Awareness of intending to act following parietal cortex resection

Neuroimaging and neuropsychological studies have provided evidence suggesting that the inferior parietal lobule (IPL) plays a crucial role in the awareness of motor intentions. For instance, patients with IPL lesions caused by stroke selectively differ in the temporal judgements of their intentions to move compared with healthy controls [Sirigu, A., Daprati, E., Ciancia, S., Giraux, P., Nighoghossian, N., Posada, A., et al. (2004). Altered awareness of voluntary action after damage to the parietal cortex. Nature Neuroscience, 7(1), 80-84]: they experience the will to move only at the moment they start moving, and not before, as it should normally be the case. In the study presented here, we failed to replicate the main behavioral findings of the study quoted above in three patients with surgical resection of the right IPL following slow-growing lesions. Their performances contrasted with that of stroke patients. The timing of their intentions to act but also the delay between their judgements of intention and movement onsets were in the normal range of values for matched controls, when tested with the temporal judgement task developed by Benjamin Libet. There are in the literature some reported cases of functional neuroplasticity following surgical resection of large amount of cerebral tissue. This mainly concerns the brain regions underpinning language and primary sensorimotor functions. Because of the small number of patients our data must be regarded cautiously. They provide preliminary behavioral support to extend to conscious awareness of willing the functional neuroplasticity potentialities of the brain, in human adults. A new perspective towards a hodological view for higher-order cognitive processes seems open.