The ‘when’ and ‘where’ of semantic coding in the anterior temporal lobe: Temporal representational similarity analysis of electrocorticogram data

Abstract

Electrocorticograms (ECoG) provide a unique opportunity to monitor neural activity directly at the cortical surface. Ten patients with subdural electrodes covering ventral and lateral anterior temporal regions (ATL) performed a picture naming task. Temporal representational similarity analysis (RSA) was used, for the first time, to compare spatio-temporal neural patterns from the ATL surface with pre-defined theoretical models. The results indicate that the neural activity in the ventral subregion of the ATL codes semantic representations from 250 msec after picture onset. The observed activation similarity was not related to the visual similarity of the pictures or the phonological similarity of their names. In keeping with convergent evidence for the importance of the ATL in semantic processing, these results provide the first direct evidence of semantic coding from the surface of the ventral ATL and its time-course.

Enhancing vs. inhibiting semantic performance with repetitive transcranial magnetic stimulation over the anterior temporal lobe: frequency- and task- specific effects

“…Semantic dementia (SD; the temporal lobe variant of frontotemporal dementia) is a most striking example supporting this hypothesis – SD patients with atrophy centred in the ATL exhibit a selective semantic impairment in both verbal and non-verbal domains (Bozeat S et al 2000; Mummery CJ et al 2000; Hodges JR and K Patterson 2007). This hypothesis was subsequently supported and extended by recent investigations using intracranial recording (Abel TJ et al 2015; Shimotake A et al 2015; Chen Y et al 2016), magnetoencephalography (MEG) (Clarke A et al 2011; Mollo G et al 2017), and functional magnetic resonance imaging (fMRI) (Visser M et al 2010; Peelen MV and A Caramazza 2012; Coutanche MN and SL Thompson-Schill 2015; Murphy C et al 2017).…”

Reverse-Engineering the Cortical Architecture for Controlled Semantic Cognition

“…The reverse-engineered architecture mirrors the known anatomy of the cortical semantic system remarkably well. The ventral ATL forms a multimodal conceptual hub, as demonstrated in SD 10-12 , brain imaging 32,54-56 , neurostimulation 36,37 and intracortical electrode recording 34,57 . The progression from unimodal perceptual representations to multimodal conceptual representations occurs in a graded fashion across many cortical areas 55,58 corresponding well to a deep network.…”

The Role of the Left Anterior Temporal Lobe for Unpredictable and Complex Mappings in Word Reading

“…Specifically, the ventral ATLs, which include portions of the anterior fusiform and inferior temporal gyri, have been linked to processing various types of stimuli such as pictures, environmental sounds, words (Visser and Lambon Ralph, 2011; Visser et al, 2012; Chen et al, 2016) and faces (Collins et al, 2016; De Winter et al, 2016; Harry et al, 2016; Jonas et al, 2016). Therefore, the ventral ATLs appear to be involved in the conceptual processing of stimuli, thus playing a central role in semantic processing (Binney et al, 2010; Collins et al, 2016).…”