Short Gyri Research Articles

An MRI-based study of the insula in a South African population.

The insula, a cortical structure buried deep within the sylvian fissure, has long posed a surgical challenge. Comprehensive knowledge of the insular anatomy is therefore integral to preoperative planning and safe interventional procedures. Since magnetic resonance imaging (MRI) is a favoured modality for the identification of cerebral structures, this study aimed to investigate the morphology and morphometry of the insula in a South African population, using MRI scans. One-hundred MRI studies of insulae (n = 200 hemispheres) were retrospectively analysed for morphological features and morphometric parameters. The insulae were predominantly trapezoidal in shape (Laterality: Left: 82%; Right: 78%; Sex: Male: 84%, Female: 76%). The central insular sulcus was almost always "well seen" (Laterality: Left: 97%; Right: 99%; Sex: Male: 99%, Female: 97%). The middle short insular gyrus (MSG) was most variable in visibility, especially when compared across the sexes (p = 0.004). Insular gyri widths were comparable in both cerebral hemispheres; the posterior long gyrus (PLG) presented with the smallest mean widths. Anterior lobule (AL) widths were larger than those of the posterior lobule (PL). Widths of the insular gyri and lobules were generally larger in males than in females. The MSG and PLG widths in the left hemisphere, AL width in the right hemisphere, and the PL width in both hemispheres were significantly larger in males than in females (p = 0.001; p = 0.005; p = 0.041; p = 0.001, p = 0.015, respectively). MRI scans may be used to accurately interpret insular anatomy. The data obtained may aid neurosurgeons to perform safe insula-related surgical procedures.

348 Comparison of Brain Functional Imaging of Pain States Using Resting-State fMRI and Multi-Delay pCASL to Clinical Scores of Pain in Chronic Low Back Pain Patients Implanted With Thoracic Spinal Cord Stimulation

INTRODUCTION: Thoracic spinal cord stimulation (tSCS) is an interventional option for patients with refractory chronic low back pain (cLBP). The use of functional imaging of brain regions involved in pain as a quantitative method to evaluate treatment effectiveness has not yet been studied. METHODS: pCASL data using 5 post-label delays (0.5-2.5s) alongside rs-fMRI data was gathered from five patients (4 M, 1F) post-tSCS with cLBP post-implantation with the SCS device turned off at a 3.0T scanner. Arterial transit time (ATT), cerebral blood flow (CBF), and cerebral blood volume (CBV) were derived from pCASL data. Amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), degree of centrality (DC) and regional homogeneity (ReHo) were derived from rs-fMRI data. These data were registered against a pain-ROI atlas. The following clinical pain scores were assessed in the same five patients: Numerical Pain Rating Scale (NPRS), Visual Analogue Scale (VAS), Central Sensitization Inventory (CSI), Oswestry Disability Index (ODI), Pain Catastrophizing Scale (PCS), Pittsburgh Sleep Quality Index (PSQI) and Hospital Anxiety and Depression Scale (HADS). Predictive linear associations between pain ROIs and clinical scores were investigated using linear regression. RESULTS: Significant linear associations (p-value < 0.001) were found between pCASL-derived ATT to the dorsolateral prefrontal cortex (DLPC) and the NPRS; CBF to the ventral posterolateral thalamus (VPL) and the VAS, and of the posterior cingulate cortex (PCC) and the VAS; CBV of the posterior short gyrus (PS) and the VAS; and rs-fMRI-derived fALFF of the amygdala and the CSI. CONCLUSIONS: A comparison of functional imaging results and clinical pain scores suggest predictive relationships between resting-state function/brain perfusion in regions involved in pain perception and processing and various clinical pain assessments.

