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• During visual naming, high-gamma modulation occurs in a posteroanterior sequential pattern with overlapping temporal profiles. • Cortical activations during visual naming represent cognitive sub-components with different relative contributions from the left and right cerebral hemispheres. • Post-surgical neuropsychological deficits correlated with the location of resected parcels within the visual naming network. Cerebral spatiotemporal dynamics of visual naming were investigated in epilepsy patients undergoing stereo-electroencephalography (SEEG) monitoring. Brain networks were defined by Parcel-Activation-Resection-Symptom matching (PARS) approach by matching high-gamma (50–150 Hz) modulations (HGM) in neuroanatomic parcels during visual naming, with neuropsychological outcomes after resection/ablation of those parcels. Brain parcels with >50% electrode contacts simultaneously showing significant HGM were aligned, to delineate spatiotemporal course of naming-related HGM. In 41 epilepsy patients, neuroanatomic parcels showed sequential yet temporally overlapping HGM course during visual naming. From bilateral occipital lobes, HGM became increasingly left lateralized, coursing through limbic system. Bilateral superior temporal HGM was noted around response time, and right frontal HGM thereafter. Correlations between resected/ablated parcels, and post-surgical neuropsychological outcomes showed specific regional groupings. Convergence of data from spatiotemporal course of HGM during visual naming, and functional role of specific parcels inferred from neuropsychological deficits after resection/ablation of those parcels, support a model with six cognitive subcomponents of visual naming having overlapping temporal profiles. Cerebral substrates supporting visual naming are bilaterally distributed with relative hemispheric contribution dependent on cognitive demands at a specific time. PARS approach can be extended to study other cognitive and functional brain networks. [ABSTRACT FROM AUTHOR]

Objective This prospective study compared presurgical language localization with visual naming-associated high-γ modulation ( HGM) and conventional electrical cortical stimulation ( ECS) in children with intracranial electrodes. Methods Patients with drug-resistant epilepsy who were undergoing intracranial monitoring were included if able to name pictures. Electrocorticography ( ECoG) signals were recorded during picture naming (overt and covert) and quiet baseline. For each electrode the likelihood of high-γ (70-116 Hz) power modulation during naming task relative to the baseline was estimated. Electrodes with significant HGM were plotted on a three-dimensional (3D) cortical surface model. Sensitivity, specificity, and accuracy were calculated compared to clinical ECS. Results Seventeen patients with mean age of 11.3 years (range 4-19) were included. In patients with left hemisphere electrodes (n = 10), HGM during overt naming showed high specificity (0.81, 95% confidence interval [ CI] 0.78-0.85), and accuracy (0.71, 95% CI 0.66-0.75, p < 0.001), but modest sensitivity (0.47) when ECS interference with naming (aphasia or paraphasic errors) and/or oral motor function was regarded as the gold standard. Similar results were reproduced by comparing covert naming-associated HGM with ECS naming sites. With right hemisphere electrodes (n = 7), no ECS-naming deficits were seen without interference with oral-motor function. HGM mapping showed a high specificity (0.81, 95% CI 0.78-0.84), and accuracy (0.76, 95% CI 0.71-0.81, p = 0.006), but modest sensitivity (0.44) compared to ECS interference with oral-motor function. Naming-associated ECoG HGM was consistently observed over Broca's area (left posterior inferior-frontal gyrus), bilateral oral/facial motor cortex, and sometimes over the temporal pole. Significance This study supports the use of ECoG HGM mapping in children in whom adverse events preclude ECS, or as a screening method to prioritize electrodes for ECS testing. [ABSTRACT FROM AUTHOR]

