RESUMEN
The data on the microbiological investigation of clinical materials from patients with complicated skin and soft tissue infections in 6 European countries were analysed. The analysis of the bacterial pathogens spectrum provided the microbial view and efficient use of novel antimicrobials in clinical trials.
Asunto(s)
Bacterias Grampositivas/aislamiento & purificación , Infecciones por Bacterias Grampositivas/microbiología , Enfermedades Cutáneas Bacterianas/microbiología , Infecciones de los Tejidos Blandos/microbiología , Farmacorresistencia Bacteriana , Europa Oriental/epidemiología , Bacterias Gramnegativas/clasificación , Bacterias Gramnegativas/aislamiento & purificación , Bacterias Grampositivas/clasificación , Infecciones por Bacterias Grampositivas/epidemiología , Humanos , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Prevalencia , Enfermedades Cutáneas Bacterianas/epidemiología , Infecciones de los Tejidos Blandos/epidemiologíaRESUMEN
Food-related operant conditioned reflexes to light were developed in four cats on the basis of the "active choice" of reinforcement quality: short-latency pedal presses were reinforced with a mixture of meat and bread, while long-latency presses were reinforced with meat. Animals showed differences in their behavioral strategies: two preferred long-latency pedal presses (animals with "self-control"), while the other two preferred short-latency pedal presses ("impulsive" animals). At the second stage of the study, animals of both groups were retrained to a short-delay (1 sec) conditioned operant food-related reflex in response to light with meat reinforcement. Chronically implanted Nichrome semimicroelectrodes were used to record multicellular activity in the frontal cortex and hippocampus (field CA3). The interaction of neighboring neurons within the frontal cortex and hippocampus (local neural networks) and neurons of the frontal cortex and hippocampus (distributed frontohippocampal and hippocampofrontal neural networks) were assessed by statistical cross-correlation analysis of spike trains with an analysis epoch of 100 msec. The frontal and frontohippocampal neural networks had different modes of functional organization in the simplified task for the animals of the two groups. However, intergroup differences in local networks of the hippocampus persisted in conditions of the simplified task lacking the requirement for the animals to select the quality of the reinforcement, indicating the likely genetic determinacy of these networks.
Asunto(s)
Conducta Animal/fisiología , Condicionamiento Clásico/fisiología , Condicionamiento Operante/fisiología , Lóbulo Frontal/fisiología , Hipocampo/fisiología , Red Nerviosa/fisiología , Neuronas/fisiología , Potenciales de Acción/fisiología , Animales , Gatos , Masculino , Vías Nerviosas/fisiologíaRESUMEN
Four cats were subjected to appetitive instrumental conditioning with light as a conditioned stimulus by the method of "active choice" of the reinforcement quality: short-delay conditioned bar-press responses were followed by bread-meat mixture and the delayed responses--by meat. The animals differed in behavior strategy: four animals preferred bar-pressing with long delay (so called "self-control" group); two animal preferred bar-pressing with short-delay (so called "impulsive" group). Then all the animals were learned to short-delay (1 s) instrumental conditioned reflex to light (CS+) reinforced by meat. The multiunit activity in the frontal cortex and the hippocampus (CA3) was recorded through chronically implanted nichrome-wire semimicroelectrodes. The interactions among the neighboring neurons in the frontal cortex and hippocampus (within the local neuronal networks) and between the neurons of the frontal cortex and hippocampus (distributed neuronal networks of frontal-hippocampal and hippocampal-frontal directions) were evaluated by means of statistical crosscorrelation analysis of the spike trains. Crosscorrelation interneuronal connections in the delay range 0-100 ms were explored. It was shown that the functional organization of the frontal and hippocampal neuronal networks differed in choice behavior and was similar during realization of short-delayed conditioned reflex. We suggest that the local and distributed neural networks of the frontal cortex and hippocampus take part in the realization of cognitive behavior, in particularly in the processes of the decision making.