354 Feasibility and Clinical Imaging of Pain States Based on Multi-Delay Arterial Spin Labeling in Chronic Low Back Pain Patients Implanted With Thoracic Spinal Cord Stimulation

INTRODUCTION: Multi-delay, pseudo-continuous arterial spin labelling (PCASL) is a novel technique capable of perfusion imaging without contrast. It overcomes the limitation of a low signal-to-noise ratio of pulsed-ASL, and multiple post-label delays allow it to account for and measure arterial transit time (ATT). This makes it a suitable tool for the perfusion assessment. To date, there have been no studies to assess changes in ASL-measured perfusion in chronic low-back pain (cLBP) patients treated with thoracic spinal cord stimulation (tSCS). METHODS: PCASL data was acquired in five patients post-tSCS and five healthy subjects. ATT was estimated using weighted delays from multiple delay times, and it was used to calculate cerebral blood flow (CBF) and cerebral blood volume (CBV). Maps were normalized into MNI space and smoothed. Averaged values of ATT, CBF and CBV from pain ROI atlas were extracted and compared between cLBP and healthy control groups. Statistics comparing perfusion changes between patients and healthy subjects were conducted after Box-Cox transformation of data using Wilcoxon rank sum. RESULTS: Our results demonstrated the feasibility of MRI scanning with ASL sequence in patients with SCS. Specific absorption rates ranged from 0.031–0.042W/kg. Wilcoxon test indicated that ATT was significantly greater in cLBP patients within the supplementary motor area, posterior short gyrus, and the orbitofrontal cortex. There were no significant differences in patients and controls in CBF or CBV. CONCLUSIONS: Rate of perfusion as indexed by PCASL-derived ATT is reduced in cLBP treated with SCS patients in regions associated with pain processing, cognition, and motor planning. Insignificant results in CBF and CBV measures are likely due to low sample size of patients.

Identification of group differences in predictive anticipatory biasing of pain during uncertainty: preparing for the worst but hoping for the best.

Pain anticipation during conditions of uncertainty can unveil intrinsic biases, and understanding these biases can guide pain treatment interventions. This study used machine learning and functional magnetic resonance imaging to predict anticipatory responses in a pain anticipation experiment. One hundred forty-seven participants that included healthy controls (n = 57) and individuals with current and/or past mental health diagnosis (n = 90) received cues indicating upcoming pain stimuli: 2 cues predicted high and low temperatures, while a third cue introduced uncertainty. Accurate differentiation of neural patterns associated with specific anticipatory conditions was observed, involving activation in the anterior short gyrus of the insula and the nucleus accumbens. Three distinct response profiles emerged: subjects with a negative bias towards high pain anticipation, those with a positive bias towards low pain anticipation, and individuals whose predictions during uncertainty were unbiased. These profiles remained stable over one year, were consistent across diagnosed psychopathologies, and correlated with cognitive coping styles and underlying insula anatomy. The findings suggest that individualized and stable pain anticipation occurs in uncertain conditions.

Noninvasive neuromodulation of subregions of the human insula differentially affect pain processing and heart-rate variability: a within-subjects pseudo-randomized trial.

The insula is an intriguing target for pain modulation. Unfortunately, it lies deep to the cortex making spatially specific noninvasive access difficult. Here, we leverage the high spatial resolution and deep penetration depth of low-intensity focused ultrasound (LIFU) to nonsurgically modulate the anterior insula (AI) or posterior insula (PI) in humans for effect on subjective pain ratings, electroencephalographic (EEG) contact heat-evoked potentials, as well as autonomic measures including heart-rate variability (HRV). In a within-subjects, repeated-measures, pseudo-randomized trial design, 23 healthy volunteers received brief noxious heat pain stimuli to the dorsum of their right hand during continuous heart-rate, electrodermal, electrocardiography and EEG recording. Low-intensity focused ultrasound was delivered to the AI (anterior short gyrus), PI (posterior longus gyrus), or under an inert Sham condition. The primary outcome measure was pain rating. Low-intensity focused ultrasound to both AI and PI similarly reduced pain ratings but had differential effects on EEG activity. Low-intensity focused ultrasound to PI affected earlier EEG amplitudes, whereas LIFU to AI affected later EEG amplitudes. Only LIFU to the AI affected HRV as indexed by an increase in SD of N-N intervals and mean HRV low-frequency power. Taken together, LIFU is an effective noninvasive method to individually target subregions of the insula in humans for site-specific effects on brain biomarkers of pain processing and autonomic reactivity that translates to reduced perceived pain to a transient heat stimulus.

Let's focus on the insula in addiction: A refined anatomical exploration of insula in severe alcohol and cocaine use disorders.

