Some characteristics of unit activity in the frontal cortex of alert monkeys

Spontaneous activity of frontal cortical neurons (middle part of sulcus principalis) and their responses to stimuli of different biological significance were studied in alert monkeys. The region studied is characterized by a lower level of spontaneous activity than the motor cortex. Fluctuations in the level of spontaneous activity are connected with changes in the experimental situation. Two types of unit responses were distinguished to repetitive stimulation: preservation of responses and habituation. The type of unit response depends on the relationship of the stimuli to the animal's motivational sphere.A. A. Ukhtomskii Physiological Research Institute, A. A. Zhdanov Leningrad State University. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 3–12, January–February, 1980.     

Studies on projections of somatic afferentation in the neocortex of the hedgehog Erinaceus europaeus]

Cortical projections of the somatic system in the hedgehog cortex were studied by means of the evoked potential (EP) technique. The EPs were shown to arise at a large area of the lateral cortex, the area in question being enlarged under chloralose anaesthesia. In the focus of projection of corresponding modalities the EPs posessed the least latency. Functional differences in the EP generation system both in the focus of projection and outside it are discussed. The wide EPs spreading in the lateral cortex as well as the presence of relatively differentiated projections is supposed to depend on the afferent volley dispersion to the polysynaptic pathways at the thalamic level. Considerable overlapping of sensory projection zones in the cortex is conditioned by the latter and indicates low degree of the somatic analyser organization.     

Mitochondria as a target for neuroprotection

Despite all the efforts of modern medical and biomedical sciences, the effective therapeutic treatments that would restore the brain functions lost after stroke have not been found yet. At the same time, experimental preclinical studies revealed an arsenal of effectors having potential for clinical applications. Identification of the key signaling pathways, both damaging and protective, can accelerate the development and implementation of new effective neuroprotectors. One of the key elements of these pathways is mitochondrion. In this context, we studied various therapeutic approaches to the treatment and prevention of cerebral ischemia, which are aimed at modulation of mitochondrial functions. The spectrum of tested neuroprotectors included antioxidants, uncouplers of respiration and phosphorylation, as well as ischemic, remote, and pharmacological preconditioning. Their efficacy and therapeutic windows were compared and the possibility of combining different methods in order to maximize their efficiency was considered.     

Estimation of localization and dipole moment of alpha- and theta-rhythm sources by cluster analysis in healthy subjects and schizophrenics

In 12 healthy subjects and 9 schizophrenic patients in the background conditions (with eyes closed) EEG was recorded from 16 standard derivations (10-20 system) during 3 min. The record underwent the spectral analysis detecting alpha- and theta-frequency bands. After the preliminary narrow band filtration for the main frequencies the sources of the spontaneous rhythms were localized. The data on localization for all healthy subjects and patients were summarized. The K-means clustering was used for identification of the sources clusters which were revealed in occipital and parietal lobes and limbic cortex for alpha-rhythm and also in frontal, temporal and parietal regions, limbic cortex and hippocampus for theta-rhythm. In schizophrenic patients in comparison with healthy subjects there was revealed significant increase of the numbers of dipole sources of alpha-rhythm in the clusters localized in limbic cortex and hippocampus. For theta-rhythm there was significant increase of the dipole moment of the sources in the clusters localized in the temporal and frontal cortices and hippocampus in patients in comparison with the norm.