@article{MTMT:3358985,
	title = {Interictal high-frequency oscillations generated by seizure onset and eloquent areas may be differentially coupled with different slow waves.},
	url = {https://m2.mtmt.hu/api/publication/3358985},
	author = {Nonoda, Y and Miyakoshi, M and Ojeda, A and Makeig, S and Juhász, Csaba and Sood, S and Asano, E},
	doi = {10.1016/j.clinph.2016.03.022},
	journal-iso = {CLIN NEUROPHYSIOL},
	journal = {CLINICAL NEUROPHYSIOLOGY},
	volume = {127},
	unique-id = {3358985},
	issn = {1388-2457},
	abstract = {OBJECTIVE: High-frequency oscillations (HFOs) can be spontaneously generated by seizure-onset and functionally-important areas. We determined if consideration of the spectral frequency bands of coupled slow-waves could distinguish between epileptogenic and physiological HFOs. METHODS: We studied a consecutive series of 13 children with focal epilepsy who underwent extraoperative electrocorticography. We measured the occurrence rate of HFOs during slow-wave sleep at each electrode site. We subsequently determined the performance of HFO rate for localization of seizure-onset sites and undesirable detection of nonepileptic sensorimotor-visual sites defined by neurostimulation. We likewise determined the predictive performance of modulation index: MI(XHz)&(YHz), reflecting the strength of coupling between amplitude of HFOsXHz and phase of slow-waveYHz. The predictive accuracy was quantified using the area under the curve (AUC) on receiver-operating characteristics analysis. RESULTS: Increase in HFO rate localized seizure-onset sites (AUC0.72; p<0.001), but also undesirably detected nonepileptic sensorimotor-visual sites (AUC0.58; p<0.001). Increase in MI(HFOs)&(3-4Hz) also detected both seizure-onset (AUC0.74; p<0.001) and nonepileptic sensorimotor-visual sites (AUC0.59; p<0.001). Increase in subtraction-MIHFOs [defined as subtraction of MI(HFOs)&(0.5-1Hz) from MI(HFOs)&(3-4Hz)] localized seizure-onset sites (AUC0.71; p<0.001), but rather avoided detection of nonepileptic sensorimotor-visual sites (AUC0.42; p<0.001). CONCLUSION: Our data suggest that epileptogenic HFOs may be coupled with slow-wave3-4Hz more preferentially than slow-wave0.5-1Hz, whereas physiologic HFOs with slow-wave0.5-1Hz more preferentially than slow-wave3-4Hz during slow-wave sleep. SIGNIFICANCE: Further studies in larger samples are warranted to determine if consideration of the spectral frequency bands of slow-waves coupled with HFOs can positively contribute to presurgical evaluation of patients with focal epilepsy.},
	keywords = {Adolescent; Female; Male; Humans; Child; sleep; Epilepsy/*physiopathology; *Brain Mapping; *Brain Waves; Sensorimotor Cortex/physiology/*physiopathology},
	year = {2016},
	eissn = {1872-8952},
	pages = {2489-2499}
}

@article{MTMT:3359001,
	title = {Evaluating the arcuate fasciculus with combined diffusion-weighted MRI tractography and electrocorticography.},
	url = {https://m2.mtmt.hu/api/publication/3359001},
	author = {Brown, EC and Jeong, JW and Muzik, O and Rothermel, R and Matsuzaki, N and Juhász, Csaba and Sood, S and Asano, E},
	doi = {10.1002/hbm.22331},
	journal-iso = {HUM BRAIN MAPP},
	journal = {HUMAN BRAIN MAPPING},
	volume = {35},
	unique-id = {3359001},
	issn = {1065-9471},
	abstract = {The conventional model of language-related brain structure describing the arcuate fasciculus as a key white matter tract providing a direct connection between Wernicke's region and Broca's area has been called into question. Specifically, the inferior precentral gyrus, possessing both primary motor (Brodmann Area [BA] 4) and premotor cortex (BA 6), has been identified as a potential alternative termination. The authors initially localized cortical sites involved in language using measurement of event-related gamma-activity on electrocorticography (ECoG). The authors then determined whether language-related sites of the temporal lobe were connected, via white matter structures, to the inferior frontal gyrus more tightly than to the precentral gyrus. The authors found that language-related sites of the temporal lobe were far more likely to be directly connected to the inferior precentral gyrus through the arcuate fasciculus. Furthermore, tractography was a significant predictor of frontal language-related ECoG findings. Analysis of an interaction between anatomy and tractography in this model revealed tractrography to have the highest predictive value for language-related ECoG findings of the precentral gyrus. This study failed to support the conventional model of language-related brain structure. More feasible models should include the inferior precentral gyrus as a termination of the arcuate fasciculus. The exact functional significance of direct connectivity between temporal language-related sites and the precentral gyrus requires further study.},
