole body and myself with life, with the world, with the ‘All’” . Another subject explained: “This would result in a sense of vividness which derived from the fact that each object in my visual ﬁeld was emphasized, so to speak, by everything else” . 3. The insula According to Picard and Craig's hypothesis, the symptomatic zone of the ecstatic aura would be the anterior insula, for a variety of reasons. Speciﬁcally, the results of ictal nuclear imaging reported in the literature for three patients [3–5] described a maximum of activity in this region. Ictal SPECT showed an increased blood ﬂow in the whole right anterior insula in the ﬁrst patient ; in the left anterior insula and mid-insula on both sides in the second patient ; and at the junction of the right dorsal mid-insula and central operculum in the last patient . In addition, ecstatic auras were induced by electrical stimulation of the anterior–dorsal insula in a new patient with ecstatic seizures who underwent a presurgical depth electrode evaluation . Finally, the different physiological roles of this region are abundantly described in literature. The insula is both, segregated into different subregions that are involved in a variety of functional systems, and at the same time a major hub for integrating the information from these different functional systems . Speciﬁcally, the insula's functionally deﬁned subregions are involved in interoception, gustation, olfaction, somatosensation, processing of emotions, and cognition. Connectivity studies in animals revealed that the different parts of the insula are extremely well interconnected , which enables a rapid ﬂow of information to the anterior insula. In the anterior insula, this incoming interoceptive/ sensory, emotional, and cognitive information is ﬁnally integrated into a sense of well-being  and emotional regulation [6,9], and used in salience detection, switching between brain states, and predictive coding [10–12]. This integration has been hypothesized to produce self-awareness and the experience of a present moment [9,13]. The rich interconnection between insular subregions  may well enable a rapid propagation of seizure activity. This rapid propagation may lead to ecstatic seizures with different attendant symptoms like gustatory, olfactory, or auditory sensations (depending on the exact location of the ictal discharge), which were previously described [3,4]. Interestingly, very close connections also exist between the insula and the temporopolar region . These connections, as well as the observation that ictal discharges can propagate directly from the temporal neocortex to the insula without a mesiotemporal relay , may explain how seizures originating in the temporal pole may immediately propagate to the insula . Once ictal activity reaches the anterior insula, it may directly alter its functioning and elicit ecstatic seizures rather than classical temporal lobe epilepsy symptoms . Speciﬁcally, changes in well-being, emotional regulation, and awareness of the present moment as reported in ecstatic seizures can be expected. In the following sections, we will discuss alterations in salience detection and switching brain states, changes in “awareness of the present moment”, as well as possible effects on predictive coding. 4. Possible underlying mechanisms of ecstatic seizures The anterior insula shows highly correlated activity with the dorsal anterior cingulate cortex (dACC) during the resting state, constituting a functional network which has been implicated in a broad range of affective and cognitive processes, including interoceptive–autonomic arousal, salience detection (that is, behaviorally relevant stimuli
detection), emotional processing, tonic alertness, and decision-making, in order to adequately process high-priority signals [9,16–19]. The most ventral part of this network was referred to as the “salience network” because of its role in the identiﬁcation of the most salient stimuli and switching between the default mode network (which is activated during mind wandering) and the executive network, which enables the ability to ﬁx attention on the external world and associative interoceptive state/changes [9–11,17,20,21]. It inhibits the default mode network and initiates the executive network (with a consequent activation of other attentional control-related networks). The salience network is implicated in the detection of salient external events as well as internally generated events, such as conscious awareness of errors. Hasenkamp et al. reported robust activations in the bilateral anterior insula and dACC when subjects became aware that their mind had wandered away from the breathing sensations on which they had to maintain attention [22,23]. During ecstatic seizures, the capacity to feel “more present” and have an increased perception of external stimuli could be related to a sustained activation of the salience network despite the absence of salient stimuli. An abnormal (seizure-induced) activation of this network would give rise to a switch away from mind wandering and to an unusual state of sustained high alertness and awareness without cause and without speciﬁc aim. Any current internal or external stimulus would then be perceived as if it was salient, giving rise to a feeling of extreme inner and external vividness at any given moment during the ecstatic