Asunto(s)
Conducta Animal/fisiología , Condicionamiento Operante/fisiología , Toma de Decisiones/fisiología , Lóbulo Frontal/fisiología , Hipocampo/fisiología , Red Nerviosa/fisiología , Animales , Gatos , Luz , Neuronas/fisiología , Refuerzo en PsicologíaRESUMEN
Six cats were trained to food-related operant conditioned reflexes to light using the "active choice" of reinforcement method: short-latency pedal pressings were reinforced with meat and bread, while long-latency responses were reinforced with meat. Animals were divided in terms of their behavioral strategies: four preferred long-latency pedal pressings (the "self-controlled" group), while the other two preferred short-latency pedal pressings ("impulsive" animals). Implanted Nichrome semimicroelectrodes were used to record multicellular activity in the frontal cortex and hippocampus (field CA3). Interactions of neighboring neurons within the frontal cortex and the hippocampus (local neuronal networks) and between frontal cortex and hippocampal neurons (distributed neural networks in the frontohippocampal and hippocampofrontal directions) were assessed by statistical cross-correlation analysis of spike series with analysis epochs of 100 msec. The number of cross-correlational connections between the discharges of neurons in both local and distributed networks were significantly greater in the group of animals demonstrating self-control, i.e., preferring long-latency pedal pressings to receive the more valuable reinforcement. It is suggested that the predominance of functional interneuronal connections in the local networks of the frontal cortex and hippocampus and in frontohippocampal distributed networks in animals operating in the self-control regime as compared with impulsive animals demonstrates the dominant role of these informational structures in the organization of self-controlled behavior.
Asunto(s)
Conducta de Elección/fisiología , Lóbulo Frontal/fisiología , Hipocampo/fisiología , Vías Nerviosas/fisiología , Recompensa , Animales , Gatos , Condicionamiento Operante/fisiología , Electrofisiología , Potenciales Evocados , Lóbulo Frontal/citología , Hipocampo/citología , Conducta Impulsiva , Masculino , Vías Nerviosas/citología , Neuronas/fisiología , Tiempo de Reacción/fisiología , Periodo Refractario Electrofisiológico/fisiologíaRESUMEN
Six cats were subjected to the procedure of appetitive instrumental conditioning (with light as a conditioned stimuls) by the method of the "active choice" of reinforcement quality. Short-delay conditioned bar-press responses were rewarded with bread-meat mixture, and the delayed responses were reinforced by meat. The animals differed in behavior strategy: four animals preferred the bar-pressing with a long delay (the so-called "self-control" group), and two cats preferred the bar-pressing with a short delay (the so-called "impulsive" group). Multiunit activity in the frontal cortex and hippocampus (CA3) was recorded via chronically implanted nichrome wire semimicroelectrodes. An interaction between the neighboring neurons in the frontal cortex and hippocampus (within local neural networks) and between the neurons of the frontal cortex and hippocampus (distributed neural networks in frontal-hippocampal and hippocampal-frontal directions) was evaluated by means of statistical crosscorrelation analysis of spike trains. Crosscorrelations between neuronal spike trains in the delay range of 0-100 ms were explored. It was shown that the number of crosscorrelations between the neuronal discharges both in the local and distributed networks was significantly higher in the "self-control" cats. It was suggested that the local and distributed neural networks of the frontal cortex and hippocampus are involved in the system of brain structures which determine the behavioral strategy of animals in the "self-control" group.
Asunto(s)
Conducta de Elección/fisiología , Lóbulo Frontal/fisiología , Hipocampo/fisiología , Refuerzo en Psicología , Animales , Gatos , Condicionamiento Operante/fisiología , Electrodos Implantados , Conducta Alimentaria/fisiología , Lóbulo Frontal/citología , Hipocampo/citología , Interneuronas/fisiología , Masculino , Microelectrodos , Neuronas/citología , Neuronas/fisiología , Estimulación Luminosa , Tiempo de Reacción/fisiologíaRESUMEN
Experiments on five cats already trained to an operant conditioned food-procuring reflex to light were used to study the network activity of cells in the frontal and motor areas of the cortex accompanying disruption of conditioned reflex behavior in conditions of systemic administration of m-cholinoreceptor blockers. The activity of cortical neurons and their network properties were assessed using auto- and cross-correlation histograms. Doses of central m-cholinoreceptor blockers (the non-selective blocker scopolamine and the relatively selective m1-cholinoreceptor blocker trihexyphenidyl) disrupted performance of the operant motor reflex but had no effect on the appearance of contextual behavior and responses to switching on of the conditioned signal (standing up, elevating the paw). This was accompanied by 1) changes in the patterns of neuron activity in the moor and frontal areas of the cortex, with increases in train, rhythmic, and rhythmic train activity in cortical cells; 2) appearance of synchronicity in the operation of cortical neurons; 3) decreases in the numbers of direct interneuronal connections in the motor and frontal areas of the cortex and in the numbers of connections between these structures.
