Homotopic reciprocal functional connectivity between anterior human insulae

Lacuey, Nuria; Zonjy, Bilal; Kahriman, Emine; Marashly, Ahmad; Miller, Jonathan P.; Lhatoo, Samden D.; Lüders, Hans

doi:10.1007/s00429-015-1065-0

Cited by 19 publications

(12 citation statements)

References 15 publications

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“…33 The SEEG investigations of insular lobe seizures have shown the following: (1) Seizure onset patterns can be variable in the insula, but low-voltage fast discharge 34 or high-frequency gamma activity 7 are not uncommon (Figure 3B and C); (2) seizures often start very focally with a limited intrainsular spread before extrainsular propagation (Figure 3B-D), which therefore allows tailored limited resections (Figure 3E) 35 ; (3) extrainsular spread explains clinical variability of insular lobe seizures; in particular, complex motor manifestations were shown to occur when the discharge spread over frontomesial and/or mesial and lateral temporal regions. 16 This is in accordance with directed functional coupling analysis that reported a specific association between the insula and mesial frontal lobe during the propagation of insular seizures 34 ; (4) corticocortical evoked potentials have showed that the 2 insulas are closely connected, 36 with 8- to 24-milliseconds time to propagate from one to the other homotopic insular parcel 37 ; therefore, insular seizures may propagate very quickly to the contralateral insula (Figure 3B) so that false lateralization may occur in insular or even temporo(-insular) epilepsy 38 ; (5) typical insular signs can occur in seizures of extrainsular origin; in particular, insular spread is very common in seizures of temporal lobe origin 22,39 and therefore may result in misleading seizure auras; and (6) the morbidity rate directly related to insular electrodes is low. In particular, none of the patients (including children) reported in 3 recent large studies experienced any hemorrhagic complications.…”

Section: Invasive Recordings Of Insular Lobe Seizuressupporting

confidence: 85%

The Insula and Its Epilepsies

et al. 2019

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Insular seizures are great mimickers of seizures originating elsewhere in the brain. The insula is a highly connected brain structure. Seizures may only become clinically evident after ictal activity propagates out of the insula with semiology that reflects the propagation pattern. Insular seizures with perisylvian spread, for example, manifest first as throat constriction, followed next by perioral and hemisensory symptoms, and then by unilateral motor symptoms. On the other hand, insular seizures may spread instead to the temporal and frontal lobes and present like seizures originating from these regions. Due to the location of the insula deep in the brain, interictal and ictal scalp electroencephalogram (EEG) changes can be variable and misleading. Magnetic resonance imaging, magnetic resonance spectroscopy, magnetoencephalography, positron emission tomography, and single-photon computed tomography imaging may assist in establishing a diagnosis of insular epilepsy. Intracranial EEG recordings from within the insula, using stereo-EEG or depth electrode techniques, can prove insular seizure origin. Seizure onset, most commonly seen as low-voltage, fast gamma activity, however, can be highly localized and easily missed if the insula is only sparsely sampled. Moreover, seizure spread to the contralateral insula and other brain regions may occur rapidly. Extensive sampling of the insula with multiple electrode trajectories is necessary to avoid these pitfalls. Understanding the functional organization of the insula is helpful when interpreting the semiology produced by insular seizures. Electrical stimulation mapping around the central sulcus of the insula results in paresthesias, while stimulation of the posterior insula typically produces painful sensations. Visceral sensations are the next most common result of insular stimulation. Treatment of insular epilepsy is evolving, but poses challenges. Surgical resections of the insula are effective but risk significant morbidity if not carefully planned. Neurostimulation is an emerging option for treatment, especially for seizures with onset in the posterior insula. The close association of the insula with marked autonomic changes has led to interest in the role of the insula in sudden unexpected death in epilepsy and warrants additional study with larger patient cohorts.

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Section: Invasive Recordings Of Insular Lobe Seizuressupporting

confidence: 85%

The Insula and Its Epilepsies

et al. 2019

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“…In some circumstances, the rat posterior insula shows no lateralization of cardiovascular function in response to stimulation ( 90 ); while differences between rat and humans ( 74 ) may extend to lateralization, these recent data, nevertheless, show that the insula has complex topographic organizational and different response patterns arise from different stimulation types. The two hemispheres also show strong connections in the anterior insula ( 99 ). Nevertheless, human stroke findings are consistent with a right-sided sympathetic regulatory role ( 28 , 100 , 101 ).…”

