A test group consisting of 104 healthy men from the ages of 19 to 21 was divided into two groups according to the magnitude of their individual α- frequency (ІАF) median―groups with high (n = 53, IA ≥ 10,04 Hz) and low (n = 51, IAF ≤ 10,03 Hz) levels of ІАF. Changes in power and coherence of the EEG oscillations during the usual manual movements as well as intergroup differences were evaluated. The higher level of the background tone of the cortex activation in men with a high IAF (individual alpha-frequency) was found as correlative with a signiicant selection of the relevant sensory information and a nonspecific input afferentation and its weakening under the performance of habitual manual movements. A functional state of the cortex is relatively lower in men with a low IAF and compensated by the tension of brain processes associated with a low level of the selective attention and the increase of the reticular influences and their significance during the finger movements. Men with a high IAF are characterized by the greater locality and asymmetry of processes of the cortical excitation under the dominant role of the left hemisphere. Activation changes are more diffuse in nature in subjects having a low frequency
Experiments were carried out on seven anestrus ewes. The animals were implanted with bipolar electrodes in the horns and corpus uteri. The electrical activity was registered by Reega Duplex electroencephalograph. The experiments were carried out on non-sensitized ewes and ewes sensitized by stilboestrol. The sheep were first fitted with an external jugular vein catheter and histamine (Histaminům hydrochloricum - Polfa) - 3 μg . kg-1 • min-1 - or H1 -receptors blocker (Clemastinum-Polfa) - 50 μg • kg-1 - were introduced. It was found that in sheep sensitized by stilboestrol histamine caused an increase in myoelectrical activity of the uterus by stimulation of H1 - histaminergic receptors.
Our aims were to describe the myoelectrical activity in the single very thin layer of muscle of the canine gallbladder. The study was performed on 22 freshly removed canine gallbladders. Electrical activity was studied by the single sucrose-gap method and contractility of the tissue was measured simultaneously using a force transducer. The strips (15x1 mm) from different regions of gallbladder (fundus, corpus, neck) were cut in longitudinal, circular and oblique axes. The sucrose-gap apparatus together with connecting tubes, solutions and electrodes were kept at 37°C and the initial tension applied to the tissue was set to 1 g. In 82.7% of recordings, spontaneous myoelectrical activity consisted of regular rhythmic changes in membrane potential similar to slow waves recorded in intestinal tissue. The overall mean frequency was 11.4 ± 5.2 (mean ±SD) cycles per min: 11.1 ± 4.4 cycles per min in fundus, 11.9 ± 6.2 cycles per min in corpus and 10.8 ± 3.8 cycles per min in the neck of the gallbladder. In 84.2% of cases electrical activity correlated with mechanical activity and preceded it. No significant differences were seen between the electrical patterns in strips with different orientations or from the different regions of the gallbladder.
The work presents complex methods of simultaneous registration of electric activity of the lower extremity muscles and efforts developed in the process of jumping test performance to exhaustion with revealing structural changes of muscles, their capillaries and other energy supply elements. Methodology reveals inborn predisposition of the system of execution and management of locomotion to loads of different character as well as the level of neuromuscular system reserve capacities in the process of long-term adaptation to physical loads.
The relationship between evoked electrical activity and stem movements in three-week old sunflowers was demonstrated. Electrical potential changes (recorded by Ag/AgCl extracellular electrodes) and time-lapse images (from a top view camera) were recorded and analyzed. A heat stimulus applied to the tip of one of the second pair of leaves evoked a variation potential, transmitted basipetally along one side of the stem. After stimulation, disturbances of circumnutations occurred. They included: changes in the period, disorders in the elliptical shape, and, in some cases, reversion of direction (of movement). We suggest that asymmetrically propagated variation potential induces asymmetric stem shrinking and bending, which strongly disturbs circumnutations. Our results confirm the involvement of electrical potential changes in the mechanism of stem nutations.
The long-term objective is to understand how large masses of neurons in the brain process information during various learning and memory paradigms. Both time- and space-dependent processes have been identified in animals through computer-based analytic quantifications of event-related extracellular potentials. New nonlinear analyses have been introduced that presume that the fine-grain variation in the signal is determined and patterned in phase-space. Some neurons in the primary visual cortex manifest gamma-band oscillations. These cells show both a nonspecific phase-alignment (response synchrony) and a specific tuning (orientation tuning) when stimuli are presented to their receptive fields. This dual regulation of the sensory cells is proposed to underlie stimulus binding, a theoretical mechanism for "object" perception. Nonlinear analytic results from gamma-activities in a simple model neuropil (olfactory bulb) suggest that neuroplasticity may arise through self-organization, a process in which a nonlinear change in the dynamics of the oscillatory field potentials is the hallmark. This self-organization may follow simple dynamical laws in which global cooperativity among the neurons is transiently brought about that, over trials, results in enduring changes in the nonlinear dynamics of some neurons. In conclusion, the sculpturing of the synaptic throughput in the sensory cortex (stimulus binding) may be associated with the irregular phases of the gamma-activities and may result from both specific and nonspecific systems operating together in a nonlinear self-organizing manner.
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