Asunto(s)
Antagonistas Colinérgicos/farmacología , Condicionamiento Operante/efectos de los fármacos , Corteza Motora/fisiología , Red Nerviosa/efectos de los fármacos , Neuronas/efectos de los fármacos , Corteza Prefrontal/fisiología , Receptores Colinérgicos/efectos de los fármacos , Animales , Gatos , Electrofisiología , Microinyecciones , Corteza Motora/citología , Movimiento/efectos de los fármacos , Corteza Prefrontal/citología , Escopolamina/farmacología , Trihexifenidilo/farmacologíaRESUMEN
Experiments on cats showed that lesions affecting retrieval of an operant food-procuring reflex. occurring on a background of systemic administration of the centrally-acting muscarinic cholinoceptor blocker scopolamine (a non-selective M-cholinoceptor blocker) and trihexyphenidyl (a relatively selective M1-cholinoceptor blocker), might be associated with the central and peripheral side effects of these blockers, preventing performance of the conditioned reflex. It was established that when no side effects were present (low doses of trihexyphenidyl, 1 mg/kg), blockade of M1-cholinoceptors led to selective loss of the motor operant reflex while contextual behavior and other conditioned responses were retained or led to errors in performance of the reflex: this appears to be evidence that derangement of launching and performing the motor program is the most important component of the conditioned reflex. Systemic administration of trihexyphenidyl at a dose of 10 mg/kg, scopolamine at doses of 0.03 and 0.06 mg/kg, and the peripherally-acting non-selective blocker methylscopolamine at a dose of 0.03 mg/kg led to changes in the general functional state (disturbances in the emotional-motivational sphere), the extent of which depended on the individual sensitivity of the animal to the anticholinergic agents. The presence of side effects led to complete cessation of conditioned reflex activity, though this appeared not to be associated with memory impairment.
Asunto(s)
Condicionamiento Operante/efectos de los fármacos , Receptores Muscarínicos/efectos de los fármacos , Animales , Gatos , Alimentos , Motivación , Antagonistas Muscarínicos/farmacología , Refuerzo en Psicología , Escopolamina/efectos adversos , Escopolamina/farmacología , Trihexifenidilo/farmacologíaRESUMEN
It was shown previously that peripherally administered antagonists of the central 1 M-cholinoreceptors led to a selective impairment of bar-pressing response in a food-reinforced operant conditioned task but did not alter contextual behavior and functions such as motivation, perception, and locomotion. To obtain information about the central mechanisms of the conditioning impairment, we recorded simultaneously the extracellular multiunit activity from the frontal and motor neocortical areas of five cats trained to acquisition criteria in a food-reinforced operant conditioning task. Multiunit recordings were performed drur 1) normal conditioning; 2) conditioning during subcutaneous administration of muscarinic antagonists scopolamine (0.03 mg/kg), trihexyphenidyl (1 mg/kg), and methylscopolamine (0.03 mg/kg). Autocorrelation analysis showed that scopolamine and trihexyphenidyl but not methylscopolamine led to a significant increase in the tendency of cortical cells to fire in a cyclic way (i.e., the shift of the firing pattern from a single-spike discharge to burst, rhythmic, or rhythmic-burst discharge) both in the motor and frontal areas. Cross-correlation analysis showed that the bursting and rhythmic-bursting cells synchronized their activity within and (in a number of cases) between the cortical areas. These changes in the neuronal activity within the motor cortex and frontal cortex were accompanied by a significant decrease in the functional connectivity both inside and between the cortical areas in parallel with selective impairment of the conditioned response.