	keywords = {Adolescent; Female; Male; Humans; Child; Imaging, Three-Dimensional; Functional Laterality; LANGUAGE; Young Adult; *Diffusion Magnetic Resonance Imaging; Neural Pathways/physiology; *Electroencephalography; Nerve Net/physiology; *Brain Mapping; Brain Waves/*physiology; Arcuate Nucleus of Hypothalamus/*anatomy & histology/*physiology},
	year = {2014},
	eissn = {1097-0193},
	pages = {2333-2347}
}

@article{MTMT:2716516,
	title = {Corticocortical evoked potentials reveal projectors and integrators in human brain networks.},
	url = {https://m2.mtmt.hu/api/publication/2716516},
	author = {Keller, CJ and Honey, CJ and Entz, László and Bickel, S and Groppe, DM and Tóth, Emília and Ulbert, István and Lado, FA and Mehta, AD},
	doi = {10.1523/JNEUROSCI.4289-13.2014},
	journal-iso = {J NEUROSCI},
	journal = {JOURNAL OF NEUROSCIENCE},
	volume = {34},
	unique-id = {2716516},
	issn = {0270-6474},
	abstract = {The cerebral cortex is composed of subregions whose 
		functional specialization is largely determined by their 
		incoming and outgoing connections with each other. In the 
		present study, we asked which cortical regions can exert the 
		greatest influence over other regions and the cortical 
		network as a whole. Previous research on this question has 
		relied on coarse anatomy (mapping large fiber pathways) or 
		functional connectivity (mapping inter-regional statistical 
		dependencies in ongoing activity). Here we combined direct 
		electrical stimulation with recordings from the cortical 
		surface to provide a novel insight into directed, inter-
		regional influence within the cerebral cortex of awake 
		humans. These networks of directed interaction were 
		reproducible across strength thresholds and across subjects. 
		Directed network properties included (1) a decrease in the 
		reciprocity of connections with distance; (2) major projector 
		nodes (sources of influence) were found in peri-Rolandic 
		cortex and posterior, basal and polar regions of the temporal 
		lobe; and (3) major receiver nodes (receivers of influence) 
		were found in anterolateral frontal, superior parietal, and 
		superior temporal regions. Connectivity maps derived from 
		electrical stimulation and from resting electrocorticography 
		(ECoG) correlations showed similar spatial distributions for 
		the same source node. However, higher-level network topology 
		analysis revealed differences between electrical stimulation 
		and ECoG that were partially related to the reciprocity of 
		connections. Together, these findings inform our 
		understanding of large-scale corticocortical influence as 
		well as the interpretation of functional connectivity 
		networks.},
	year = {2014},
	eissn = {1529-2401},
	pages = {9152-9163},
	orcid-numbers = {Ulbert, István/0000-0001-9941-9159}
}

@article{MTMT:3359016,
	title = {Evaluating reverse speech as a control task with language-related gamma activity on electrocorticography.},
	url = {https://m2.mtmt.hu/api/publication/3359016},
	author = {Brown, EC and Muzik, O and Rothermel, R and Matsuzaki, N and Juhász, Csaba and Shah, AK and Atkinson, MD and Fuerst, D and Mittal, S and Sood, S and Diwadkar, VA and Asano, E},
	doi = {10.1016/j.neuroimage.2012.02.040},
	journal-iso = {NEUROIMAGE},
	journal = {NEUROIMAGE},
	volume = {60},
	unique-id = {3359016},
	issn = {1053-8119},
	abstract = {Reverse speech has often been used as a control task in brain-mapping studies of language utilizing various non-invasive modalities. The rationale is that reverse speech is comparable to forward speech in terms of auditory characteristics, while omitting the linguistic components. Thus, it may control for non-language auditory functions. This finds some support in fMRI studies indicating that reverse speech resulted in less blood-oxygen-level-dependent (BOLD) signal intensity in perisylvian regions than forward speech. We attempted to externally validate a reverse speech control task using intracranial electrocorticography (ECoG) in eight patients with intractable focal epilepsy. We studied adolescent and adult patients who underwent extraoperative ECoG prior to resective epilepsy surgery. All patients received an auditory language task during ECoG recording. Patients were presented 115 audible question stimuli, including 30 reverse speech trials. Reverse speech trials more strongly engaged bilateral superior temporal sites than did the corresponding forward speech trials. Forward speech trials elicited larger gamma-augmentation at frontal lobe sites not attributable to sensorimotor function. Other temporal and frontal sites of significant augmentation showed no significant difference between reverse and forward speech. Thus, we failed to validate reported evidence of weaker activation of temporal neocortices during reverse compared to forward speech. Superior temporal lobe engagement may indicate increased attention to reverse speech. Reverse speech does not appear to be a suitable task for the control of non-language auditory functions on ECoG.},
