Markovian analysis of the sequential behavior of the spontaneous spinal cord dorsum potentials induced by acute nociceptive stimulation in the anesthetized cat

In a previous study we developed a Machine Learning procedure for the automatic identification and classification of spontaneous cord dorsum potentials (CDPs). This study further supported the proposal that in the anesthetized cat, the spontaneous CDPs recorded from different lumbar spinal segments are generated by a distributed network of dorsal horn neurons with structured (non-random) patterns of functional connectivity and that these configurations can be changed to other non-random and stable configurations after the noceptive stimulation produced by the intradermic injection of capsaicin in the anesthetized cat. Here we present a study showing that the sequence of identified forms of the spontaneous CDPs follows a Markov chain of at least order one. That is, the system has memory in the sense that the spontaneous activation of dorsal horn neuronal ensembles producing the CDPs is not independent of the most recent activity. We used this markovian property to build a procedure to identify portions of signals as belonging to a specific functional state of connectivity among the neuronal networks involved in the generation of the CDPs. We have tested this procedure during acute nociceptive stimulation produced by the intradermic injection of capsaicin in intact as well as spinalized preparations. Altogether, our results indicate that CDP sequences cannot be generated by a renewal stochastic process. Moreover, it is possible to describe some functional features of activity in the cord dorsum by modeling the CDP sequences as generated by a Markov order one stochastic process. Finally, these Markov models make possible to determine the functional state which produced a CDP sequence. The proposed identification procedures appear to be useful for the analysis of the sequential behavior of the ongoing CDPs recorded from different spinal segments in response to a variety of experimental procedures including the changes produced by acute nociceptive stimulation. They are envisaged as a useful tool to examine alterations of the patterns of functional connectivity between dorsal horn neurons under normal and different pathological conditions, an issue of potential clinical concern.Peer ReviewedPostprint (published version

Supraspinal shaping of adaptive transitions in the state of functional connectivity between segmentally distributed dorsal horn neuronal populations in response to nociception and antinociception

In the anesthetized cat the correlation between the ongoing cord dorsum potentials(CDPs) recorded from different lumbar spinal segments has a non-random structure,suggesting relatively stable patterns of functional connectivity between the dorsalhorn neuronal ensembles involved in the generation of these potentials. During thenociception induced by the intradermic injection of capsaicin, the patterns of segmentalcorrelation between the spontaneous CDPs acquire other non-random configurationsthat are temporarily reversed to their pre-capsaicin state by the systemic injectionof lidocaine, a procedure known to decrease the manifestation of neuropathic painin both animals and humans. We have now extended these studies and utilizedmachine learning for the automatic extraction and selection of particular classes ofCDPs according to their shapes and amplitudes. By using a Markovian analysis, wedisclosed the transitions between the different kinds of CDPs induced by capsaicinand lidocaine and constructed a global model based on the changes in the behaviorof the CDPs generated along the whole set of lumbar segments. This allowed theidentification of the different states of functional connectivity within the whole ensembleof dorsal horn neurones attained during nociception and their transitory reversal bysystemic administration of lidocaine in preparations with the intact neuroaxis and afterspinalization. The present observations provide additional information on the stateof self-organized criticality that leads to the adaptive behavior of the dorsal hornneuronal networks during nociception and antinociception both shaped by supraspinaldescending influencesPeer ReviewedPostprint (published version

Markovian Analysis of the Sequential Behavior of the Spontaneous Spinal Cord Dorsum Potentials Induced by Acute Nociceptive Stimulation in the Anesthetized Cat

