title: Exploring the role of the posterior middle temporal gyrus in semantic cognition: Integration of anterior temporal lobe with executive processes.
abstract: Making sense of the world around us depends upon selectively retrieving information relevant to our current goal or context. However, it is unclear whether selective semantic retrieval relies exclusively on general control mechanisms recruited in demanding non-semantic tasks, or instead on systems specialised for the control of meaning. One hypothesis is that the left posterior middle temporal gyrus (pMTG) is important in the controlled retrieval of semantic (not non-semantic) information; however this view remains controversial since a parallel literature links this site to event and relational semantics. In a functional neuroimaging study, we demonstrated that an area of pMTG implicated in semantic control by a recent meta-analysis was activated in a conjunction of (i) semantic association over size judgements and (ii) action over colour feature matching. Under these circumstances the same region showed functional coupling with the inferior frontal gyrus - another crucial site for semantic control. Structural and functional connectivity analyses demonstrated that this site is at the nexus of networks recruited in automatic semantic processing (the default mode network) and executively demanding tasks (the multiple-demand network). Moreover, in both task and task-free contexts, pMTG exhibited functional properties that were more similar to ventral parts of inferior frontal cortex, implicated in controlled semantic retrieval, than more dorsal inferior frontal sulcus, implicated in domain-general control. Finally, the pMTG region was functionally correlated at rest with other regions implicated in control-demanding semantic tasks, including inferior frontal gyrus and intraparietal sulcus. We suggest that pMTG may play a crucial role within a large-scale network that allows the integration of automatic retrieval in the default mode network with executively-demanding goal-oriented cognition, and that this could support our ability to understand actions and non-dominant semantic associations, allowing semantic retrieval to be 'shaped' to suit a task or context.
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: James
authors.initials: J
authors.lastname: Davey
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: Hannah E
authors.initials: HE
authors.lastname: Thompson
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: Glyn
authors.initials: G
authors.lastname: Hallam
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Karapanagiotidis
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Murphy
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: Irene
authors.initials: I
authors.lastname: De Caso
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: Katya
authors.initials: K
authors.lastname: Krieger-Redwood
authors.affiliation: McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, QC H3A 2B4, Canada.
authors.forename: Boris C
authors.initials: BC
authors.lastname: Bernhardt
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Smallwood
authors.affiliation: Department of Psychology and York Neuroimaging Centre, University of York, UK. Electronic address: beth.jefferies@york.ac.uk.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Jefferies
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods; D003071:Cognition / Q000502:physiology*; D003210:Concept Formation / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D012660:Semantics; D013647:Task Performance and Analysis; D013702:Temporal Lobe / Q000502:physiology*; D014706:Verbal Learning / Q000502:physiology*; D055815:Young Adult
keywords: Default mode network; Memory retrieval; Multidemand network; Posterior middle temporal gyrus; Semantic control