Structural and Diffusion Tensor Imaging of the Fornix in Childhood- and Adolescent-Onset Schizophrenia

Kendi, Mustafa; Kendi, Ayşe Tuba Karagülle; Lehericy, Stéphane; Ducros, Mathieu; Lim, Kelvin O.; Uğurbil, Kâmil; Schulz, Sean; White, Tonya

doi:10.1097/chi.0b013e318172ef36

Cited by 20 publications

(30 citation statements)

References 43 publications

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“…The fornix belongs to the Papez circuit known to be involved in cognitive and memory abilities for review44. MRI and in particular DTI methods in humans report similar connectivity defects in schizophrenic patients with disrupted fornix integrity4546474849 associated with alterations of resting state functional connectivity50 and defective memory organization5152. Other links between abnormal neuronal axonal tract formation and specific genes have been reported in both animal models and patients.…”

Section: Discussionmentioning

confidence: 96%

Microtubule-associated protein 6 mediates neuronal connectivity through Semaphorin 3E-dependent signalling for axonal growth

et al. 2015

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Structural microtubule associated proteins (MAPs) stabilize microtubules, a property that was thought to be essential for development, maintenance and function of neuronal circuits. However, deletion of the structural MAPs in mice does not lead to major neurodevelopment defects. Here we demonstrate a role for MAP6 in brain wiring that is independent of microtubule binding. We find that MAP6 deletion disrupts brain connectivity and is associated with a lack of post-commissural fornix fibres. MAP6 contributes to fornix development by regulating axonal elongation induced by Semaphorin 3E. We show that MAP6 acts downstream of receptor activation through a mechanism that requires a proline-rich domain distinct from its microtubule-stabilizing domains. We also show that MAP6 directly binds to SH3 domain proteins known to be involved in neurite extension and semaphorin function. We conclude that MAP6 is critical to interface guidance molecules with intracellular signalling effectors during the development of cerebral axon tracts.

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Section: Discussionmentioning

confidence: 96%

Microtubule-associated protein 6 mediates neuronal connectivity through Semaphorin 3E-dependent signalling for axonal growth

et al. 2015

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“…Tracking the fimbria-fornix complex is an important issue in studies dealing with neurological (e.g. epilepsy) or psychiatric disorders (such as schizophrenia) in which the structures connected by this pathway have been hypothesized to be crucially involved (48). We show also the possibility to visualize bundles running from the optic chiasm through optic tract and arriving at the lateral geniculate nucleus, forming the posterior part of the visual pathway.…”

Section: Fiber Tracking and Probability Mapsmentioning

confidence: 95%

In vivo diffusion tensor magnetic resonance imaging and fiber tracking of the mouse brain

et al. 2010

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Until very recently, the study of neural architecture using fixed tissue has been a major scientific focus of neurologists and neuroanatomists. A non-invasive detailed insight into the brain's axonal connectivity in vivo has only become possible since the development of diffusion tensor magnetic resonance imaging (DT-MRI). This unique approach of analyzing axonal projections in the living brain was used in the present study to describe major white matter fiber tracts of the mouse brain and also to identify for the first time non-invasively the rich connectivity between the amygdala and different target regions. To overcome the difficulties associated with high spatially and temporally resolved DT-MRI measurements a 4-shot diffusion weighted spin echo (SE) echo planar imaging (EPI) protocol was adapted to mouse brain imaging at 9.4T. Diffusion tensor was calculated from data sets acquired by using 30 diffusion gradient directions while keeping the acquisition time at 91 min. Two fiber tracking algorithms were employed. A deterministic approach (fiber assignment by continuous tracking - FACT algorithm) allowed us to identify and generate the 3D representations of various neural pathways. A probabilistic approach was further used for the generation of probability maps of connectivity with which it was possible to investigate - in a statistical sense - all possible connecting pathways between selected seed points. We show here applications to determine the connection probability between regions belonging to the visual or limbic systems. This method does not require a priori knowledge about the projections' trajectories and is shown to be efficient even if the investigated pathway is long or three-dimensionally complex. Additionally, high resolution images of rotational invariant parameters of the diffusion tensor, such as fractional anisotropy, volume ratio or main eigenvalues allowed quantitative comparisons in-between regions of interest (ROIs) and showed significant differences between various white matter regions.

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“…In a structural MRI (sMRI) and fMRI study, Michael et al (2010) introduced three methods to identify correlations between sMRI and fMRI voxels within the whole brain, and observed that the linkage between gray matter and functional activation is stronger in healthy controls than in schizophrenia. In a combined sMRI and DTI study by Kendi et al (2008), it was noted that the early stages of schizophrenia are associated with a decrease in fornix volume without microstructural white matter changes and it was suggested that the volume differences may reflect an early insult to neighboring brain regions that could decrease the number of efferent fibers without necessarily disrupting fiber integrity. It is hoped that these multi-modality studies will lead to an understanding of significance of progressive brain changes over the course of illness.…”

Section: Diagnosis and Clinical Characteristicsmentioning

confidence: 99%

The 2nd Schizophrenia International Research Society Conference, 10–14 April 2010, Florence, Italy: Summaries of oral sessions

Baharnoori

Bartholomeusz

Boucher³

et al. 2010

Schizophrenia Research

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The 2nd Schizophrenia International Research Society Conference, was held in Florence, Italy, April 10–15, 2010. Student travel awardees served as rapporteurs of each oral session and focused their summaries on the most significant findings that emerged from each session and the discussions that followed. The following report is a composite of these reviews. It is hoped that it will provide an overview for those who were present, but could not participate in all sessions, and those who did not have the opportunity to attend, but who would be interested in an update on current investigations ongoing in the field of schizophrenia research.

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Structural and Diffusion Tensor Imaging of the Fornix in Childhood- and Adolescent-Onset Schizophrenia

Cited by 20 publications

References 43 publications

Microtubule-associated protein 6 mediates neuronal connectivity through Semaphorin 3E-dependent signalling for axonal growth

Microtubule-associated protein 6 mediates neuronal connectivity through Semaphorin 3E-dependent signalling for axonal growth

In vivo diffusion tensor magnetic resonance imaging and fiber tracking of the mouse brain

The 2nd Schizophrenia International Research Society Conference, 10–14 April 2010, Florence, Italy: Summaries of oral sessions

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