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  1. Article ; Online: Anatomical registration of intracranial electrodes. Robust model-based localization and deformable smooth brain-shift compensation methods.

    Blenkmann, Alejandro Omar / Leske, Sabine Liliana / Llorens, Anaïs / Lin, Jack J / Chang, Edward F / Brunner, Peter / Schalk, Gerwin / Ivanovic, Jugoslav / Larsson, Pål Gunnar / Knight, Robert Thomas / Endestad, Tor / Solbakk, Anne-Kristin

    Journal of neuroscience methods

    2024  Volume 404, Page(s) 110056

    Abstract: Background: Intracranial electrodes are typically localized from post-implantation CT artifacts. Automatic algorithms localizing low signal-to-noise ratio artifacts and high-density electrode arrays are missing. Additionally, implantation of grids/ ... ...

    Abstract Background: Intracranial electrodes are typically localized from post-implantation CT artifacts. Automatic algorithms localizing low signal-to-noise ratio artifacts and high-density electrode arrays are missing. Additionally, implantation of grids/strips introduces brain deformations, resulting in registration errors when fusing post-implantation CT and pre-implantation MR images. Brain-shift compensation methods project electrode coordinates to cortex, but either fail to produce smooth solutions or do not account for brain deformations.
    New methods: We first introduce GridFit, a model-based fitting approach that simultaneously localizes all electrodes' CT artifacts in grids, strips, or depth arrays. Second, we present CEPA, a brain-shift compensation algorithm combining orthogonal-based projections, spring-mesh models, and spatial regularization constraints.
    Results: We tested GridFit on ∼6000 simulated scenarios. The localization of CT artifacts showed robust performance under difficult scenarios, such as noise, overlaps, and high-density implants (<1 mm errors). Validation with data from 20 challenging patients showed 99% accurate localization of the electrodes (3160/3192). We tested CEPA brain-shift compensation with data from 15 patients. Projections accounted for simple mechanical deformation principles with < 0.4 mm errors. The inter-electrode distances smoothly changed across neighbor electrodes, while changes in inter-electrode distances linearly increased with projection distance.
    Comparison with existing methods: GridFit succeeded in difficult scenarios that challenged available methods and outperformed visual localization by preserving the inter-electrode distance. CEPA registration errors were smaller than those obtained for well-established alternatives. Additionally, modeling resting-state high-frequency activity in five patients further supported CEPA.
    Conclusion: GridFit and CEPA are versatile tools for registering intracranial electrode coordinates, providing highly accurate results even in the most challenging implantation scenarios. The methods are implemented in the iElectrodes open-source toolbox.
    MeSH term(s) Humans ; Electroencephalography/methods ; Electrodes, Implanted ; Magnetic Resonance Imaging/methods ; Brain/diagnostic imaging ; Cerebral Cortex/diagnostic imaging ; Electrodes
    Language English
    Publishing date 2024-01-14
    Publishing country Netherlands
    Document type Journal Article ; Review ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 282721-9
    ISSN 1872-678X ; 0165-0270
    ISSN (online) 1872-678X
    ISSN 0165-0270
    DOI 10.1016/j.jneumeth.2024.110056
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Anatomical registration of intracranial electrodes. Robust model-based localization and deformable smooth brain-shift compensation methods.

    Blenkmann, Alejandro Omar / Leske, Sabine Liliana / Llorens, Anaïs / Lin, Jack J / Chang, Edward / Brunner, Peter / Schalk, Gerwin / Ivanovic, Jugoslav / Larsson, Pål Gunnar / Knight, Robert Thomas / Endestad, Tor / Solbakk, Anne-Kristin

    bioRxiv : the preprint server for biology

    2023  

    Abstract: Precise electrode localization is important for maximizing the utility of intracranial EEG data. Electrodes are typically localized from post-implantation CT artifacts, but algorithms can fail due to low signal-to-noise ratio, unrelated artifacts, or ... ...

    Abstract Precise electrode localization is important for maximizing the utility of intracranial EEG data. Electrodes are typically localized from post-implantation CT artifacts, but algorithms can fail due to low signal-to-noise ratio, unrelated artifacts, or high-density electrode arrays. Minimizing these errors usually requires time-consuming visual localization and can still result in inaccurate localizations. In addition, surgical implantation of grids and strips typically introduces non-linear brain deformations, which result in anatomical registration errors when post-implantation CT images are fused with the pre-implantation MRI images. Several projection methods are currently available, but they either fail to produce smooth solutions or do not account for brain deformations. To address these shortcomings, we propose two novel algorithms for the anatomical registration of intracranial electrodes that are almost fully automatic and provide highly accurate results. We first present
    Language English
    Publishing date 2023-05-11
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.05.08.539503
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: A lexical semantic hub for heteromodal naming in middle fusiform gyrus.

    Forseth, Kiefer James / Kadipasaoglu, Cihan Mehmet / Conner, Christopher Richard / Hickok, Gregory / Knight, Robert Thomas / Tandon, Nitin

    Brain : a journal of neurology

    2018  Volume 141, Issue 7, Page(s) 2112–2126

    Abstract: Semantic memory underpins our understanding of objects, people, places, and ideas. Anomia, a disruption of semantic memory access, is the most common residual language disturbance and is seen in dementia and following injury to temporal cortex. While ... ...

