Event Name: Graduate Seminar Series: Clinical Stream
Graduate Seminar Series for the Institute of Biomaterials and Biomedical Engineering (IBBME). This day is for clinical stream presenters.
Location: Red Seminar Room – Donnelly Building
Presentation Title: Epileptogenic high frequency activity predicts task related neural and behavioural response
Introduction. Epilepsy is a brain disorder characterized by frequent and recurrent seizures and affects approximately 1-2% of children, and is known to result in significant behavioural and psychological comorbidities including difficulties with attention, memory, social communication, and executive function even if seizures are adequately controlled through medication. Little is known about the specific mechanisms by which these deficits arise and the interaction between the entrainment of a seizure network interfering with eloquent networks and epileptic activity including interictal discharges actively interfering with cognitive processes.
Here we show data from intracranial recordings in a series of cases that demonstrate epileptogenic activity interferes with eloquent activity.
Methods. We recruited patients with epilepsy admitted to the Hospital for Sick Children in Canada for clinically-indicated invasive monitoring with stereotactically-placed bilateral anterior cingulate cortex (ACC) depth electrodes and with or without cortical grids. Patients performed a 1-back visual working memory paradigm (174 new, 100 repeated trials, 1500±200 ms ISI) presented on a laptop placed on their tray table. Patients responded to the task using a wireless handheld controller and were asked to press a button when presented with a repeated image. The data were recorded at 2500 Hz and filtered from 1-300 Hz.
Data were analyzed using the Fieldtrip toolbox. Time-and-frequency resolved power were estimated with the wavelet transform using the 7-cycle Morlet wavelet.
Results. Induced analyses showed high frequency (HF) power (80-300 Hz, 200-350 ms) in the lesion was associated with missed (incorrect) repeat trials. Furthermore, pre-stimulus HF power (80-300 Hz, -200 to 0 ms) in the epileptogenic lesion was correlated with post-stimulus HF power (150-300 ms, 200-300 Hz) in the right ACC (R=0.51) in false alarm (incorrect hits) new trials.
Conclusions. We present data from an extremely rare and unique dataset demonstrating epileptogenic activity interference with eloquent cortical network activity. These findings further elucidate the mechanisms of cognitive deficits in children with epilepsy and may guide future clinical treatment to treat both epilepsy and the resultant comorbidities.
Supervisor Name: Dr. George Ibrahim
Year of Study: 2
Program of Study: MHSc
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