Abstract
Aphasias are caused by disruption in structural integrity and interconnectivity within a large-scale distributed language network. We investigated the distribution and behavioral consequences of altered functional connectivity in three variants of primary progressive aphasia (PPA). The goal was to clarify relationships among atrophy, resting connectivity, and the resulting behavioral changes in 73 PPA and 33 control participants. Three core regions of the left perisylvian language network: the inferior frontal gyrus (IFG), middle temporal gyrus (MTG), and anterior temporal lobe (ATL) were evaluated in agrammatic (PPA-G), logopenic (PPA-L), and semantic (PPA-S) PPA variants. All PPA groups showed decreased connectivity between IFG and MTG. The PPA-S group also showed additional loss of connectivity strength between ATL and the other language regions. Decreased connectivity between the IFG and MTG nodes in PPA-G remained significant even when controlled for the effect of atrophy. In the PPA group as a whole, IFG-MTG connectivity strength correlated with repetition and grammar scores, whereas MTG-ATL connectivity correlated with picture naming and single-word comprehension. There was no significant change in the connectivity of homologous regions in the right hemisphere. These results show that language impairments in PPA are associated with perturbations of functional connectivity within behaviorally concordant components of the language network. Altered connectivity in PPA may reflect not only the irreversible loss of cortical components indexed by atrophy, but also the dysfunction of remaining neurons.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 468-480 |
| Number of pages | 13 |
| Journal | Cortex |
| Volume | 121 |
| DOIs | |
| State | Published - Dec 2019 |
Funding
Dr. Mesulam is on the medical advisory council for the Association for Frontotemporal Degeneration , the Scientific Advisory Board of the Organization for Human Brain Mapping , is funded by NIH grants P30 AG13854 and R01 DC008552 and R01 AG045571 , U01 AG016976 . Supported by the Northwestern University Alzheimer Disease Center Rosenstone fellowship fund, pilot grant NIA P30 AG13854 , NIDCD K23 DC014303-01A1 (Bonakdarpour), NIDCD R01 DC008552 (Mesulam), NIDCD DC013386 grants (Hurley), and NINDS NS075075 AG056258 (Rogalski). Dr. Hurley is funded by NIH grants NIDCD DC013386 and NIDCD DC008552 . Supported by the Northwestern University Alzheimer Disease Center Rosenstone fellowship fund, pilot grant NIA P30 AG13854, NIDCD K23 DC014303-01A1 (Bonakdarpour), NIDCD R01 DC008552 (Mesulam), NIDCD DC013386 grants (Hurley), and NINDS NS075075 AG056258 (Rogalski).Dr. Bonakdarpour is funded by NIH K23 DC014303-01A1, and Northwestern Cognitive Neurology and Alzheimer Disease Center pilot grant (P30 AG13854).Dr. Rogalski is funded by NIH grants R01AG045571, R01 DC008552, R03 DC013386, R01NS075075, and receives research support from the Alzheimer's Association.Dr. Mesulam is on the medical advisory council for the Association for Frontotemporal Degeneration, the Scientific Advisory Board of the Organization for Human Brain Mapping, is funded by NIH grants P30 AG13854 and R01 DC008552 and R01 AG045571, U01 AG016976.Dr. Hurley is funded by NIH grants NIDCD DC013386 and NIDCD DC008552. Dr. Rogalski is funded by NIH grants R01AG045571 , R01 DC008552 , R03 DC013386 , R01NS075075 , and receives research support from the Alzheimer's Association .
Keywords
- Aphasia
- Language impairment
- Neuroimaging
- Primary progressive aphasia
- Resting state fMRI
ASJC Scopus subject areas
- Neuropsychology and Physiological Psychology
- Experimental and Cognitive Psychology
- Cognitive Neuroscience