Theoretical and empirical contributions have identified insula as key in addiction. However, anatomical modifications of the insula in addictive states, and their variations across substance use disorders (SUDs), remain to be specifically explored. We therefore explored the specificities and commonalities of insula gray matter (GM) alterations in severe alcohol use disorder (sAUD) and severe cocaine use disorder (sCUD). We explored insula GM volume through a refined parcellation in 12 subregions (six bilateral): anterior inferior cortex (AIC), anterior short gyrus, middle short gyrus, posterior short gyrus, anterior long gyrus (ALG), and posterior long gyrus (PLG). Using a linear mixed model analysis, we explored the insula volume profiles of 50 patients with sAUD, 61 patients with sCUD, and 36 healthy controls (HCs). In both sAUD and sCUD, we showed overall insular lower volume with a right-sided lateralization effect, and a major volume deficit in bilateral ALG. Moreover, differences emerged across groups, with higher left AIC and PLG volume deficits in sCUD compared to sAUD and HC. We offered the first joint exploration of GM insular volumes in two SUD through refined parcellation, thus unveiling the similarities and dissimilarities in volume deficit profiles. Our results bring evidence complementing prior ones suggesting the core role of the right and posterior insula in craving and interoception, two crucial processes in addiction. Left AIC and PLG group differences also show that, while insula is a region of interest in SUD, sCUD and sAUD generate distinct insular profiles, which might parallel clinical differences across SUD.

Imaging diagnosis and emotion recognition relationship in mild cognitive impairment

AbstractBackgroundRecent research has focused attention on social cognition impairment in Alzheimer Disease (AD). Specifically, emotion recognition can be evaluated with Reading the Mind in the Eyes Test (RMET). Some neuroanatomical changes could be related with social and cognitive deficits in patients. Therefore, future research combining cognitive indicators (RMET) with brain structure and function parameters (volumes, glucose metabolism, blood flow, amyloid deposits…) is required.MethodParticipants are patients from the Neurology Unit (Hospital Universitari i Politècnic La Fe). They were neuropsychologically evaluated, and CSF samples were obtained to determine some biomarkers (β‐amyloid‐42, β‐amyloid‐40, p‐Tau…). Also, brain imaging techniques (magnetic resonance (MR) and Positron Emission Tomography with [18F]Fluorodeoxyglucose (FDG‐PET/CT)) were applied to obtain brain structural and functional information, and to evaluate the relationship between them and emotion recognition evaluation (RMET). Imaging data were processed following SPM and CAT12 pipelines, a brain parcellation based on the Hammers atlas was used. Finally, 166 patients (with MR and/or FDG‐PET/CT) diagnosed with mild cognitive impairment (MCI) were included in the study.ResultThe correlation analysis between FDG‐PET/CT and RMET results showed significant correlations. Specifically, with prefrontal medial L and R (r = 0.36), posterior cingulate L and R (r = 0.34), parietal inferior L and R (r = 0.31), anterior cingulate L and R (r = 0.32), prefrontal lateral L and R (r = 0.32), insula R (r = 0.31) and basal ganglia R (r = 0.3). So, they are considered potential brain function biomarkers in MCI. Regarding the correlation analysis between MR (GM volumes (TIV‐corrected)) and RMET results, some significant correlations were observed. Specifically, with the straight gyrus L (r = 0.40), superior frontal gyrus L (r = 0.37), insula anterior inferior cortex R (r = 0.36), fusiform gyrus R (r = 0.36), anterior cingulate gyrus R (r = 0.36), insula anterior short gyrus L (r = 0.36), posterior and anterior cingulate gyrus L (r = 0.36, 0.35), and anterior orbital gyrus L (r = 0.35). So, they are considered potential brain structure biomarkers in MCI.ConclusionThe relationship between brain imaging parameters and emotion recognition impairment variables could provide important information for further biomarkers identification, as well as to identify potential physiopathological mechanisms involved in neurodegenerative development since early steps.

Arteries Around the Superior Limiting Sulcus: Motor Complication Avoidance in Insular and Insulo-Opercular Surgery.

