Little has been done yet to study the synchronization properties of the sources estimated from the MEG/EEG inverse problem, despite the growing interest in the role of phase relations in brain functions. In order to achieve this aim, we propose a novel approach to the MEG/EEG inverse problem based on some regularization using spectral priors: The MEG/EEG raw data are filtered in a frequency band of interest and blurred with some specific “regularization noise” prior to the inversion process. This formalism uses non quadratic regularization and a deterministic optimization algorithm. We proceed to Monte Carlo simulations using the chaotic Rössler oscillators to model the neural generators. Our results demonstate that it is possible to reveal some phase-locking between brain sources with great accuracy following the computation of the inverse problem based on scalp MEG/EEG measurements.
In the present study we have analyzed the changes in the expressed antibody repertoire and in temporal fluctuations of antibody levels in serum that followed infusion of normal IgG (IVIg) in a patient with autoimmune thyroiditis. Administration of IVIg resulted in the stimulation of IgM production, in alterations of expressed antibody activity in serum that could not merely be accounted for by the passive transfer of antibody specificities contained in IVIg, in transient down-regulation of B cells clones expressing a specific disease-related idiotype and in the increase in serum in recipient’s autoantibodies specifically reactive with F(ab′)2 fragments of IVIg. In addition, infusion of IVIg shifted the pattern of spontaneous fluctuations of autoantibody activities in the patient’s serum from a pattern indicative of disconnected events in the immune network to a pattern similar to that which is consistently observed in healthy controls. These results suggest that normal IgG may modulate autoreactivity by selecting expressed antibody repertoire through V region-dependent interactions with antibodies.
The degree of interdependence between intracranial electroencephalographic (EEG) channels was investigated in epileptic patients with temporal lobe seizures during interictal (between seizures) periods.With a novelmethod to characterize nonlinear cross-predictability, that is, the predictability of one channel using another channel as data base, we demonstrated here a possibility to extract information on the spatio-temporal organization of interactions between multichannel recording sites. This method determines whether two channels contain common activity, and often, whether one channel contains activity induced by the activity of the other channel. In particular, the technique and the comparison with surrogate data demonstrated that transient large-scale nonlinear entrainments by the epileptogenic region can be identified, this with or without epileptic activity. Furthermore, these recurrent activities related with the epileptic foci occurred in well-defined spatio-temporal patterns. This suggests that the epileptogenic region can exhibit very subtle influences on other brain regions during an interictal period and raises the possibility that the cross-predictability analysis of interictal data may be used as a significant aid in locating epileptogenic foci.
This article applies Maturana’s theory of ‘bringing forth’ reality to the clinical domain. Many common features of therapy are redefined including the notions of ‘psychopathology’, languaging and conversations, the family, and cognition. New concepts are introduced, notably those of the multiversa and the placing of objectivity in parenthesis. The rôle of the socially sanctioned specialist (expert) is examined and criticised for pretending to have a privileged access to an objectively existing reality. The authors propose a radical change in epistemology, premised upon the changes in understanding which they propose in relation to the ontology of the phenomenon of cognition. Particular attention is given to the orthogonality of the therapist’s approach to interacting with families.
Francisco Varela, a leading neurobiologist and cognitive scientist, made a 10-year-long incursion into immunology. His in-depth contributions aimed to develop a systemic description to replace the standard stimulus/response/regulation scaffold that has governed immunology since its inception in the 19th century. Many of these efforts involved expansions of the notions introduced by Niels Jerne in his idiotypic network theory (Jerne, 1974a, 1974b) with the added notion of organizational closure, derived from the autopoietic theory. However, today, just like yesterday, the immunological community remains inclined to neglect these efforts and instead rests satisfied with half-a-century old clonal selection concepts (Burnet, 1959).