1
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Autonomous Purkinje cell activation instructs bidirectional motor learning through evoked dendritic calcium signaling. Nat Commun 2021; 12:2153. [PMID: 33846328 PMCID: PMC8042043 DOI: 10.1038/s41467-021-22405-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 03/01/2021] [Indexed: 01/19/2023] Open
Abstract
The signals in cerebellar Purkinje cells sufficient to instruct motor learning have not been systematically determined. Therefore, we applied optogenetics in mice to autonomously excite Purkinje cells and measured the effect of this activity on plasticity induction and adaptive behavior. Ex vivo, excitation of channelrhodopsin-2-expressing Purkinje cells elicits dendritic Ca2+ transients with high-intensity stimuli initiating dendritic spiking that additionally contributes to the Ca2+ response. Channelrhodopsin-2-evoked Ca2+ transients potentiate co-active parallel fiber synapses; depression occurs when Ca2+ responses were enhanced by dendritic spiking. In vivo, optogenetic Purkinje cell activation drives an adaptive decrease in vestibulo-ocular reflex gain when vestibular stimuli are paired with relatively small-magnitude Purkinje cell Ca2+ responses. In contrast, pairing with large-magnitude Ca2+ responses increases vestibulo-ocular reflex gain. Optogenetically induced plasticity and motor adaptation are dependent on endocannabinoid signaling, indicating engagement of this pathway downstream of Purkinje cell Ca2+ elevation. Our results establish a causal relationship among Purkinje cell Ca2+ signal size, opposite-polarity plasticity induction, and bidirectional motor learning. Plastic reweighting of parallel fiber synaptic strength is a mechanism for the acquisition of cerebellum-dependent motor learning. Here, the authors found that optogenetic activation of PCs generates dendritic Ca2+ signals that induce plasticity in vitro and instruct learned changes to coincident eye movements in vivo.
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2
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Moussa-Tooks AB, Hetrick WP, Green JT. Differential effects of two early life stress paradigms on cerebellar-dependent delay eyeblink conditioning. Neurobiol Stress 2020; 13:100242. [PMID: 33344698 PMCID: PMC7739029 DOI: 10.1016/j.ynstr.2020.100242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/23/2020] [Accepted: 07/14/2020] [Indexed: 11/11/2022] Open
Abstract
Early life stress paradigms have become prominent in the animal literature to model atypical development. Currently, two models have prevailed within the literature: (1) limited bedding or nesting and (2) maternal separation or deprivation. Both models have produced aberrations spanning behavior and neural circuitry. Surprisingly, these two models have yet to be directly compared. The current study utilized delay eyeblink conditioning, an associative learning task with a well-defined cerebellar circuit, to compare the behavioral effects of standard limited bedding (postnatal day 2–9, n = 15) and maternal separation (60 min per day during postnatal day 2–14, n = 13) early life stress paradigms. Animals in all groups exhibited robust learning curves. Surprisingly, facilitated conditioning was observed in the maternal separation group. Rats that underwent limited bedding did not differ from the control or maternal separation groups on any conditioning measures. This study contributes to a clearer understanding of early life stress paradigms and the claims made about their mechanisms, which if better clarified can be properly leveraged to increase translational value.