Insulo-opercular surgery can cause ischemic motor complications. A source of this is the arteries around the superior limiting sulcus (SLS), which reach the corona radiata, but the detailed anatomy remains unclear. To characterize arteries around the SLS including the long insular arteries (LIAs) and long medullary arteries, we classified them and examined their distribution in relation to the SLS, which helps reduce the risk of ischemia. Twenty adult cadaveric hemispheres were studied. Coronal brain slices were created perpendicular to the SLS representing insular gyri (anterior short, middle short, posterior short, anterior long, and posterior long). The arteries within 10-mm proximity of the SLS that reached the corona radiata were excavated and classified by the entry point. A total of 122 arteries were identified. Sixty-three (52%), 20 (16%), and 39 (32%) arteries penetrated the insula (LIAs), peak of the SLS, and operculum (long medullary arteries), respectively. 100 and six (87%) arteries penetrated within 5 mm of the peak of the SLS. The arteries were distributed in the anterior short gyrus (19%), middle short gyrus (17%), posterior short gyrus (20%), anterior long gyrus (19%), and posterior long gyrus (25%). Seven arteries (5.7%) had anastomoses after they penetrated the parenchyma. Approximately 90% of the arteries that entered the parenchyma and reached the corona radiata were within a 5-mm radius of the SLS in both the insula and operculum side. This suggests that using the SLS as a landmark during insulo-opercular surgery can decrease the chance of ischemia.

Insular volumetry in severe alcohol use disorder and Korsakoff's syndrome through an anatomical parcellation: Let us go back to basics.

Functional neuroimaging has demonstrated the key role played by the insula in severe alcohol use disorder (sAUD), notably through its involvement in craving and body signals processing. However, the anatomical counterpart of these functional modifications in sAUD patients with and without neurological complications remains largely unexplored, especially using state-of-the-art parcellation tools. We thus compared the grey matter volume of insular subregions (form anterior to posterior: anterior inferior cortex, anterior short gyrus, middle short gyrus, posterior short gyrus, anterior long gyrus, posterior long gyrus) in 50 recently detoxified patients with sAUD, 19 patients with Korsakoff's syndrome (KS) and 36 healthy controls (HC). We used a mixed linear model analysis to explore group differences in the six subregions grey matter volume and lateralization differences. Insular macrostructure was globally affected to the same extent in sAUD with and without KS, indicating that these brain abnormalities may be related to alcohol consumption per se, rather than to the presence of alcohol-related neurological complications. Insular atrophy showed a right-sided lateralization effect and was especially marked in the posterior insula, a region associated with visceral information processing and the embodiment effect of a substance, from which craving arises. Anatomical damages might thus underlie the previously reported altered insular activations and their behavioural counterparts.

Anatomical variations in the insular cortex in individuals at a clinical high-risk state for psychosis and patients with schizophrenia.

Since the number of insular gyri is higher in schizophrenia patients, it has potential as a marker of early neurodevelopmental deviations. However, it currently remains unknown whether the features of the insular gross anatomy are similar between schizophrenia patients and individuals at risk of psychosis. Furthermore, the relationship between anatomical variations in the insular cortex and cognitive function has not yet been clarified. The gross anatomical features (i.e., the number of gyri and development pattern of each gyrus) of the insular cortex were examined using magnetic resonance imaging, and their relationships with clinical characteristics were investigated in 57 subjects with an at-risk mental state (ARMS) and 63 schizophrenia patients in comparison with 61 healthy controls. The number of insular gyri bilaterally in the anterior subdivision was higher in the ARMS and schizophrenia groups than in the control group. The schizophrenia group was also characterized by a higher number of insular gyri in the left posterior subdivision. A well-developed right middle short insular gyrus was associated with symptom severity in first-episode schizophrenia patients, whereas chronic schizophrenia patients with a well-developed left accessory gyrus were characterized by less severe cognitive impairments in motor and executive functions. The features of the insular gross anatomy were not associated with clinical characteristics in the ARMS group. The features of the insular gross anatomy that were shared in the ARMS and schizophrenia groups may reflect a vulnerability to psychosis that may be attributed to anomalies in the early stages of neurodevelopment. However, the contribution of the insular gross anatomy to the clinical characteristics of schizophrenia may differ according to illness stages.

Gross anatomical features of the insular cortex in schizophrenia and schizotypal personality disorder: Potential relationships with vulnerability, illness stages, and clinical subtypes.

