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Interictal epileptiform discharges shape large-scale intercortical communication
Dahal, Prawesh; Ghani, Naureen; Flinker, Adeen; Dugan, Patricia; Friedman, Daniel; Doyle, Werner; Devinsky, Orrin; Khodagholy, Dion; Gelinas, Jennifer N
Dynamic interactions between remote but functionally specialized brain regions enable complex information processing. This intercortical communication is disrupted in the neural networks of patients with focal epilepsy, and epileptic activity can exert widespread effects within the brain. Using large-scale human intracranial electroencephalography recordings, we show that interictal epileptiform discharges (IEDs) are significantly coupled with spindles in discrete, individualized brain regions outside of the epileptic network. We found that a substantial proportion of these localized spindles travel across the cortical surface. Brain regions that participate in this IED-driven oscillatory coupling express spindles that have a broader spatial extent and higher tendency to propagate than spindles occurring in uncoupled regions. These altered spatiotemporal oscillatory properties identify areas that are shaped by epileptic activity independent of IED or seizure detection. Our findings suggest that IED-spindle coupling may be an important mechanism of interictal global network dysfunction that could be targeted to prevent disruption of normal neural activity.
PMID: 31501850
ISSN: 1460-2156
CID: 4087702
iEEG-BIDS, extending the Brain Imaging Data Structure specification to human intracranial electrophysiology
Holdgraf, Christopher; Appelhoff, Stefan; Bickel, Stephan; Bouchard, Kristofer; D'Ambrosio, Sasha; David, Olivier; Devinsky, Orrin; Dichter, Benjamin; Flinker, Adeen; Foster, Brett L; Gorgolewski, Krzysztof J; Groen, Iris; Groppe, David; Gunduz, Aysegul; Hamilton, Liberty; Honey, Christopher J; Jas, Mainak; Knight, Robert; Lachaux, Jean-Philippe; Lau, Jonathan C; Lee-Messer, Christopher; Lundstrom, Brian N; Miller, Kai J; Ojemann, Jeffrey G; Oostenveld, Robert; Petridou, Natalia; Piantoni, Gio; Pigorini, Andrea; Pouratian, Nader; Ramsey, Nick F; Stolk, Arjen; Swann, Nicole C; Tadel, François; Voytek, Bradley; Wandell, Brian A; Winawer, Jonathan; Whitaker, Kirstie; Zehl, Lyuba; Hermes, Dora
PMCID:6592874
PMID: 31239438
ISSN: 2052-4463
CID: 3953832
Spectrotemporal modulation provides a unifying framework for auditory cortical asymmetries
Flinker, Adeen; Doyle, Werner K; Mehta, Ashesh D; Devinsky, Orrin; Poeppel, David
The principles underlying functional asymmetries in cortex remain debated. For example, it is accepted that speech is processed bilaterally in auditory cortex, but a left hemisphere dominance emerges when the input is interpreted linguistically. The mechanisms, however, are contested, such as what sound features or processing principles underlie laterality. Recent findings across species (humans, canines and bats) provide converging evidence that spectrotemporal sound features drive asymmetrical responses. Typically, accounts invoke models wherein the hemispheres differ in time-frequency resolution or integration window size. We develop a framework that builds on and unifies prevailing models, using spectrotemporal modulation space. Using signal processing techniques motivated by neural responses, we test this approach, employing behavioural and neurophysiological measures. We show how psychophysical judgements align with spectrotemporal modulations and then characterize the neural sensitivities to temporal and spectral modulations. We demonstrate differential contributions from both hemispheres, with a left lateralization for temporal modulations and a weaker right lateralization for spectral modulations. We argue that representations in the modulation domain provide a more mechanistic basis to account for lateralization in auditory cortex.
PMID: 30971792
ISSN: 2397-3374
CID: 3809292
Hippocampal gamma predicts associative memory performance as measured by acute and chronic intracranial EEG
Henin, Simon; Shankar, Anita; Hasulak, Nicholas; Friedman, Daniel; Dugan, Patricia; Melloni, Lucia; Flinker, Adeen; Sarac, Cansu; Fang, May; Doyle, Werner; Tcheng, Thomas; Devinsky, Orrin; Davachi, Lila; Liu, Anli
Direct recordings from the human brain have historically involved epilepsy patients undergoing invasive electroencephalography (iEEG) for surgery. However, these measurements are temporally limited and affected by clinical variables. The RNS System (NeuroPace, Inc.) is a chronic, closed-loop electrographic seizure detection and stimulation system. When adapted by investigators for research, it facilitates cognitive testing in a controlled ambulatory setting, with measurements collected over months to years. We utilized an associative learning paradigm in 5 patients with traditional iEEG and 3 patients with chronic iEEG, and found increased hippocampal gamma (60-100 Hz) sustained at 1.3-1.5 seconds during encoding in successful versus failed trials in surgical patients, with similar results in our RNS System patients (1.4-1.6 seconds). Our findings replicate other studies demonstrating that sustained hippocampal gamma supports encoding. Importantly, we have validated the RNS System to make sensitive measurements of hippocampal dynamics during cognitive tasks in a chronic ambulatory research setting.
