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PubMed1975

[A correlation analysis of changes in the bioelectric activity of the brain in associative speech experiments].

The paper deals with a correlational analysis of brain biopotentials in the process of speech activity in 9 normals and 10 patients with residual symptoms of brain strokes. The authors dt and erroneous fulfillment of different types of tests (free and determined associations). It was established that in a difficult fulfillment of a speech instruction there is a compensatory involvement into the activity of the right normal hemisphere.

Adolescent↗
PubMed1991

Propagation of human complex-partial seizures: a correlation analysis.

Inter- and intrahemispheric propagation of ictal discharges was analysed in 7 epileptic patients having chronic intracranial electrodes. Five had temporal foci and two had frontal mesial foci. Correlation analysis of seizure discharge was used to detect the emergence of linear relationships between different structures both intra- and interhemispherically. This analysis included mesial and lateral temporal sites, cingulate gyri, anterior ventral and dorsomedial thalamic nuclei during the discharges of 13 ictal episodes. Correlation between temporal mesial structures was found to be low throughout seizure onset. Propagation of paroxysmal activity through the anterior ventral thalamic nuclei and cingulate gyri was observed in all cases with temporal or frontal mesial focus. Propagation of the discharge from the temporal lateral cortex to the contralateral homologue area was observed with a short delay during 4 complex-partial seizures originating in the temporal lobe. These results show that, even though the commissural pathways may have a role in propagation, it is a relatively unimportant one and they suggest that ictal activity during mesial temporal seizures may spread preferentially through the thalamic nuclei and cortical structures.

Adult↗
PubMedDate not supplied

[A spectral-correlational analysis of the electrical activity of the sensorimotor cortex and the internal geniculate body during a motor-polarization dominant].

By spectral-correlative analysis the dynamics was studied of structural changes of coherent relations of the electrical activity of the sensorimotor cortex and medial geniculate body (MGB) of the rabbit under motor polarization dominant created by the action of DC anode on the sensorimotor cortex area. It was shown, that in the power spectra of the MGB, besides the increase of the delta-region components in interstimulus intervals at the dominant, during the action of the sound stimulus a distinct maximum appeared in the alpha-rhythm range of the electrical activity of MGB of the "dominant" hemisphere. The coherence increase of the delta-range of the MGB and the sensorimotor cortex electrical activity in the "dominant" part of the brain was manifested exclusively in the period of sound stimulus action.

Alpha Rhythm↗
PubMed1991

Horizontal interactions between visual cortical neurones studied by cross-correlation analysis in the cat.

1. To explore the functional significance of horizontal neural connections in the extent of a 'hypercolumn' of the cat visual cortex, we carried out cross-correlation analysis of spike trains recorded simultaneously from a pair of neurones separated horizontally by less than 1 mm. 2. Significantly correlated firings, which were found in sixty-eight pairs of cells among 327 pairs analysed, were classified into three types on the basis of their functional implications: (1) excitatory interactions, (2) inhibitory interactions and (3) common inputs to both neurones of a pair from other sources. 3. Of these three types, common inputs were encountered most frequently. Excitatory interactions were always accompanied by common inputs. Inhibitory interactions were observed least frequently. 4. The proportion of cell pairs with correlated firings was high in pairs with a horizontal separation of less than 200 microns and decreased markedly with a horizontal separation of more than 400 microns. 5. Regarding laminar locations of cells, common inputs and excitatory interactions were often observed in layers II + III and V, whereas laminar bias was not seen in inhibitory interactions. 6. With respect to difference in orientation preference between two cells, all the three types of correlations were observed, mostly in cell pairs with a difference of less than 45 deg. In particular, common inputs and excitatory interactions were often seen in cell pairs with matched orientation preferences, but inhibitory interactions were found mostly in those with slightly different orientation preferences. In addition, common inputs and excitatory interactions tended to be found between cells with the same eye preference. 7. These results suggest that horizontal functional interactions exist mainly in a range of up to 400 microns as far as the extent of a hypercolumn of the visual cortex is concerned, and these interactions operate effectively between cortical cells with similar receptive field properties except for inhibitory interactions.

