Space and time in words: exploring neural overlap and specificity.

BACKGROUND: A common magnitude system-consistently involving the right intraparietal sulcus (IPS)-has been proposed to support the representation of space, time and numerosity. While shared mechanisms are acknowledged, domain-specific contributions have also been suggested. Among these, the role of the right precuneus remains debated, with inconclusive evidence regarding its involvement in spatial and temporal processing. Translating this question into the language domain and within a grounded cognition framework, we investigated the causal contribution of the IPS and precuneus to the processing of spatial and temporal concepts (e.g., circuit, eternity) using a state-dependent Transcranial Magnetic Stimulation (TMS) priming paradigm. Twenty healthy participants received stimulation over the IPS and precuneus, and a sham stimulation over the control site (vertex).

RESULTS: Results showed that stimulation of the IPS abolished the priming effect observed under the sham control condition for both spatial and temporal concepts, whereas stimulation of the precuneus selectively disrupted priming for temporal concepts only.

CONCLUSIONS: These findings support the role of the right IPS as a key area for magnitude processing in language, while also highlighting a more specific contribution of the precuneus-particularly its ventral portion-to temporal concepts.