George Dragoi, MD, PhD
Research & Publications
Biography
News
Research Summary
Our cognitive life depends on our ability to generate internal representations of the external world. Internal representations can be driven by the external stimuli (e.g., perceptions) or can be internally-generated in their absence (e.g., imagining, memory). The dynamic interplay between externally-driven and internally-generated representations is thought to be disrupted in neuropsychiatric conditions such as schizophrenia, autism, and Alzheimer’s disease. The long-term goal of the lab is to map and dissect the neural circuits and decipher the neuronal codes underlying the formation of internal representations within hippocampal-neocortical networks that support innate and learned behavior, with implications for our understanding of neuropsychiatric diseases.
Extensive Research Description
Learned information is not encoded in isolation, but is integrated within a network of preexisting knowledge stored in patterns of neuronal ensemble functional connectivity. Our immediate goal is to investigate:
1. How these patterns emerge during development
2. How are they utilized in behavior
3. How are they disrupted in neuropsychiatric diseases.
The hippocampus, a brain structure initially implicated in rapid learning and formation of episodic memory, is now recognized to encode internally-generated spatial-temporal sequence representations. Its dysfunctions have resulted in anterograde amnesia, impaired imagining of new experiences, and hallucinations. Achieving our goal will be facilitated by our use of electrophysiological recordings of ensembles of neurons in behaving mice and rats, optogenetic manipulation of neurons, optical imaging of neuronal ensembles, and computational methods for decoding neuronal population activity.
Coauthors
Research Interests
Behavior, Animal; Cognition; Electrophysiology; Hippocampus; Learning; Neuronal Plasticity; Spatial Behavior; Spatial Memory; Psychiatry and Psychology
Public Health Interests
Mental Health
Selected Publications
- The generative grammar of the brain: a critique of internally generated representationsDragoi G. The generative grammar of the brain: a critique of internally generated representations. Nature Reviews Neuroscience 2023, 25: 60-75. PMID: 38036709, DOI: 10.1038/s41583-023-00763-0.
- Orientation selectivity enhances context generalization and generative predictive coding in the hippocampusLiu K, Sibille J, Dragoi G. Orientation selectivity enhances context generalization and generative predictive coding in the hippocampus. Neuron 2021, 109: 3688-3698.e6. PMID: 34506724, PMCID: PMC8602755, DOI: 10.1016/j.neuron.2021.08.013.
- The Ontogeny of Hippocampus-Dependent Memories.Donato F, Alberini CM, Amso D, Dragoi G, Dranovsky A, Newcombe NS. The Ontogeny of Hippocampus-Dependent Memories. Journal Of Neuroscience 2020, 41: 920-926. PMID: 33328296, PMCID: PMC7880290, DOI: 10.1523/jneurosci.1651-20.2020.
- Cell assemblies, sequences and temporal coding in the hippocampusDragoi G. Cell assemblies, sequences and temporal coding in the hippocampus. Current Opinion In Neurobiology 2020, 64: 111-118. PMID: 32375084, PMCID: PMC7606333, DOI: 10.1016/j.conb.2020.03.003.
- A consensus statement: defining terms for reactivation analysisGenzel L, Dragoi G, Frank L, Ganguly K, de la Prida L, Pfeiffer B, Robertson E. A consensus statement: defining terms for reactivation analysis. Philosophical Transactions Of The Royal Society B Biological Sciences 2020, 375: 20200001. PMID: 32248790, PMCID: PMC7209922, DOI: 10.1098/rstb.2020.0001.
- Strengthened Temporal Coordination within Pre-existing Sequential Cell Assemblies Supports Trajectory ReplayFarooq U, Sibille J, Liu K, Dragoi G. Strengthened Temporal Coordination within Pre-existing Sequential Cell Assemblies Supports Trajectory Replay. Neuron 2019, 103: 719-733.e7. PMID: 31253469, PMCID: PMC7197404, DOI: 10.1016/j.neuron.2019.05.040.
- Emergence of preconfigured and plastic time-compressed sequences in early postnatal developmentFarooq U, Dragoi G. Emergence of preconfigured and plastic time-compressed sequences in early postnatal development. Science 2019, 363: 168-173. PMID: 30630930, PMCID: PMC6794005, DOI: 10.1126/science.aav0502.
- Preconfigured patterns are the primary driver of offline multi‐neuronal sequence replayLiu K, Sibille J, Dragoi G. Preconfigured patterns are the primary driver of offline multi‐neuronal sequence replay. Hippocampus 2018, 29: 275-283. PMID: 30260526, PMCID: PMC6793999, DOI: 10.1002/hipo.23034.
- Generative Predictive Codes by Multiplexed Hippocampal Neuronal TupletsLiu K, Sibille J, Dragoi G. Generative Predictive Codes by Multiplexed Hippocampal Neuronal Tuplets. Neuron 2018, 99: 1329-1341.e6. PMID: 30146305, DOI: 10.1016/j.neuron.2018.07.047.