Action Potentials↗
PubMedDate not supplied

[Spectral correlation analysis of the potentials of the neocortex and certain subcortical structures during low-frequency electrical stimulation of nonspecific thalamic nuclei].

The spectral-correlation analysis of biopotentials in the cortex and some other brain structures (the anteroventral thalamic nucleus, dorsal hippocampus, lateral geniculate body, mid-brain reticular formation), in chronic experiments on alert rabbits, revealed that during electrical stimulation of thalamic mid-line nuclei within the ranges of 1-3, 4-7 and 8-10 c/s, there occured a rearrangement of the EEG frequencies; a dominant, narrow-band peak at the stimulation frequency, appeared. The coherence of the biopotentials of different cortical areas, of the cortex and subcortical formations increased during the stimulation at the frequency of the stimulation, reaching maximum values between the potentials of the visual and sensorimotor cortical areas.

Animals↗
PubMed1975

Correlation analysis of EEG changes during recognition of images of objects.

This work reports the results of both psychological and electrophysiological experiments. It was carried out on 15 normal subjects by the method of cross-correlation analysis of EEGs recorded during recognition of tachistoscopically presented images of objects. Changes in the random component Cr of the cross-correlation were larger during recognition than during simple mobilization of the subject's attention.

Brain↗
PubMed1986

Relationships between horizontal interactions and functional architecture in cat striate cortex as revealed by cross-correlation analysis.

Anatomical studies in the visual cortex have shown the presence of long-range horizontal connections with clustered axonal collaterals, suggesting interactions over distances of several millimeters. We used cross-correlation analysis in cat striate cortex to detect interactions between cells over comparable distances. Using one cell as a reference, we recorded from other cells with a second electrode at varying distances and looked for correlated firing between the two recording sites. This technique allowed us to combine a physiological measure of the strength and type of connection between cells with a characterization of their receptive field properties. The observed interactions were excitatory, and extended over horizontal distances of several millimeters. Furthermore, the interactions were between orientation columns of like specificity, resulting in a waxing and waning in the strength of interaction as the electrodes passed through different orientation columns. We studied relationships between strength of correlation and other receptive field properties and found a tendency for facilitatory interactions between cells sharing the same eye preference. A large proportion of our correlations was due to common input. This feature, and the similarity of interactions between cells in the same column with the reference cell, suggest a high degree of interconnectivity between and within the columns. As the distance between the two electrodes increased, the overlap of the receptive fields of the cells participating in the interactions gradually diminished. At the furthest distances recorded, the cell pairs had nonoverlapping receptive fields separated by several degrees. The distribution and range of these interactions corresponded to the clustering and extent of the horizontal connections observed anatomically.

Animals↗
PubMed1989

[Multiple correlation analysis of hormone parameters in sterile female patients with hyperandrogenism (correction of endometriosis)].

The authors examined 100 infertile women of reproductive age with various degrees of hyperandrogenism. As a result of multiple correlation analysis it was found that the state of hirsutism and the ratio of body weight to height are the most sensitive indicators of the testosterone action in reproductive age (r = + 0.56, p less than 0.1, r = + 0.60, p less than 0.05). There was no correlation between LH, FSH, PRLI, E2 T and K values. The assembled results suggest the variable character of factors which influence clinical manifestations of the disease and explain the heterogeneity of symptoms.

Adult↗
PubMed1976

[Spectral-correlation analysis of the bioelectrical activity of rabbit brain structures during electrosleep].

Changes of electric activity of the rabbit cortical and subcortical structures were studied by means of spectrum-correlation analysis during sleep caused by low-frequency stimulation of the supraoptic hypothalamic nucleus. The electrosleep affected the similarity of the electric events in neocortex and subcortical structures. The disturbance of the spatial synchronization is supposed to be due to the activity of nonsynchronized autonomous bioelectric pace-makers in different brain structures.

Animals↗
PubMed1987

HLA-DR-DQ haplotypes defined by restriction fragment analysis. Correlation to serology.

