Callosal and association neurons in the cortical space: a spectral analysis approach.
The tangential distributions of callosal neurons of area 5 projecting homotopically to the contralateral hemisphere and of association neurons of areas 4 and 6 projecting to ipsilateral area 5 were determined in the macaque monkey by using neuroanatomical methods based on the retrograde transport of horseradish peroxidase. Both distributions were studied qualitatively through 2-dimensional reconstructions of the cortical areas of origin and quantitatively through a spectral analysis. This approach facilitated the characterization of the spatial periodicities contained in these distributions revealing that, in area 5, callosal neurons were organized in bands of various shapes and width; these bands were composed of more discrete clusters of cells. In the frontal lobe, association neurons projecting to ipsilateral area 5 were arranged similarly. This study suggests that a common principle underlies the tangential organization of both callosal and association projecting cells in different cortical areas and emphasizes a basic similarity of interhemispheric and intrahemispheric connections.
Caminiti
R
R
Istituto di Fisiologia umana, Facoltà di Medicina, Università di Roma, Italy.
Johnson
P B
PB
Urbano
A
A
Georgopoulos
A P
AP
Zeger
S
S
D000818:Animals; D001931:Brain Mapping / Q000295:instrumentation; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D003196:Computer Graphics; D003337:Corpus Callosum / Q000033:anatomy & histology*; D004292:Dominance, Cerebral / Q000502:physiology; D004525:Efferent Pathways / Q000033:anatomy & histology; D005583:Fourier Analysis; D005625:Frontal Lobe / Q000033:anatomy & histology; D007091:Image Processing, Computer-Assisted; D008251:Macaca; D009474:Neurons / Q000648:ultrastructure; D010296:Parietal Lobe / Q000033:anatomy & histology