Electroencephalographic intercentral interaction as a reflection of normal and pathological human brain activity

The authors summarized EEG findings and defined the nature of the intercentral EEG relationships in different functional states in healthy subjects and patients with organic cerebral pathology, based on a coherence analysis. Similar EEG characteristics in healthy individuals were identified: an anterior-posterior gradient of average coherence levels, the type of cortical-subcortical relationships in anterior cerebral structures. Right- and left-handed individuals showed frequent and regional differences in EEG coherence, which mainly reflected specificity of intracortical relationships. Development and regression of pathology in right-and left-handed individuals with organic brain lesions were thought to be caused by these differences. Lesions of regulatory structures (diencephalic, brain stem and limbic structures) provoked a more diffused kind of changes of intercentral relationships, in contrast to cortical pathology. These changes tended to reciprocate. The dynamic nature of intercentral relationships and their interhemispheric differences was revealed when changing functional states of the brain (increase and decrease of functional level) in healthy individuals and patients with organic cerebral pathology in the process of conscious and psychic activity restoration. Changing activity predominance of certain regulatory structures was considered one of the most important factors determining the dynamic nature of EEG coherence. Keywords: EEG, coherence analysis, interhemispheric asymmetry, brain pathology Los autores resumen los resultados de las investigaciones de las relaciones intercentrales de EEG de personas sanas en distintos estados funcionales y de enfermos con lesiones organicas del SNC, mediante analisis de coherencia. Se revelan caracteristicas semejantes de la estructura de relaciones de EEG de personas sanas: la gradiente anterior-posterior de niveles medios de coherencia, el caracter de la interaccion cortical-subcortical de las secciones anteriores de los hemisferios. A su vez, se detectan diferencias de frecuencia y regionales en la coherencia de EEG en diestros y zurdos, que reflejan mayoritariamente la especificidad de la interaccion intracortical. Se cree que estas diferencias causan la especificidad del desarrollo y la regresion de los estados patologicos de diestros y zurdos en lesiones cerebrales organicas. Se senala que en las lesiones de formaciones reguladoras (diencefalicas, troncales, limbicas) Provocan unos cambios de las rela