Early postnatal development of the primary visual areas 17 and 18 of the cat cerebral cortex: An SMI‐32 study

• Published in: Journal of neuroscience research 2024-08, Vol.102 (8), p.e25375-n/a
• Main Authors: Mikhalkin, A. A., Nikitina, N. I., Merkulyeva, N. S.
• Format: Article
• Language: English
• Subjects: Accumulation; Animals; Animals, Newborn; area 17; area 18; cat; Cats; Cerebral cortex; Circuits; Density; Information processing; Labeling; Laminates; Motion detection; Neurofilament Proteins - metabolism; Neurofilaments; Neurons; Neurons - metabolism; ontogenesis; Parameters; primary visual cortex; Primary Visual Cortex - growth & development; Primary Visual Cortex - physiology; RRID:AB_2298772; RRID:AB_2336171; RRID:AB_2715852; SMI‐32; Thalamus
• ISSN: 0360-4012; 1097-4547; 1097-4547
• DOI: 10.1002/jnr.25375

Using anti‐neurofilament H non‐phosphorylated antibodies (SMI‐32) as markers for the neuronal maturation level and Y channel responsible for motion processing, we investigated early postnatal development of the primary visual areas 17 and 18 in cats aged 0, 10, 14, and 34 days and in adults. Two analyzed parameters of SMI‐32‐immunolabeling were used: the total proportion of SMI‐32‐labeling and the density of labeled neurons. (i) The developmental time course of the total proportion of SMI‐32‐labeling shows the general increase in the accumulation of heavy‐chain neurofilaments. This parameter showed a different time course for cortical layer development; the maximal increment in the total labeling in layer V occurred between the second and fifth postnatal weeks and in layers II–III and VI after the fifth postnatal week. In addition, the delay in accumulation of SMI‐32‐labeling was shown in layer V of the area 17 periphery representation during the first two postnatal weeks. (ii) The density of SMI‐32‐labeled neurons decreased in all layers of area 18, but was increased, decreased, or had a transient peak in layers II–III, V, and VI of area 17, respectively. The transient peak is in good correspondence with some transient neurochemical features previously revealed for different classes of cortical and thalamic neurons and reflects the time course of the early development of the thalamocortical circuitry. Some similarities between the time courses for the development of SMI‐32‐labeling in areas 17/18 and in A‐ and C‐laminae of the LGNd allow us to propose heterochronous postnatal development of two Y sub‐channels. Age dynamic of density of SMI‐32‐immunopositive neurons in the dorsal part of the lateral geniculate nucleus (LGNd) and primary visual cortex (areas 17 and 18) of cats. SMI‐32 antibodies as markers for the neuronal maturation level and the Y channel responsible for motion processing. The darker the hue, the more the neuronal density; the hues were calculated independently for every region of analysis. The gray and black arrows in the left scheme show the predominant connections of LGNd layers with areas 17 and 18. The transient peaks in the SMI‐32 density are in a good correspondence with some transient neurochemical features previously revealed for different classes of cortical and thalamic neurons and reflects the peculiarities of the early development of the thalamocortical circuitry and intracortical communication. Some similarities between the