A MEG study of the neural substrates of semantic processing in semantic variant primary progressive aphasia

ABSTRACT

Despite a well-documented pattern of semantic impairment, the patterns of brain activation during semantic processing in semantic variant primary progressive aphasia (svPPA) still remain poorly understood. In the current study, one svPPA patient (EC) and six elderly controls carried out a general-level semantic categorization task while their brain activity was recorded using magnetoencephalography (MEG). Despite similar behavioral performance, EC showed hyperactivation of the left inferior temporal gyrus (ITG) and right anterior temporal lobe (ATL) relative to controls. This suggests that periatrophic regions within the ATL region may support preserved semantic abilities in svPPA.

KEYWORDS:

• Semantic memory
• single-case study
• semantic variant primary progressive aphasia
• functional neuroimaging

Disclosure statement

The authors declare they have no actual or potential conflicts of interest that could prejudice or bias the results and outcomes reported in this manuscript.

Notes

1. A significance statistical threshold of p > .001 uncorrected was used for the VBM analyses.

2. Peaks of hyperactivation in EC relative to the control group. A significance statistical threshold at q ≤ .05 FDR has been used. Talairach (MNI) coordinates are provided.

3. Peaks of hyperactivation for the crossover interaction. A significance statistical threshold at q ≤ .05 FDR has been used.

Additional information

Funding

We thank all participants for taking part in this study, Ping Hei Lam, computer engineer, for his helpful assistance, as well as Nathalie Bouloute and Manon Robert for their technical work during MEG recordings. This work was supported by a research grant from the Alzheimer Society of Canada awarded to Sven Joubert and Pierre Jolicoeur, Sven Joubert held a Chercheur boursier senior award from the Fonds de Recherche du Québec en Santé (FRQS), and Jessica Pineault held a Canadian Institutes of Health Research (CIHR) doctoral award.