Objective Methods Results Significance We evaluated changes in cognitive domains after neurosurgical lesioning of cortical sites with significant high‐gamma power modulations (HGM) during a visual naming task, although these sites were found language‐negative on standard‐of‐care electrical stimulation mapping (ESM).In drug‐resistant epilepsy patients who underwent resection/ablation after stereo‐electroencephalography (SEEG), we computed reliable change indices (RCIs) from a battery of presurgical and 1‐year postsurgical neuropsychological assessments. We modeled RCIs as a function of lesioning even one HGM language site, number of HGM language sites lesioned, and the magnitude of naming‐related HGM. The analyses were adjusted for 1‐year seizure freedom, operated hemispheres, and the volumes of surgical lesions.In 37 patients with 4455 SEEG electrode contacts (1839 and 2616 contacts in right and left hemispheres, respectively), no ESM language sites were lesioned. Patients with lesioning of even one HGM language site showed significantly lower RCIs for Peabody Picture Vocabulary Test (PPVT), working memory, and verbal learning immediate (VLI) scores. RCI declines with higher number of HGM language sites lesioned were seen in PPVT (slope [β] = −.10), working memory (β = −.10), VLI (β = −.14), and letter–word identification (LWI; β = −.14). No neuropsychological domains improved after lesioning of HGM language sites. Significant effects of the HGM magnitude at lesioned sites were seen on working memory (β = −.31), story memory immediate (β = −.27), verbal learning recognition (β = −.18), LWI (β = −.16), spelling (β = −.49), and passage comprehension (β = −.33). Because working memory was significantly affected in all three analyses, patients with maximal working memory decline were examined post hoc, revealing that all such patients had HGM naming sites lesioned in the posterior quadrants of either hemisphere.HGM language mapping should be used as an adjunct to ESM in clinical practice and may help counsel patients/families about postsurgical cognitive deficits. [ABSTRACT FROM AUTHOR]

• Stimulation within auditory cortex produced facial expressions and perioral motor responses in approximately one-third of patients. • Cortical sites with motor and language responses within transverse temporal gyrus and adjacent cortex (TGG+) showed different yet overlapping neurophysiologic characteristics. • TTG+ likely participates in non-verbal responses to low-level auditory and/or emotional cues during a communicative discourse. We investigated the role of transverse temporal gyrus and adjacent cortex (TTG+) in facial expressions and perioral movements. In 31 patients undergoing stereo-electroencephalography monitoring, we describe behavioral responses elicited by electrical stimulation within the TTG+. Task-induced high-gamma modulation (HGM), auditory evoked responses, and resting-state connectivity were used to investigate the cortical sites having different types of responses on electrical stimulation. Changes in facial expressions and perioral movements were elicited on electrical stimulation within TTG+ in 9 (29%) and 10 (32%) patients, respectively, in addition to the more common language responses (naming interruptions, auditory hallucinations, paraphasic errors). All functional sites showed auditory task induced HGM and evoked responses validating their location within the auditory cortex, however, motor sites showed lower peak amplitudes and longer peak latencies compared to language sites. Significant first-degree connections for motor sites included precentral, anterior cingulate, parahippocampal, and anterior insular gyri, whereas those for language sites included posterior superior temporal, posterior middle temporal, inferior frontal, supramarginal, and angular gyri. Multimodal data suggests that TTG+ may participate in auditory-motor integration. TTG+ likely participates in facial expressions in response to emotional cues during an auditory discourse. [ABSTRACT FROM AUTHOR]

• Stereo-EEG sensorimotor mapping was prospectively compared with reference neuroanatomy. • Electrical stimulation mapping localized anatomic sensorimotor parcels with high accuracy. • Sensorimotor thresholds below after-discharge thresholds suggest safety of stereo-EEG ESM. We evaluated stereo-EEG electrical stimulation mapping (ESM) for localization of anatomic sensorimotor parcels in pediatric patients with drug-resistant epilepsy. We also analyzed sensorimotor and after-discharge thresholds, and the somatotopy of sensorimotor responses. ESM was performed with 50 Hz, biphasic, 2–3 s trains, using 1–9 mA current. Pre- and post-implant neuroimaging was co-registered and intersected with Neurosynth reference, to classify each electrode contact as lying within/outside an anatomic sensorimotor parcel. Indices of diagnostic performance were computed. Sensorimotor and after-discharge thresholds were analyzed using multivariable linear mixed models. In 15 patients (6 females), aged 5.5–21.2 years, ESM showed high accuracy (0.80), high specificity (0.86), and diagnostic odds ratio (11.4, p < 0.0001) for localization of sensorimotor parcels. Mean sensorimotor threshold (3.4 mA) was below mean after-discharge threshold (4.2 mA, p = 0.0004). Sensorimotor and after-discharge thresholds showed a significant decrease with increasing intelligence quotient. Somatotopy of sensorimotor responses was mapped to standardized brain parcels. We provide evidence for diagnostic validity and safety of stereo-EEG sensorimotor ESM. The somatotopy of sensorimotor responses elicited with electrical stimulation provide new insights into mechanisms of motor control and sensory perception. [ABSTRACT FROM AUTHOR]

