The neural basis of semantic memory: evidence from semantic dementia.
Semantic dementia (SD) is a syndrome of progressive impairment in semantic memory. Fifty-eight brain regions were measured in seven post mortem SD cases, ten normal controls and two disease controls (diagnosis frontotemporal dementia and motor neuron disease, FTD-MND). Manual segmentation of the whole brain has not previously been undertaken in a series of SD cases, either post mortem or during life. Widespread volume loss relative to controls was found in SD, with anterior temporal lobe regions bearing the brunt (>60% atrophy of temporopolar and perirhinal cortices bilaterally). Comparison of regional volumes in SD and FTD-MND found greater atrophy in SD only in temporopolar and perirhinal volumes. The sole region showing atrophy relative to controls in FTD-MND but not SD was motor cortex. Posterior temporal and frontal regions were not consistently affected and no significant asymmetry of atrophy was found. In summary, whole-brain regional evaluation in SD, in comparison with normal controls and FTD-MND, found anterior temporal atrophy encompassing the perirhinal cortex with relative sparing of adjacent posterior temporal regions.
Davies
R Rhys
RR
Department of Clinical Neurosciences, University of Cambridge, Addenbrooke's Hospital Hills Road, Cambridge CB2 2QQ, UK. rrd22@cam.ac.uk
Halliday
Glenda M
GM
Xuereb
John H
JH
Kril
Jillian J
JJ
Hodges
John R
JR
D000368:Aged; D001921:Brain / Q000473:pathology*; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000473:pathology*; D006801:Humans; D008297:Male; D008568:Memory; D008569:Memory Disorders / Q000473:pathology; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000473:pathology; D009929:Organ Size; D011569:Psychiatric Status Rating Scales; D012660:Semantics; D013997:Time Factors