aura. It has been suggested that the anterior insula is a key structure for the “present-moment awareness” , another possible underlying mechanism. Different studies showed that the anterior insula is consistently involved at the moment of perceptual recognition, for example, when subjects become aware that their mind has wandered away from the task . However, this involvement has been particularly shown in conscious error perception or “error awareness”. In a visual saccade task in which it was possible to be either aware or unaware of errors, the anterior insula was activated only when participants could signal awareness of such errors [24,25]. The anterior insula can also analyze intersensory temporal synchrony and is activated during visual–auditory asynchrony detection . According to Craig, the anterior insula integrates internal (interoceptive), external (sensory), and emotional information at each moment, giving rise to an image of ‘the material me’ or the sentient self at the immediate moment of time – ‘now’ – which he calls a “global emotional moment” [9,13,27]. The succession of global emotional moments would produce a cinemascopic ‘image’ of the sentient self that is continuous across a moving window of present time and would constitute the basis of time perception with an approximate frame rate of 8 Hz (i.e., each global emotional moment lasting about 125 ms) [3,13,27]. An important aspect of this model is that the sampling rate is not ﬁxed but is rather dependent on salience. That is, sampling occurs more frequently for salient moments, leading to a subjective dilation of time, thus explaining the strong link between emotions and subjective time perception. The ecstatic seizures could allow a sustained “present-moment awareness” state. Patients all indicate a subjective time dilation [3,4]: their several-second seizures seem to last much longer, as if time had stretched (“I could not say if it lasts one second, hours or months”, Dostoevsky). In the present model, if each stimulus is perceived as salient, the extremely high number of consecutive salient moments would increase the sampling rate to a maximum, leaving the patient subjectively timeless in the ‘here and now’. Finally, a third possible mechanism involves uncertainty. Overall, there is a strong motivation to avoid ambiguity and uncertainty , since these have been characterized as aversive states . Generally speaking, uncertainty can be minimized by making inferences about future states with the greatest possible precision . For this purpose, the brain predicts future states and continuously compares these predictions with current states while trying to minimize the prediction
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error (predictive coding). A mismatch between prediction and actual experience (i.e., prediction error) has been associated with generating negative emotional arousal or anxiety [31–33]. There is accumulating evidence for a role of the anterior insula in predictive coding and eliciting feelings of anxiety and negative emotional arousal in case of prediction errors [10,18,34,35]. As detailed previously, the anterior insula is thought to generate a cinemascopic ‘image’ of the sentient self across time, including the immediate past, present, and anticipated immediate future [9,13,27]. This cinemascopic ‘image’ may provide a means to compare the experienced global moment with its prediction (the anticipated immediate future). A comparison of interoceptive signals and their prediction in this region has recently been proposed as a model of conscious presence . Speciﬁcally, an accurate prediction (in other words, a minimized prediction error) was associated with a possible sense of presence in a virtual environment. If we assume that during ecstatic seizures, the sampling rate increases as described above, the cinemascopic image would be ‘ﬁlled up’ with present-moment samples. Consequently, at an extremely high sampling rate, the predictive coding would cease to work or at least would not make predictions at the high frequency of actual experience. The nonexisting prediction error may consequently prevent negative emotions and instill the feeling of certainty and the absence of worries and doubts that was reported by patients . 5. Common mechanisms with meditation The peculiarity of the state induced by the ecstatic seizures is a total immersion in the present moment without any intrusion of thoughts regarding the past or the future, without any mind wandering; i.e., the patient is just in a state of contemplation. The sudden immersion into this unusual state of “accordance with the present moment” is so unexpected and powerful that people may have the impression that they have an understanding of “the Supreme Principle of life”, as indicated by Dostoevsky and some of our patients, even if they had no previous religious beliefs. Enhanced awareness of the present moment and the cognitive reappraisal of emotionally salient sensory events, which were described to involve the anterior insula as reported in different studies, are the goals in meditation [36–42]. In functional studies, activity in the anterior–dorsal insula has been reported to be increased during the advanced stage of meditation training  and associated with the self-reported intensity of the meditation . In addition, a modulation