Neural correlates of an illusory touch experience investigated with fMRI

Lloyd, Donna M. and McKenzie, Kirsten J. and Brown, Richard J. and Poliakoff, Ellen (2011) Neural correlates of an illusory touch experience investigated with fMRI. Neuropsychologia, 49 (12). pp. 3430-8. ISSN 0028-3932

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Item Type:Article
Item Status:Live Archive

Abstract

When asked to judge the presence or absence of near-threshold tactile stimuli, participants often report touch experiences when no tactile stimulation has been delivered ('false alarms'). The simultaneous presentation of a light flash during the stimulation period can increase the frequency of touch reports, both when touch is and is not present. Using fMRI, we investigated the BOLD response during both light-present and light-absent false alarms, testing predictions concerning two possible neural mechanisms underlying these illusory touch experiences: activation of a tactile representation in primary somatosensory cortex (SI) and/or activation of a tactile representation in late processing areas outside of sensory-specific cortex, such as medial prefrontal cortex (MPC). Our behavioural results showed that participants made false alarms in light-present and light-absent trials, both of which activated regions of the medial parietal and medial prefrontal cortex including precuneus, posterior cingulate and paracingulate cortex, suggesting the same underlying mechanism. However, only a non-significant increase in SI activity was measured in response to false alarm vs. correct rejection trials. We argue that our results provide evidence for the role of top-down regions in somatic misperception, consistent with findings from studies in humans and non-human primates.

Keywords:fMRI;, Medial prefrontal cortex, Posterior cingulate cortex, Signal detection theory, Touch, Vision
Subjects:B Subjects allied to Medicine > B140 Neuroscience
C Biological Sciences > C850 Cognitive Psychology
C Biological Sciences > C830 Experimental Psychology
Divisions:College of Social Science > School of Psychology
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ID Code:17305
Deposited On:26 Apr 2015 20:51

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