Activity-Dependent Modulation of Layer 1 Inhibitory Neocortical Circuits by Acetylcholine

158

124

How the brain takes in information, makes a decision, and acts on this decision is strongly influenced by the ongoing and constant fluctuations of state. Understanding the nature of these brain states and how they are controlled is critical to making sense of how the nervous system operates, both normally and abnormally. While broadly projecting neuromodulatory systems acting through metabotropic pathways have long been appreciated to be critical for determining brain state, more recent investigations have revealed a prominent role for fast acting neurotransmitter pathways for temporally and spatially precise control of neural processing. Corticocortical and thalamocortical glutamatergic projections can rapidly and precisely control brain state by changing both the nature of ongoing activity and by controlling the gain and precision of neural responses.

Section: Neurotransmitter Systems Involved In State Controlmentioning

confidence: 99%

Neural control of brain state

Zagha

McCormick

2014

158

124

“…[101] found an M1-mediated hyperpolarization of NGFCs produced by the activation of SK Ca 2+ -activated K + channels by the same signaling cascade as that producing hyperpolarization of pyramidal cells (see note d). The muscarinic inhibition of the NGFCs disinhibited the apical dendrites of layer II/III pyramidal neurons by removing the GABA B receptor-mediated inhibition of the apical dendrites produced by the GABA released by NGFCs.…”

Section: Figurementioning

confidence: 99%

Spatiotemporal specificity in cholinergic control of neocortical function

Muñoz

Rudy

2014

127

112

Cholinergic actions are critical for normal cortical cognitive functions. The release of acetylcholine (ACh) in neocortex and the impact of this neuromodulator on cortical computations exhibit remarkable spatiotemporal precision, as required for the regulation of behavioral processes underlying attention and learning. We discuss how the organization of the cholinergic projections to the cortex and their release properties might contribute to this specificity. We also review recent studies suggesting that the modulatory influences of ACh on the properties of cortical neurons can have the necessary temporal dynamic range, emphasizing evidence of powerful interneuron subtype-specific effects. We discuss areas that require further investigation and point to technical advances in molecular and genetic manipulations that promise to make headway in understanding the neural bases of cholinergic modulation of cortical cognitive operations.

“…In the cortex, both excite CGE-derived/5HT3aR+ interneurons via ionotropic receptors [14**] while causing metabotropic receptor mediated presynaptic depression of PV+ interneurons [38]. Furthermore, although cortical neurogliaform cells (which are 5HT3aR+) strongly inhibit layer 2/3 pyramidal cells [48], they are selectively hyperpolarized by activation of mAChRs, which may further enhance pyramidal cell disinhibition [49]. However, this is of course only one, of many, possible circuit configurations which likely vary depending on brain region.…”

Section: Neuromodulation Of Distinct Interneuron Subtypes Has Differementioning

confidence: 99%

Behavioral state-dependent modulation of distinct interneuron subtypes and consequences for circuit function

Wester¹,

McBain²

2014

Multiple neuromodulators regulate neuronal response properties and synaptic connections in order to adjust circuit function. Inhibitory interneurons are a diverse group of cells that are differentially modulated depending on neuronal subtype and play key roles in regulating local circuit activity. Importantly, new tools to target specific subtypes are greatly improving our understanding of interneuron circuits and their modulation. Indeed, recent work has demonstrated that during different behavioral states interneuron activity changes in a subtype specific manner in both neocortex and hippocampus. Furthermore, in neocortex, modulation of specific interneuron microcircuits results in pyramidal cell disinhibition with important consequences for synaptic plasticity and animal behavior. Thus, neurmodulators tune the output of different interneuron subtypes to provide neural circuits with great flexibility.