	keywords = {Adult; Adolescent; Female; Male; Humans; Child; Electroencephalography; LANGUAGE; Young Adult; Brain Mapping/*methods; Brain/*physiology; Speech; Magnetic Resonance Imaging/*methods; Auditory Perception/*physiology},
	year = {2012},
	eissn = {1095-9572},
	pages = {2335-2345}
}

@article{MTMT:3359013,
	title = {Olfactory hallucinations elicited by electrical stimulation via subdural electrodes: effects of direct stimulation of olfactory bulb and tract.},
	url = {https://m2.mtmt.hu/api/publication/3359013},
	author = {Kumar, G and Juhász, Csaba and Sood, S and Asano, E},
	doi = {10.1016/j.yebeh.2012.03.027},
	journal-iso = {EPILEPSY BEHAV},
	journal = {EPILEPSY & BEHAVIOR},
	volume = {24},
	unique-id = {3359013},
	issn = {1525-5050},
	abstract = {In 1954, Penfield and Jasper briefly described that percepts of unpleasant odor were elicited by intraoperative electrical stimulation of the olfactory bulb in patients with epilepsy. Since then, few peer-reviewed studies have reported such phenomena elicited by stimulation mapping via subdural electrodes implanted on the ventral surface of the frontal lobe. Here, we determined what types of olfactory hallucinations could be reproduced by such stimulation in children with focal epilepsy. This study included 16 children (age range: 5 to 17 years) who underwent implantation of subdural electrodes to localize the presumed epileptogenic zone and eloquent areas. Pairs of electrodes were electrically stimulated, and clinical responses were observed. In case a patient reported a perception, she/he was asked to describe its nature. We also described the stimulus parameters to elicit a given symptom. Eleven patients reported a perception of smell in response to electrical stimulation while the remaining five did not. Nine patients perceived an unpleasant smell (like bitterness, smoke, or garbage) while two perceived a pleasant smell (like strawberry or good food). Such olfactory hallucinations were induced by stimulation proximal to the olfactory bulb or tract on either hemisphere but not by that of orbitofrontal gyri lateral to the medial orbital sulci. The range of stimulus parameters employed to elicit olfactory hallucinations was comparable to those for other sensorimotor symptoms. Our systematic study of children with epilepsy replicated stimulation-induced olfactory hallucinations. We failed to provide evidence that a positive olfactory perception could be elicited by conventional stimulation of secondary olfactory cortex alone.},
	keywords = {Adolescent; Female; Male; Humans; Child; Electrodes, Implanted; Electric Stimulation; Magnetic Resonance Imaging; Electroencephalography; Child, Preschool; Neurosurgical Procedures; Subdural Space; Olfactory Bulb/*physiology; Smell/*physiology; Frontal Lobe/physiology; Olfactory Pathways/*physiology; Hallucinations/*etiology/psychology; Epilepsy/surgery/therapy},
	year = {2012},
	eissn = {1525-5069},
	pages = {264-268}
}

@article{MTMT:1788335,
	title = {First-Pass Selectivity for Semantic Categories in Human Anteroventral Temporal Lobe.},
	url = {https://m2.mtmt.hu/api/publication/1788335},
	author = {Chan, AM and Baker, JM and Eskandar, E and Schomer, D and Ulbert, István and Marinkovic, K and Cash, SS and Halgren, E},
	doi = {10.1523/JNEUROSCI.3122-11.2011},
	journal-iso = {J NEUROSCI},
	journal = {JOURNAL OF NEUROSCIENCE},
	volume = {31},
	unique-id = {1788335},
	issn = {0270-6474},
	abstract = {How the brain encodes the semantic concepts represented by words 
		is a fundamental question in cognitive neuroscience. Hemodynamic 
		neuroimaging studies have robustly shown that different areas of 
		posteroventral temporal lobe are selectively activated by images 
		of animals versus manmade objects. Selective responses in these 
		areas to words representing animals versus objects are sometimes 
		also seen, but they are task-dependent, suggesting that 
		posteroventral temporal cortex may encode visual categories, 
		while more anterior areas encode semantic categories. Here, 
