 | Single trial regional activations elicited by simple sensory stimuli: the organization hidden behind variability
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| | | 1) Brain Science Institute, RIKEN |
| | Magnetic field tomography (MFT) was used to extract tomographic estimates of activity throughout the brain millisecond by millisecond from single trial magnetoencephalographic (MEG) signals elicited by simple auditory, somatosensory and visual stimuli. The resulting direct view of brain activity was used to quantify and hence better understand the origin of the response variability before, during and after identical stimuli in each modality were repetitively presented. We find that the strength and timing of a given regional response to a stimulus is influenced by previous activations in the same region, both the ones elicited by the preceding stimuli and from endogenous activations generated without any apparent external stimuli. When responses are examined together from different regional activations, evidence emerges for well-defined distinct response modes elicited by the same stimulus, very likely corresponding to distinct neural networks winning the competition from trial to trial. |
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