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Altidor LKP, Bruner MM, Deslauriers JF, Garman TS, Ramirez S, Dirr EW, Olczak KP, Maurer AP, Lamb DG, Otto KJ, Burke SN, Bumanglag AV, Setlow B, Bizon JL. Acute vagus nerve stimulation enhances reversal learning in rats. Neurobiol Learn Mem 2021; 184:107498. [PMID: 34332068 DOI: 10.1016/j.nlm.2021.107498] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/24/2021] [Indexed: 01/19/2023]
Abstract
Cognitive flexibility is a prefrontal cortex-dependent neurocognitive process that enables behavioral adaptation in response to changes in environmental contingencies. Electrical vagus nerve stimulation (VNS) enhances several forms of learning and neuroplasticity, but its effects on cognitive flexibility have not been evaluated. In the current study, a within-subjects design was used to assess the effects of VNS on performance in a novel visual discrimination reversal learning task conducted in touchscreen operant chambers. The task design enabled simultaneous assessment of acute VNS both on reversal learning and on recall of a well-learned discrimination problem. Acute VNS delivered in conjunction with stimuli presentation during reversal learning reliably enhanced learning of new reward contingencies. Enhancement was not observed, however, if VNS was delivered during the session but was not coincident with presentation of to-be-learned stimuli. In addition, whereas VNS delivered at 30 HZ enhanced performance, the same enhancement was not observed using 10 or 50 Hz. Together, these data show that acute VNS facilitates reversal learning and indicate that the timing and frequency of the VNS are critical for these enhancing effects. In separate rats, administration of the norepinephrine reuptake inhibitor atomoxetine also enhanced reversal learning in the same task, consistent with a noradrenergic mechanism through which VNS enhances cognitive flexibility.
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Affiliation(s)
| | - Matthew M Bruner
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | | | - Tyler S Garman
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Saúl Ramirez
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Elliott W Dirr
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Kaitlynn P Olczak
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Andrew P Maurer
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA; Engineering School of Sustainable Infrastructure and Environment, University of Florida, Gainesville, FL, USA
| | - Damon G Lamb
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA; Brain Rehabilitation Research Center, Malcom Randall VAMC, Gainesville, FL, USA
| | - Kevin J Otto
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Sara N Burke
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Argyle V Bumanglag
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Barry Setlow
- Department of Psychiatry, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA
| | - Jennifer L Bizon
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Evelyn F. & William L. McKnight Brain Institute, University of Florida, USA.
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Greathouse KM, Boros BD, Deslauriers JF, Henderson BW, Curtis KA, Gentry EG, Herskowitz JH. Distinct and complementary functions of rho kinase isoforms ROCK1 and ROCK2 in prefrontal cortex structural plasticity. Brain Struct Funct 2018; 223:4227-4241. [PMID: 30196430 PMCID: PMC6252131 DOI: 10.1007/s00429-018-1748-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [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: 03/28/2018] [Accepted: 09/04/2018] [Indexed: 12/13/2022]
Abstract
Rho-associated protein kinases (ROCK) 1 and 2 are attractive drug targets for a range of neurologic disorders; however, a critical barrier to ROCK-based therapeutics is ambiguity over whether there are isoform-specific roles for ROCKs in neuronal structural plasticity. Here, we used a genetics approach to address this long-standing question by analyzing both male and female adult ROCK1+/- and ROCK2+/- mice compared to littermate controls. Individual pyramidal neurons in the medial prefrontal cortex (mPFC) were targeted for iontophoretic microinjection of fluorescent dye, followed by high-resolution confocal microscopy and neuronal 3D reconstructions for morphometry analysis. Increased apical and basal dendritic length and intersections were observed in ROCK1+/- but not ROCK2+/- mice. Although dendritic spine densities were comparable among genotypes, apical spine length was decreased in ROCK1+/- but increased in ROCK2+/- mice. Spine head and neck diameter were reduced similarly in ROCK1+/- and ROCK2+/- mice; however, certain spine morphologic subclasses were more affected than others in a genotype-dependent manner. Biochemical analyses of ROCK substrates in synaptic fractions revealed that phosphorylation of LIM kinase and cofilin were reduced in ROCK1+/- and ROCK2+/- mice, while phosphorylation of myosin light chain was decreased exclusively in ROCK1+/- mice. Collectively, these observations implicate ROCK1 as a novel regulatory factor of neuronal dendritic structure and detail distinct and complementary roles of ROCKs in mPFC dendritic spine structure.
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Affiliation(s)
- Kelsey M Greathouse
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, 35294, USA
| | - Benjamin D Boros
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, 35294, USA
| | - Josue F Deslauriers
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, 35294, USA
| | - Benjamin W Henderson
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, 35294, USA
| | - Kendall A Curtis
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, 35294, USA
| | - Erik G Gentry
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, 35294, USA
| | - Jeremy H Herskowitz
- Department of Neurology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, 35294, USA.
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