Asunto(s)
Lóbulo Frontal/fisiología , Corteza Motora/fisiología , Antagonistas Muscarínicos/farmacología , Neuronas/fisiología , Animales , Gatos , Lóbulo Frontal/citología , Lóbulo Frontal/efectos de los fármacos , Corteza Motora/citología , Corteza Motora/efectos de los fármacos , Neuronas/efectos de los fármacos , Escopolamina/farmacología , Derivados de Escopolamina , Trihexifenidilo/farmacologíaRESUMEN
The organization of distributed amygdalo-hypothalamic and local amygdalar and hypothalamic neural networks was studied in three cats, trained to perform a food-related operant conditioned reflex to light by the "active choice" of reinforcement quality method; pressing the pedal with a short latent period provided the cats with a bread/meat mixture, while pressing with a long latent period yielded meat. Animals showed sharp differences in their individual abilities to choose one or the other reinforcement. Two cats preferred long-latency pedal-pressing to obtain meat, and were considered to be "self-controlled," while the third cat, which preferred short-latency pedal-pressing to obtain the less valuable reinforcement (the bread/meat mixture) was described as "impulsive." Chronically implanted semimicroelectrodes were used to record multineuron activity in the basolateral nucleus of the amygdala and the lateral nucleus of the hypothalamus. Interactions between the discharge trains of neighboring and distant neurons were assessed by cross-correlation analysis. Interneuron functional connections were found to predominate significantly in the local neural networks of the basolateral amygdala and distributed amygdalar-hypothalamic networks in the "impulsive" animal as compared with the "self-controlled" animals, suggesting a role for these types of connection in forming the individual characteristics of higher nervous activity. The identical incidences of interneuron interactions in the lateral nucleus of the hypothalamus in cats with different individual preferences suggest that local networks in this formation are not involved in analyzing reinforcement quality.
Asunto(s)
Amígdala del Cerebelo/fisiología , Condicionamiento Clásico/fisiología , Hipotálamo/fisiología , Neuronas/fisiología , Amígdala del Cerebelo/citología , Animales , Gatos , Potenciales Evocados/fisiología , Alimentos , Hipotálamo/citología , Interneuronas/fisiología , Carne , Red Nerviosa/fisiología , Refuerzo en PsicologíaRESUMEN
It was demonstrated in cat experiments that impairment of the retrieval of appetitive instrumental conditioning observed after systemic administration of antagonists of muscarinic central cholinoreceptors scopolamine (a nonselective M1 antagonist) and trihexyphenidyl (relatively selective M1 antagonist) could be connected with central and peripheral side effects of these antagonists. It was established that in case of the absence of side effects (low doses of trihexyphenidyl, 1 mg/kg) the blockade of M1-cholinoreceptors led either to selective fall-off of the motor instrumental reaction with in the presence of contextual behavior and other conditioned reactions or the appearance of errors that seemingly was indicative of the disturbance of triggering and realization of the motor program as the most important component of conditioning performance. The systemic injection of trihexyphenidyl (10 mg/kg), scopolamine (0.03 and 0.06 mg/kg) and nonselective peripheral antagonist methylscopolamine (0.03 mg/kg) led to changes in the general functional state (disorders in the emotional and motivational sphere), the expression of which depended on the individual sensitivity to anticholinergic drugs. The disturbance of CR retrieval observed in parallel with side reactions was characterized by a complete cessation of conditioning and apparently was not associated with memory deterioration.
