Development of GABA innervation in the cerebral and cerebellar cortices

Abstract

In many areas of the vertebrate brain, such as the cerebral and cerebellar cortices, neural circuits rely on inhibition mediated by GABA (gamma-aminobutyric acid) to shape the spatiotemporal patterns of electrical signalling. The richness and subtlety of inhibition are achieved by diverse classes of interneurons that are endowed with distinct physiological properties. In addition, the axons of interneurons display highly characteristic and class-specific geometry and innervation patterns, and thereby distribute their output to discrete spatial domains, cell types and subcellular compartments in neural networks. The cellular and molecular mechanisms that specify and modify inhibitory innervation patterns are only just beginning to be understood.

Transmitter-receptor mismatch in GABAergic synapses in the absence of activity

“…This model allows the description of the entire process of new synapse formation. Therefore, although cellular and subcellular selectivity of GABAergic axons seem to be genetically determined (14), our results support the view that the density of GABAergic innervation is regulated by neuronal activity and by experience, both necessary to prevent the reconfiguration of circuits (15)(16)(17)(18).…”

Adrenergic Gating of Hebbian Spike-Timing-Dependent Plasticity in Cortical Interneurons

“…According to the pull-push model of neuromodulation tipping, the Gs/Gq11 balance toward Gs, by stimulation of ␤-adrenergic receptors, for example, should result in a state where only LTP is induced regardless of the order of presynaptic and postsynaptic firing (Seol et al, 2007;Huang et al, 2012). Conversely, stimulation of ␣1-adrenergic receptors should promote an LTD-only state.…”

“…Next, we examined whether stimulation of ␤-adrenergic receptors (coupled to Gs) and ␣1-adrenergic receptors (coupled to Gq/11) in conjunction with STDP protocols enable the induction of LTP and LTD in FS-PV cells as predicted by the pull-push model (Seol et al, 2007;Huang et al, 2012). In these experiments, the STDP pairings (pre-then-post to induce LTP, or post-thenpre to induce LTD; 10 ms delay in both cases) were selectively delivered to one pathway after a 10 min bath application of either the ␤-adrenergic agonist isoproterenol (Iso: 10 M) or the ␣1-adrenergic agonist methoxamine (Met: 10 M).…”

MicroRNA-134 activity in somatostatin interneurons regulates H-Ras localization by repressing the palmitoylation enzyme, DHHC9

“…Like most studies involving brain microRNAs, these reports make the implicit assumption that miR-134 is expressed uniformly in excitatory neurons. It is well known, however, that brain neurons are highly heterogeneous, and in many regions, excitatory (largely glutamatergic) and inhibitory (largely GABAergic) interneurons form complex networks that balance opposing actions (10). Although many microRNAs are probably expressed in both excitatory and inhibitory neurons, some are likely to be restricted to one or the other subclass.…”