engleski

Ventro-dorsal differences in proportions of gabaergic interneuron populations in the human prefrontal cortex

GABAergic interneurons are a diverse group of cortical neurons commonly identified with the following molecular markers – calretinin, parvalbumin, calbindin and somatostatin. We performed quantitative and qualitative analysis of these interneuron populations in dorsal (Brodmann area 9) and ventral (Brodmann area 14r) regions of the human prefrontal cortex (PFC) on five adult specimens using double labelling immunofluorescence. The interneuron markers were combined with each other as well as with NeuN. The proportion of each interneuron population within the total neuron population in both Brodmann areas (BA) was compared using a paired t-test. The analysis revealed substantial differences in ratios of interneuron populations between supragranular layers but not between infragranular layers. Calretinin neurons were the most numerous interneuron population in supragranular layers and somatostatin neurons were the most numerous in infragranular layers. Furthermore, somatostatin and calbindin neurons had different laminar molecular profiles – in supragranular layers, the level of somatostatin and calbindin co-expression was high, whereas in infragranular layers the level of co- expression was extremely low. The proportion of calretinin neurons was significantly higher in BA14r (average: 10.24%) than in BA9 (average: 8.21%). The proportions of other interneuron populations did not differ significantly between the two cortical regions, though the proportion of somatostatin neurons was on average higher in BA14r than in BA9. In addition, the ratio between calretinin and parvalbumin neurons was significantly higher in BA14r (average: 1.62) than in BA9 (average: 1.15). In conclusion, different proportions of GABAergic interneurons, particularly calretinin neurons, reflect the structural and functional differences between cortical regions.

GABAergic neurons ; calretinin ; parvalbumin ; calbindin ; somatostatin ; prefrontal cortex

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