Microstructure of Neuronal Connections between the Visual Areas of the Cortex at Different Hierarchical Levels

• Published in: Neuroscience and behavioral physiology 2022-10, Vol.52 (8), p.1270-1276
• Main Authors: Alekseenko, S. V., Shkorbatova, P. Yu
• Format: Article
• Language: English
• Subjects: Behavioral Sciences; Biomedical and Life Sciences; Biomedicine; Cats; Horseradish peroxidase; Laboratory animals; Neurobiology; Neurons; Neurosciences; Physiology
• ISSN: 0097-0549; 1573-899X
• DOI: 10.1007/s11055-023-01356-1

The direct neuronal connections of the cortical visual areas at the lower level of the hierarchy with the areas of subsequent levels were studied by microiontophoretic administration of horseradish peroxidase into individual vertical columns in areas 19 and 21a and the distribution of retrograde labeled neurons in areas 17 and 18 was analyzed in cats. Columns in areas 19 and 21a, as compared with the eye-dominant columns of area 18, receive additional cortical inputs from the ipsilateral transition zone 17/18, which indicates a more complex structure of neuronal connections. The locations of input neurons from the transition zones 17/18 of different hemispheres were found to be mirror symmetrical, such that neurons in areas 19 and 21a columns can be tuned to loci located in the central sagittal plane of three-dimensional space. Inputs from areas 17 and 18 of the ipsilateral hemisphere, located outside the transition zone 17/18, were also identified, and these, in combination with inputs from both transition zones, can enable neurons in areas 19 and 21a columns to encode more complex stereo-features of objects.