Out of touch? Visual load induces inattentional numbness.
Ontology highlight
ABSTRACT:
SUBMITTER: Murphy S
PROVIDER: S-EPMC4873046 | biostudies-other | 2016 Jun
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The spatial context in which we view a visual stimulus strongly determines how we perceive the stimulus. In the visual tilt illusion, the perceived orientation of a visual grating is affected by the orientation signals in its surrounding context. Conceivably, the spatial context in which a visual grating is perceived can be defined by interactive multisensory information rather than visual signals alone. Here, we tested the hypothesis that tactile signals engage the neural mechanisms supporting visual contextual modulation. Because tactile signals also convey orientation information and touch can selectively interact with visual orientation perception, we predicted that tactile signals would modulate the visual tilt illusion. We applied a bias-free method to measure the tilt illusion while testing visual-only, tactile-only or visuo-tactile contextual surrounds. We found that a tactile context can influence visual tilt perception. Moreover, combining visual and tactile orientation information in the surround results in a larger tilt illusion relative to the illusion achieved with the visual-only surround. These results demonstrate that the visual tilt illusion is subject to multisensory influences and imply that non-visual signals access the neural circuits whose computations underlie the contextual modulation of vision.
| S-EPMC6226493 | biostudies-literature
Project description:BACKGROUND: While the sense of bodily ownership has now been widely investigated through the rubber hand illusion (RHI), very little is known about the sense of disownership. It has been hypothesized that the RHI also affects the ownership feelings towards the participant's own hand, as if the rubber hand replaced the participant's actual hand. Somatosensory changes observed in the participants' hand while experiencing the RHI have been taken as evidence for disownership of their real hand. Here we propose a theoretical framework to disambiguate whether such somatosensory changes are to be ascribed to the disownership of the real hand or rather to the anomalous visuo-proprioceptive conflict experienced by the participant during the RHI. METHODOLOGY/PRINCIPAL FINDINGS: In experiment 1, reaction times (RTs) to tactile stimuli delivered to the participants' hand slowed down following the establishment of the RHI. In experiment 2, the misalignment of visual and proprioceptive inputs was obtained via prismatic displacement, a situation in which ownership of the seen hand was doubtless. This condition slowed down the participants' tactile RTs. Thus, similar effects on touch perception emerged following RHI and prismatic displacement. Both manipulations also induced a proprioceptive drift, toward the fake hand in the first experiment and toward the visual position of the participants' hand in the second experiment. CONCLUSIONS/SIGNIFICANCE: These findings reveal that somatosensory alterations in the experimental hand resulting from the RHI result from cross-modal mismatch between the seen and felt position of the hand. As such, they are not necessarily a signature of disownership.
| S-EPMC2732904 | biostudies-literature
Project description:Social dysfunction has been recognized as an elementary feature of schizophrenia, but it remains a crucial issue whether social deficits in schizophrenia concern the inter-subjective domain or primarily have their roots in disturbances of self-experience. Social perception comprises vicarious processes grounding an experiential inter-relationship with others as well as self-regulation processes allowing to maintain a coherent sense of self. The present study investigated whether the functional neural basis underlying these processes is altered in first-episode schizophrenia (FES). Twenty-four FES patients and 22 healthy control participants underwent functional magnetic resonance imaging during a social perception task requiring them to watch videos depicting other individuals' inanimate and animate/social tactile stimulations, and a tactile localizer condition. Activation in ventral premotor cortex for observed bodily tactile stimulations was reduced in the FES group and negatively correlated with self-experience disturbances. Moreover, FES patients showed aberrant differential activation in posterior insula for first-person tactile experiences and observed affective tactile stimulations. These findings suggest that social perception in FES at a pre-reflective level is characterized by disturbances of self-experience, including impaired multisensory representations and self-other distinction. However, the results also show that social perception in FES involves more complex alterations of neural activation at multiple processing levels.
| S-EPMC3624951 | biostudies-literature
Project description:Every human being spontaneously touches its eyes, cheeks, chin and mouth manifold every day. These spontaneous facial self-touches (sFST) are elicited with little or no awareness and are distinct from gestures and instrumental acts. Self-touch frequency has been shown to be influenced by negative affect and attention distraction and may be involved in regulating emotion and working memory functions. Yet, even though self-touch research dates back several decades fundamental aspects, like the temporal progression of sFST or the effects of executing hand and touched face area, have not yet been analyzed. For the first time, the present study measured sFST temporal aspects to the millisecond using accelerometers and EMG. Spontaneous self-touch was triggered in sixty participants who completed a delayed memory task of complex haptic relief stimuli while listening to distracting aversive sounds. We found that while both hands were used equally often and with the same overall movement times and contact durations, significant effects occurred for face area in both frequency and contact durations. Ergo the point of touch seems to have some relevance of its own, independently of which hand is used to perform it. The results show that not only frequency but also the point of touch and contact durations are influenced by cognitive and emotional demands. We argue that investigating the fundamental characteristics of sFST will further the understanding of cognitive focusing and attentional mechanisms.
| S-EPMC6413902 | biostudies-literature
Project description:BackgroundHealth services research can benefit from frontline clinician input across all stages of research, yet their key perspectives are often not meaningfully engaged.ObjectiveHow can we improve clinician engagement in research?DesignConvenience sampling and semi-structured interviews followed by descriptive content analysis with an inductive approach, followed by group participatory listening sessions with interviewees to further contextualize findings.ParticipantsTwenty-one multidisciplinary clinicians from one healthcare system.Key resultsWe identified two major themes: perceptions of research (how research fits within job role) and characterizing effective engagement (what works and what does not work in frontline clinician engagement). "Perceptions of Research" encompassed three subthemes: prior research experience; desired degree of engagement; and benefits to clinicians engaging in research. "Characterizing Effective Engagement" had these subthemes: engagement barriers; engagement facilitators; and impact of clinician's racial identity.ConclusionsInvesting in frontline clinicians as research collaborators is beneficial to clinicians themselves, the health systems that employ them, and those for which they care. Yet, there are multiple barriers to meaningful engagement.
