Parvalbumin-positive basket cells differentiate among hippocampal pyramidal cells.
CA1 pyramidal cells (PCs) are not homogeneous but rather can be grouped by molecular, morphological, and functional properties. However, less is known about synaptic sources differentiating PCs. Using paired recordings in vitro, two-photon Ca(2+) imaging in vivo, and computational modeling, we found that parvalbumin-expressing basket cells (PVBCs) evoked greater inhibition in CA1 PCs located in the deep compared to superficial layer of stratum pyramidale. In turn, analysis of reciprocal connectivity revealed more frequent excitatory inputs to PVBCs by superficial PCs, demonstrating bias in target selection by both the excitatory and inhibitory local connections in CA1. Additionally, PVBCs further segregated among deep PCs, preferentially innervating the amygdala-projecting PCs but receiving preferential excitation from the prefrontal cortex-projecting PCs, thus revealing distinct perisomatic inhibitory interactions between separate output channels. These results demonstrate the presence of heterogeneous PVBC-PC microcircuits, potentially contributing to the sparse and distributed structure of hippocampal network activity.
Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA. Electronic address: sanghun.lee@uci.edu.
Sang-Hun
SH
Lee
Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA; Center for Autism Research and Treatment, University of California, Irvine, CA 92697, USA.
Ivan
I
Marchionni
Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA.
Marianne
M
Bezaire
Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA.
Csaba
C
Varga
Department of Neuroscience, Columbia University, New York, NY 10032, USA.
Nathan
N
Danielson
Department of Neuroscience, Columbia University, New York, NY 10032, USA.
Matthew
M
Lovett-Barron
Department of Neuroscience, Columbia University, New York, NY 10032, USA.
Attila
A
Losonczy
Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA; Center for Autism Research and Treatment, University of California, Irvine, CA 92697, USA.
Ivan
I
Soltesz
D000679:Amygdala / Q000166:cytology / Q000502:physiology; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000166:cytology* / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D018728:Entorhinal Cortex / Q000166:cytology / Q000502:physiology; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009415:Nerve Net / Q000502:physiology*; D010320:Parvalbumins / Q000378:metabolism; D010805:Physical Conditioning, Animal; D017397:Prefrontal Cortex / Q000166:cytology / Q000502:physiology; D017966:Pyramidal Cells / Q000502:physiology*
D010320:Parvalbumins; D002118:Calcium