		using the spatiotemporal resolution provided by intracranial 
		macroelectrode and microelectrode arrays, we report category-
		selective responses to words representing animals and objects in 
		human anteroventral temporal areas including inferotemporal, 
		perirhinal, and entorhinal cortices. This selectivity 
		generalizes across tasks and sensory modalities, suggesting that 
		it represents abstract lexicosemantic categories. Significant 
		category-specific responses are found in measures sensitive to 
		synaptic activity (local field potentials, high gamma power, 
		current sources and sinks) and unit-firing (multiunit and 
		single-unit activity). Category-selective responses can occur at 
		short latency (as early as 130 ms) in middle cortical layers and 
		thus are extracted in the first pass of activity through the 
		anteroventral temporal lobe. This activation may provide input 
		to posterior areas for iconic representations when required by 
		the task, as well as to the hippocampal formation for 
		categorical encoding and retrieval of memories, and to the 
		amygdala for emotional associations. More generally, these 
		results support models in which the anteroventral temporal lobe 
		plays a primary role in the semantic representation of words.},
	year = {2011},
	eissn = {1529-2401},
	pages = {18119-18129},
	orcid-numbers = {Ulbert, István/0000-0001-9941-9159}
}

@article{MTMT:3359040,
	title = {Electrocorticographic correlates of cognitive control in a Stroop task-intracranial recording in epileptic patients.},
	url = {https://m2.mtmt.hu/api/publication/3359040},
	author = {Koga, S and Rothermel, R and Juhász, Csaba and Nagasawa, T and Sood, S and Asano, E},
	doi = {10.1002/hbm.21129},
	journal-iso = {HUM BRAIN MAPP},
	journal = {HUMAN BRAIN MAPPING},
	volume = {32},
	unique-id = {3359040},
	issn = {1065-9471},
	abstract = {The human brain executes cognitive control, such as selection of relevant information in the presence of competing irrelevant information, and cognitive control is essential for us to yield a series of optimal behaviors in our daily life. This study assessed electrocorticographic gamma-oscillations elicited by cognitive control in the context of the Stroop color-naming paradigm, with a temporal resolution of 10 msec and spatial resolution of 1 cm. Subjects were instructed to overtly read a color word printed in an incongruent color in the reading task, and to overtly name the ink color of a color word printed in an incongruent color in the Stroop color-naming task. The latter task specifically elicited larger gamma-augmentations in the dorsolateral-premotor, dorsolateral-prefrontal and supplementary motor areas with considerable inter-subject spatial variability. Such Stroop color-naming-specific gamma-augmentations occurred 500 to 200 msec prior to overt responses. Electrical stimulation of the sites showing Stroop color-naming-specific gamma-augmentations resulted in temporary naming impairment more frequently than that of the remaining sites. This study has provided direct evidence that a critical process of cognitive control in the context of Stroop color-naming paradigm consists of recruitment of neurons essential for naming located in variable portions of the dorsolateral premotor and prefrontal areas.},
	keywords = {Adolescent; Female; Male; Humans; Child; Imaging, Three-Dimensional; Time Factors; Magnetic Resonance Imaging; Statistics as Topic; Electroencephalography; Brain/*physiopathology; Reading; Acoustic Stimulation; Photic Stimulation; Video Recording; Cognition Disorders/*etiology; Brain Waves/*physiology; *Stroop Test; Names; Epilepsy/*complications/*pathology},
	year = {2011},
	eissn = {1097-0193},
	pages = {1580-1591}
}

@article{MTMT:3359023,
	title = {Occipital gamma-oscillations modulated during eye movement tasks: simultaneous eye tracking and electrocorticography recording in epileptic patients.},
	url = {https://m2.mtmt.hu/api/publication/3359023},
	author = {Nagasawa, T and Matsuzaki, N and Juhász, Csaba and Hanazawa, A and Shah, A and Mittal, S and Sood, S and Asano, E},
	doi = {10.1016/j.neuroimage.2011.07.043},
	journal-iso = {NEUROIMAGE},
	journal = {NEUROIMAGE},
	volume = {58},
	unique-id = {3359023},
	issn = {1053-8119},