Patients with schizophrenia have a higher number of insular gyri; however, it currently remains unclear whether the brain characteristics of patients with schizotypal personality disorder (SPD), a mild form of schizophrenia, are similar. It is also unknown whether insular gross anatomical features are associated with the illness stages and clinical subtypes of schizophrenia. This magnetic resonance imaging study examined gross anatomical variations in the insular cortex of 133 patients with schizophrenia, 47 with SPD, and 88 healthy controls. The relationships between the insular gross anatomy and schizophrenia subgroups (71 first-episode and 58 chronic groups, 38 deficit and 37 non-deficit subtype groups) were also investigated. The number of insular gyri was higher in the schizophrenia and SPD patients than in the controls, where the patients were characterized by well-developed accessory, middle short, and posterior long insular gyri. The insular gross anatomy did not significantly differ between the first-episode and chronic schizophrenia subgroups; however, the relationship between the developed accessory gyrus and more severe positive symptoms was specific to the first-episode group. The prevalence of a right middle short gyrus was higher in the deficit schizophrenia group than in the non-deficit group. These findings suggest that schizophrenia and SPD patients may share an altered insular gross morphology as a vulnerability factor associated with early neurodevelopmental anomalies, which may also contribute to positive symptomatology in the early illness stages and clinical subtypes of schizophrenia.

Morphology and Morphometry of Human Paracentral Lobule: An Anatomical Study with its Application in Neurosurgery.

Background:The human paracentral lobule (PCL) is the medial continuation of the precentral and postcentral gyri. It has important functional area related to the lower limb and perineum. Its visible surface that corresponds to magnetic resonance imaging scout images varies in morphology, so it requires exact data. Studies related to such data are rare. With such a facile, we studied the morphology and morphometry of PCL.Materials and Methods:Fifty formalin-fixed adult human brains dissected in the midsagittal plane were used in this study. First, the morphological types of PCL and its boundary were determined, followed by morphometry of its extrasulcal surface using digital vernier calipers. Measurements were done along the anteroposterior axis (length) and vertical axis (height). In addition to that, the extent of motor and sensory area into PCL was also measured.Results:Three distinct morphological types of PCL were found: continuous (2%), partially segmented (91%), and completely segmented type (7%). In completely segmented type, a short transitional lobulolimbic gyrus was also found in three cases. The mean extrasulcal surface of the left PCL was significantly larger, both in males (left 10.67 cm2 vs. right 8.80 cm2) and in females (left 8.80 cm2 vs. right 6.99 cm2). Irrespective of gender and sidedness, motor area was significantly larger than the sensory area.Conclusion:Reported data will be useful in diagnosis and treatment of diseases affecting the human PCL. Variations in the distribution of sensorimotor cortex over PCL may help further assessment of hemispheric lateralization and the location of central sulcus as a reliable indicator of cytoarchitectonic borders.

Role of anatomical insular subdivisions in interoception: Interoceptive attention and accuracy have dissociable substrates.

Prior neuroimaging studies have supported the idea that the human insular cortex plays an important role in processing and representing internal bodily states, also termed "interoception." According to recent theoretical studies, interoception includes several aspects such as attention and accuracy. However, there is no consensus on the laterality and location of the insula to support each aspect of interoception. Thus, we aimed to identify the anatomical insular subdivisions involved in interoceptive attention and accuracy; we examined 28 healthy volunteers who completed the behavioral heartbeat counting task and interoceptive attention paradigm using functional magnetic resonance imaging. First, interoceptive attention induced significant activation in the bilateral frontal operculum, precentral gyrus, middle insula, middle cingulate cortex, and supplementary motor area. Then, we compared the activation in anatomically predefined insular subdivisions during interoceptive attention. The highest activation of the middle short gyrus was noted within the insular cortex, followed by the anterior short gyrus and posterior short gyrus, while no significant hemispheric differences were observed. Finally, the interoceptive accuracy index, measured using the heartbeat counting task, strongly correlated with the activity of the right dorsal anterior insula/frontal operculum. These findings suggest that interoceptive attention is associated with the bilateral dorsal mid-anterior insula, which supports the processing and representation of bodily signals. In contrast, the more dorsal anterior portion of the right insula plays a key role in obtaining accurate interoception.

