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the vestibular system. A summary on spatial orientation and body representation is provided, with concepts on the perception of unreality, to augment the literature available on the relationship between sensory deficits and symptoms of depersonalization/derealization. 2. Spatial Orientation

In: Multisensory Research

various senses as well as motor feedback to maintain spatial constancy, such as efference copy, vestibular, and optic flow signals. The involvement of these different sources in the spatial updating process is task-dependent. For example, efference copy is only available during intended and active

In: Multisensory Research

1. Introduction The term vestibular cognition has made a relatively recent appearance. In the absence of a clear definition, there is much room for interpretation about what it could actually mean. At what point does the processing of vestibular information enter the realm of cognition

In: Multisensory Research

Abstract

Patients with an acquired sensory dysfunction may experience symptoms of detachment from self or from the environment, which are related primarily to nonspecific symptoms of common mental disorders and secondarily, to the specific sensory dysfunction. This is consistent with the proposal that sensory dysfunction could provoke distress and a discrepancy between the multi-sensory frame given by experience and the actual perception. Both vestibular stimuli and vestibular dysfunction can underlie unreal experiences. Vestibular afferents provide a frame of reference (linear and angular head acceleration) within which spatial information from other senses is interpreted. This paper reviews evidence that symptoms of depersonalization/derealization associated with vestibular dysfunction are a consequence of a sensory mismatch between disordered vestibular input and other sensory signals of orientation.

In: Vestibular Cognition

1. Introduction One way of understanding the contribution that a sensory system makes to higher cognitive function is to remove its influence completely and immediately in experimental animals. In the context of the vestibular system, and most other sensory systems, this can be a

In: Multisensory Research

Imbalance among patients with vestibular hypofunction has been related to inadequate compensatory eye movements in response to head movements. However, symptoms of imbalance might also occur due a temporal mismatch between vestibular and other balance-related sensory cues. This temporal mismatch could be reflected in a widened temporal binding window (TBW), or the length of time over which simultaneous sensory stimuli may be offset and still perceived as simultaneous. We hypothesized that decreased vestibular input would lead to a widening of the temporal binding window. We performed whole-body rotations about the earth-vertical axis following a sinusoidal trajectory at 0.5 Hz with a peak velocity of 60°/s in four normal subjects. Dichotic auditory clicks were presented through headphones at various phases relative to the rotations. Subjects were asked to indicate whether the cues were synchronous or asynchronous and the TBW was calculated. We then simulated decreased vestibular input by rotating at diminished peak velocities of 48, 24 and 12°/s in four normal subjects. TBW was calculated between ±1 SD away from the mean on the psychometric curve. We found that the TBW increases as amplitude of rotation decreases. Average TBW of 251 ms at 60°/s increased to 309 ms at 12°/s. This result leads to the novel conclusion that changes in temporal processing may be a mechanism for imbalance in patients with vestibular hypofunction.

In: Seeing and Perceiving

Abstract

Vestibular cognition has recently gained attention. Despite numerous experimental and clinical demonstrations, it is not yet clear what vestibular cognition really is. For future research in vestibular cognition, adopting a computational approach will make it easier to explore the underlying mechanisms. Indeed, most modeling approaches in vestibular science include a top-down or a priori component. We review recent Bayesian optimal observer models, and discuss in detail the conceptual value of prior assumptions, likelihood and posterior estimates for research in vestibular cognition. We then consider forward models in vestibular processing, which are required in order to distinguish between sensory input that is induced by active self-motion, and sensory input that is due to passive self-motion. We suggest that forward models are used not only in the service of estimating sensory states but they can also be drawn upon in an offline mode (e.g., spatial perspective transformations), in which interaction with sensory input is not desired. A computational approach to vestibular cognition will help to discover connections across studies, and it will provide a more coherent framework for investigating vestibular cognition.

In: Vestibular Cognition
In this volume specific cognitive sub-functions are identified and indications of how basic vestibular input contributes to each are described. The broad range of these functions is consistent with the broad spread of vestibular projections throughout the cortex. Combining vestibular signals about the head’s orientation relative to gravity with information about head position relative to the body provides sufficient information to map body position onto the ground surface and underlie the sense of spatial position. But vestibular signals are also fundamental to sensorimotor control and even to high-level bodily perception such as the sense of body ownership and the anchoring of perspective to the body. Clinical observations confirm the essential role of vestibular signals in maintaining a coherent self-representation and suggest some novel rehabilitation strategies.

The chapters presented in this volume are previously published in a Special Issue of Multisensory Research, Volume 28, Issue 5-6 (2015).

Contributors are: M. Barnett-Cowan, O. Blanke, J. Blouin, G. Bosco, G. Bottini, J.-P. Bresciani, J.C. Culham, C.L. Darlington, A.W. Ellis, E.R. Ferrè, M. Gandola, L. Grabherr, S. Gravano, P. Grivaz, E. Guillaud, P. Haggard, L.R. Harris, A.E.N. Hoover, I. Indovina, K. Jáuregu Renaud, M. Kaliuzhna, F. Lacquaniti, B. Lenggenhager, C. Lopez, G. Macauda, V. Maffei, F.W. Mast, B. La Scaleia, B.M. Seemungal, M. Simoneau, P.F. Smith, J.C. Snow, D. Vibert, M. Zago, and Y. Zheng.

Abstract

Our studies conducted over the last 14 years have demonstrated that a complete bilateral vestibular deafferentation (BVD) in rats results in spatial memory deficits in a variety of behavioural tasks, such as the radial arm maze, the foraging task and the spatial T maze, as well as deficits in other tasks such as the five-choice serial reaction time task (5-CSRT task) and object recognition memory task. These deficits persist long after the BVD, and are not simply attributable to ataxia, anxiety, hearing loss or hyperactivity. In tasks such as the foraging task, the spatial memory deficits are evident in darkness when vision is not required to perform the task. The deficits in the radial arm maze, the foraging task and the spatial T maze, in particular, suggest hippocampal dysfunction following BVD, and this is supported by the finding that both hippocampal place cells and theta rhythm are dysfunctional in BVD rats. Now that it is clear that the hippocampus is adversely affected by BVD, the next challenge is to determine what vestibular information is transmitted to it and how that information is used by the hippocampus and the other brain structures with which it interacts.

In: Vestibular Cognition

1. Introduction The purpose of this brief review is to summarize historical and current knowledge about the temporal properties of processing vestibular information, to highlight the dissociation between fast physiological responses and slow perceived timing of vestibular information, to

In: Multisensory Research