	abstract = {We determined the spatio-temporal dynamics of cortical gamma-oscillations modulated during eye movement tasks, using simultaneous eye tracking and intracranial electrocorticography (ECoG) recording. Patients with focal epilepsy were instructed to follow a target moving intermittently and unpredictably from one place to another either in an instantaneous or smooth fashion during extraoperative ECoG recording. Target motion elicited augmentation of gamma-oscillations in the lateral, inferior and polar occipital regions in addition to portions of parietal and frontal regions; subsequent voluntary eye movements elicited gamma-augmentation in the medial occipital region. Such occipital gamma-augmentations could not be explained by contaminations of ocular or myogenic artifacts. The degree of gamma-augmentation was generally larger during saccade compared to pursuit trials, while a portion of the polar occipital region showed pursuit-preferential gamma-augmentations. In addition to the aforementioned eye movement task, patients were asked to read a single word popping up on the screen. Gamma-augmentation was elicited in widespread occipital regions following word presentation, while gamma-augmentation in the anterior portion of the medial occipital region was elicited by an involuntary saccade following word presentation rather than word presentation itself. Gamma-augmentation in the lateral, inferior and polar occipital regions can be explained by increased attention to a moving target, whereas gamma-augmentation in the anterior-medial occipital region may be elicited by images in the peripheral field realigned following saccades. In functional studies comparing brain activation between two tasks, eye movement patterns during tasks may need to be considered as confounding factors.},
	keywords = {Adolescent; Female; Male; Humans; Child; Reaction Time/physiology; Electrodes, Implanted; Young Adult; Reading; Epilepsy/*physiopathology; *Electroencephalography; Attention/physiology; Photic Stimulation; Saccades/*physiology; Psychomotor Performance/*physiology; Visual Cortex/physiology; Occipital Lobe/physiology; Eye Movements/*physiology; Fixation, Ocular/physiology},
	year = {2011},
	eissn = {1095-9572},
	pages = {1101-1109}
}

@article{MTMT:3359046,
	title = {Somatosensory-related gamma-, beta- and alpha-augmentation precedes alpha- and beta-attenuation in humans.},
	url = {https://m2.mtmt.hu/api/publication/3359046},
	author = {Fukuda, M and Juhász, Csaba and Hoechstetter, K and Sood, S and Asano, E},
	doi = {10.1016/j.clinph.2009.10.036},
	journal-iso = {CLIN NEUROPHYSIOL},
	journal = {CLINICAL NEUROPHYSIOLOGY},
	volume = {121},
	unique-id = {3359046},
	issn = {1388-2457},
	abstract = {OBJECTIVE: Several human studies have demonstrated that the amplitudes of cortical oscillations are altered by various sensorimotor and cognitive tasks. Event-related augmentation of gamma oscillations and attenuation of alpha and beta oscillations have been often used as surrogate markers of cortical activation elicited by tasks especially in presurgical identification of eloquent cortices. In the present study, we addressed a question whether somatosensory-related gamma augmentation 'precedes' or 'co-occurs with' somatosensory-related attenuation of alpha-beta oscillations. METHODS: We studied 10 patients who underwent intracranial electrocorticography for epilepsy surgery, and determined the temporal and spatial characteristics of median-nerve somatosensory-related amplitude changes at gamma- (30-100Hz), beta- (14-28Hz) and alpha-band (8-12Hz) oscillations. RESULTS: We found that somatosensory-related gamma augmentation involving the post- and pre-central gyri evolved into beta and alpha augmentation, which was subsequently followed by beta and alpha attenuation involving the post- and pre-central gyri. CONCLUSIONS: These observations support the hypothesis that somatosensory-related gamma augmentation but not alpha-beta attenuation represents the initial cortical processing for external somatosensory stimuli. Somatosensory-related alpha-beta attenuation appears to represent a temporally distinct stage of somatosensory processing. SIGNIFICANCE: The present study has increased our understanding of event-related gamma augmentation and alpha-beta attenuation seen on electrocorticography.},
	keywords = {Adolescent; Female; Male; Humans; Child; Reaction Time/physiology; Electric Stimulation; Action Potentials/physiology; Algorithms; Time Factors; Child, Preschool; Somatosensory Cortex/*physiology; Sensory Thresholds/physiology; Biological Clocks/physiology; Nerve Net/physiology; *Beta Rhythm; Signal Processing, Computer-Assisted; *Alpha Rhythm; Neural Conduction/physiology; Evoked Potentials, Somatosensory/*physiology; Motor Cortex/physiology; Median Nerve/physiology; Touch Perception/physiology},
	year = {2010},
	eissn = {1872-8952},
	pages = {366-375}
}

@article{MTMT:3359050,
