Cross-modal Interactions in Time and Space: Auditory Influence on Visual Attention in Hemispatial Neglect

Abstract

Recent studies indicate that auditory tone presentation and auditory alerting can temporarily ameliorate visuospatial attention deficits in patients with unilateral neglect [Frassinetti, F., Pavani, F., & Ladavas, E. Acoustical vision of neglected stimuli: Interaction among spatially converging audiovisual inputs in neglect patients. Journal of Cognitive Neuroscience, 14, 62-69, 2002; Robertson, I. H., Mattingley, J. B., Rorden, C., & Driver, J. Phasic alerting of neglect patients overcomes their spatial deficit in visual awareness. Nature, 395, 169-172, 1998]. The current study investigated proposed mechanisms of cross-modal interaction to determine conditions in which auditory stimulation affects spatial and nonspatially lateralized attention deficits in a patient with hemispatial neglect. In Experiment 1, a target was presented among related distracters (conjunction search) while a tone was presented either bilaterally or in a congruent or incongruent spatial location with respect to the visual target. Whereas the results suggest a benefit of both general alerting and cross-modal spatial integration on visual search efficiency, the most significant improvement occurred when the target and tone were both presented in contralesional space. In Experiment 2, the effect of auditory alerting on selective attention was examined in a rapid serial visual search procedure with visual targets embedded in a stream of distracters presented at central fixation. When two targets were presented without an alerting tone, the patient missed the second target for up to 1000 msec after the first target appeared (a finding known as the "attentional blink" [AB] and, on average, about 400-500 msec in normals). An alerting tone presented at a fixed temporal location significantly reduced the AB in a tone-duration-dependent manner. Experiment 3 examined the effect of cross-modal space on selective attention in an AB paradigm in which T2 occurred randomly to the left or right of T1 with a spatially congruent or incongruent tone. Discrimination of T2 in contralesional space significantly improved when the tone was presented in the same location, and was impaired when the tone was presented on the ipsilesional side. The findings are discussed as they relate to cross-modal interactions and their influence on spatial and nonspatially lateralized attention deficits in neglect.

The parietal cortex and the representation of time, space, number and other magnitudes

“…Other studies support Battelli's view and report deficits similar in nature to the visual timing of events, and bilateral timing deficits have been reported for visual search tasks requiring spatiotemporal segmentation (e.g. Van Vleet & Robertson 2006). The regions of damage that lead to temporal deficits also frequently cause spatial, numerical and velocity perception deficits (e.g.…”

A re-examination of the impact of object processing on shifts of spatial attention

“…First, there is substantial overlap between areas that represent object properties such as shape and size and dorsal areas involved in spatial vision and attention (e.g., Konen & Kastner, 2008). Second, the AB is prolonged in visual neglect patients (Husain, Shapiro, Martin, & Kennard, 1997;Shapiro, Hillstrom, & Husain, 2002;Van Vleet & Robertson, 2006), implicating common pathways for the two deficits. Finally, studies have linked the AB with neural activity in the intraparietal sulcus (IPS; Marois, Chun, & Gore, 2000;Kihara et al, 2007), and the temporo-parietal junction (TPJ; Gross et al, 2004;Marois, Yi, & Chun, 2004).…”

Attenuation of Neural Responses in Primary Visual Cortex during the Attentional Blink

“…For example, Luck et al (1997) and Rees et al (1997) have all shown evidence consistent with the notion that variations in V1 activity reflect biasing signals from later, extrastriate visual areas. It is also notable that patients with visual neglect reliably display prolonged AB deficits (Husain et al 1997;Van Vleet and Robertson, 2006), suggesting a further link between spatial and temporal attention. Such parallels between theoretical and empirical considerations demonstrate the importance of examining links between capacity limitations across a variety of behavioral paradigms to better understand how such bottlenecks affect human perception.…”

“…First, parietal neglect patients, who have difficulty allocating attention to the contralesional side of space, also show a prolonged AB for sequential displays at the fovea (Husain et al 1997;Van Vleet and Robertson, 2006), implying a functional overlap between the two deficits that may extend to early visual areas. Second, studies of the primate visual system suggest that modulations of early visual processing (Hupé et al, 1998) are instantiated by extensive feedback projections from extrastriate regions of the temporal and parietal cortex to the V1 (Noesselt et al, 2002;Weidner et al, 2006;Hinrichs et al, 2008).…”