eprintid: 2918
rev_number: 6
eprint_status: archive
userid: 69
dir: disk0/00/00/29/18
datestamp: 2015-11-18 10:59:48
lastmod: 2016-09-13 09:49:55
status_changed: 2015-11-18 10:59:48
type: article
metadata_visibility: show
creators_name: Gaglianese, Anna
creators_name: Costagli, Mauro
creators_name: Bernardi, Giulio
creators_name: Ricciardi, Emiliano
creators_name: Pietrini, Pietro
creators_id: 
creators_id: 
creators_id: 
creators_id: emiliano.ricciardi@imtlucca.it
creators_id: pietro.pietrini@imtlucca.it
title: Evidence of a direct influence between the thalamus and hMT + independent of V1 in the human brain as measured by fMRI
ispublished: pub
subjects: RC0321
divisions: CSA
full_text_status: none
keywords: Visual motion; hMT +; Thalamus; fMRI; Connectivity; Conditional Granger Causality; Phase delay
abstract: In the present study we employed Conditional Granger Causality (CGC) and Coherence analysis to investigate whether visual motion-related information reaches the human middle temporal complex (hMT +) directly from the Lateral Geniculate Nucleus (LGN) of the thalamus, by-passing the primary visual cortex (V1). Ten healthy human volunteers underwent brain scan examinations by functional magnetic resonance imaging (fMRI) during two optic flow experiments. In addition to the classical LGN-V1-hMT + pathway, our results showed a significant direct influence of the blood oxygenation level dependent (BOLD) signal recorded in {LGN} over that in hMT+, not mediated by {V1} activity, which strongly supports the existence of a bilateral pathway that connects {LGN} directly to hMT + and serves visual motion processing. Furthermore, we evaluated the relative latencies among areas functionally connected in the processing of visual motion. Using {LGN} as a reference region, hMT + exhibited a statistically significant earlier peak of activation as compared to V1. In conclusion, our findings suggest the co-existence of an alternative route that directly links {LGN} to hMT+, bypassing V1. This direct pathway may play a significant functional role for the faster detection of motion and may contribute to explain persistence of unconscious motion detection in individuals with severe destruction of primary visual cortex (blindsight).
date: 2012
date_type: published
publication: NeuroImage
volume: 60
number: 2
publisher: Elsevier
pagerange: 1440 - 1447
id_number: 10.1016/j.neuroimage.2012.01.093
refereed: TRUE
issn: 1053-8119
official_url: http://www.sciencedirect.com/science/article/pii/S1053811912001103
citation:   Gaglianese, Anna and Costagli, Mauro and Bernardi, Giulio and Ricciardi, Emiliano and Pietrini, Pietro  Evidence of a direct influence between the thalamus and hMT + independent of V1 in the human brain as measured by fMRI.  NeuroImage, 60 (2).  1440 - 1447.  ISSN 1053-8119      (2012)