TY - JOUR
T1 - Regional structural hypo- and hyperconnectivity of frontal–striatal and frontal–thalamic pathways in behavioral variant frontotemporal dementia
AU - Jakabek, David
AU - Power, Brian D.
AU - Macfarlane, Matthew D.
AU - Walterfang, Mark
AU - Velakoulis, Dennis
AU - van Westen, Danielle
AU - Lätt, Jimmy
AU - Nilsson, Markus
AU - Looi, Jeffrey C.L.
AU - Santillo, Alexander F.
PY - 2018
Y1 - 2018
N2 - Behavioral variant frontotemporal dementia (bvFTD) has been predominantly considered as a frontotemporal cortical disease, with limited direct investigation of frontal–subcortical connections. We aim to characterize the grey and white matter components of frontal–thalamic and frontal–striatal circuits in bvFTD. Twenty-four patients with bvFTD and 24 healthy controls underwent morphological and diffusion imaging. Subcortical structures were manually segmented according to published protocols. Probabilistic pathways were reconstructed separately from the dorsolateral, orbitofrontal and medial prefrontal cortex to the striatum and thalamus. Patients with bvFTD had smaller cortical and subcortical volumes, lower fractional anisotropy, and higher mean diffusivity metrics, which is consistent with disruptions in frontal–striatal–thalamic pathways. Unexpectedly, regional volumes of the striatum and thalamus connected to the medial prefrontal cortex were significantly larger in bvFTD (by 135% in the striatum, p =.032, and 217% in the thalamus, p =.004), despite smaller dorsolateral prefrontal cortex connected regional volumes (by 67% in the striatum, p =.002, and 65% in the thalamus, p =.020), and inconsistent changes in orbitofrontal cortex connected regions. These unanticipated findings may represent compensatory or maladaptive remodeling in bvFTD networks. Comparisons are made to other neuropsychiatric disorders suggesting a common mechanism of changes in frontal–subcortical networks; however, longitudinal studies are necessary to test this hypothesis.
AB - Behavioral variant frontotemporal dementia (bvFTD) has been predominantly considered as a frontotemporal cortical disease, with limited direct investigation of frontal–subcortical connections. We aim to characterize the grey and white matter components of frontal–thalamic and frontal–striatal circuits in bvFTD. Twenty-four patients with bvFTD and 24 healthy controls underwent morphological and diffusion imaging. Subcortical structures were manually segmented according to published protocols. Probabilistic pathways were reconstructed separately from the dorsolateral, orbitofrontal and medial prefrontal cortex to the striatum and thalamus. Patients with bvFTD had smaller cortical and subcortical volumes, lower fractional anisotropy, and higher mean diffusivity metrics, which is consistent with disruptions in frontal–striatal–thalamic pathways. Unexpectedly, regional volumes of the striatum and thalamus connected to the medial prefrontal cortex were significantly larger in bvFTD (by 135% in the striatum, p =.032, and 217% in the thalamus, p =.004), despite smaller dorsolateral prefrontal cortex connected regional volumes (by 67% in the striatum, p =.002, and 65% in the thalamus, p =.020), and inconsistent changes in orbitofrontal cortex connected regions. These unanticipated findings may represent compensatory or maladaptive remodeling in bvFTD networks. Comparisons are made to other neuropsychiatric disorders suggesting a common mechanism of changes in frontal–subcortical networks; however, longitudinal studies are necessary to test this hypothesis.
KW - behavioral variant frontotemporal dementia
KW - connectivity
KW - DTI
KW - MRI
KW - probabilistic tractography
U2 - 10.1002/hbm.24233
DO - 10.1002/hbm.24233
M3 - Article
C2 - 29923666
AN - SCOPUS:85052942647
SN - 1065-9471
VL - 39
SP - 4083
EP - 4093
JO - Human Brain Mapping
JF - Human Brain Mapping
IS - 10
ER -