- Impaired Tuning of Neural Ensembles and the Pathophysiology of Schizophrenia: A Translational and Computational Neuroscience PerspectiveKrystal JH, Anticevic A, Yang GJ, Dragoi G, Driesen NR, Wang XJ, Murray JD. Impaired Tuning of Neural Ensembles and the Pathophysiology of Schizophrenia: A Translational and Computational Neuroscience Perspective. Biological Psychiatry 2017, 81: 874-885. PMID: 28434616, PMCID: PMC5407407, DOI: 10.1016/j.biopsych.2017.01.004.
- Selection of preconfigured cell assemblies for representation of novel spatial experiences.Dragoi G, Tonegawa S. Selection of preconfigured cell assemblies for representation of novel spatial experiences. Philosophical Transactions Of The Royal Society Of London. Series B, Biological Sciences 2014, 369: 20120522. PMID: 24366134, PMCID: PMC3866444, DOI: 10.1098/rstb.2012.0522.
- Development of schemas revealed by prior experience and NMDA receptor knock-out.Dragoi G, Tonegawa S. Development of schemas revealed by prior experience and NMDA receptor knock-out. ELife 2013, 2: e01326. PMID: 24327561, PMCID: PMC3851680, DOI: 10.7554/eLife.01326.
- Distinct preplay of multiple novel spatial experiences in the rat.Dragoi G, Tonegawa S. Distinct preplay of multiple novel spatial experiences in the rat. Proceedings Of The National Academy Of Sciences Of The United States Of America 2013, 110: 9100-5. PMID: 23671088, PMCID: PMC3670374, DOI: 10.1073/pnas.1306031110.
- Internal operations in the hippocampus: single cell and ensemble temporal coding.Dragoi G. Internal operations in the hippocampus: single cell and ensemble temporal coding. Frontiers In Systems Neuroscience 2013, 7: 46. PMID: 24009564, PMCID: PMC3756298, DOI: 10.3389/fnsys.2013.00046.
- Preplay of future place cell sequences by hippocampal cellular assemblies.Dragoi G, Tonegawa S. Preplay of future place cell sequences by hippocampal cellular assemblies. Nature 2011, 469: 397-401. PMID: 21179088, PMCID: PMC3104398, DOI: 10.1038/nature09633.
- Temporal encoding of place sequences by hippocampal cell assemblies.Dragoi G, Buzsáki G. Temporal encoding of place sequences by hippocampal cell assemblies. Neuron 2006, 50: 145-57. PMID: 16600862, DOI: 10.1016/j.neuron.2006.02.023.
- Place representation within hippocampal networks is modified by long-term potentiation.Dragoi G, Harris KD, Buzsáki G. Place representation within hippocampal networks is modified by long-term potentiation. Neuron 2003, 39: 843-53. PMID: 12948450, DOI: 10.1016/s0896-6273(03)00465-3.
- Organization of cell assemblies in the hippocampus.Harris KD, Csicsvari J, Hirase H, Dragoi G, Buzsáki G. Organization of cell assemblies in the hippocampus. Nature 2003, 424: 552-6. PMID: 12891358, DOI: 10.1038/nature01834.
- Homeostatic maintenance of neuronal excitability by burst discharges in vivo.Buzsáki G, Csicsvari J, Dragoi G, Harris K, Henze D, Hirase H. Homeostatic maintenance of neuronal excitability by burst discharges in vivo. Cerebral Cortex (New York, N.Y. : 1991) 2002, 12: 893-9. PMID: 12183388, DOI: 10.1093/cercor/12.9.893.
- Spike train dynamics predicts theta-related phase precession in hippocampal pyramidal cells.Harris KD, Henze DA, Hirase H, Leinekugel X, Dragoi G, Czurkó A, Buzsáki G. Spike train dynamics predicts theta-related phase precession in hippocampal pyramidal cells. Nature 2002, 417: 738-41. PMID: 12066184, DOI: 10.1038/nature00808.
- Hippocampal pyramidal cell-interneuron spike transmission is frequency dependent and responsible for place modulation of interneuron discharge.Marshall L, Henze DA, Hirase H, Leinekugel X, Dragoi G, Buzsáki G. Hippocampal pyramidal cell-interneuron spike transmission is frequency dependent and responsible for place modulation of interneuron discharge. The Journal Of Neuroscience : The Official Journal Of The Society For Neuroscience 2002, 22: RC197. PMID: 11784809, PMCID: PMC6758681.
- Interactions between hippocampus and medial septum during sharp waves and theta oscillation in the behaving rat.Dragoi G, Carpi D, Recce M, Csicsvari J, Buzsáki G. Interactions between hippocampus and medial septum during sharp waves and theta oscillation in the behaving rat. The Journal Of Neuroscience : The Official Journal Of The Society For Neuroscience 1999, 19: 6191-9. PMID: 10407055.