	title = {Quantitative brain surface mapping of an electrophysiologic/metabolic mismatch in human neocortical epilepsy.},
	url = {https://m2.mtmt.hu/api/publication/3359050},
	author = {Alkonyi, B and Juhász, Csaba and Muzik, O and Asano, E and Saporta, A and Shah, A and Chugani, HT},
	doi = {10.1016/j.eplepsyres.2009.08.002},
	journal-iso = {EPILEPSY RES},
	journal = {EPILEPSY RESEARCH},
	volume = {87},
	unique-id = {3359050},
	issn = {0920-1211},
	abstract = {The spatial relationship between an intracranial EEG-defined epileptic focus and cortical hypometabolism on glucose PET has not been precisely described. In order to quantitatively evaluate the hypothesis that ictal seizure onset and/or rapid seizure propagation, detected by subdural EEG monitoring, commonly involves normometabolic cortex adjacent to hypometabolic cortical regions, we applied a novel, landmark-constrained conformal mapping approach in 14 children with refractory neocortical epilepsy. The 3D brain surface was parcellated into finite cortical elements (FCEs), and hypometabolism was defined using lobe- and side-specific asymmetry indices derived from normal adult controls. The severity and location of hypometabolic areas vs. ictal intracranial EEG abnormalities were compared on the 3D brain surface. Hypometabolism was more severe in the seizure onset zone than in cortical areas covered by non-onset electrodes. However, similar proportions of the onset electrodes were located over and adjacent to (within 2 cm) hypometabolic regions (46% vs. 41%, respectively), whereas rapid seizure spread electrodes preferred these "adjacent areas" rather than the hypometabolic area itself (51% vs. 22%). On average, 58% of the hypometabolic regions had no early seizure involvement. These findings strongly support that the seizure onset zone often extends from hypometabolic to adjacent normometabolic cortex, while large portions of hypometabolic cortex are not involved in seizure onset or early propagation. The clinical utility of FDG PET in guiding subdural electrode placement in neocortical epilepsy could be greatly enhanced by extending grid coverage to at least 2 cm beyond hypometabolic cortex, when feasible.},
	keywords = {Radionuclide Imaging; Adolescent; Female; Male; Humans; Child; Brain Mapping; Retrospective Studies; Analysis of Variance; Image Processing, Computer-Assisted; Severity of Illness Index; Magnetic Resonance Imaging; Electroencephalography; Child, Preschool; Glucose/metabolism; Patient Selection; energy metabolism; Epilepsy/diagnostic imaging/*metabolism/*physiopathology; Cerebral Cortex/diagnostic imaging/*metabolism/*physiopathology},
	year = {2009},
	eissn = {1872-6844},
	pages = {77-87}
}

@article{MTMT:3359056,
	title = {Differential visually-induced gamma-oscillations in human cerebral cortex.},
	url = {https://m2.mtmt.hu/api/publication/3359056},
	author = {Asano, E and Nishida, M and Fukuda, M and Rothermel, R and Juhász, Csaba and Sood, S},
	doi = {10.1016/j.neuroimage.2008.12.003},
	journal-iso = {NEUROIMAGE},
	journal = {NEUROIMAGE},
	volume = {45},
	unique-id = {3359056},
	issn = {1053-8119},
	abstract = {Using intracranial electrocorticography, we determined how cortical gamma-oscillations (50-150 Hz) were induced by different visual tasks in nine children with focal epilepsy. In all children, full-field stroboscopic flash-stimuli induced gamma-augmentation in the anterior-medial occipital cortex (starting on average at 31 ms after stimulus presentation) and subsequently in the lateral-polar occipital cortex; minimal gamma-augmentation was noted in the inferior occipital-temporal cortex; occipital gamma-augmentation was followed by gamma-attenuation in three children. Central-field picture-stimuli induced sustained gamma-augmentation in the lateral-polar occipital cortex (starting on average at 69 ms) and subsequently in the inferior occipital-temporal cortex in all children and in the posterior frontal cortex in three children; the anterior-medial occipital cortex showed no gamma-augmentation but rather gamma-attenuation. Electrical stimulation of the anterior-medial occipital cortex induced a phosphene in the peripheral-field or eye deviation to the contralateral side, whereas that of the lateral-polar occipital cortex induced a phosphene in the central-field. In summary, full-field, simple and short-lasting visual information might be preferentially processed by the anterior-medial occipital cortex, and subsequently by the lateral-polar occipital cortex. Gamma-attenuation following augmentation in the striate cortex might be associated with a relative refractory-period to flash-stimuli or feed-forward inhibition by other areas. Central-field complex visual information might be processed by a network involving the lateral-polar occipital cortex and the inferior occipital-temporal cortex. A plausible interpretation of posterior frontal gamma-augmentation during central-field picture stimuli includes activation of the frontal-eye-field for visual searching. Gamma-attenuation in the anterior-medial occipital cortex during central-field picture-stimuli might be associated with relative inattention to the peripheral visual field during central-field object visualization.},