PMID: 30679734
ISSN: 2045-2322
CID: 3610122
Reconstructing Speech Stimuli From Human Auditory Cortex Activity Using a WaveNet Approach
Chapter by: Wang, Ran; Wang, Yao; Flinker, Adeen
in: 2018 IEEE Signal Processing in Medicine and Biology Symposium, SPMB 2018 - Proceedings by
[S.l.] : Institute of Electrical and Electronics Engineers Inc., 2019
pp. ?-?
ISBN: 9781538659168
CID: 3996842
Closed-loop acoustic stimulation enhances sleep oscillations but not memory performance
Henin, Simon; Borges, Helen; Shankar, Anita; Sarac, Cansu; Melloni, Lucia; Friedman, Daniel; Flinker, Adeen; Parra, Lucas C; Buzsaki, Gyorgy; Devinsky, Orrin; Liu, Anli
Slow-oscillations and spindle activity during non-REM sleep have been implicated in memory consolidation. Closed-loop acoustic stimulation has previously been shown to enhance slow oscillations and spindle activity during sleep and improve verbal associative memory. We assessed the effect of closed-loop acoustic stimulation during a daytime nap on a virtual reality spatial navigation task in 12 healthy human subjects in a randomized within-subject crossover design. We show robust enhancement of slow-spindle activity during sleep. However, no effects on behavioral performance were observed when comparing real versus sham stimulation. To explore whether memory enhancement effects were task-specific and dependent on nocturnal sleep, in a second experiment with 19 healthy subjects, we aimed to replicate a previous study which used closed-loop acoustic stimulation to enhance memory for word pairs. Methods were as close as possible to the original study, except we used a double-blind protocol, in which both subject and experimenter were unaware of the test condition. Again, we successfully enhanced slow-spindle power, but again did not strengthen associative memory performance with stimulation. We conclude that enhancement of slow-spindle oscillations may be insufficient to enhance memory performance in spatial navigation or verbal association tasks, and provide possible explanations for lack of behavioral replication.SIGNIFICANCE STATEMENT Prior studies have demonstrated that a closed-loop acoustic pulse paradigm during sleep can enhance verbal memory performance. This technique has widespread scientific and clinical appeal due to its non-invasive nature and ease of application. We tested with a rigorous double-blind design whether this technique could enhance key sleep rhythms associated sleep-dependent memory performance. We discovered that we could reliably enhance slow and spindle rhythms, but did not improve memory performance in the stimulation condition compared to sham condition. Our findings suggest that enhancing slow-spindle rhythms is insufficient to enhance sleep-dependent learning.
PMID: 31604814
ISSN: 2373-2822
CID: 4130772
Hippocampal Gamma Predicts Associative Memory Performance as Measured by Acute and Chronic Intracranial EEG [Meeting Abstract]
Henin, Simon; Shankar, Anita; Hasulak, Nicholas; Friedman, Daniel; Dugan, Patricia; Melloni, Lucia; Flinker, Adeen; Sarac, Cansu; Fang, May; Doyle, Werner; Tcheng, Thomas; Devinsky, Orrin; Davachi, Lila; Liu, Anli
ISI:000446520900467
ISSN: 0364-5134
CID: 3726232
Broca's area in comprehension and production, insights from intracranial studies in humans
Flinker, Adeen; Knight, Robert T
Broca's area has long been considered central for speech production. Recently, several intracranial studies have challenged this view by elucidating the temporal and causal dynamics of cortical networks including Broca's area. Here we review intracranial perturbation and recording studies leading up to recent advances and remaining questions in the field.
PSYCH:2018-35423-028
ISSN: 2352-1554
CID: 4331472
Neural correlates of sign language and spoken language revealed by electrocorticography [Meeting Abstract]
Shum, Jennifer; Friedman, Daniel; Dugan, Patricia C; Devinsky, Orrin; Flinker, Adeen
ORIGINAL:0013456
ISSN: 1872-8952
CID: 3939932
Differential Sources for 2 Neural Signatures of Target Detection: An Electrocorticography Study
Kam, J W Y; Szczepanski, S M; Canolty, R T; Flinker, A; Auguste, K I; Crone, N E; Kirsch, H E; Kuperman, R A; Lin, J J; Parvizi, J; Knight, R T
Electrophysiology and neuroimaging provide conflicting evidence for the neural contributions to target detection. Scalp electroencephalography (EEG) studies localize the P3b event-related potential component mainly to parietal cortex, whereas neuroimaging studies report activations in both frontal and parietal cortices. We addressed this discrepancy by examining the sources that generate the target-detection process using electrocorticography (ECoG). We recorded ECoG activity from cortex in 14 patients undergoing epilepsy monitoring, as they performed an auditory or visual target-detection task. We examined target-related responses in 2 domains: high frequency band (HFB) activity and the P3b. Across tasks, we observed a greater proportion of electrodes that showed target-specific HFB power relative to P3b over frontal cortex, but their proportions over parietal cortex were comparable. Notably, there was minimal overlap in the electrodes that showed target-specific HFB and P3b activity. These results revealed that the target-detection process is characterized by at least 2 different neural markers with distinct cortical distributions. Our findings suggest that separate neural mechanisms are driving the differential patterns of activity observed in scalp EEG and neuroimaging studies, with the P3b reflecting EEG findings and HFB activity reflecting neuroimaging findings, highlighting the notion that target detection is not a unitary phenomenon.
PMID: 29253249
ISSN: 1460-2199
CID: 2911192