Highlights • Resection of HGM language sites is associated with worse neuropsychological outcomes. • Working memory was significantly worse in patients with resection of HGM naming sites. • Neuropsychological evaluation of children with epilepsy should include multiple cognitive and language domains. Abstract Background Language mapping with high-gamma modulation (HGM) has compared well with electrical cortical stimulation mapping (ESM). However, there is limited prospective data about its functional validity. We compared changes in neuropsychological evaluation (NPE) performed before and 1-year after epilepsy surgery, between patients with/without resection of cortical sites showing HGM during a visual naming task. Methods Pediatric drug-resistant epilepsy (DRE) patients underwent pre-surgical language localization with ESM and HGM using a visual naming task. Surgical decisions were based solely on ESM results. NPE difference scores were compared between patients with/without resection of HGM naming sites using principal component (PC) analysis. Follow-up NPE scores were modeled with resection group as main effect and respective pre-surgical score as a covariate, using analysis of covariance. Results Seventeen native English speakers (12 females), aged 6.5–20.2 years, were included. One year after epilepsy surgery, first PC score increased by (mean ± standard deviation) 14.4 ± 16.5 points in patients without resection, whereas it decreased by 7.6 ± 24.6 points in those with resection of HGM naming sites (p = 0.040). This PC score represented verbal comprehension, working memory, perceptual reasoning (Wechsler subscales); Woodcock-Johnson Tests of Achievement; and Peabody Picture Vocabulary Test. Subsequent analysis showed significant difference in working memory score between patients with/without resection of HGM naming sites (−15.2 points, 95% confidence limits −29.7 to −0.7, p = 0.041). Conclusion We highlight the functional consequences of resecting HGM language sites, and suggest that NPE of DRE patients should include comprehensive assessment of multiple linguistic and cognitive domains besides naming ability. [ABSTRACT FROM AUTHOR]

We prospectively validated stereo-electroencephalography (EEG) electrical stimulation mapping (ESM) of language against a reference standard of meta-analytic functional magnetic resonance imaging (fMRI) framework (Neurosynth). Language ESM was performed using 50 Hz, biphasic, bipolar, stimulation at 1–8 mA, with a picture naming task. Electrode contacts (ECs) were scored as ESM + if ESM interfered with speech/language function. For each patient, presurgical MRI was transformed to a standard space and coregistered with computed tomographic (CT) scan to obtain EC locations. After whole-brain parcellation, this fused image data were intersected with three-dimensional language fMRI (Neurosynth), and each EC was classified as lying within/outside the fMRI language parcel. Diagnostic odds ratio (DOR) and other indices were estimated. Current thresholds for language inhibition and after-discharges (ADs) were analyzed using multivariable linear mixed models. In 10 patients (5 females), aged 5.4–21.2 years, speech/language inhibition was noted with ESM on 87/304 (29%) ECs. Stereo-EEG language ESM was a valid classifier of fMRI (Neurosynth) language sites (DOR: 9.02, p < 0.0001), with high specificity (0.87) but poor sensitivity (0.57). Similar diagnostic indices were seen for ECs in frontal or posterior regions, and gray or white matter. Language threshold (3.1 ± 1.5 mA) was lower than AD threshold (4.0 ± 2.0 mA, p = 0.0001). Language and AD thresholds decreased with age and intelligence quotient. Electrical stimulation mapping triggered seizures/auras represented patients' habitual semiology with 1 Hz stimulation. Stereo-EEG ESM can reliably identify cerebral parcels with/without language function but may under detect all language sites. We suggest a 50-Hz stimulation protocol for language ESM with stereo-EEG. • We validated electrical stimulation mapping with stereo-EEG for localization of language functional neuroanatomy • Stereo-EEG electrical stimulation classified language sites (diagnostic odds ratio 9.0) with high specificity (0.87) • We suggest 50 Hz stimulation for language localization and 1 Hz stimulation for attempt to reproduce habitual seizures [ABSTRACT FROM AUTHOR]