PT  - JOURNAL ARTICLE
AU  - Catarina Teige
AU  - Giovanna Mollo
AU  - Rebecca Millman
AU  - Nicola Savill
AU  - Jonathan Smallwood
AU  - Piers L. Cornelissen
AU  - Elizabeth Jefferies
TI  - Dynamic semantic cognition: Characterising coherent and controlled conceptual retrieval through time using magnetoencephalography and chronometric transcranial magnetic stimulation
AID  - 10.1101/168203
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 168203
4099  - http://biorxiv.org/content/early/2017/07/25/168203.short
4100  - http://biorxiv.org/content/early/2017/07/25/168203.full
AB  - Distinct neural processes are thought to support the retrieval of semantic information that is (i) coherent with strongly-encoded aspects of knowledge, and (ii) non-dominant yet relevant for the current task or context. While the brain regions that support coherent and controlled patterns of semantic retrieval are relatively well-characterised, the temporal dynamics of these processes are not well-understood. This study used magnetoencephalography (MEG) and dual-pulse chronometric transcranial magnetic stimulation (cTMS) in two separate experiments to examine temporal dynamics within the temporal lobe during the retrieval of strong and weak associations. MEG results revealed a dissociation within left temporal cortex: anterior temporal lobe (ATL) showed greater oscillatory response for strong than weak associations, while posterior middle temporal gyrus (pMTG) showed the reverse pattern. In the cTMS experiment, stimulation of ATL at ~150ms disrupted the efficient retrieval of strong associations, indicating a necessary role for ATL in coherent conceptual activations. Stimulation of pMTG at the onset of the second word disrupted the retrieval of weak associations, suggesting this site may maintain information about semantic context from the first word, allowing engagement of semantic control. Together these studies provide converging evidence for a functional dissociation within the temporal lobe, across both tasks and time.