Fronto-thalamo-striatal gray and white matter volumes and anisotropy of their connections in bipolar spectrum illnesses.
BACKGROUND
Neurons in the basal ganglia are connected to areas of prefrontal cerebral cortex involved in higher cognitive functions, and these connections occur primarily via the thalamus. In patients with bipolar disorder, regardless of age, neuroimaging studies have consistently reported an increased number of white matter hyperintensities, indicating possible alterations in striatum-thalamus and thalamus-prefrontal cortex connections.


METHODS
In the current study, we acquired high-resolution magnetic resonance imaging (MRI) and diffusion tensor (DT) scans of 40 patients with bipolar spectrum (BPS) illnesses (bipolar type I = 17, bipolar type II = 7, cyclothymia = 16) and 36 sex- and age-matched control subjects. Two researchers, without knowledge of diagnosis, outlined the caudate, putamen, and thalamus on contiguous axial MRI slices. We measured the volumes of the basal ganglia, thalamus, and gray/white matter of the frontal cortex.


RESULTS
Bipolar spectrum patients as a single group did not differ from control subjects in thalamus and the basal ganglia volumes, but the cyclothymia patients had reductions in the volumes of putamen and the thalamus compared with control subjects. The BPS patients had significantly reduced volume of the white and the gray matter of the frontal cortex. Furthermore, compared with control subjects, BPS patients as a group showed alterations in anisotropy of the internal capsule adjacent to the striatum and thalamus and the frontal white matter.


CONCLUSIONS
Our findings indicate that BPS patients may have distinct anatomical alterations in brain structures involved in the regulation of mood and cognition, as well as alterations in these structures' connection to related brain areas.
Haznedar
M Mehmet
MM
Department of Psychiatry, Mount Sinai School of Medicine, New York, New York 10029-6574, USA. haznedar@mssm.edu
Roversi
Francesca
F
Pallanti
Stefano
S
Baldini-Rossi
Nicolo
N
Schnur
David B
DB
Licalzi
Elizabeth M
EM
Tang
Cheuk
C
Hof
Patrick R
PR
Hollander
Eric
E
Buchsbaum
Monte S
MS
D000328:Adult; D000368:Aged; D016880:Anisotropy; D001714:Bipolar Disorder / Q000145:classification / Q000473:pathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D017072:Neostriatum / Q000473:pathology*; D009434:Neural Pathways / Q000473:pathology*; D017397:Prefrontal Cortex / Q000473:pathology*; D013788:Thalamus / Q000473:pathology*