Anterior transperiinsular approach to the head of the caudate nucleus and mediobasal frontal lobe

The head of the caudate nucleus and adjacent mediobasal frontal lobe are deeply localized and have complex anatomical and topographic relationships with surrounding functionally significant cerebral structures. These aspects determine difficult surgical treatment of pathology in this zone. To propose a new anterior transperiinsular approach for optimizing surgical access to the head of the caudate nucleus and mediobasal frontal lobe. Two patients with cavernoma of the head of the caudate nucleus and oligodendroglioma of the head of the caudate nucleus and mediobasal frontal lobe underwent resection via transsylvian anterior transperiinsular approach in 2018. In both cases, tumors were localized in dominant hemisphere. Standard MRI was performed before and after surgery. Luria's neurological and neuropsychological examination was carried out before surgery, in 7 days after surgery and then every 3 months. Surgical access was performed via stage-by-stage proximal dissection of Sylvian fissure with visualization of anterior and superior periinsular grooves. After that, periinsular groove was dissected at the base of anterior short gyrus. Then, we moved apart white matter using microinstruments and approached the area of interest. In case of this trajectory, surgical approach was performed at the level of the upper parts of inferior frontooccipital fascicle under the arcuate fascicle. Both patients underwent total resection of tumors that was confirmed by MRI. No pre- and postoperative neurological or neuropsychological abnormalities were observed. Anterior transperiinsular approach provides minimally invasive access to the head of the caudate nucleus and mediobasal frontal lobe. It can be used on dominant hemisphere without significant risk of speech or other cognitive impairments. The advantages of this approach are minimal damage to associative pathways and small distance between periinsular groove and zone of interest. Dissection of commissural fibers of the corpus callosum is not required compared to conventional transcallosal approach.

Bilateral asymmetric tonic seizure in insulo-opercular epilepsy: an anatomo-electro-clinical study

BackgroundInsulo-opercular seizures are highly heterogeneous in seizure semiology and electrical features. Bilateral asymmetric limb posturing, as a classical pattern of supplementary sensorimotor area (SMA) seizure, also occurs in insulo-opercular epilepsy. This study was aimed to study the anatomo-electro-clinical correlations in bilateral asymmetric tonic seizures (BATS), in order to advance the understanding of insulo-opercular epilepsy.MethodsEight patients with insulo-opercular epilepsy as confirmed by stereoelectroencephalography (SEEG) and manifesting BATS as the major ictal motor sign, in Guangdong Sanjiu Brain Hospital Epilepsy Center from 2014 to 2018, were employed in this study. The BATS of the patients were evaluated, and the semiologic features and concomitant intracerebral EEG changes were quantified. Then the variables were examined with Cluster Analysis, and the semiologic features were correlated with anatomic localization using the Kendall correlation test.ResultsOf the 8 patients, the most frequent initial motor sign was bilateral asymmetric tonic posturing (62.5%). Facial tonic-clonic sign also had a high prevalence in the evolution of seizures (87.5%). The results of Cluster Analysis showed that the semiologic features were subdivided into two main groups, one group comprising exclusively BATS and the other including signs of focal tonic seizure, aura, focal limb tonic-clonic seizure (TCS), facial TCS, hypermotor behavior, eye movement, autonomic changes and generalized TCS. The BATS was strongly associated with the posterior long gyrus (PLG) of insula (t = 0.732) and parietal operculum (t = 1.000); the hypermotor behaviors were associated with the anterior long gyrus (ALG) (t = 0.770); and the autonomic changes were associated with the anterior limiting sulcus (ALS) (t = 0.734) and middle short gyrus (MSG) (t = 0.700).ConclusionsThe seizure semiology of insulo-opercular epilepsy is characterized, in temporal order, by BATS, with or without simultaneous hypermotor behaviors, and frequently ends up with facial tonic-clonic signs, which is different from that of the SMA seizure. The early spread network involving the posterior insular lobe and parietal operculum may contribute to this pattern of manifestation.

Evaluation of cortical thickness and brain volume on 3 Tesla magnetic resonance imaging in children with frontal lobe epilepsy.

