Differences between endogenous attention to spatial locations and sensory modalities

Sound-modulations of visual motion perception implicate the cortico-vestibular brain

A widely used example of the intricate (yet poorly understood) intertwining of multisensory signals in the brain is the audiovisual bounce inducing effect (ABE). This effect presents two identical objects moving along the azimuth with uniform motion and towards opposite directions. The perceptual interpretation of the motion is ambiguous and is modulated if a transient (sound) is presented in coincidence with the point of overlap of the two objects' motion trajectories. This phenomenon has long been written-off to simple attentional or decision-making mechanisms, although the neurological underpinnings for the effect are not well understood. Using behavioural metrics concurrently with event-related fMRI, we show that sound-induced modulations of motion perception can be further modulated by changing motion dynamics of the visual targets. The phenomenon engages the posterior parietal cortex and the parieto-insular-vestibular cortical complex, with a close correspondence of activity in these regions with behaviour. These findings suggest that the insular cortex is engaged in deriving a probabilistic perceptual solution through the integration of multisensory data.

Poking Left To Be Right? A Model-Based Analysis of Temporal Order Judged by Mice

The theory of visual attention (TVTVA) provides a formal framework for the assessment of visual attention and related processes. Its center is a mathematical model of visual encoding processes and discretely defined components of attention. Building on this model, TVTVA offers quantitative and process-related explanations for a variety of phenomena in the domain of visual attention. Because the theory relies on very general assumptions which might hold true for other domains of sensory processing, we tested its possible explanatory value for tactile processing in mice. Reanalyzing published data of temporal-order judgments by mice, we show how a TVTVA-based analysis identifies the processes which drive observable behavior and that it comes to conclusions quite different from those of conventional analyses of temporal-order judgments. According to this analysis, despite the same overall capacity dedicated to the task, some mice assume attentional biases toward one side, possibly to optimize their overall performance. We suggest that TVTVA's concepts provide a powerful point of vantage to find explanations for observable behavior where conventional analysis easily leads to dead ends.