    Abstract Semantic memory underpins our understanding of objects, people, places, and ideas. Anomia, a disruption of semantic memory access, is the most common residual language disturbance and is seen in dementia and following injury to temporal cortex. While such anomia has been well characterized by lesion symptom mapping studies, its pathophysiology is not well understood. We hypothesize that inputs to the semantic memory system engage a specific heteromodal network hub that integrates lexical retrieval with the appropriate semantic content. Such a network hub has been proposed by others, but has thus far eluded precise spatiotemporal delineation. This limitation in our understanding of semantic memory has impeded progress in the treatment of anomia. We evaluated the cortical structure and dynamics of the lexical semantic network in driving speech production in a large cohort of patients with epilepsy using electrocorticography (n = 64), functional MRI (n = 36), and direct cortical stimulation (n = 30) during two generative language processes that rely on semantic knowledge: visual picture naming and auditory naming to definition. Each task also featured a non-semantic control condition: scrambled pictures and reversed speech, respectively. These large-scale data of the left, language-dominant hemisphere uniquely enable convergent, high-resolution analyses of neural mechanisms characterized by rapid, transient dynamics with strong interactions between distributed cortical substrates. We observed three stages of activity during both visual picture naming and auditory naming to definition that were serially organized: sensory processing, lexical semantic processing, and articulation. Critically, the second stage was absent in both the visual and auditory control conditions. Group activity maps from both electrocorticography and functional MRI identified heteromodal responses in middle fusiform gyrus, intraparietal sulcus, and inferior frontal gyrus; furthermore, the spectrotemporal profiles of these three regions revealed coincident activity preceding articulation. Only in the middle fusiform gyrus did direct cortical stimulation disrupt both naming tasks while still preserving the ability to repeat sentences. These convergent data strongly support a model in which a distinct neuroanatomical substrate in middle fusiform gyrus provides access to object semantic information. This under-appreciated locus of semantic processing is at risk in resections for temporal lobe epilepsy as well as in trauma and strokes that affect the inferior temporal cortex-it may explain the range of anomic states seen in these conditions. Further characterization of brain network behaviour engaging this region in both healthy and diseased states will expand our understanding of semantic memory and further development of therapies directed at anomia.
    MeSH term(s) Adult ; Anomia/physiopathology ; Brain/physiopathology ; Brain Mapping/methods ; Cognition/physiology ; Comprehension ; Electrocorticography ; Epilepsy, Temporal Lobe/pathology ; Female ; Humans ; Language ; Magnetic Resonance Imaging ; Male ; Memory/physiology ; Memory Disorders/physiopathology ; Middle Aged ; Occipital Lobe/physiopathology ; Prefrontal Cortex/physiopathology ; Semantics ; Speech/physiology ; Temporal Lobe/pathology ; Temporal Lobe/physiology
    Language English
    Publishing date 2018-05-29
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 80072-7
    ISSN 1460-2156 ; 0006-8950
    ISSN (online) 1460-2156
    ISSN 0006-8950
    DOI 10.1093/brain/awy120
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Correction: ERP Correlates of Proactive and Reactive Cognitive Control in Treatment-Naïve Adult ADHD.

    Grane, Venke Arntsberg / Brunner, Jan Ferenc / Endestad, Tor / Aasen, Ida Emilia S / Kropotov, Juri / Knight, Robert Thomas / Solbakk, Anne-Kristin

    PloS one

    2016  Volume 11, Issue 9, Page(s) e0163404

    Abstract: This corrects the article DOI: 10.1371/journal.pone.0159833.]. ...

    Abstract [This corrects the article DOI: 10.1371/journal.pone.0159833.].
    Language English
    Publishing date 2016
    Publishing country United States
    Document type Journal Article ; Published Erratum
    ISSN 1932-6203
    ISSN (online) 1932-6203
    DOI 10.1371/journal.pone.0163404
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: ERP Correlates of Proactive and Reactive Cognitive Control in Treatment-Naïve Adult ADHD.

    Grane, Venke Arntsberg / Brunner, Jan Ferenc / Endestad, Tor / Aasen, Ida Emilia S / Kropotov, Juri / Knight, Robert Thomas / Solbakk, Anne-Kristin

    PloS one

    2016  Volume 11, Issue 7, Page(s) e0159833

    Abstract: This study investigated whether treatment naïve adults with Attention Deficit Hyperactivity Disorder (ADHD; n = 33; 19 female) differed from healthy controls (n = 31; 17 female) in behavioral performance, event-related potential (ERP) indices of ... ...

    Abstract This study investigated whether treatment naïve adults with Attention Deficit Hyperactivity Disorder (ADHD; n = 33; 19 female) differed from healthy controls (n = 31; 17 female) in behavioral performance, event-related potential (ERP) indices of preparatory attention (CueP3 and late CNV), and reactive response control (Go P3, NoGo N2, and NoGo P3) derived from a visual cued Go/NoGo task. On several critical measures, Cue P3, late CNV, and NoGo N2, there were no significant differences between the groups. This indicated normal preparatory processes and conflict monitoring in ADHD patients. However, the patients had attenuated Go P3 and NoGoP3 amplitudes relative to controls, suggesting reduced allocation of attentional resources to processes involved in response control. The patients also had a higher rate of Go signal omission errors, but no other performance decrements compared with controls. Reduced Go P3 and NoGo P3 amplitudes were associated with poorer task performance, particularly in the ADHD group. Notably, the ERPs were not associated with self-reported mood or anxiety. The results provide electrophysiological evidence for reduced effortful engagement of attentional resources to both Go and NoGo signals when reactive response control is needed. The absence of group differences in ERP components indexing proactive control points to impairments in specific aspects of cognitive processes in an untreated adult ADHD cohort. The associations between ERPs and task performance provided additional support for the altered electrophysiological responses.
    Language English
    Publishing date 2016
    Publishing country United States
    Document type Journal Article
    ISSN 1932-6203
    ISSN (online) 1932-6203
    DOI 10.1371/journal.pone.0159833
    Database MEDical Literature Analysis and Retrieval System OnLINE

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