Asunto(s)
Condicionamiento Operante/fisiología , Receptores Muscarínicos/fisiología , Animales , Gatos , Alimentos , Antagonistas Muscarínicos/farmacología , N-Metilescopolamina/farmacología , Receptor Muscarínico M1 , Receptores Muscarínicos/efectos de los fármacos , Escopolamina/farmacología , Trihexifenidilo/farmacologíaRESUMEN
Three cats were subjected to appetitive instrumental conditioning to light by the method of the "active choice" of the reinforcement quality. The short-delayed conditioned bar-pressings were reinforced by bread-meat mixture and the delayed response by meat. The animals differed in behavior strategy: two animals preferred bar-pressing with long delay (the so-called "self-control" group) and one animal preferred bar-pressing with short delay (the so-called "impulsive" group). The multiunit activity of the basolateral amygdala and nucleus lateralis of the hypothalamus was recorded through chronically implanted nichrome wire semimicroelecrodes. The interactions between the neighboring neurons in the lateral hypothalamus and basolateral amygdala (within the local neuronal network) and between the neurons of the basolateral amygdala and lateral hypothalamus (distributed neuronal networks in the direction amygdala--hypothalamus and vice versa) were evaluated by means of statistical crosscorrelation analysis of spike trains. The crosscorrelational interneuronal connections in the delay range of 0-100 ms were examined. It was shown that the number of crosscorrelations between the discharges on neurons both in the local networks of basolateral amygdala and distributed networks was significantly higher in "impulsive" cats. In both groups of animals, the percentage of crosscorrelations between neighbouring neurons in the local networks of the lateral hypothalamus was similar. We suggest that the local networks of the basolateral amygdala and amygdalar-hypothalamic distributed neuronal networks are involved in the system of brain structures which determine the individual features of animal behavior.
Asunto(s)
Amígdala del Cerebelo/fisiología , Condicionamiento Operante/fisiología , Hipotálamo/fisiología , Neuronas/fisiología , Refuerzo en Psicología , Amígdala del Cerebelo/citología , Animales , Gatos , Alimentos , Hipotálamo/citología , MicroelectrodosRESUMEN
The multiunit activity of neurons in the motor cortex was recorded in 6 rabbits during glutamate (or physiological saline) iontophoretic application. Interaction between the neighboring neurons was evaluated by means of statistical cross-correlation analysis of spike trains. It was found that glutamate did not produce significant changes in cross-correlations.
Asunto(s)
Ácido Glutámico/administración & dosificación , Interneuronas/efectos de los fármacos , Iontoforesis , Corteza Motora/efectos de los fármacos , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Distribución de Chi-Cuadrado , Relación Dosis-Respuesta a Droga , Ácido Glutámico/farmacología , Interneuronas/fisiología , Corteza Motora/fisiología , Conejos , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Cloruro de Sodio/farmacología , Factores de Tiempo , Vigilia/efectos de los fármacos , Vigilia/fisiologíaRESUMEN
Experiments were performed on eight rabbits to study the effects of acetylcholine on interneuronal intracortical interactions. Multineuronal activity was recorded in the motor cortex during local iontophoretic administration of acetylcholine and physiological saline. Interneuronal connections were identified by cross-correlation analysis. A role for acetylcholine in intracortical connection reorganization processes is proposed. These studies demonstrated that acetylcholine has an activating effect on intracortical connections; application of acetylcholine leads to increases in the intensity of short-latency, constantly functioning (stable) connections. Acetylcholine application also resulted in the formation of unstable, long-latency connections. Additionally, the data suggest that iontophoretic application of acetylcholine does not lead to the formation of new short-latency interneuronal connections. The modulatory effects of acetylcholine on the network activity of cortical neurons are discussed.
Asunto(s)
Acetilcolina/farmacología , Corteza Motora/efectos de los fármacos , Corteza Motora/fisiología , Neuronas/efectos de los fármacos , Acetilcolina/administración & dosificación , Animales , Potenciales Evocados/efectos de los fármacos , Potenciales Evocados/fisiología , Miembro Anterior/inervación , Miembro Anterior/fisiología , Iontoforesis , Corteza Motora/citología , Red Nerviosa/efectos de los fármacos , Vías Nerviosas/citología , Vías Nerviosas/efectos de los fármacos , ConejosRESUMEN
The multiunit activity of the neurons in the motor cortex was recorded in 8 rabbits under conditions of acetylcholine (or physiological saline) iontophoretic application. Crosscorrelation analysis of pulse trains was carried out. It was found out that acetylcholine activated the intracortical connections. Its application led to an increase in intensity of permanently existing short-latency interneuronal connections (i.e. the stable ones). Moreover, it led to a formation of the long-latency unstable connections. However, the obtained data do not suggests that acetylcholine promotes the formation of new short-latency connections between neurons. The modulatory influence of acetylcholine is discussed on the network activity of cortical neurons.
