Gaglianese, Anna and Costagli, Mauro and Ueno, Kenichi and Ricciardi, Emiliano and Bernardi, Giulio and Pietrini, Pietro and Cheng, Kang The direct, not V1-mediated, functional influence between the thalamus and middle temporal complex in the human brain is modulated by the speed of visual motion. Neuroscience, 284. 833 - 844. ISSN 0306-4522 (2015)
Full text not available from this repository.Abstract
Abstract The main visual pathway that conveys motion information to the middle temporal complex (hMT+) originates from the primary visual cortex (V1), which, in turn, receives spatial and temporal features of the perceived stimuli from the lateral geniculate nucleus (LGN). In addition, visual motion information reaches hMT+ directly from the thalamus, bypassing the V1, through a direct pathway. We aimed at elucidating whether this direct route between {LGN} and hMT+ represents a ‘fast lane’ reserved to high-speed motion, as proposed previously, or it is merely involved in processing motion information irrespective of speeds. We evaluated functional magnetic resonance imaging (fMRI) responses elicited by moving visual stimuli and applied connectivity analyses to investigate the effect of motion speed on the causal influence between {LGN} and hMT+, independent of V1, using the Conditional Granger Causality (CGC) in the presence of slow and fast visual stimuli. Our results showed that at least part of the visual motion information from {LGN} reaches hMT+, bypassing V1, in response to both slow and fast motion speeds of the perceived stimuli. We also investigated whether motion speeds have different effects on the connections between {LGN} and functional subdivisions within hMT+: direct connections between {LGN} and MT-proper carry mainly slow motion information, while connections between {LGN} and {MST} carry mainly fast motion information. The existence of a parallel pathway that connects the {LGN} directly to hMT+ in response to both slow and fast speeds may explain why {MT} and {MST} can still respond in the presence of {V1} lesions.
| Item Type: | Article |
|---|---|
| Identification Number: | https://doi.org/10.1016/j.neuroscience.2014.10.042 |
| Uncontrolled Keywords: | Conditional Granger Causality, fMRI, hMT+, Speeds, Thalamus, Visual motion |
| Subjects: | R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry |
| Research Area: | Computer Science and Applications |
| Depositing User: | Caterina Tangheroni |
| Date Deposited: | 10 Nov 2015 11:31 |
| Last Modified: | 13 Sep 2016 09:43 |
| URI: | http://eprints.imtlucca.it/id/eprint/2868 |
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