	keywords = {Adolescent; Female; Male; Humans; Child; Brain Mapping; Child, Preschool; Epilepsy/*physiopathology; Cerebral Cortex/*physiopathology; Electrocardiography/*methods; *Biological Clocks; *Evoked Potentials, Visual; Photic Stimulation/*methods; Stroboscopy/methods},
	year = {2009},
	eissn = {1095-9572},
	pages = {477-489}
}

@article{MTMT:3359054,
	title = {Role of subdural electrocorticography in prediction of long-term seizure outcome in epilepsy surgery.},
	url = {https://m2.mtmt.hu/api/publication/3359054},
	author = {Asano, E and Juhász, Csaba and Shah, A and Sood, S and Chugani, HT},
	doi = {10.1093/brain/awp025},
	journal-iso = {BRAIN},
	journal = {BRAIN},
	volume = {132},
	unique-id = {3359054},
	issn = {0006-8950},
	abstract = {Since prediction of long-term seizure outcome using preoperative diagnostic modalities remains suboptimal in epilepsy surgery, we evaluated whether interictal spike frequency measures obtained from extraoperative subdural electrocorticography (ECoG) recording could predict long-term seizure outcome. This study included 61 young patients (age 0.4-23.0 years), who underwent extraoperative ECoG recording prior to cortical resection for alleviation of uncontrolled focal seizures. Patient age, frequency of preoperative seizures, neuroimaging findings, ictal and interictal ECoG measures were preoperatively obtained. The seizure outcome was prospectively measured [follow-up period: 2.5-6.4 years (mean 4.6 years)]. Univariate and multivariate logistic regression analyses determined how well preoperative demographic and diagnostic measures predicted long-term seizure outcome. Following the initial cortical resection, Engel Class I, II, III and IV outcomes were noted in 35, 6, 12 and 7 patients, respectively. One child died due to disseminated intravascular coagulation associated with pseudomonas sepsis 2 days after surgery. Univariate regression analyses revealed that incomplete removal of seizure onset zone, higher interictal spike-frequency in the preserved cortex and incomplete removal of cortical abnormalities on neuroimaging were associated with a greater risk of failing to obtain Class I outcome. Multivariate logistic regression analysis revealed that incomplete removal of seizure onset zone was the only independent predictor of failure to obtain Class I outcome. The goodness of regression model fit and the predictive ability of regression model were greatest in the full regression model incorporating both ictal and interictal measures [R(2) 0.44; Area under the receiver operating characteristic (ROC) curve: 0.81], slightly smaller in the reduced model incorporating ictal but not interictal measures (R(2) 0.40; Area under the ROC curve: 0.79) and slightly smaller again in the reduced model incorporating interictal but not ictal measures (R(2) 0.27; Area under the ROC curve: 0.77). Seizure onset zone and interictal spike frequency measures on subdural ECoG recording may both be useful in predicting the long-term seizure outcome of epilepsy surgery. Yet, the additive clinical impact of interictal spike frequency measures to predict long-term surgical outcome may be modest in the presence of ictal ECoG and neuroimaging data.},
	keywords = {Adolescent; Female; Male; Humans; Child; Prognosis; Treatment Outcome; Child, Preschool; Young Adult; Infant; Epidemiologic Methods; Electroencephalography/methods; Signal Processing, Computer-Assisted; Subdural Space; Epilepsies, Partial/physiopathology/*surgery},
	year = {2009},
	eissn = {1460-2156},
	pages = {1038-1047}
}

@article{MTMT:3359063,
	title = {In vivo animation of auditory-language-induced gamma-oscillations in children with intractable focal epilepsy.},
	url = {https://m2.mtmt.hu/api/publication/3359063},
	author = {Brown, EC and Rothermel, R and Nishida, M and Juhász, Csaba and Muzik, O and Hoechstetter, K and Sood, S and Chugani, HT and Asano, E},
	doi = {10.1016/j.neuroimage.2008.03.011},
	journal-iso = {NEUROIMAGE},
	journal = {NEUROIMAGE},
	volume = {41},
	unique-id = {3359063},
	issn = {1053-8119},