Asunto(s)
Acetilcolina/administración & dosificación , Iontoforesis , Corteza Motora/efectos de los fármacos , Neuronas/efectos de los fármacos , Acetilcolina/farmacología , Animales , Distribución de Chi-Cuadrado , Microelectrodos , Corteza Motora/fisiología , Neuronas/fisiología , Conejos , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiologíaRESUMEN
The present study comprises an attempt to investigate the influence of acetylcholine on the functional connections of the cortical cells and their frequency characteristics. The multineuronal activity was recorded in the sensorimotor cortex of immobilized and freely moving rats, and was subsequently analyzed using the method of cross-correlational analysis. In the first series of experiments, the influence of the neuromediator, acetylcholine (ACh), and calcium chelation, ethyleneglycol tetraacetate (EGTA), on the functional characteristics of adjacent neurons during the iontophoretic application of these substances to cells of the sensorimotor cortex of unanesthetized immobilized rats was investigated. In this case, the iontophoretic application of ACh led to a change in the frequency characteristics of individual neurons, and in the majority of cases did not influence the character of the interneuronal interactions. The application of EGTA led to a decrease in the average frequency of impulse activity for the majority of the neurons, as well as to the disappearance, independent of the running frequency, of excitatory connections in the cross-correlograms, with their subsequent recovery following the termination of exposure to the EGTA. In the second series of experiments, carried out in freely moving rats with a chronically implanted recording electrode, the systemic administration of the acetylcholinesterase blocker, galantamine, led to a substantial intensification of the impulse activity of the cortical neurons, and at the same time did not exert a substantial influence on the network activity of the same neurons. The hypothesis is advanced that the intracortical neuronal interactions may be accomplished independently of extracortical influences that are expressed in the fluctuations of the baseline impulse activity of individual cells. The qualitative assessment that was carried out of the influence of ACh on the functional characteristics of the cortical neurons does not make it possible to identify an influence of ACh (including a modulatory influence) on the formation of intracortical connections. The methods used in this investigation may be used for a further study of the influence of various mediator systems of the brain on the functioning of intracortical interneuronal connections.
Asunto(s)
Corteza Cerebral/efectos de los fármacos , Interneuronas/efectos de los fármacos , Acetilcolina/farmacología , Animales , Corteza Cerebral/metabolismo , Quelantes/farmacología , Inhibidores de la Colinesterasa/farmacología , Ácido Egtácico/farmacología , Electrodos Implantados , Interneuronas/metabolismo , Iontoforesis , Ratas , Corteza Somatosensorial/citología , Corteza Somatosensorial/efectos de los fármacos , Corteza Somatosensorial/fisiología , Técnicas Estereotáxicas , Sinapsis/efectos de los fármacos , Sinapsis/metabolismo , Sinapsis/fisiologíaRESUMEN
An attempt is made to study the influence of acetylcholine on functional connections of cortical neurons and their frequency characteristics. Multiunit activity was recorded in the sensorimotor cortex of immobilized and freely moving rats. Crosscorrelation analysis was used. Influence of acetylcholine (Ach) and Ca chelator ethyleneglicoltetraacetat (EGTA) on the functional characteristics of the neighbouring neurons was studied in the first series of experiments. The substances were iontophoretically applied to the sensorimotor cortex neurons of the immobilized unanesthetized rats. Application of Ach led to variation in the frequency characteristics of single neurons and in the majority cases did not affect the neuronal interrelations. EGTA application, independently on the background frequency of the neuronal activity, resulted in disappearance of interneuronal connections which recovered after the end of EGTA effect. The second series of experiments was carried out in freely moving rats. System injection of galantamine essentially increased the frequency of activity of the cortical neurons not affecting their network activity. We suppose that intracortical relations can be realized independently on the extracortical influences which are manifested in variations in the background impulsation of the single neurons. Qualitative estimation of Ach influence on the functional characteristics of the cortical neurons do not reveal Ach effects on formation of intracortical connections. The technique used by us may be applied in further studies of intracortical neurons connections.