PT  - JOURNAL ARTICLE
AU  - Eriko Kuramoto
AU  - Yasuhiro R. Tanaka
AU  - Hiroyuki Hioki
AU  - Tetsuya Goto
AU  - Takeshi Kaneko
TI  - Local Connections of Pyramidal Neurons to Parvalbumin-Producing Interneurons in Motor-Associated Cortical Areas of Mice
AID  - 10.1523/ENEURO.0567-20.2021
DP  - 2021 Dec 20
TA  - eneuro
PG  - ENEURO.0567-20.2021
4099  - http://www.eneuro.org/content/early/2021/12/20/ENEURO.0567-20.2021.short
4100  - http://www.eneuro.org/content/early/2021/12/20/ENEURO.0567-20.2021.full
AB  - Parvalbumin (PV)-producing neurons are the largest subpopulation of cortical GABAergic interneurons, which mediate lateral, feedforward, and feedback inhibition in local circuits and modulate the activity of pyramidal neurons. Clarifying the specific connectivity between pyramidal and PV neurons is essential for understanding the role of PV neurons in local circuits. In the present study, we visualized somas and dendrites of PV neurons using transgenic mice in which PV neurons specifically express membrane-targeted GFP, and intracellularly labeled local axons of 26 pyramidal neurons in layers 2–6 in acute slices of the motor-associated cortex from transgenic mice. We mapped morphologically distribution of inputs from a pyramidal neuron to PV neurons based on contact sites (appositions) between the axons from an intracellularly filled pyramidal neuron and the dendrites of PV neurons. Layer 6 corticothalamic-like pyramidal neurons formed appositions to PV neurons at a significantly higher rate than other pyramidal neurons. The percentage of apposed varicosities to all the labeled varicosities of layer 6 corticothalamic-like neurons was 28%, and that of the other pyramidal neurons was 12%–19%. Layer 6 corticothalamic-like neurons preferentially formed appositions with PV neurons in layers 5b–6, while other pyramidal neurons uniformly formed appositions with PV neurons in all layers. Furthermore, both layer 6 corticothalamic-like and corticocortical-like neurons more frequently formed compound appositions, where two or more appositions were located on a dendritic branch, than other pyramidal neurons. Layer 6 CT neurons may contribute to intracortical information processing through preferential connections with PV neurons in layers 5b–6.Significance StatementLocal axons of 26 pyramidal neurons in layers 2–6 were intracellularly labeled in slices of the motor-associated cortex from transgenic mice in which somas/dendrites of PV neurons were labeled with GFP. We mapped the distribution of inputs to PV neurons based on contact sites (appositions) between axon varicosities of each pyramidal neuron and PV-neuron dendrites. The rate of appositions from layer 6 corticothalamic-like pyramidal neurons to PV neurons was higher than those of other pyramidal neurons, and connections were preferentially made in layers 5b–6. In contrast, other pyramidal neurons uniformly connected to PV neurons across all layers. Layer 6 CT neurons may contribute to intracortical information processing through preferential connections with PV neurons in layers 5b–6.