Through the analysis of RFLP (restriction fragment length polymorphism) of the HLA-DR beta, -DQ alpha, and -DQ beta genes from 70 serologically well-characterized individuals, we have established unique HLA-DR-DQ RFLP haplotypes correlating to all of the DR1-w14 specificities. The RFLP of DR beta, DQ alpha, and DQ beta genes is very high using the restriction enzyme TaqI and 21 DR-DQ RFLP haplotypes were defined with this restriction enzyme. Our analysis confirms the strong linkage disequilibrium between alleles in the DR and DQ loci. DR beta RFLP indicates a common ancestor for the DR alleles within either of the supertypic DRw52 and DRw53 specificities. The DQ beta gene shows a high degree of RFLP, and the RFLP alleles partly reflect the serologic DQw1-w3 specificities. The results presented here also demonstrate the heterogeneity of DRw6 (DRw13 and DRw14) associated haplotypes, and the DRw13 related Dw18 and Dw19 specificities were found to have distinct DR-DQ haplotypes. The DQw1 positive haplotypes DR1, 2, w10, w13, and w14 are related with regard to DQ alpha and DQ beta RFLPs and the DRw52 positive haplotypes DR3, w11, and w12, as well as the DRw53 positive haplotypes DR4, 7, and w9, are related with regard to DR beta and DQ alpha RFLPs. These findings indicate that polymorphic sequences around the DQ alpha gene are associated with DR beta and DQ beta polymorphism, which suggests a location of the DQ alpha gene between DR beta and DQ beta.

Alleles↗
PubMed1976

[Correlative analysis of chemical structure - biological activity using Hansch's method: principles and development of the method].

The basic principles and developments on which the Hansch multiple parameter approach depends are described. A correlation analysis on the antibacterial activity of 2-Y-4-(X-phenyl)-3H-1,5-benzodiazepines is discussed. The use of indicator varioables is shown to greatly increase one's ability to formulate quantitative structure-activity relationships. This approach allows one to carry out objective studies of massive amounts of chemical and biological data.

Bacteria↗
PubMed1977

Correlation analysis of delta activity generated in cerebral hypoxia.

1. Differences in spatial and temporal characteristics between polymorphous delta activity (PDA) and "standard slow complexes" (SSCS) resulting from grave cerebral hypoxia have been demonstrated by means of digital correlation analysis and on line recording of correlograms. 2. PDA observed in the human EEG and the ECoG of dogs is characterized by the absence of periodic organization (high extinction indices of auto- and crosscorrelation functions) and absence of spatial synchronization when recorded from widely separated areas of the hemispheres (low correlation coefficients, significant and variable time shifts), with bilateral symmetry of slow waves being preserved. 3. Delta waves recorded from nucleus amygdalae, nucleus caudatus, thalamus, hypothalamus and midbrain in the dog differ from cortical PDA by a more synchronous and rhythmically arranged process. 4. During the establishment of SSC activity correlograms show a synchronous process common to all cortical aand subcortical areas characteized by very high values of correlation coefficients. 5. It is suggested that the unorganized slow wave PDA process could arise under conditions of hypoxic dysfunction of distant cortico-cortical relationships, accompanied by weak subcortical pacemaker influences. The process reflects local coexcitation of relatively limited cortical areas. The particular statistical characteristics of SSCs generated during further increase in oxygen deficit can be accounted for by simultaneous generation of responses in some subcortical areas to single volleys of impulses from a hypothetical pacemaker, accompanied by a passive wave propagation towards a cortex completetly depressed by hypoxia

Adolescent↗
PubMed1989

[Studies on the origin of different discharge pattern of the two types of phrenic motoneurones by cross-correlation analysis].

Experiments were performed on twenty five anesthetized, paralyzed, vagotomized and artificially ventilated rabbits. Discharges of single phrenic nerve fibers were recorded. According to their discharge patterns, phrenic motoneurones were divided into two types: tonic units (TU) and phasic units (PU). A cross-correlation analysis was done between TU and TU, PU and PU, or TU and PU. In 21/36 pairs of phrenic motoneurones, the cross-correlation histogram showed a significant central peak, which represented synchronization of the pair of units resulting from a common input. There were three types of synchronization: short-term, broad peak and high frequency-oscillatory synchronization. The difference in synchronization number between heterogeneous pairs (1 TU and 1PU, 2/10 showing synchronization) and homogeneous pairs (2 TU or 2 PU, 19/26 showing synchronization) was statistically significant (x2-test, P less than 0.05). These results suggest that TU and PU have different central inputs, which result in their different discharge patterns between the TU and PU.

