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White matter tracts in first-episode psychosis: a DTI tractography study of the uncinate fasciculus.

Price G, Cercignani M, Parker GJ, Altmann DR, Barnes TR, Barker GJ, Joyce EM, Ron MA - Neuroimage (2007)

Bottom Line: Fractional anisotropy (FA) and probability of connection were obtained for every voxel in the tract, and the group means and distributions of these variables were compared.The spread of the FA distribution in the upper tail, as measured by the squared coefficient of variance (SCV), was reduced in the left UF in the patient group, indicating that the number of voxels with high FA values was reduced in the core of the tract and suggesting the presence of changes in fibre alignment and tract coherence in the patient group.The SCV of FA was lower in females across both groups and there was no correlation between the SCV of FA and clinical ratings.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neurology, University College London, Queen Square, London, UK. g.price@ion.ucl.ac.uk

ABSTRACT
A model of disconnectivity involving abnormalities in the cortex and connecting white matter pathways may explain the symptoms and cognitive abnormalities of schizophrenia. Recently, diffusion imaging tractography has made it possible to study white matter pathways in detail, and we present here a study of patients with first-episode psychosis using this technique. We studied the uncinate fasciculus (UF), the largest white matter tract that connects the frontal and temporal lobes, two brain regions significantly implicated in schizophrenia. Nineteen patients with first-episode schizophrenia and 23 controls were studied using a probabilistic tractography algorithm (PICo). Fractional anisotropy (FA) and probability of connection were obtained for every voxel in the tract, and the group means and distributions of these variables were compared. The spread of the FA distribution in the upper tail, as measured by the squared coefficient of variance (SCV), was reduced in the left UF in the patient group, indicating that the number of voxels with high FA values was reduced in the core of the tract and suggesting the presence of changes in fibre alignment and tract coherence in the patient group. The SCV of FA was lower in females across both groups and there was no correlation between the SCV of FA and clinical ratings.

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Group histograms of FA values in the left and right uncinate. Histogram ‘A’ is the left uncinate in the patient group. Histogram ‘B’ is the left uncinate in the control group. Histogram ‘C’ is the right uncinate in the patient group. Histogram ‘D’ is the right uncinate in the control group.
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fig3: Group histograms of FA values in the left and right uncinate. Histogram ‘A’ is the left uncinate in the patient group. Histogram ‘B’ is the left uncinate in the control group. Histogram ‘C’ is the right uncinate in the patient group. Histogram ‘D’ is the right uncinate in the control group.

Mentions: The results of the weighted regression analysis of the SCV of FA, incorporating age and gender, revealed a significant difference between patients and controls for the left, but not the right, uncinate fasciculus (coefficient = − 0.035, t = − 2.78, p = 0.008, 95% CI = − 0.0632 to − 0.009), with lower SCV of FA in the patient group. The SCV probability of connection was not significantly different between the two groups for the left or the right fasciculus. Histograms of FA values for the subject groups for each tract are shown in Fig. 3.


White matter tracts in first-episode psychosis: a DTI tractography study of the uncinate fasciculus.

Price G, Cercignani M, Parker GJ, Altmann DR, Barnes TR, Barker GJ, Joyce EM, Ron MA - Neuroimage (2007)

Group histograms of FA values in the left and right uncinate. Histogram ‘A’ is the left uncinate in the patient group. Histogram ‘B’ is the left uncinate in the control group. Histogram ‘C’ is the right uncinate in the patient group. Histogram ‘D’ is the right uncinate in the control group.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2387199&req=5

fig3: Group histograms of FA values in the left and right uncinate. Histogram ‘A’ is the left uncinate in the patient group. Histogram ‘B’ is the left uncinate in the control group. Histogram ‘C’ is the right uncinate in the patient group. Histogram ‘D’ is the right uncinate in the control group.
Mentions: The results of the weighted regression analysis of the SCV of FA, incorporating age and gender, revealed a significant difference between patients and controls for the left, but not the right, uncinate fasciculus (coefficient = − 0.035, t = − 2.78, p = 0.008, 95% CI = − 0.0632 to − 0.009), with lower SCV of FA in the patient group. The SCV probability of connection was not significantly different between the two groups for the left or the right fasciculus. Histograms of FA values for the subject groups for each tract are shown in Fig. 3.

Bottom Line: Fractional anisotropy (FA) and probability of connection were obtained for every voxel in the tract, and the group means and distributions of these variables were compared.The spread of the FA distribution in the upper tail, as measured by the squared coefficient of variance (SCV), was reduced in the left UF in the patient group, indicating that the number of voxels with high FA values was reduced in the core of the tract and suggesting the presence of changes in fibre alignment and tract coherence in the patient group.The SCV of FA was lower in females across both groups and there was no correlation between the SCV of FA and clinical ratings.

View Article: PubMed Central - PubMed

Affiliation: Institute of Neurology, University College London, Queen Square, London, UK. g.price@ion.ucl.ac.uk

ABSTRACT
A model of disconnectivity involving abnormalities in the cortex and connecting white matter pathways may explain the symptoms and cognitive abnormalities of schizophrenia. Recently, diffusion imaging tractography has made it possible to study white matter pathways in detail, and we present here a study of patients with first-episode psychosis using this technique. We studied the uncinate fasciculus (UF), the largest white matter tract that connects the frontal and temporal lobes, two brain regions significantly implicated in schizophrenia. Nineteen patients with first-episode schizophrenia and 23 controls were studied using a probabilistic tractography algorithm (PICo). Fractional anisotropy (FA) and probability of connection were obtained for every voxel in the tract, and the group means and distributions of these variables were compared. The spread of the FA distribution in the upper tail, as measured by the squared coefficient of variance (SCV), was reduced in the left UF in the patient group, indicating that the number of voxels with high FA values was reduced in the core of the tract and suggesting the presence of changes in fibre alignment and tract coherence in the patient group. The SCV of FA was lower in females across both groups and there was no correlation between the SCV of FA and clinical ratings.

Show MeSH
Related in: MedlinePlus