Spatio-Temporal Updating in the Left Posterior Parietal Cortex

Abstract

Adopting an unusual posture can sometimes give rise to paradoxical experiences. For example, the subjective ordering of successive unseen tactile stimuli delivered to the two arms can be affected when people cross them. A growing body of evidence now highlights the role played by the parietal cortex in spatio-temporal information processing when sensory stimuli are delivered to the body or when actions are executed; however, little is known about the neural basis of such paradoxical feelings resulting from such unusual limb positions. Here, we demonstrate increased fMRI activation in the left posterior parietal cortex when human participants adopted a crossed hands posture with their eyes closed. Furthermore, by assessing tactile temporal order judgments (TOJs) in the same individuals, we observed a positive association between activity in this area and the degree of reversal in TOJs resulting from crossing arms. The strongest positive association was observed in the left intraparietal sulcus. This result implies that the left posterior parietal cortex may be critically involved in monitoring limb position and in spatio-temporal binding when serial events are delivered to the limbs.

Arm crossing updates brain functional connectivity of the left posterior parietal cortex

“…In fact, as described above, our research group reported that the crossing of one’s arms causes increased BOLD activation in the left PPC9. Taken together, these results suggest that, when activated by arm crossing, the left PPC is responsible for the neural representation of the configuration of body parts.…”

“…The left IPS may also play an important role in the confusion/reversal that is associated with arm crossing during a TOJ task913 and may be responsible for neural representations that overlap with the representation of peripersonal space42. Furthermore, as suggested above, the left IPS may be associated with the self due to its inclusion in the DMN.…”

Visual experience shapes the neural networks remapping touch into external space

“…Because the task requirements have nothing 39 spatial (in theory, the task could be solved by using somatotopic coordinates only), this crossing-40 hand effect compellingly illustrates how the external remapping of touch is automatic in sighted 41 people (Heed and Azañón, 2014). Specific brain networks including parietal and premotor areas 42 have been demonstrated to support this automatic remapping of touch into an external spatial 43 coordinate system (Lloyd et al, 2003;Matsumoto et al, 2004;Azañón et al, 2010a;Takahashi et al, 44 2013; Wada et al, 2012). 45…”

Testing the exteroceptive function of nociception: the role of visual experience in shaping the spatial representations of nociceptive inputs

“…Based on the present data, we can hypothesize an involvement of premotor and posterior parietal areas in nociception and pain. These cortical regions have been indeed demonstrated to play a role in coding tactile inputs according to spatiotopic reference frames (Azanon, Longo, Soto-Faraco, & Haggard, 2010;Bolognini & Maravita, 2007;Crollen, Lazzouni, et al, 2017;Lloyd, Shore, Spence, & Calvert, 2003;Takahashi, Kansaku, Wada, Shibuya, & Kitazawa, 2013;Wada et al, 2012) and in participating in crossmodal interactions within peripersonal frames of reference (Avillac, Deneve, Olivier, Pouget, & Duhamel, 2005;Brozzoli, Gentile, Petkova, & Ehrsson, 2011;Graziano et al, 1997;Makin, Holmes, & Zohary, 2007). Premotor and posterior parietal areas have also been shown to be activated by nociceptive and painful stimuli (see review in Apkarian, Bushnell, Treede, & Zubieta, 2005).…”