of the state anxiety by mindfulness meditation was shown to engage a network of brain regions including the anterior insula . Structural studies have likewise indicated more gray matter concentration , a thicker cortex , and a stronger gyriﬁcation  in the anterior insula in meditators compared to controls, as well as positive correlations between the number of meditation years and gyriﬁcation in this region . The insula's above-discussed role in switching between different brain networks may be important for meditators to achieve and maintain a meditative state. This switch may induce a different brain state away from daydreaming, mind wandering, and projections to the past and the future as mediated by the default mode network, which may then bring meditators into the “present moment”. This role in switching was conﬁrmed during a task in which the subjects had to focus their attention on breath (breath-focused meditation) . The anterior insula was involved in shifting attention back on the “object” (here, the breath), when subjects became aware of mind wandering, conﬁrming the role of the anterior insula in switching to and maintaining a state of “present-moment conscious awareness” . In this context, it is interesting that the anterior insula may be the focus of ecstatic seizures. That is, similar to the willful process of meditation, these seizures may induce a feeling of heightened awareness, similar to the state sought through meditative practice. Moreover, these seizures may alter the brain state by switching away
from the default mode network as discussed above, thus “locking” the patients in a feeling of the “present moment”. 6. Common mechanisms with states induced by drugs of abuse A blissful state can be experienced with some addictive drugs of abuse. Stimulant drugs of abuse, such as amphetamine, cocaine, and ecstasy (3,4-methylene-dioxy-methamphetamine) can induce a feeling of enhanced introspective attention and a heightened awareness of the surroundings, together with extreme bliss and inner peace. Interestingly, neuroimaging studies have shown alterations in the anterior insula when taking stimulant drugs of abuse; in addition, a major role of the anterior insula in addiction is now well recognized . The insula is known to represent the interoceptive effects of drug use, giving rise to “a subjective feeling which includes conscious appreciation of interoceptive effects in addition to pleasure” . A comparison of the emotional effects of nicotine (which acts as a stimulant at small doses) in patients with left insula lesions and in patients with lesions in noninsula regions showed that subjects with left insula lesions failed to ﬁnd puffs with nicotine more pleasurable and desirable than puffs without nicotine . In rats, a positive correlation was shown between the dose of administered cocaine and the activity within the insula, cingulate cortex, and nucleus accumbens . In nonhuman primates, acute cocaine administration was shown to induce immediate early gene expression in the insula and ventromedial prefrontal cortex . In humans, chronic cocaine abuse is associated with a decreased gray matter concentration in these regions . A longer duration of cocaine dependence was shown to correlate with a greater gray matter volume reduction in the insular, cingulate, and orbitofrontal cortices . A bilateral activation of the anterior insula was also shown under the effect of the psychoactive ayahuasca tea, a central element of Amazonian shamanism which produces enhanced introspective attention and euphoria . The likely involvement of the anterior insula in both ecstatic epileptic seizures and in the use of stimulant addictive drugs could underlie the similarity of symptoms . The activation of the anterior insula observed during the taking of a stimulant drug of abuse could also explain a sustained state of “present-moment conscious awareness” which takes the subject away from mind wandering and projections to the past and the future, all of which can cause doubts and worries. The inner peace could be related to the lack of worries of the past and future. In conclusion, besides the classical impairment of consciousness that often accompanies epileptic seizures and which is one of the most disabling manifestations of epileptic seizures, an almost opposite effect on consciousness may occur in some focal seizures, the ecstatic seizures, with a feeling of heightened consciousness, affecting self-awareness and, possibly, also awareness of external world. This increased awareness seems related to a complete, sustained focus on the present moment, which, according to some arguments, could be caused by an epileptic discharge within the anterior insula, already known for its role in present-moment awareness. Future experiments could explore this issue with functional imaging studies using new paradigms for the investigation of the neural circuits underlying present-moment awareness and, possibly, by studying patients with pharmacoresistant focal epilepsy with ecstatic auras who undergo intracerebral EEG recordings during a presurgical evaluation of their epilepsy. Conﬂict of interest The authors declare that there are no conﬂicts of interest. Acknowledgments We would like to thank Dr. Anil Seth (University of Sussex) for helpful comments.
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