Figure 1.

The unusual complexity of clinicopathological correlations in PPA. a | Drawing of an axial section of a structural MRI scan from a 57-year-old familial left-handed man with right-hemisphere language dominance and logopenic PPA;¹⁶³ the right cerebral hemisphere is on the left-hand side. Areas of substantial atrophy can be observed in the right perisylvian cortex, including the posterior STG (arrow). b | Illustration of findings based on fMRI evaluation of the same patient performed soon after the structural scan, revealing that the atrophic area of the right hemisphere was activated (arrow) during a task in which the patient was asked to determine whether two words had the same meaning. c | The patient died 8 years later; pathology of autopsy tissue demonstrated features consistent with frontotemporal lobar degeneration with TAR DNA-binding protein 43 pathology. In particular, despite the severe atrophy at the time of the structural MRI scan and progressive neuronal loss over the subsequent 8 years before death, the photomicrograph of a cresyl violet-stained region of the right STG demonstrates identifiable neurons (arrows), some of which might have contributed to the activation of this region during the fMRI assessment. Abbreviations: fMRI, functional MRI; PPA, primary progressive aphasia; STG, superior temporal gyrus.