A Novel Interhemispheric Interaction: Modulation of Neuronal Cooperativity in the Visual Areas

Background: The cortical representation of the visual field is split along the vertical midline, with the left and the right hemi-fields projecting to separate hemispheres. Connections between the visual areas of the two hemispheres are abundant near the representation of the visual midline. It was suggested that they re-establish the functional continuity of the visual field by controlling the dynamics of the responses in the two hemispheres. Methods/Principal Findings: To understand if and how the interactions between the two hemispheres participate in processing visual stimuli, the synchronization of responses to identical or different moving gratings in the two hemi-fields were studied in anesthetized ferrets. The responses were recorded by multiple electrodes in the primary visual areas and the synchronization of local field potentials across the electrodes were analyzed with a recent method derived from dynamical system theory. Inactivating the visual areas of one hemisphere modulated the synchronization of the stimulus-driven activity in the other hemisphere. The modulation was stimulus-specific and was consistent with the fine morphology of callosal axons in particular with the spatio-temporal pattern of activity that axonal geometry can generate. Conclusions/Significance: These findings describe a new kind of interaction between the cerebral hemispheres and highlight the role of axonal geometry in modulating aspects of cortical dynamics responsible for stimulus detection and/or categorization

Functional depletion of T cells by vincristine and methylprednisolone as an in vitro model for the prevention of graft versus host disease

The outcome of mismatched bone marrow transplantation is still severely hampered by graft versus host disease (GVHD) and graft rejection. Procedures for the recognition and selective elimination of T cells are still unsatisfactory due to the increased incidence of graft failure and late rejection. Lymphocyte proliferation and generation of cytotoxic T cells (CTL) in response to allogeneic cells are considered good in vitro correlates of GVHD and have been used in the present study to asses the capacity of two drugs (vincristine, VCR, and methylprednisolone, MP) to affect the T cells involved in these reactions. Treatment in vitro with VCR and MP has been shown to inhibit the functional capacity of peripheral blood lymphocytes to proliferate (mean reduction 95.8%) and to generate CTL in response to haploidentical stimulator cells. Responsiveness to antigens and mitogens was affected to a minor extent (mean reduction 40% and 65.5%, respectively), and the method allowed recovery of hemopoietic precursors. The results suggest that treatment of donor bone marrow with VCR and MP is worth studying as a new approach to the prevention of GVHD in haploidentical bone marrow transplantation

Implicazioni diagnostiche e prognostiche del gene NPM-ALK nel linfoma anaplastico a grandi cellule

Haematologic