Development of a simple MR-compatible vibrotactile stimulator using a planar-coil-type actuator

Müller

et al. 2015

Front. Hum. Neurosci.

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According to the hierarchical view of human somatosensory network, somatic sensory information is relayed from the thalamus to primary somatosensory cortex (S1), and then distributed to adjacent cortical regions to perform further perceptual and cognitive functions. Although a number of neuroimaging studies have examined neuronal activity correlated with tactile stimuli, comparatively less attention has been devoted toward understanding how vibrotactile stimulus information is processed in the hierarchical somatosensory cortical network. To explore the hierarchical perspective of tactile information processing, we studied two cases: (a) discrimination between the locations of finger stimulation; and (b) detection of stimulation against no stimulation on individual fingers, using both standard general linear model (GLM) and searchlight multi-voxel pattern analysis (MVPA) techniques. These two cases were studied on the same data set resulting from a passive vibrotactile stimulation experiment. Our results showed that vibrotactile stimulus locations on fingers could be discriminated from measurements of human functional magnetic resonance imaging (fMRI). In particular, it was in case (a) we observed activity in contralateral posterior parietal cortex (PPC) and supramarginal gyrus (SMG) but not in S1, while in case; (b) we found significant cortical activations in S1 but not in PPC and SMG. These discrepant observations suggest the functional specialization with regard to vibrotactile stimulus locations, especially, the hierarchical information processing in the human somatosensory cortical areas. Our findings moreover support the general understanding that S1 is the main sensory receptive area for the sense of touch, and adjacent cortical regions (i.e., PPC and SMG) are in charge of a higher level of processing and may thus contribute most for the successful classification between stimulated finger locations.

Section: Methodsmentioning

confidence: 99%

Distributed functions of detection and discrimination of vibrotactile stimuli in the hierarchical human somatosensory system

Müller

et al. 2015

Front. Hum. Neurosci.

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“…I). Stimuli were generated by the torque exerted on the current-carrying coils in the presence of an external magnetic field [5].…”

Section: Design and Proceduresmentioning

confidence: 99%

A multi-voxel pattern analysis of neural representation of vibrotactile location

2013 13th International Conference on Control, Automation and Systems (ICCAS 2013)

et al. 2013

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Previous neural decoding studies have mainly focused on discrimination of activation patterns evoked by active movements. Nonetheless, comparatively, little attention has been devoted toward understanding how brain signals are observed with passive stimulus. In this study, we examined whether the stimulus locations on between fingers, one of the most fundamental features of passive vibrotactile stimulation, can be distinguished from human functional magnetic resonance imaging (fMRI) data. Whole brain searchlight multi-voxel pattern analysis (MVPA) has found two brain regions, which make a contribution to decode stimulus sites, in contralateral posterior parietal cortex (PPC) and contralateral secondary somatosensory cortex (S2). No significant area for the decoding of activity to stimulus site in primary somatosensory cortex (S1), which is well-developed brain region for finger somatotopy. On the other hand, a whole brain univariate group analysis has discovered activity in S1, not in PPC and S2 areas. These results suggest that PPC and S2 regions play a key role in the differentiation of passive vibrotactile stimulus locations, and thus decode tactile events from finger somatotopic

“…Vibrotactile stimuli from 20 to 200 Hz with an increment of 20 Hz were applied to the tip of the right index finger using an MR compatible stimulation device developed in our group [9]. The vibration stimulation was delivered through a 10×10 mm 2 pad attached on the fingertip.…”

Section: A Experimental Proceduresmentioning

confidence: 99%

Evaluation of somatosensory cortical differences between flutter and vibration tactile stimuli

Han

2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

et al. 2013

In parallel with advances in haptic-based mobile computing systems, understanding of the neural processing of vibrotactile information becomes of great importance. In the human nervous system, two types of vibrotactile information, flutter and vibration, are delivered from mechanoreceptors to the somatosensory cortex through segregated neural afferents. To investigate how the somatosensory cortex differentiates flutter and vibration, we analyzed the cortical responses to vibrotactile stimuli with a wide range of frequencies. Specifically, we examined whether cortical activity changed most around 50 Hz, which is known as a boundary between flutter and vibration. We explored various measures to evaluate separability of cortical activity across frequency and found that the hypothesis margin method resulted in the greatest separability between flutter and vibration. This result suggests that flutter and vibration information may be processed by different neural processes in the somatosensory cortex.