Brown-Séquard: On neural networks and brain localization of functions

Abstract

The notion that the brain (encephalon) is a network of interconnected neurons has a long and memorable history. Cytoarchitectonic and hodological studies coupled with advanced neuroimaging techniques have produced a substantial body of knowledge on structural and functional organization. Acquiring the rich knowledge held today took a long and winding journey. Important advancements were made in the 19th century, with the remarkable Brown-Séquard figuring as one of the protagonists. Regarding the brain, he proposed nine mental and physical functions (organs) related to distributed cell clusters, interconnected according to their roles, the "network of anastomosing cells", dynamically submitted to "dynamogenic and inhibitory activities", and "action at a distance" concepts, the latter also related to his notion of "recovery". It is remarkable that someone was able to propose, ahead of his time, and with the limited technical resources available, such significant concepts that paved the way for the current state of knowledge.

Diagnóstico do comprometimento cognitivo vascular: recomendações do Departamento Científico de Neurologia Cognitiva e do Envelhecimento da Academia Brasileira de Neurologia

“…In addition, there are no widely accepted criteria in relation to the location and number of lesions necessary for the neuropathological diagnosis of VCI 34 )-( 37 . Several neuropathologic events seem to contribute to the occurrence of VCI, including loss of white matter integrity with consequent disconnection between strategic areas for cognitive networks 16 , changes in the coagulation cascade 38 and oligodendrocytes 39 , and changes in endothelial cells with alterations in cerebral blood perfusion 40 .…”

“…As lesões cerebrais vasculares compreendem as modalidades isquêmicas (infartos, microinfartos, lacunas, hiperintensidades da substância branca, espaços perivasculares alargados) e hemorrágicas (infartos hemorrágicos, hemorragias cerebrais e microhemorragias), que se apresentam de modo variável, não havendo uma lesão neuropatológica única para a caracterização do CCV, assim como não há critérios amplamente aceitos em relação à localização e quantidade necessária de lesões para o diagnóstico neuropatológico de CCV [34][35][36][37] . Diversos eventos neuropatológicos parecem contribuir para a ocorrência de DCV, entre eles, perda da integridade da substância branca com consequente desconexão entre áreas estratégicas para as redes cognitivas 16 , alterações da cascata de coagulação 38 , dos oligodendrócitos 39 , modificações das células endoteliais 40 , com alterações na perfusão sanguínea cerebral.…”

Diagnosis of vascular cognitive impairment: recommendations of the scientific department of cognitive neurology and aging of the Brazilian Academy of Neurology

“…In addition, there are no widely accepted criteria in relation to the location and number of lesions necessary for the neuropathological diagnosis of VCI [34][35][36][37] . Several neuropathologic events seem to contribute to the occurrence of VCI, including loss of white matter integrity with consequent disconnection between strategic areas for cognitive networks 16 , changes in the coagulation cascade 38 and oligodendrocytes 39 , and changes in endothelial cells with alterations in cerebral blood perfusion 40 .…”