	abstract = {We determined if high-frequency gamma-oscillations (50- to 150-Hz) were induced by simple auditory communication over the language network areas in children with focal epilepsy. Four children (aged 7, 9, 10 and 16 years) with intractable left-hemispheric focal epilepsy underwent extraoperative electrocorticography (ECoG) as well as language mapping using neurostimulation and auditory-language-induced gamma-oscillations on ECoG. The audible communication was recorded concurrently and integrated with ECoG recording to allow for accurate time lock on ECoG analysis. In three children, who successfully completed the auditory-language task, high-frequency gamma-augmentation sequentially involved: i) the posterior superior temporal gyrus when listening to the question, ii) the posterior lateral temporal region and the posterior frontal region in the time interval between question completion and the patient's vocalization, and iii) the pre- and post-central gyri immediately preceding and during the patient's vocalization. The youngest child, with attention deficits, failed to cooperate during the auditory-language task, and high-frequency gamma-augmentation was noted only in the posterior superior temporal gyrus when audible questions were given. The size of language areas suggested by statistically significant high-frequency gamma-augmentation was larger than that defined by neurostimulation. The present method can provide in vivo imaging of electrophysiological activities over the language network areas during language processes. Further studies are warranted to determine whether recording of language-induced gamma-oscillations can supplement language mapping using neurostimulation in presurgical evaluation of children with focal epilepsy.},
	keywords = {Adolescent; Female; Male; Humans; Child; Electrodes, Implanted; Magnetic Resonance Imaging; Electroencephalography; Verbal Behavior/*physiology; *Language; Brain/*physiology; Acoustic Stimulation; Epilepsy/*physiopathology; *Brain Mapping},
	year = {2008},
	eissn = {1095-9572},
	pages = {1120-1131}
}

@article{MTMT:3359060,
	title = {Cortical glucose metabolism positively correlates with gamma-oscillations in nonlesional focal epilepsy.},
	url = {https://m2.mtmt.hu/api/publication/3359060},
	author = {Nishida, M and Juhász, Csaba and Sood, S and Chugani, HT and Asano, E},
	doi = {10.1016/j.neuroimage.2008.06.027},
	journal-iso = {NEUROIMAGE},
	journal = {NEUROIMAGE},
	volume = {42},
	unique-id = {3359060},
	issn = {1053-8119},
	abstract = {Why do the epileptogenic foci appear hypometabolic on interictal glucose metabolism positron emission tomography (PET) in a substantial proportion of patients with focal epilepsy but appear normo- or even hyper-metabolic in others? Such observations on interictal PET have not been fully explained by the frequency of interictal spike discharges alone. In the present study using digital electrocorticography monitoring system with high-frequency sampling, we determined how well regression models using spectral ECoG measures and spike frequency derived from 651 intracranial electrode sites explained cortical glucose metabolic patterns in six children with nonlesional focal epilepsy. Univariate regression analysis demonstrated that spectral amplitudes at gamma ranges (32-64, 64-100, and 100-200 Hz) were tightly correlated with interictal glucose uptake in the given electrode site in all children. Spike frequency was negatively correlated with interictal glucose uptake in three patients, whose epileptogenic focus appeared hypometabolic and interictal epileptiform discharge often consisted of a spike followed by a subsequent delta-wave. Conversely, spike frequency was positively correlated with interictal glucose uptake in the other three patients, whose epileptogenic foci appeared more hypermetabolic compared to the surrounding regions and associated with frequent interictal spike bursts. The spatial pattern of interictal glucose metabolism in nonlesional focal epilepsy may be better explained by gamma-oscillations derived from epileptiform and physiological neuronal activities rather than the frequency of interictal epileptiform discharges alone.},
	keywords = {Female; Male; Humans; Child; Statistics as Topic; Child, Preschool; Brain Mapping/*methods; Glucose/*metabolism; Electroencephalography/methods; Biological Clocks; Radiopharmaceuticals/pharmacokinetics; Positron-Emission Tomography/methods; Brain/diagnostic imaging/*physiopathology; Fluorodeoxyglucose F18/*pharmacokinetics; Epilepsy/*diagnosis/*physiopathology},
	year = {2008},
	eissn = {1095-9572},
	pages = {1275-1284}
}