Frontal lobe epilepsy (FLE) is the most common epilepsy syndrome in the pediatric population; however, brain magnetic resonance imaging (MRI) of the children with FLE is frequently normal. We use both cortical thickness and brain volume measurements to report on cortical changes in children with FLE. Our aim was to determine cortical thickness and brain volume changes on 3 Tesla MRI of children with FLE and normal brain magnetic resonance imaging. Twenty-seven children with FLE and 27 healthy controls received brain magnetic resonance imaging. Cortical thickness and regional brain volumes were assessed using three-dimensional volumetric T1-weighted imaging and patients were compared with controls. In children with FLE, statistically significant (p < 0.05) cortical thinning were found in the bilateral middle frontal gyrus, bilateral occipitotemporal and medial lingual gyrus, left subcallosal gyrus, left short insular gyrus, and right long insular gyrus. Statistically significant volume reductions in right and left hemisphere cortical white matter, total cortical white matter, bilateral thalamus, bilateral putamen, bilateral globus pallidus, right caudate nucleus, brain stem, and right cerebellar cortex were found. Cortical thinning in frontal and extra-frontal lobes and volume loss in a variety of brain regions were found in children with FLE.

Neurosurgical anatomy of the insular cortex

ObjectiveThe purpose of this study was to clarify the morphology of the insular cortex focusing not only on the shape of the insula, but also on sulcal and gyral organization. Patients and methodsSixty formalin-fixed adult brain hemispheres had their insula exposed and photographed. The dimensions of each gyrus and sulcus were measured using an image analysis software. The morphometric data obtained was statistically analysed. ResultsThe insular cortex shape alternates between triangular and trapezoid, being the triangular shape the most common (75%). The angle between the posterior and inferior peri-insular sulcus in the trapezoid insulae had a mean range of 131.17° (SD = 12.277). A minimum of 3 and a maximum of 6 insular gyri were observed, being 5 the most common total number of gyri observed. The accessory gyrus was present in 66% of the insulae and well-developed in 38% of the cases. A statistical association between the number of gyri in the posterior lobe and the presence of a novel gyrus or a more developed accessory gyrus in the anterior lobe was found (P = 0.006). The posterior short gyrus was the longest of the short gyri (P < 0.001), followed by the anterior short gyrus (P < 0.001). The anterior long gyrus was the largest of the long gyri (P = 0.003). The contribution of each of the short gyri to the formation of the insular apex was inconstant. The most common observed apex arrangement was the combination of the anterior and of the middle short gyri. ConclusionsThis study makes a strong contribution to the understanding of the insular cortex anatomy, allowing neurosurgeons to be more capable to decide the best approach to this cortical area.

F122. Non-lesional eating epilepsy with mesial temporal and inferior insular onset: A stereo-EEG study

Introduction Reflex epilepsy is characterized by seizures that are triggered by internal or external stimuli. Based on the complexity of the trigger, the reflex epilepsies can be subdivided into simple and complex. Eating Epilepsy (EE) is a subtype of the complex reflex epilepsies and represents a heterogeneous electro-clinical syndrome. The body of literature on EE consists mostly of a few case series with variable medical and surgical outcomes. We present a case of non-lesional EE with excellent outcome from resective epilepsy surgery after an extensive pre-surgical investigation to identify of the seizure onset zone (SOZ). Methods We retrospectively evaluated a case of drug-resistant eating-induced seizures referred for pre surgical assessment at London Health Sciences Centre Epilepsy Program, London, Canada. Patient’s data was reviewed including clinical history, neurological exam, imaging (Brain MRI and FDG-PET), neuropsychology assessment, scalp video-EEG, Stereoelectroencephalography (SEEG) and the surgical management. Results A 34-year-old gentleman has a 4-year history of seizures characterized by diffuse tingling sensation followed by loss of awareness with staring and right hand automatisms that lasted 1–2 min. 90% of his seizures were observed to be induced by eating at the beginning of a meal. His neuropsychological testing was essentially normal. Scalp video-EEG showed independent bilateral temporal spikes (R > L). Five eating-induced seizures were recorded immediately after initiation of eating with 2–3 Hz rhythmic activity over the right temporal region with perisylvian spreading. Brain MRI and PET studies were normal. Based on the electro-clinical data, the working hypothesis was right perisylvian onset of the seizures. The patient underwent intracranial recordings with stereo-EEG sampling the right temporal pole, amygdala, hippocampus, parietal operculum, temporal operculum and insula. Five seizures were captured induced by eating with stereotypical electrographic onset involving the right amygdala and hippocampus and inferior insula. Extra operative cortical stimulation (1–3.5 mA) elicited many prolonged after discharges in the same regions but they did not provoke clinical seizures. The patient thus underwent a right anterior temporal lobectomy and partial inferior insulectomy with decortication of the posterior short insular gyrus & the anterior and posterior gyri. Pathology revealed transcortical and hippocampal gliosis. He remained seizure-free (Engel 1) at his 8 months post-surgical follow-up. Conclusion This case of a drug-resistant non-lesional EE illustrates the value of stereo-EEG in the presurgical work-up that led to seizure-freedom following combined right anterior temporal lobectomy and right inferior insula resection. In non-lesional cases of drug-resistant EE, the epileptogenic zone is likely wide and it requires stereo-EEG to determine the SOZ.

