1,721,001 research outputs found
Beyond the Non-Specific Attentional Effect of Caloric Vestibular Stimulation: Evidence from Healthy Subjects and Patients
No full textCaloric vestibular stimulation (CVS) is a simple physiological manipulation that has been used for a long time in different clinical fields due to its rapid and relevant effects on behaviour. One of the most debated issues in this research field concerns the degree of specificity of such stimulation, namely whether the effects of CVS can be, and to what extent are, independent of the mere influence of non-specific factors such as general arousal, ocular movements or attentional shift towards the stimulated side. The hypothesis that CVS might cause a shift of attention towards the side of the stimulation has been largely supported; moreover, a large amount of evidence is available nowadays to corroborate the specific effect of CVS, providing behavioural and neurophysiological data in both patients and normal subjects. These data converge in indicating that the effects of CVS can be independent of eye deviation and general arousal, can modulate different symptoms in different directions, and do not merely depend on a general shift of attention. The present article is divided into three main sections. In the first section, we describe classical studies that investigate the effects of CVS on neglect and related symptoms. In the second and third parts, we provide an overview of the modulatory effects of CVS on somatosensory processes and body representation in both brain-damaged patients and healthy subjects. Finally, we conclude by discussing the relevance of these new findings for the understanding of the neural mechanisms underlying the modulatory effects of CVS
Self-touch facilitates the recognition of the dis-owned left hand in somatoparaphrenia: a single case study
No full text: We investigated whether self-administered tactile stimulation could act as a temporary restorative mechanism for body ownership disorders, both implicitly and explicitly. We tested this hypothesis in a patient with somatoparaphrenia, who displayed increased accuracy in explicitly recognizing their left hand during self-touch. Furthermore, the patient implicitly perceived their hand and the experimenter's hand as more belonging to their own body compared to conditions where vision was the sole sensory input. These findings highlight the importance of self-touch in maintaining a coherent body representation, while also demonstrating the potential dissociation between the recovery of explicit and implicit perceptions of body ownership
Arousal responses to noxious stimuli in somatoparaphrenia and anosognosia: clues to body awareness.
No full textMultiple dissociations in patients with disorders of body awareness: Implications for the study of consciousness
No full textA Breakdown of Imagined Visuomotor Transformations and Its Neural Correlates in Young Elderly Subjects
Full text linkSeveral studies have shown age-related changes in motor imagery (MI) in older adults and the associated compensatory brain activation patterns; most of these studies have used explicit MI tasks or implicit MI tasks focused on mental rotation of body parts. Here, we address the effect of ageing on MI for the more complex visuomotor transformations entailed by mentally simulated hand-tool interactions triggered by a grip selection task (GST) for tools used in daily life. We studied 22 young and 22 elderly subjects performing the GST, in which they were asked to report whether they would grip a portrayed tool with an overhand or an underhand grip. We found a behavioral decline in the elderly group, accompanied by reduced activations of the left posterior parietal lobule, in a subregion associated specifically with reaching behavior by previous investigations. No differences were observed in the temporal cortices associated with object semantics. These results suggested a specific age-related vulnerability of the neural substrates, particularly for the imaginary reaching component of the task, rather than for the semantically driven grasping component. The combination of behavioral deficits and reduced activation of specific brain regions speaks in favor of a specific age-associated deficit for the complex imaginary movements required by the GST
Productive and defective impairments in the neglect syndrome: graphic perseveration, drawing productions and optic prism exposure
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