| S-EPMC10112825 | biostudies-literature
Project description:Crossmodal studies have demonstrated inhibitory as well as facilitatory neural effects in higher sensory association and primary sensory cortices. A recent human behavioral study reported touch-induced visual perceptual suppression (TIVS). Here, we introduced an experimental setting in which TIVS could occur and investigated brain activities underlying visuo-tactile interactions using a functional magnetic resonance imaging technique. While the suppressive effect of touch on vision was only found for half of the participants who could maintain their baseline performance above chance level (i.e. TIVS was not well replicated here), we focused on individual differences in the effect of touch on vision. This effect could be suppressive or enhancement, and the neuronal basis of these differences was analyzed. We found larger inhibitory responses in the anterior part of the right visual cortex (V1, V2) with higher TIVS magnitude when visuo-tactile stimuli were presented as spatially congruent. Activations in the right anterior superior temporal region, including the secondary somatosensory cortical area, were more strongly related to those in the visual cortex (V1, V2) with higher TIVS magnitude. These results indicate that inhibitory neural modulations from somatosensory to visual cortices and the resulting inhibitory neural responses in the visual cortex could be involved in TIVS.
| S-EPMC5118811 | biostudies-other
Project description:BackgroundEmergency medicine (EM) physicians sometimes respond to critical events outside the emergency department. To prepare for these complex cases-typically called "rapid responses" (RRs)-EM residents receive simulation-based training involving four practice tasks and three exam tasks during a 1-day session. Cognitive load (CL) theory describes how humans function with limited working memories to perform complex tasks. RRs are expected to generate high levels of CL, but the profile of CL across providers and RR cases is not well understood. In this study, we analyzed resident's CL during RR training. We hypothesized variations in CL across individual and case and that exam cases would cause higher CLs than practice cases.MethodsResidents anonymously self-reported CL levels after each case using the Paas scale, a single-item, 9-point scale from "very, very low CL" to "very, very high CL." To examine case-based differences in CL, data were rescaled by individual residents. "High CL" was defined as a score of 9/9.ResultsAmong 18 residents participating, CLs ranged from 4 to 9, with median of 7 and interquartile range of 7-8. While many cases showed bell curve-like distributions of CLs, one case-a bleeding tracheostomy-showed a rightward skew reflecting higher levels of CL. No significant difference was found in CL between practice and exam cases. There were 20 reports (16.5%) of "high" CL with variation across residents (0/7 [0%] to 5/6 [83.3%] cases) and across cases (1/18 [5.6%) to 8/18 [44.4%]).ConclusionsThe CL that EM residents experienced did show considerable interpersonal and intercase variation, but there was no significant difference between practice and exam cases. These results highlight several questions about how to optimally design future training, including how best to balance low and high CL training cases and which cases may require further training.
| S-EPMC9125507 | biostudies-literature
Project description:Autism spectrum disorder (ASD) research portrays a mixed picture of attentional abilities with demonstrations of enhancements (e.g., superior visual search) and deficits (e.g., higher distractibility). Here we test a potential resolution derived from the Load Theory of Attention (e.g., Lavie, 2005). In Load Theory, distractor processing depends on the perceptual load of the task and as such can only be eliminated under high load that engages full capacity. We hypothesize that ASD involves enhanced perceptual capacity, leading to the superior performance and increased distractor processing previously reported. Using a signal-detection paradigm, we test this directly and demonstrate that, under higher levels of load, perceptual sensitivity was reduced in typical adults but not in adults with ASD. These findings confirm our hypothesis and offer a promising solution to the previous discrepancies by suggesting that increased distractor processing in ASD results not from a filtering deficit but from enhanced perceptual capacity.
| S-EPMC3357114 | biostudies-other
Project description:Self-touch plays a central role in the construction and plasticity of the bodily self. But which mechanisms support this role? Previous accounts emphasize the convergence of proprioceptive and tactile signals from the touching and the touched body parts. Here, we hypothesise that proprioceptive information is not necessary for self-touch modulation of body-ownership. Because eye movements do not rely on proprioceptive signals as limb movements do, we developed a novel oculomotor self-touch paradigm where voluntary eye movements generated corresponding tactile sensations. We then compared the effectiveness of eye versus hand self-touch movements in generating an illusion of owning a rubber hand. Voluntary oculomotor self-touch was as effective as hand-driven self-touch, suggesting that proprioception does not contribute to body ownership during self-touch. Self-touch may contribute to a unified sense of bodily self by binding voluntary actions toward our own body with their tactile consequences.
| S-EPMC9988563 | biostudies-literature
Project description:Perceiving the spatial location and physical dimensions of touched objects is crucial for goal-directed actions. To achieve this, our brain transforms skin-based coordinates into a reference frame by integrating visual and posture information. In the current study, we examine the role of posture in mapping tactile sensations to a visual image. We developed a new visual-to-touch sensory substitution device that transforms images into a sequence of vibrations on the arm. 52 blindfolded participants performed spatial recognition tasks in three different arm postures and had to switch postures between trial blocks. As participants were not told which side of the device is down and which is up, they could choose how to map its vertical axis in their responses. Contrary to previous findings, we show that new proprioceptive inputs can be overridden in mapping tactile sensations. We discuss the results within the context of the spatial task and the various sensory contributions to the process.
| S-EPMC8137949 | biostudies-literature