MEG's ability to localise accurately weak transient neural sources
MEG's ability to localise accurately weak transient neural sources
Objective: to investigate the accurate localisation of weak, transient, neural sources under conditions of varying difficulty.
Methods: multiple dipolar sources placed within a head-shaped phantom at superficial and deep locations were driven separately or simultaneously by a short-lasting current with varied amplitudes. Artificial MEG signals that were very similar to the human High Frequency Oscillations (HFO) were produced. MEG signals of HFO were also recorded from median nerve stimulation. Different inverse techniques were used to localise the phantom dipoles and the human HFO generators.
Results: the human HFO were measured around 200 and 600 Hz by using only 120 trials. The 200 Hz HFO were localised to BA3b. The superficial phantom’s source was localised with an accuracy of 2–3 mm by all inverse techniques (120 trials). The ‘subcortical’ source was localised with an error of 5 mm. Localisation of deeper ‘thalamic’ sources required more trials.
Conclusion: MEG can detect and localise weak transient activations and the human HFO with an accuracy of a few mm at cortical and subcortical regions even when a small number of trials are used.
Significance: localizing HFO to specific anatomical structures has high clinical utility, for example in epilepsy, where discrete HFO appears to be generated just before focal epileptic activity
1958-1970
Papadelis, C.
9a28e897-0b4f-4aa2-acb8-d12429b58392
Poghosyan, V.
7dbdfd1f-33c9-4a52-9ea6-41e45c0de53d
Fenwick, P.
6f2f3b2c-ec19-49a0-8109-e7008623cf40
Ioannides, A.A.
eb175f78-0faa-4983-b33e-b2b651bad365
November 2009
Papadelis, C.
9a28e897-0b4f-4aa2-acb8-d12429b58392
Poghosyan, V.
7dbdfd1f-33c9-4a52-9ea6-41e45c0de53d
Fenwick, P.
6f2f3b2c-ec19-49a0-8109-e7008623cf40
Ioannides, A.A.
eb175f78-0faa-4983-b33e-b2b651bad365
Papadelis, C., Poghosyan, V., Fenwick, P. and Ioannides, A.A.
(2009)
MEG's ability to localise accurately weak transient neural sources.
Clinical Neurophysiology, 120 (11), .
(doi:10.1016/j.clinph.2009.08.018).
Abstract
Objective: to investigate the accurate localisation of weak, transient, neural sources under conditions of varying difficulty.
Methods: multiple dipolar sources placed within a head-shaped phantom at superficial and deep locations were driven separately or simultaneously by a short-lasting current with varied amplitudes. Artificial MEG signals that were very similar to the human High Frequency Oscillations (HFO) were produced. MEG signals of HFO were also recorded from median nerve stimulation. Different inverse techniques were used to localise the phantom dipoles and the human HFO generators.
Results: the human HFO were measured around 200 and 600 Hz by using only 120 trials. The 200 Hz HFO were localised to BA3b. The superficial phantom’s source was localised with an accuracy of 2–3 mm by all inverse techniques (120 trials). The ‘subcortical’ source was localised with an error of 5 mm. Localisation of deeper ‘thalamic’ sources required more trials.
Conclusion: MEG can detect and localise weak transient activations and the human HFO with an accuracy of a few mm at cortical and subcortical regions even when a small number of trials are used.
Significance: localizing HFO to specific anatomical structures has high clinical utility, for example in epilepsy, where discrete HFO appears to be generated just before focal epileptic activity
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Published date: November 2009
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Local EPrints ID: 162381
URI: http://eprints.soton.ac.uk/id/eprint/162381
PURE UUID: 2770d904-ee34-4f36-88c4-cc56c2ca5b2c
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Date deposited: 20 Aug 2010 08:36
Last modified: 14 Mar 2024 02:02
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Author:
C. Papadelis
Author:
V. Poghosyan
Author:
P. Fenwick
Author:
A.A. Ioannides
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