Involvement of Medial Pulvinar Thalamic Nucleus in Human Temporal Lobe Seizures

Rosenberg, Dominique; Mauguı̀ere, François; Demarquay, Geneviève; Ryvlin, Philippe; Isnard, Jean; Fischer, Catherine; Guénot, Marc; Magnin, M.

doi:10.1111/j.1528-1167.2006.00375.x

Cited by 121 publications

(109 citation statements)

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“…To delineate the extent of the cortical epileptogenic area and to plan a tailored surgical treatment, depth EEG recording electrodes were implanted according to the stereotactic technique of Talairach and Bancaud (44) (SI Methods). The thalamus, and more specifically the PuM, was a target of stereotactic implantation because, given its reciprocal connections with temporal cortical areas, it might be an important relay in the building of epileptic discharges (45). Intracortical exploration of temporal neocortical areas and of the PuM nucleus was possible using a single multicontact electrode, so that thalamic exploration did not increase the risk of the procedure by requiring an additional electrode track specifically devoted to the study of PuM activity.…”

Section: Methodsmentioning

confidence: 99%

Thalamic deactivation at sleep onset precedes that of the cerebral cortex in humans

Magnin

Rey

Bastuji

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Thalamic and cortical activities are assumed to be time-locked throughout all vigilance states. Using simultaneous intracortical and intrathalamic recordings, we demonstrate here that the thalamic deactivation occurring at sleep onset most often precedes that of the cortex by several minutes, whereas reactivation of both structures during awakening is synchronized. Delays between thalamus and cortex deactivations can vary from one subject to another when a similar cortical region is considered. In addition, heterogeneity in activity levels throughout the cortical mantle is larger than previously thought during the descent into sleep. Thus, asynchronous thalamocortical deactivation while falling asleep probably explains the production of hypnagogic hallucinations by a still-activated cortex and the common self-overestimation of the time needed to fall asleep.A bundant electrophysiological and functional imaging data have revealed that sleep-related brain activity is not the result of a global deactivation of cerebral structures but rather is a multifocal process associated with local changes in brain activities (1-10). Examples of such functional heterogeneities are, among others, the fronto-occipital gradient in cortical activity during sleep (1, 2), the preponderant fronto-parietal localization of sleep spindles (3, 4), and interhemispheric imbalanced activity (5, 6). So far, very few studies have addressed the time course of these regional differences during transitions between vigilance states (11)(12)(13)(14), and most of these studies were based on scalp recordings performed during stable periods of wakefulness or sleep. Although reports that favor some asynchrony of sleep-onset activity between the different cortical areas are accumulating, there still is a firm belief that thalamic and cortical activities are tightly coupled, at both the cellular and integrative level, during wakefulness and sleep (15)(16)(17)(18). Recent intracranial data in humans, however, indicate that, during both paradoxical (rapid eye movement) sleep and sleep stage 2, thalamic and cortical activities may alternate periods of coupling and decoupling (19,20). In this context, the question is whether the dynamics of the neuronal deactivation that characterizes the transition from wakefulness to sleep is identical in thalamus and cortex, or, conversely, whether transient decoupling may occur at this transition time that would suggest different sleep-onset timing in these two structures. The opportunity to record thalamic and cortical activities simultaneously in epileptic patients chronically implanted with intracerebral electrodes allowed us to address this issue. In contrast to the generally accepted view that thalamic and cortical activities are tightly locked along the different vigilance states, we found that the thalamic activity most often decreased to sleep levels several minutes before the cortical activity started to abate. This finding suggests that the cortex remains neurophysiologically awake but decoupled from thalamic i...

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Section: Methodsmentioning

confidence: 99%

Thalamic deactivation at sleep onset precedes that of the cerebral cortex in humans

Magnin

Rey

Bastuji

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

197

147

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“…The involvement of thalamus during TLE seizures was directly shown by direct intracerebral recordings [27,35]. In one study, the degree of thalamic involvement was correlated to the presence of AOC during seizures [27].…”

Section: No Visual Attention (0 or 1)mentioning

confidence: 99%

The Global Workspace (GW) Theory of Consciousness and Epilepsy

Bartolomei

Naccache

2011

Behavioural Neurology

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Abstract. The global workspace (GW) theory proposes that conscious processing results from coherent neuronal activity between widely distributed brain regions, with fronto-parietal associative cortices as key elements. In this model, transition between conscious and non conscious states are predicted to be caused by abrupt non-linear massive changes of the level of coherence within this distributed neural space. Epileptic seizures offer a unique model to explore the validity of this central hypothesis. Seizures are often characterized by the occurrence of brutal alterations of consciousness (AOC) which are largely negatively impacting patients' lives. Recently, we have shown that these sudden AOC are contemporary to non-linear increases of neural synchrony within distant cortico-cortical and cortico-thalamic networks. We interpreted these results in the light of GW theory, and suggested that excessive synchrony could prevent this distributed network to reach the minimal level of differentiation and complexity necessary to the coding of conscious representations. These observations both confirm some predictions of the GW model, and further specify the physiological window of neural coherence (minimum and maximum) associated with conscious processing.

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“…He mentioned that in the Rosenberg et al study (Rosenberg et al, 2006), 'LVFA (low voltage fast activity), which is the hallmark of cortical seizure onset, was significantly more frequently observed in PuM for seizures with lateral temporal onset than for those with mesial temporal onset'.…”

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confidence: 99%

“…In the third case, a larger part of the lateral neocortex, including the second temporal gyrus and the parietal cortex, rapidly involved the PuM in the form of a We think that there are no real discrepancies between our data and those published by Rosemberg et al Any apparent differences are probably due to differences in the population studied. Indeed the so-called lateral-TLE cases included in the Lyon study actually involved a large territory of not only lateral temporal cortex but also extra temporal cortices (see for example Figure 5 in the article of Rosenberg et al (2006), which corresponds to an occipito-temporal seizure). These features are therefore not characteristic of 'pure' lateral temporal lobe seizures.…”

mentioning

confidence: 99%