Article

Functional Maturation of GABA Synapses During Postnatal Development of the Monkey Dorsolateral Prefrontal Cortex

Cerebral Cortex (Impact Factor: 8.67). 06/2014; 25(11). DOI: 10.1093/cercor/bhu122
Source: PubMed

ABSTRACT

Development of inhibition onto pyramidal cells may be crucial for the emergence of cortical network activity, including gamma
oscillations. In primate dorsolateral prefrontal cortex (DLPFC), inhibitory synaptogenesis starts in utero and inhibitory
synapse density reaches adult levels before birth. However, in DLPFC, the expression levels of γ-aminobutyric acid (GABA)
synapse-related gene products changes markedly during development until young adult age, suggesting a highly protracted maturation
of GABA synapse function. Therefore, we examined the development of GABA synapses by recording GABAAR-mediated inhibitory postsynaptic currents (GABAAR-IPSCs) from pyramidal cells in the DLPFC of neonatal, prepubertal, peripubertal, and adult macaque monkeys. We found that
the decay of GABAAR-IPSCs, possibly including those from parvalbumin-positive GABA neurons, shortened by prepubertal age, while their amplitude
increased until the peripubertal period. Interestingly, both GABAAR-mediated quantal response size, estimated by miniature GABAAR-IPSCs, and the density of GABAAR synaptic appositions, measured with immunofluorescence microscopy, were stable with age. Simulations in a computational
model network with constant GABA synapse density showed that the developmental changes in GABAAR-IPSC properties had a significant impact on oscillatory activity and predicted that, whereas DLPFC circuits can generate
gamma frequency oscillations by prepubertal age, mature levels of gamma band power are attained at late stages of development.

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Available from: Guillermo Gonzalez Burgos, Oct 01, 2014
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