The Response of the Left Ventral Attentional System to Invalid Targets and its Implication for the Spatial Neglect Syndrome : a Multivariate fMRI Investigation

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In humans, invalid visual targets that mismatch spatial expectations induced by attentional cues are considered to selectively engage a right hemispheric "reorienting" network that includes the temporal parietal junction (TPJ), the inferior frontal gyrus (IFG), and the medial frontal gyrus (MFG). However, recent findings suggest that this hemispheric dominance is not absolute and that it is rather observed because the TPJ and IFG areas in the left hemisphere are engaged both by invalid and valid cued targets. Because of this, the BOLD response of the left hemisphere to invalid targets is usually cancelled out by the standard "invalid versus valid" contrast used in functional magnetic resonance imaging investigations of spatial attention. Here, we used multivariate pattern recognition analysis (MVPA) to gain finer insight into the role played by the left TPJ and IFG in reorienting to invalid targets. We found that in left TPJ and IFG blood oxygen level-dependent (BOLD) responses to invalid and valid targets were associated to different patterns of neural activity, possibly reflecting the presence of functionally distinct neuronal populations. Pattern segregation was significant at group level, it was present in almost all of the participants to the study and was observed both for targets in the left and right side of space. A control whole-brain MVPA ("Searchlight" analysis) confirmed the results obtained in predefined regions of interest and highlighted that also other areas, that is, superior parietal and frontal-polar cortex, show different patterns of BOLD response to valid and invalid targets. These results confirm and expand previous evidence highlighting the involvement of the left hemisphere in reorienting of visual attention (Doricchi et al. 2010; Dragone et al. 2015). These findings suggest that asymmetrical reorienting deficits suffered by right brain damaged patients with left spatial neglect, who have severe impairments in contralesional reorienting and less severe impairments in ipsilesional reorienting, are due to preserved reorienting abilities in the intact left hemisphere.

Medienart:

E-Artikel

Erscheinungsjahr:

2016

Erschienen:

2016

Enthalten in:

Zur Gesamtaufnahme - volume:26

Enthalten in:

Cerebral cortex (New York, N.Y. : 1991) - 26(2016), 12 vom: 24. Dez., Seite 4551-4562

Sprache:

Englisch

Beteiligte Personen:

Silvetti, Massimo [VerfasserIn]
Lasaponara, Stefano [VerfasserIn]
Lecce, Francesca [VerfasserIn]
Dragone, Alessio [VerfasserIn]
Macaluso, Emiliano [VerfasserIn]
Doricchi, Fabrizio [VerfasserIn]

Links:

Volltext

Themen:

Attention
Journal Article
Multivariate fMRI
Oxygen
Reorienting
Research Support, Non-U.S. Gov't
S88TT14065
Spatial neglect
TPJ

Anmerkungen:

Date Completed 10.01.2018

Date Revised 16.04.2018

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1093/cercor/bhv208

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM253085624