Page 208 - MEGIN Book Of Abstracts - 2023

produced by brain electrical currents, and is used most connectivity analysis for optimal neurophysiological
fruitfully to evaluate epilepsy patients. While other and anatomical localisation.
modalities infer brain function indirectly by measuring
changes in blood flow, metabolism, and oxygenation, METHODS We consecutively recruited 26 patients
magnetoencephalography measures neuronal and with JME who underwent resting state MEG recording,
synaptic function directly with submillisecond tempo- along with 26 age-and-sex matched controls. Whole
ral resolution. The brain's magnetic field is recorded brain connectivity was determined through correla-
by neuromagnetometers surrounding the head in a tion of Automated Anatomical Labelling (AAL) atlas
helmet-shaped sensor array. Because magnetic signals source space MEG timeseries in conventional frequency
are not distorted by anatomy, magnetoencephalogra- bands of interest delta (1-4 Hz), theta (4-8 Hz), alpha
phy allows for a more accurate measurement and local- (8-13 Hz), beta (13-30 Hz) and gamma (40-60 Hz). We
ization of brain activities than electroencephalography. used a Linearly Constrained Minimum Variance (LCMV)
Magnetoencephalography has become an indispens- beamformer to extract voxel wise time series of 'virtual
able part of the armamentarium at epilepsy centers. sensors' for the desired frequency bands, followed
by connectivity analysis using correlation between
Keywords: Dipole, Gradiometer, Head model, Magnetic frequency- and node-specific power fluctuations, for
source imaging, Magnetoencephalography, Magnetom- the voxel maxima in each AAL atlas label, correcting for
eter, Source localization, Source model noise, potentially spurious connections and multiple
comparisons.
Neuroimaging clinics of North America (2020), Vol. 30, No.
2 (32336403) (5 citations) RESULTS We found increased connectivity in the theta
band in posterior brain regions, surviving statistical cor-
rection for multiple comparisons (corrected p < 0.05),
Juvenile myoclonic epilepsy shows increased and decreased connectivity in the beta band in senso-
posterior theta, and reduced sensorimotor beta rimotor cortex, between right pre- and post- central
resting connectivity (2020) gyrus (p < 0.05) in JME compared to controls.

Routley, Bethany; Shaw, Alexander; CONCLUSIONS Altered resting-state MEG connectivity
Muthukumaraswamy, Suresh D; Singh, Krish D; in JME comprised increased connectivity in posterior
Hamandi, Khalid theta - the frequency band associated with long range
connections affecting attention and arousal - and
Cardiff University Brain Research Imaging, School of Psychol- decreased beta-band sensorimotor connectivity. These
ogy, Cardiff University, United Kingdom; School of Phar- findings likely relate to altered regulation of the senso-
macy, Faculty of Medical and Health Sciences, University of rimotor network and seizure prone states in JME.
Auckland, Auckland, New Zealand; Cardiff University Brain
Research Imaging, School of Psychology, Cardiff University, Keywords: Connectivity, JME, Juvenile myoclonic epilepsy,
United Kingdom; The Wales Epilepsy Unit, Department of MEG, Magnetoencephalography
Neurology, University Hospital of Wales, Cardiff, United King-
dom. Electronic address: [email protected] Epilepsy research (2020), Vol. 163 (32335503) (14 citations)

BACKGROUND Widespread structural and functional
brain network changes have been shown in Juvenile
Myoclonic Epilepsy (JME) despite normal clinical neuro-
imaging. We sought to better define these changes us-
ing magnetoencephalography (MEG) and source space

 ontents  Index 187
C