Anatomical variations of the insular gyri: A morphological study and proposal of unified classification.

The locations of gyral landmarks vary among individuals. This can be crucial during local landmark-based mapping of the human cortex, so the aim of the present study was to establish criteria for classifying the morphological variability of the human insula. The study was conducted on 50 isolated, randomly-selected adult cadaveric hemispheres, fixed in 10% formalin, and preserved in 70% ethanol (24 right and 26 left hemispheres). A thorough rating system, including bifid form (i.e., divided on top), branching or hypoplasia, was used to analyze the insular gyri. The number of all insular gyri ranged from four to six (mean = 5.16, SD = 0.65). Within the anterior lobule, the number of short gyri ranged from two to four (mean = 3.3, SD = 0.54). The middle short gyrus was the most variable. It was well-developed in 25 of the 50 cases (50%). Within the posterior lobule there were one or two long insular gyri (mean = 1.88, SD = 0.32). In 48 cases (96%), the anterior long gyrus was well-developed. A complete lack of the posterior long gyrus was noted in six of the 50 cases (12%). In conclusions, the accessory, the middle short, and the posterior long gyri of the insula were the most variable. The middle short gyrus was well-developed in only half of the cases. The number of insular gyri found in horizontal sections of the brain does not necessarily indicate their true number. Clin. Anat. 31:347-356, 2018. © 2018 Wiley Periodicals, Inc.

Microsurgical anatomy of the central core of the brain.

OBJECTIVE The purpose of this study was to describe in detail the cortical and subcortical anatomy of the central core of the brain, defining its limits, with particular attention to the topography and relationships of the thalamus, basal ganglia, and related white matter pathways and vessels. METHODS The authors studied 19 cerebral hemispheres. The vascular systems of all of the specimens were injected with colored silicone, and the specimens were then frozen for at least 1 month to facilitate identification of individual fiber tracts. The dissections were performed in a stepwise manner, locating each gray matter nucleus and white matter pathway at different depths inside the central core. The course of fiber pathways was also noted in relation to the insular limiting sulci. RESULTS The insular surface is the most superficial aspect of the central core and is divided by a central sulcus into an anterior portion, usually containing 3 short gyri, and a posterior portion, with 2 long gyri. It is bounded by the anterior limiting sulcus, the superior limiting sulcus, and the inferior limiting sulcus. The extreme capsule is directly underneath the insular surface and is composed of short association fibers that extend toward all the opercula. The claustrum lies deep to the extreme capsule, and the external capsule is found medial to it. Three fiber pathways contribute to form both the extreme and external capsules, and they lie in a sequential anteroposterior disposition: the uncinate fascicle, the inferior fronto-occipital fascicle, and claustrocortical fibers. The putamen and the globus pallidus are between the external capsule, laterally, and the internal capsule, medially. The internal capsule is present medial to almost all insular limiting sulci and most of the insular surface, but not to their most anteroinferior portions. This anteroinferior portion of the central core has a more complex anatomy and is distinguished in this paper as the "anterior perforated substance region." The caudate nucleus and thalamus lie medial to the internal capsule, as the most medial structures of the central core. While the anterior half of the central core is related to the head of the caudate nucleus, the posterior half is related to the thalamus, and hence to each associated portion of the internal capsule between these structures and the insular surface. The central core stands on top of the brainstem. The brainstem and central core are connected by several white matter pathways and are not separated from each other by any natural division. The authors propose a subdivision of the central core into quadrants and describe each in detail. The functional importance of each structure is highlighted, and surgical approaches are suggested for each quadrant of the central core. CONCLUSIONS As a general rule, the internal capsule and its vascularization should be seen as a parasagittal barrier with great functional importance. This is of particular importance in choosing surgical approaches within this region.