Visual area V5/hMT+ contributes to perception of tactile motion direction: a TMS study

Abstract

Human imaging studies have reported activations associated with tactile motion perception in visual motion area V5/hMT+, primary somatosensory cortex (SI) and posterior parietal cortex (PPC; Brodmann areas 7/40). However, such studies cannot establish whether these areas are causally involved in tactile motion perception. We delivered double-pulse transcranial magnetic stimulation (TMS) while moving a single tactile point across the fingertip, and used signal detection theory to quantify perceptual sensitivity to motion direction. TMS over both SI and V5/hMT+, but not the PPC site, significantly reduced tactile direction discrimination. Our results show that V5/hMT+ plays a causal role in tactile direction processing, and strengthen the case for V5/hMT+ serving multimodal motion perception. Further, our findings are consistent with a serial model of cortical tactile processing, in which higher-order perceptual processing depends upon information received from SI. By contrast, our results do not provide clear evidence that the PPC site we targeted (Brodmann areas 7/40) contributes to tactile direction perception.

The Role of Demographic and Symbolic Features in Clinical Arabic Graphesthesia Testing

“…Successful identification of a moving tactile stimulus of a symbolic nature relies on pre-existing cortical representations of these symbols and on working memory [3]. More recent studies have even demonstrated that kinetic tactile stimuli undergo processing in extrastriate dorsal visual regions [4]. Lesions anywhere along the afferent sensory pathways or those that affect the parietal lobe can lead to impairments in this recognition process [1,2,5], this condition is referred to as agraphesthesia.…”

The Left Posterior Parietal Cortex Contributes to the Selection Process for the Initial Swing Leg in Gait Initiation

“…The most likely explanation for the change in the probability of leg selection induced by TMS over P3 is that the change in the cortical activity under P3 biased the selection process of the initial swing leg of gait initiation. P3 is considered to be the site over the left PPC [10][11][12]. Thus, our hypothesis, that the left PPC contributes to the selection process of the initial swing leg of gait initiation, is the most likely explanation for the effect.…”

“…A coil was placed over F3, P3, F4 or P4. P3 is considered to be the site over the left PPC, and P4 is considered to be the site over the right PPC [10][11][12]. The participants wore a swim cap.…”

“…In the present study, an investigation was undertaken to determine whether the left PPC contributes to the selection process of the initial swing leg of gait initiation. This investigation involved giving TMS over P3, which is considered to be the site corresponding to the left PPC [10][11][12]. The control TMS sites were P4, F3, and F4.…”

Directional biases in whole hand motion perception revealed by mid-air tactile stimulation

“…In this sense, BA1 seems to subserve a similar function to 459 the middle temporal (MT)/V5 complex in visual motion processing [Pack 460 and Bensmaia, 2015]. Evidence from human studies suggests that tactile 461 motion also elicits more widespread activity in anterior intraparietal and 462 inferior parietal areas [Kitada et al, 2003], as well as activation of an area 463 of MT distinct from that implicated in visual motion [Summers et al, 2009, 464 Wacker et al, 2011, Amemiya et al, 2017]; however the latter may be an 465 epiphenomenon of visual imagery [Lacey and Sathian, 2011]. Directional 466 19/30 biases in tactile motion perception appear to be independent of visual 467 input, as tactile perceptual anisotropy has been observed previously in 468 blind individuals [Lechelt, 1988].…”