ABSTRACT
Synchronous recruitment of fast-spiking (FS) parvalbumin (PV) interneurons generates gamma oscillations, rhythms that emerge during performance of cognitive tasks. Administration of N-methyl-D-aspartate (NMDA) receptor antagonists alters gamma rhythms, and can induce cognitive as well as psychosis-like symptoms in humans. The disruption of NMDA receptor (NMDAR) signaling specifically in FS PV interneurons is therefore hypothesized to give rise to neural network dysfunction that could underlie these symptoms. To address the connection between NMDAR activity, FS PV interneurons, gamma oscillations and behavior, we generated mice lacking NMDAR neurotransmission only in PV cells (PV-Cre/NR1f/f mice). Here, we show that mutant mice exhibit enhanced baseline cortical gamma rhythms, impaired gamma rhythm induction after optogenetic drive of PV interneurons and reduced sensitivity to the effects of NMDAR antagonists on gamma oscillations and stereotypies. Mutant mice show largely normal behaviors except for selective cognitive impairments, including deficits in habituation, working memory and associative learning. Our results provide evidence for the critical role of NMDAR in PV interneurons for expression of normal gamma rhythms and specific cognitive behaviors.
Subject(s)
Association Learning/physiology , Brain Waves/physiology , GABAergic Neurons/physiology , Interneurons/physiology , Memory, Short-Term/physiology , Receptors, N-Methyl-D-Aspartate/physiology , Animals , Association Learning/drug effects , Brain Waves/drug effects , Conditioning, Psychological/drug effects , Conditioning, Psychological/physiology , Excitatory Postsynaptic Potentials/drug effects , Excitatory Postsynaptic Potentials/physiology , GABA Antagonists/pharmacology , GABAergic Neurons/metabolism , Interneurons/drug effects , Male , Maze Learning/drug effects , Maze Learning/physiology , Memory, Short-Term/drug effects , Mice , Mice, Transgenic , Parvalbumins/metabolism , Photic Stimulation/methods , Picrotoxin/pharmacology , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Receptors, N-Methyl-D-Aspartate/genetics , Sensory Gating/drug effects , Sensory Gating/physiology , Stereotyped Behavior/drug effects , Stereotyped Behavior/physiologyABSTRACT
Recent studies have shown that cells expressing neuronal antigens can be derived from a bone marrow transplant. A new report lends support to and extends these previous results by presenting compelling morphological evidence for the generation and integration of highly differentiated bone marrow-derived neurons.
