Vestibular and oculomotor influences on visual dependency

The degree to which a person relies on visual stimuli for spatial orientation is termed visual dependency (VD). VD is considered a perceptual trait or cognitive style influenced by psychological factors and mediated by central re-weighting of the sensory inputs involved in spatial orientation. VD is often measured using the rod-and-disk test, wherein participants align a central rod to the subjective visual vertical (SVV) in the presence of a background that is either stationary or rotating around the line of sight - dynamic SVV. Although this task has been employed to assess VD in health and vestibular disease, it is unknown what effect torsional nystagmic eye movements may have on individual performance. Using caloric ear irrigation, 3D video-oculography and the rod-and-disk test, we show that caloric torsional nystagmus modulates measures of visual dependency and demonstrate that increases in tilt after irrigation are positively correlated with changes in ocular torsional eye movements. When the direction of the slow phase of the torsional eye movement induced by the caloric is congruent with that induced by the rotating visual stimulus, there is a significant increase in tilt. When these two torsional components are in opposition there is a decrease. These findings show that measures of visual dependence can be influenced by oculomotor responses induced by caloric stimulation. The findings are of significance for clinical studies as they indicate that VD, which often increases in vestibular disorders, is not only modulated by changes in cognitive style but also by eye movements, in particular nystagmus.

Cosmic Topologies of Imitation: From the Horror of Digital Autotoxicus to the Auto-Toxicity of the Social

This article expands on an earlier concept of horror autotoxicus linked to digital contagions of spam and network Virality.1 It aims to present, as such, a broader conception of cosmic topologies of imitation (CTI) intended to better grasp the relatively new practices of social media marketing. Similar to digital autotoxicity, CTI provide the perfect medium for sharing while also spreading contagions that can potentially contaminate the medium itself. However, whereas digital contagions are perhaps limited to the toxicity of a technical layer of information viruses, the contagions of CTI are an all pervasive auto-toxicity which can infect human bodies and technologies increasingly in concert with each other. This is an exceptional autotoxicus that significantly blurs the immunological line of exemption between self and nonself, and potentially, the anthropomorphic distinction between individual self and collective others.