The Semantic Network at Work and Rest: Differential Connectivity of Anterior Temporal Lobe Subregions

Abstract

The anterior temporal lobe (ATL) makes a critical contribution to semantic cognition. However, the functional connectivity of the ATL and the functional network underlying semantic cognition has not been elucidated. In addition, subregions of the ATL have distinct functional properties and thus the potential differential connectivity between these subregions requires investigation. We explored these aims using both resting-state and active semantic task data in humans in combination with a dual-echo gradient echo planar imaging (EPI) paradigm designed to ensure signal throughout the ATL. In the resting-state analysis, the ventral ATL (vATL) and anterior middle temporal gyrus (MTG) were shown to connect to areas responsible for multimodal semantic cognition, including bilateral ATL, inferior frontal gyrus, medial prefrontal cortex, angular gyrus, posterior MTG, and medial temporal lobes. In contrast, the anterior superior temporal gyrus (STG)/superior temporal sulcus was connected to a distinct set of auditory and language-related areas, including bilateral STG, precentral and postcentral gyri, supplementary motor area, supramarginal gyrus, posterior temporal cortex, and inferior and middle frontal gyri. Complementary analyses of functional connectivity during an active semantic task were performed using a psychophysiological interaction (PPI) analysis. The PPI analysis highlighted the same semantic regions suggesting a core semantic network active during rest and task states. This supports the necessity for semantic cognition in internal processes occurring during rest. The PPI analysis showed additional connectivity of the vATL to regions of occipital and frontal cortex. These areas strongly overlap with regions found to be sensitive to executively demanding, controlled semantic processing.

Shared Reading Quality and Brain Activation during Story Listening in Preschool-Age Children

“…52 Smaller areas of activation included anterior middle temporal gyrus, supporting multi-modal (especially audio-visual) semantic processing 53 ; inferior temporal gyrus pars opercularis (Broca’s Area), supporting phonological and syntactic processing 54 ; parahippocampus, a hub for episodic memory encoding and retrieval 52, 55 ; and putamen, supporting instrumental learning 56 and language initiation. 50, 57 Areas of activation are shown in Figure 3 and Figure 4, a 3-dimensional rendering identifying neurological Brodmann Areas (BA) provided in Figure 5.…”

Dysfunction of the Default Mode Network in Drug-Naïve Parkinson’s Disease with Mild Cognitive Impairments: A Resting-State fMRI Study

“…Interestingly, we also found decreased FC between ATL and IFG. The ATL, with a high degree of anatomical heterogeneity, makes a critical contribution to semantic cognition (Hurley et al, 2015; Jackson et al, 2016). In addition, semantic cognition depends on a distributed network including the IFG, mPFC, posterior middle temporal gyrus and lateral parietal regions besides ATL (Jefferies, 2013) and is also considered a major component during the resting state (Binder et al, 2009).…”

An individual differences analysis of the neurocognitive architecture of the semantic system at rest

“…Ventral ATL might provide a multimodal semantic hub anticipated by Patterson et al (2007), since it responds across tasks and modalities (e.g., to pictures, environmental sounds, spoken and written words; Binney et al, 2010, Visser and Lambon Ralph, 2011; Visser, Embleton, Jefferies, Parker, & Lambon Ralph, 2010; Rice, Lambon Ralph, & Hoffman, 2015; Humphreys, Hoffman, Visser, Binney, & Lambon Ralph, 2015). Ventral ATL is functionally connected with semantic and default mode regions (Binney et al, 2010, Hoffman et al, 2015, Jackson et al, 2016, Pascual et al, 2015, Spitsyna et al, 2006). However, magnetic susceptibility artefacts produce signal loss and distortion in this region in standard EPI sequences, which mean it is consequently under-represented in the fMRI literature (compared with studies employing PET; Visser, Jefferies, & Lambon Ralph, 2010).…”