In a previous study we developed a Machine Learning procedure for the automatic identification and classification of spontaneous cord dorsum potentials (CDPs). This study further supported the proposal that in the anesthetized cat, the spontaneous CDPs recorded from different lumbar spinal segments are generated by a distributed network of dorsal horn neurons with structured (non-random) patterns of functional connectivity and that these configurations can be changed to other non-random and stable configurations after the noceptive stimulation produced by the intradermic injection of capsaicin in the anesthetized cat. Here we present a study showing that the sequence of identified forms of the spontaneous CDPs follows a Markov chain of at least order one. That is, the system has memory in the sense that the spontaneous activation of dorsal horn neuronal ensembles producing the CDPs is not independent of the most recent activity. We used this markovian property to build a procedure to identify portions of signals as belonging to a specific functional state of connectivity among the neuronal networks involved in the generation of the CDPs. We have tested this procedure during acute nociceptive stimulation produced by the intradermic injection of capsaicin in intact as well as spinalized preparations. Altogether, our results indicate that CDP sequences cannot be generated by a renewal stochastic process. Moreover, it is possible to describe some functional features of activity in the cord dorsum by modeling the CDP sequences as generated by a Markov order one stochastic process. Finally, these Markov models make possible to determine the functional state which produced a CDP sequence. The proposed identification procedures appear to be useful for the analysis of the sequential behavior of the ongoing CDPs recorded from different spinal segments in response to a variety of experimental procedures including the changes produced by acute nociceptive stimulation. They are envisaged as a useful tool to examine alterations of the patterns of functional connectivity between dorsal horn neurons under normal and different pathological conditions, an issue of potential clinical concern

Studies of the 3-phosphoglycerate kinase gene of Penicillium chrysogenum

SIGLEAvailable from British Library Document Supply Centre- DSC:D174210 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Markovian analysis of the sequential behavior of the spontaneous spinal cord dorsum potentials induced by acute nociceptive stimulation in the anesthetized cat

In a previous study we developed a Machine Learning procedure for the automatic identification and classification of spontaneous cord dorsum potentials (CDPs). This study further supported the proposal that in the anesthetized cat, the spontaneous CDPs recorded from different lumbar spinal segments are generated by a distributed network of dorsal horn neurons with structured (non-random) patterns of functional connectivity and that these configurations can be changed to other non-random and stable configurations after the noceptive stimulation produced by the intradermic injection of capsaicin in the anesthetized cat. Here we present a study showing that the sequence of identified forms of the spontaneous CDPs follows a Markov chain of at least order one. That is, the system has memory in the sense that the spontaneous activation of dorsal horn neuronal ensembles producing the CDPs is not independent of the most recent activity. We used this markovian property to build a procedure to identify portions of signals as belonging to a specific functional state of connectivity among the neuronal networks involved in the generation of the CDPs. We have tested this procedure during acute nociceptive stimulation produced by the intradermic injection of capsaicin in intact as well as spinalized preparations. Altogether, our results indicate that CDP sequences cannot be generated by a renewal stochastic process. Moreover, it is possible to describe some functional features of activity in the cord dorsum by modeling the CDP sequences as generated by a Markov order one stochastic process. Finally, these Markov models make possible to determine the functional state which produced a CDP sequence. The proposed identification procedures appear to be useful for the analysis of the sequential behavior of the ongoing CDPs recorded from different spinal segments in response to a variety of experimental procedures including the changes produced by acute nociceptive stimulation. They are envisaged as a useful tool to examine alterations of the patterns of functional connectivity between dorsal horn neurons under normal and different pathological conditions, an issue of potential clinical concern.Peer Reviewe

Markovian analysis reveals dynamic changes in the sequential behavior of dorsal horn neuronal activity induced by nociceptive stimulation

Automatic generation control (AGC) in multi-area interconnected power systems is experiencing several adaptions due to increasing level of power converter based components in the system. The concept of virtual synchronous power (VSP) to simulate the dynamic effects of virtual inertia emulations by HVDC links for higher level control applications is introduced and reflected in the multi-area AGC model. By using this proposed combination in the AGC model, the dynamic performance of the studied system shows a significant improvement. The proposed formulation is generalized for multi-area systems with multiple HVDC links. The active power loop control in VSP-based HVDC links has a second-order characteristic, which makes a simultaneous enabling of damping and inertia emulations into the system. Trajectory sensitivities are also used to analyze the effects of VSP's parameters on the system stability. The effectiveness of the proposed concept on dynamic improvements is tested through MATLAB simulation of a four-area system.This work was partially supported by the FI-DGR programme of AGAUR ECO/1551/2012. It was also partially supported by Rehabilitación personalizada y adaptativa en tratamientos post-ictus: El i-Walker (TEC2014-56256-C2-2-P) by NIH grant NS 09196 and CONACyT grants CB2009–127965, CB2015–255548, and by the Barcelona Supercomputing Center (BSC-CNS) and CINVESTAV agreement. EC was CONACyT fellow. GE was FI-AGAUR fellow. PR and UC are both members of the Sistema Nacional de Investigadores (CONACyT, México)