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Studtmann C, Ladislav M, Safari M, Khondaker R, Chen Y, Vaughan GA, Topolski MA, Tomović E, Balík A, Swanger SA. Ventral posterolateral and ventral posteromedial thalamocortical neurons have distinct physiological properties. J Neurophysiol 2023; 130:1492-1507. [PMID: 37937368 PMCID: PMC11068404 DOI: 10.1152/jn.00525.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 10/09/2023] [Accepted: 11/01/2023] [Indexed: 11/09/2023] Open
Abstract
Somatosensory information is propagated from the periphery to the cerebral cortex by two parallel pathways through the ventral posterolateral (VPL) and ventral posteromedial (VPM) thalamus. VPL and VPM neurons receive somatosensory signals from the body and head, respectively. VPL and VPM neurons may also receive cell type-specific GABAergic input from the reticular nucleus of the thalamus. Although VPL and VPM neurons have distinct connectivity and physiological roles, differences in their functional properties remain unclear as they are often studied as one ventrobasal thalamus neuron population. Here, we directly compared synaptic and intrinsic properties of VPL and VPM neurons in C57Bl/6J mice of both sexes aged P25-P32. VPL neurons showed greater depolarization-induced spike firing and spike frequency adaptation than VPM neurons. VPL and VPM neurons fired similar numbers of spikes during hyperpolarization rebound bursts, but VPM neurons exhibited shorter burst latency compared with VPL neurons, which correlated with larger sag potential. VPM neurons had larger membrane capacitance and more complex dendritic arbors. Recordings of spontaneous and evoked synaptic transmission suggested that VPL neurons receive stronger excitatory synaptic input, whereas inhibitory synapse strength was stronger in VPM neurons. This work indicates that VPL and VPM thalamocortical neurons have distinct intrinsic and synaptic properties. The observed functional differences could have important implications for their specific physiological and pathophysiological roles within the somatosensory thalamocortical network.NEW & NOTEWORTHY This study revealed that somatosensory thalamocortical neurons in the VPL and VPM have substantial differences in excitatory synaptic input and intrinsic firing properties. The distinct properties suggest that VPL and VPM neurons could process somatosensory information differently and have selective vulnerability to disease. This work improves our understanding of nucleus-specific neuron function in the thalamus and demonstrates the critical importance of studying these parallel somatosensory pathways separately.
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Affiliation(s)
- Carleigh Studtmann
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Marek Ladislav
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
| | - Mona Safari
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Rabeya Khondaker
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Yang Chen
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, United States
| | - Grace A Vaughan
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, Virginia, United States
| | - Mackenzie A Topolski
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
| | - Eni Tomović
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Aleš Balík
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Sharon A Swanger
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, United States
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States
- Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, Virginia, United States
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Studtmann C, Ladislav M, Topolski MA, Safari M, Swanger SA. NaV1.1 haploinsufficiency impairs glutamatergic and GABAergic neuron function in the thalamus. Neurobiol Dis 2022; 167:105672. [DOI: 10.1016/j.nbd.2022.105672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 02/08/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
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