eprintid: 2868
rev_number: 7
eprint_status: archive
userid: 69
dir: disk0/00/00/28/68
datestamp: 2015-11-10 11:31:09
lastmod: 2016-09-13 09:43:51
status_changed: 2015-11-10 11:31:09
type: article
metadata_visibility: show
creators_name: Gaglianese, Anna
creators_name: Costagli, Mauro
creators_name: Ueno, Kenichi
creators_name: Ricciardi, Emiliano
creators_name: Bernardi, Giulio
creators_name: Pietrini, Pietro
creators_name: Cheng, Kang
creators_id: 
creators_id: 
creators_id: 
creators_id: emiliano.ricciardi@imtlucca.it
creators_id: 
creators_id: pietro.pietrini@imtlucca.it
creators_id: 
title: 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
ispublished: pub
subjects: RC0321
divisions: CSA
full_text_status: none
keywords: Conditional Granger Causality, fMRI, hMT+, Speeds, Thalamus, Visual motion
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.
date: 2015
date_type: published
publication: Neuroscience
volume: 284
publisher: Elsevier
pagerange: 833 - 844
id_number: 10.1016/j.neuroscience.2014.10.042
refereed: TRUE
issn: 0306-4522
official_url: http://www.sciencedirect.com/science/article/pii/S0306452214009142
citation:   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)