Section: Discussionmentioning

confidence: 99%

Sex Differences in Insular Cortex Gyri Responses to the Valsalva Maneuver

et al. 2016

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Sex differences in autonomic regulation may underlie cardiovascular disease variations between females and males. One key autonomic brain region is the insular cortex, which typically consists of five main gyri in each hemisphere, and shows a topographical organization of autonomic function across those gyri. The present study aims to identify possible sex differences in organization of autonomic function in the insula. We studied brain functional magnetic resonance imaging (fMRI) responses to a series of four 18-s Valsalva maneuvers in 22 healthy females (age ± SD: 50.0 ± 7.9 years) and 36 healthy males (45.3 ± 9.2 years). Comparisons of heart rate (HR) and fMRI signals were performed with repeated measures ANOVA (threshold P < 0.05 for all findings). All subjects achieved the target 30 mmHg expiratory pressure for all challenges. Typical HR responses were elicited by the maneuver, including HR increases from ~4 s into the strain period (Phase II) and rapid declines to below baseline 5–10 s, following strain release (Phase IV). Small, but significant, sex differences in HR percent change occurred during the sympathetic-dominant Phase II (female < male) and parasympathetic-dominant Phase IV (female > male, i.e., greater undershoot in males). The insular cortices showed similar patterns in all gyri, with greater signal decreases in males than females. Both sexes exhibited an anterior–posterior topographical organization of insular responses during Phase II, with anterior gyri showing higher responses than more posterior gyri. The exception was the right anterior-most gyrus in females, which had lower responses than the four other right gyri. Responses were lateralized, with right-sided dominance during Phase II in both sexes, except the right anterior-most gyrus in females, which showed lower responses than the left. The findings confirm the anterior and right-sided sympathetic dominance of the insula. Although sex differences were prominent in response magnitude, organization differences between males and females were limited to the right anterior-most gyrus, which showed a lower fMRI response in females vs. males (and vs. other gyri in females). The sex differences suggest a possible differing baseline state of brain physiology or tonic functional activity between females and males, especially in the right anterior-most gyrus.

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“…28 There is no paninsular spread, and contralateral insula involvement is very fast. Corticocortical evoked potentials demonstrate both insulas are closely connected, 30 with 8to 24-millisecond propagation time between homotopic insular parcels 31 ; therefore, early contralateral insula propagation may lead to false lateralization.…”

Section: Insular Seizures Start Focally With Limited Intrainsular Spreadmentioning

confidence: 99%

Mapping the Insula with Stereo‐Electroencephalography: The Emergence of Semiology in Insula Lobe Seizures

Singh

Príncipe

Tadel

et al. 2020

Annals of Neurology

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Objective Insula epilepsy is rare and can be evaluated effectively by Stereotactic intracerebral EEG (SEEG). Many previous studies of insulo‐opercular seizures have been unable to separate insular and opercular onset. With adequate sampling of the insula, this study shows this is possible. Methods We analyzed intrainsular dynamics and extrainsular propagation in 12 patients with “pure” insula epilepsy (n = 9) or insular and only deepest opercular involvement (n = 3) at seizure onset. Review of semiology defined clinical groups, agglomerative cluster, and principal component analysis of semiological features were performed. Quantitative epileptogenicity, and intrainsular and extrainsular propagation were computed via time frequency analysis and epileptogenicity mapping. Results Seizure onset patterns were heterogeneous; the seizure onset zone was focal. Seizure onset and first ictal change within insula functional subdivision correlated with aura and reflex component. No paninsular spread occurred; contralateral insular spread was very early. While the discharge was intrainsular, clinical signs related to aura or vegetative signs. Extrainsular propagation was early and related to the emergence of the majority of clinical signs. Cluster analysis found an anterior, intermediate, and posterior insula seizure onset group. The largest principal component separated anterior insula manifestations, including early hypermotor signs, early recovery, and no aura from posterior insula features of early dystonia, early tonic motor features, and sensorimotor aura. Interpretation Aura is vital to identifying seizure onset and relates to insula functional subdivision. Seizures are heterogenous; extrainsular propagation occurs early, accounting for most of the semiology. With adequate sampling, "pure" insula epilepsy can be identified and focal curative resection is possible. ANN NEUROL 2020;88:477–488

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Homotopic reciprocal functional connectivity between anterior human insulae

Cited by 19 publications

References 15 publications

The Insula and Its Epilepsies

The Insula and Its Epilepsies

Sex Differences in Insular Cortex Gyri Responses to the Valsalva Maneuver

Mapping the Insula with Stereo‐Electroencephalography: The Emergence of Semiology in Insula Lobe Seizures

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