Impaired attentional selection following lesions to human pulvinar: Evidence for homology between human and monkey

Abstract

We examined the contributions of the human pulvinar to goal directed selection of visual targets in 3 patients with chronic, unilateral lesions involving topographic maps in the ventral pulvinar. Observers completed 2 psychophysical tasks in which they discriminated the orientation of a lateralized target grating in the presence of vertically-aligned distracters. In experiment 1, where distracter contrast was varied while target contrast remained constant, the patients' contralesional contrast thresholds for discriminating the orientation of grating stimuli were elevated only when the task required selection of a visual target in the face of competition from a salient distracter. Attentional selectivity was restored in the patients in experiment 2 where target contrast was varied while distracter contrast remained constant. These observations provide the first evidence that the human pulvinar plays a necessary role in modulating physical saliency in attentional selection, and supports a homology in global pulvinar structure between humans and monkey.salience ͉ visual attention M ultiple items within a visual scene compete for our focal attention. This competition is resolved on the basis of both the perceptual salience of the stimulus and its behavioral salience in relation to the goals of ongoing behavior (1). Visual items can compete for representation in ventral occipito-temporal brain areas, with this competition varying according to the physical distinctiveness of the items and according to whether they demand processing through the same receptive fields (2, 3). The competition can also be biased in favor of less conspicuous objects if they are nonetheless more relevant for behavior (2,4,5). These ''goaldriven'' attentional control signals arise within dorsal frontoparietal networks (6-8) and they lead to behavioral improvements in discriminating the features of the attended object (9, 10). What remains unclear is how such ''dorsal'' attentional signals are communicated to ventral occipital and temporal areas to bias visual analysis. Here, we report the first direct behavioral evidence in humans for the role of the pulvinar in coordinating these goaldriven and stimulus-driven interactions. We used a sensitive psychophysical task to examine target selection in a special group of patients with well documented chronic, unilateral lesions involving topographic maps in the ventral pulvinar. Our findings demonstrate that the pulvinar plays an important role in filtering irrelevant but salient visual distracters.The pulvinar nucleus of the thalamus has been hypothesized to play a central role in coordinating attentional effects on visual processing (11,12). Most of our current knowledge on patterns of connectivity of the pulvinar stems from anatomical studies in non-human primates. The primate pulvinar has extensive connectivity with the cortex. Based on this connectivity, several general organising principles within the pulvinar have been suggested: a global dorsal/ventral division, and an anterior/ posterior org...

Spatio-temporal indications of sub-cortical involvement in leftward bias of spatial attention

“…These connections further support our claim regarding the central involvement of sub-cortical regions such as the pulvinar nuclei in spatial attention bias. In line with our findings, neuro-imaging studies suggest that the pulvinar nucleus is related to serial search (Fairhall et al, 2009), covert shifts of attention (Nobre et al, 1997), and attentional selection (Snow et al, 2009). Moreover, lesion studies in humans showed the critical role of the pulvinar in engagement of attention (Rafal and Posner, 1987), spatial and temporal components of feature binding (Arend et al, 2008), and visual search (Ward and Arend, 2007).…”

Neural correlates of and processes underlying generalized and differential return of fear

“…Haaker et al, 2014;Vervliet et al, 2013a). In this context it is tempting to speculate that significant activation of thalamic and occipital regions, as observed for generalized RI, may reflect generally facilitated salience processing of incoming information (thalamus: Robinson and Petersen, 1992;Snow et al, 2009;primary visual areas: Khayat et al, 2006), which may support a contribution of non-associative processes to generalized RI. Interestingly a significant correlation between peak parameter estimates and SCR responses, as a measure related to arousal, was only observed for thalamic activations.…”

Different functions in the cingulate cortex, a meta-analytic connectivity modeling study

“…Moreover, the pulvinar nucleus is involved in the modulation of the physical saliency of a stimulus in both humans and non-humans primates (Snow et al, 2009; and recruited for covert forms of goal-directed searches (Fairhall et al, 2009). ROI 8 and 9 showed a more pronounced pattern of sensorimotor connectivity.…”