Animals↗
PubMed1979

A canonical correlation analysis of the Alcohol-Use Inventory and the Human Service Scale.

The responses of 312 persons with alcoholism to the Alcohol-Use Inventory and Human Service Scale were subjected to canonical correlation analysis. Results indicate that the relationship between alcohol-use constructs and psychological need satisfaction can be explained by two axes: a personal security--social dimension and a personal stress--environmental dimension. Microanalysis of the variates indicated that emotional need satisfaction was differentially influenced by social and physiological variables.

Adolescent↗
PubMed1991

Methods for correlation analysis of toxins and species present in random samples of phytoplankton.

We developed and tested two new procedures to find which species present in samples of phytoplankton is responsible for the production of a toxin. The procedures represent a different form of correlation analysis that uses information on the presence or absence of the toxin, and on the relative abundance of each species of plankton in the samples. The efficiency of the algorithms is tested by random process simulation. The algorithms were clearly superior to known techniques dealing with correlations between binary variables to show the toxin producing microorganism. We used experimental toxin isolation from phytoplankton as an example of practical success using the most efficient of the algorithms tested.

Algorithms↗
PubMed1986

Cross-correlation analysis of a recurrent inhibitory circuit in the rat thalamus.

Spontaneous activities of vibrissa-responding neurons in the rat ventrobasal complex (VB) and somatosensory part of the thalamic reticular nucleus (S-TR) were simultaneously recorded and subjected to cross-correlation analysis to investigate the functional organization of recurrent inhibitory action of the S-TR on VB neurons. Excitatory and/or inhibitory interactions were found between approximately 75% (25/34) of the pairs of S-TR and VB neurons with receptive fields (RFs) on the same vibrissa. In contrast, there was no significant interaction between 54 pairs of neurons having RFs on different vibrissae. Among the pairs of neurons with RFs on the same vibrissa, there were four types of correlations, which indicate the following connections: monosynaptic excitation from a VB to an S-TR neuron (7 pairs), monosynaptic inhibition from an S-TR to a VB neuron (10 pairs), reciprocal connection combining the above two types (7 pairs), and common excitation in addition to inhibition from an S-TR to a VB neuron (1 pair). Examples of divergence and convergence of connections between S-TR and VB neurons were demonstrated by testing one S-TR (VB) neuron with more than one VB (S-TR) neuron. Vibrissa-suppressed VB cells, which had exclusively inhibitory RFs, were included in eight pairs of the above samples. These VB cells were more likely to receive inhibitory inputs from S-TR neurons than other VB neurons. Cells with RFs on multiple vibrissae were included in the other 10 pairs. These multiple-vibrissa cells had no interaction with single-vibrissa cells but did with multiple-vibrissa cells. From the incidence of four types of correlation between S-TR and VB neurons with RFs on the same vibrissa, the following connection pattern is suggested: One S-TR neuron receives excitatory inputs from approximately 40% of the VB neurons with RFs on the same vibrissa and sends inhibitory outputs to approximately 55%. Since these two groups of VB neurons were overlapping, the S-TR neuron has reciprocal connections with approximately 20% of the VB neurons with RFs on the same vibrissa. The same estimate was applied to connectivity of one VB neuron. These results indicate that both inputs and outputs of S-TR neurons are precisely and topographically organized, although there is convergence to and divergence from a substantial number of VB neurons with RFs on the same vibrissa. It is proposed that the recurrent inhibitory circuit through the S-TR plays a role in improving discrimination of sensory information transmitted through the VB.

Action Potentials↗
PubMed1979

[Use of correlation analysis of clinical biochemical indices for a study of the pathogenesis of acute arterial obstruction].

The role of serotonin, histamine, and the kallikrein-kinin system in acute arterial occlusion during ischemia was studied from the standpoint of multivariate correlation analysis. The mechanisms of their participation in the genesis of pathophysiological disorders in the organism in acute arterial occlusion are discussed. The important role of serotonin and the kallikrein inhibitor in this pathological condition is shown.

Acute Disease↗