A functional MRI study of preparatory signals for spatial location and objects

Corbetta, Maurizio; Tansy, Aaron P.; Stanley, Christine M.; Astafiev, Serguei V.; Snyder, Abraham Z.; Shulman, Gordon L.

doi:10.1016/j.neuropsychologia.2005.03.020

Cited by 87 publications

(45 citation statements)

References 51 publications

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“…As a correlate, our observations also highlight the importance of referring neurophysiological or imaging neuronal modulations to a baseline that is free from potential confounds, such as proactive inhibition of action, and call for the reassessment of the theoretical framework used to interpret attentional modulation of visual processing. Consistent with our proposal, Corbetta et al (2005) previously failed to report expectation-related increases of signals in the visual cortex when a spatial cue directed the subjects' attention to a given location in the visual field. As discussed by the authors, when attempting to account for this surprising result, only two conditions seemed to elicit consistently spatially selective preparatory signals: 1) when early sensory mechanisms are needed to separate a weak signal from noise and 2) when nearby distracters must be filtered out (Moran and Desimone 1985;Serences et al 2004;Sylvester et al 2008).…”

Section: Attention To Baselinessupporting

confidence: 89%

Attention to baseline: does orienting visuospatial attention really facilitate target detection?

Albares

Criaud

Wardak

et al. 2011

Journal of Neurophysiology

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Albares M, Criaud M, Wardak C, Nguyen SC, Ben Hamed S, Boulinguez P. Attention to baseline: does orienting visuospatial attention really facilitate target detection? J Neurophysiol 106: 809-816, 2011. First published May 25, 2011 doi:10.1152/jn.00206.2011.-Standard protocols testing the orientation of visuospatial attention usually present spatial cues before targets and compare valid-cue trials with invalid-cue trials. The valid/invalid contrast results in a relative behavioral or physiological difference that is generally interpreted as a benefit of attention orientation. However, growing evidence suggests that inhibitory control of response is closely involved in this kind of protocol that requires the subjects to withhold automatic responses to cues, probably biasing behavioral and physiological baselines. Here, we used two experiments to disentangle the inhibitory control of automatic responses from orienting of visuospatial attention in a saccadic reaction time task in humans, a variant of the classical cue-target detection task and a sustained visuospatial attentional task. Surprisingly, when referring to a simple target detection task in which there is no need to refrain from reacting to avoid inappropriate responses, we found no consistent evidence of facilitation of target detection at the attended location. Instead, we observed a cost at the unattended location. Departing from the classical view, our results suggest that reaction time measures of visuospatial attention probably relie on the attenuation of elementary processes involved in visual target detection and saccade initiation away from the attended location rather than on facilitation at the attended location. This highlights the need to use proper control conditions in experimental designs to disambiguate relative from absolute cueing benefits on target detection reaction times, both in psychophysical and neurophysiological studies. saccades; electrooculography; inhibition; human ONE ATTRIBUTE of the selective attention system is its capacity to select a part of the environment over which an impending signal is to occur. Orienting visuospatial attention is known to facilitate information processing of stimuli at attended locations. A consistent behavioral outcome of this effect is a reduction of response latency [reaction time (RT)] to salient stimuli presented at the attended location

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Section: Attention To Baselinessupporting

confidence: 89%

Attention to baseline: does orienting visuospatial attention really facilitate target detection?

Albares

Criaud

Wardak

et al. 2011

Journal of Neurophysiology

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“…Corbetta et al, 2005 andYantis et al, 2002). In their FEF inactivation study in monkeys, Wardak et al (2006) also suggest a bilateral role in directional shifts of covert attention instead of a simple contralateral deficit (unlike saccades subsequent to inactivation which showed a clear contralateral pattern).…”

Section: Fef Activationmentioning

confidence: 96%

Orienting auditory spatial attention engages frontal eye fields and medial occipital cortex in congenitally blind humans

2007

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What happens in vision related cortical areas when congenitally blind (CB) individuals orient attention to spatial locations? Previous neuroimaging of sighted individuals has found overlapping activation in a network of frontoparietal areas including frontal eye-fields (FEF), during both overt (with eye movement) and covert (without eye movement) shifts of spatial attention. Since voluntary eye movement planning seems irrelevant in CB, their FEF neurons should be recruited for alternative functions if their attentional role in sighted individuals is only due to eye movement planning.Recent neuroimaging of the blind has also reported activation in medial occipital areas, normally associated with visual processing, during a diverse set of non-visual tasks, but their response to attentional shifts remains poorly understood.Here, we used event-related fMRI to explore FEF and medial occipital areas in CB individuals and sighted controls with eyes closed (SC) performing a covert attention orienting task, using endogenous verbal cues and spatialized auditory targets. We found robust stimulus-locked FEF activation of all CB subjects, similar but stronger than in SC, suggesting that FEF plays a role in endogenous orienting of covert spatial attention even in individuals in whom voluntary eye movements are irrelevant. We also found robust activation in bilateral medial occipital cortex in CB but not in SC subjects. The response decreased below baseline following endogenous verbal cues but increased following auditory targets, suggesting that the medial occipital area in CB does not directly engage during cued orienting of attention but may be recruited for processing of spatialized auditory targets.

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“…Such experiments typically report the engagement of a frontoparietal network during visual attention to locations (Corbetta et al, 2000(Corbetta et al, , 2005Hopfinger et al, 2000;Woldorff et al, 2004;Slagter et al, 2007) or features (Shulman et al, 1999;Vandenberghe et al, 2001;Giesbrecht et al, 2003;Luks and Simpson, 2004;Slagter et al, 2007). Importantly, the majority of such activations appear common to spatial and feature-based conditions, suggesting that selection may be overseen by a generalized topdown mechanism (see also Slagter et al, 2005a).…”

Section: Introductionmentioning

confidence: 99%