Causal Evidence for the Role of Specific GABAergic Interneuron Types in Entorhinal Recruitment of Dentate Granule Cells.
The dentate gyrus (DG) is the primary gate of the hippocampus and controls information flow from the cortex to the hippocampus proper. To maintain normal function, granule cells (GCs), the principal neurons in the DG, receive fine-tuned inhibition from local-circuit GABAergic inhibitory interneurons (INs). Abnormalities of GABAergic circuits in the DG are associated with several brain disorders, including epilepsy, autism, schizophrenia, and Alzheimer disease. Therefore, understanding the network mechanisms of inhibitory control of GCs is of functional and pathophysiological importance. GABAergic inhibitory INs are heterogeneous, but it is unclear how individual subtypes contribute to GC activity. Using cell-type-specific optogenetic perturbation, we investigated whether and how two major IN populations defined by parvalbumin (PV) and somatostatin (SST) expression, regulate GC input transformations. We showed that PV-expressing (PV+) INs, and not SST-expressing (SST+) INs, primarily suppress GC responses to single cortical stimulation. In addition, these two IN classes differentially regulate GC responses to θ and γ frequency inputs from the cortex. Notably, PV+ INs specifically control the onset of the spike series, whereas SST+ INs preferentially regulate the later spikes in the series. Together, PV+ and SST+ GABAergic INs engage differentially in GC input-output transformations in response to various activity patterns.
Institute of Neuroscience, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 112, Taiwan.
Cheng-Ta
CT
Lee
Institute of Neuroscience, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 112, Taiwan.
Min-Hua
MH
Kao
Institute of Neuroscience, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 112, Taiwan.
Wen-Hsien
WH
Hou
Institute of Neuroscience, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 112, Taiwan.
Yu-Ting
YT
Wei
Institute of Neuroscience, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 112, Taiwan.
Chin-Lin
CL
Chen
Institute of Neuroscience, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 112, Taiwan.|Institute of Brain Science, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 112, Taiwan.|Brain Research Center, National Yang-Ming University, Taipei 112, Taiwan.|Charité Universitätsmedizin Berlin, 10117 Berlin, Germany.
Cheng-Chang
CC
Lien
D000200:Action Potentials; D000818:Animals; D018891:Dentate Gyrus / Q000166:cytology*; D018728:Entorhinal Cortex / Q000166:cytology*; D005260:Female; D059330:GABAergic Neurons / Q000502:physiology*; D007395:Interneurons / Q000502:physiology*; D008297:Male; D008810:Mice, Inbred C57BL; D009415:Nerve Net; D017207:Rats, Sprague-Dawley