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Affiliation(s)
- Alexandra B Moussa-Tooks
- Psychological & Brain Sciences, Indiana University, Bloomington, IN, United States.,Program in Neuroscience, Indiana University, Bloomington, IN, United States
| | - William P Hetrick
- Psychological & Brain Sciences, Indiana University, Bloomington, IN, United States.,Program in Neuroscience, Indiana University, Bloomington, IN, United States.,Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - John T Green
- Department of Psychological Science, University of Vermont, Burlington, VT, United States
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3
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Hirono M, Yanagawa Y. Endocannabinoids regulate cerebellar GABAergic transmission in a synapse type-dependent manner. J Neurosci Res 2020; 99:898-913. [PMID: 33271631 DOI: 10.1002/jnr.24765] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 11/03/2020] [Accepted: 11/14/2020] [Indexed: 12/28/2022]
Abstract
Endocannabinoids (eCBs) act as ubiquitous modulators of synaptic transmission via the activation of cannabinoid receptors (CBRs). Cerebellar Purkinje cells (PCs) make strong inhibitory synaptic contacts not only with neurons in the deep cerebellar nuclei (DCN) but also with Lugaro cells and globular cells, whose cell bodies are located underneath the PC layer. However, little is known about the modulatory actions of eCBs on GABA release from PC axon terminals. Here, we examined the effects of eCBs on the GABAergic transmission at PC-globular cell synapses and PC-large DCN neuron synapses electrophysiologically using mouse cerebellar slices. We showed that the types 1 and 2 CBR agonist WIN55212 did not affect either spontaneous or miniature inhibitory postsynaptic currents (IPSCs) in globular cells under control conditions and in a state of enhanced synaptic activity. By contrast, another Gi/o protein-coupled receptor agonist, baclofen, significantly reduced the miniature IPSC frequency in globular cells. WIN55212 had no effects on IPSCs in large DCN neurons. A type 2 CBR agonist, HU308, also had no effects on IPSCs in either globular cells or large DCN neurons. Moreover, the PCs' target neurons did not elicit depolarization-induced suppression of inhibition. These results suggest the lack of a functional role of CBRs at PCs' axon terminals. This is in sharp contrast to the fact that PCs receive abundant excitatory and inhibitory inputs that are under eCB-mediated presynaptic inhibitory modulation. The actions of eCBs are selective to distinct synapses and possibly contribute to information processes and rigorous signal transmission in the cerebellum.
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Affiliation(s)
- Moritoshi Hirono
- Organization for Research Initiatives and Development, Doshisha University, Kyoto, Japan.,Laboratory for Motor Learning Control, RIKEN BSI, Wako, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
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4
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Albergaria C, Silva NT, Darmohray DM, Carey MR. Cannabinoids modulate associative cerebellar learning via alterations in behavioral state. eLife 2020; 9:61821. [PMID: 33077026 PMCID: PMC7575324 DOI: 10.7554/elife.61821] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/01/2020] [Indexed: 02/06/2023] Open
Abstract
Cannabinoids are notorious and profound modulators of behavioral state. In the brain, endocannabinoids act via Type 1-cannabinoid receptors (CB1) to modulate synaptic transmission and mediate multiple forms of synaptic plasticity. CB1 knockout (CB1KO) mice display a range of behavioral phenotypes, in particular hypoactivity and various deficits in learning and memory, including cerebellum-dependent delay eyeblink conditioning. Here we find that the apparent effects of CB1 deletion on cerebellar learning are not due to direct effects on CB1-dependent plasticity, but rather, arise as a secondary consequence of altered behavioral state. Hypoactivity of CB1KO mice accounts for their impaired eyeblink conditioning across both animals and trials. Moreover, learning in these mutants is rescued by walking on a motorized treadmill during training. Finally, cerebellar granule-cell-specific CB1KOs exhibit normal eyeblink conditioning, and both global and granule-cell-specific CB1KOs display normal cerebellum-dependent locomotor coordination and learning. These findings highlight the modulation of behavioral state as a powerful independent means through which individual genes contribute to complex behaviors.
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Affiliation(s)
- Catarina Albergaria
- Champalimaud Neuroscience Program, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - N Tatiana Silva
- Champalimaud Neuroscience Program, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Dana M Darmohray
- Champalimaud Neuroscience Program, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Megan R Carey
- Champalimaud Neuroscience Program, Champalimaud Center for the Unknown, Lisbon, Portugal
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5
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Moussa-Tooks AB, Larson ER, Gimeno AF, Leishman E, Bartolomeo LA, Bradshaw HB, Green JT, O'Donnell BF, Mackie K, Hetrick WP. Long-Term Aberrations To Cerebellar Endocannabinoids Induced By Early-Life Stress. Sci Rep 2020; 10:7236. [PMID: 32350298 PMCID: PMC7190863 DOI: 10.1038/s41598-020-64075-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/07/2020] [Indexed: 12/25/2022] Open
Abstract
Emerging evidence points to the role of the endocannabinoid system in long-term stress-induced neural remodeling with studies on stress-induced endocannabinoid dysregulation focusing on cerebral changes that are temporally proximal to stressors. Little is known about temporally distal and sex-specific effects, especially in cerebellum, which is vulnerable to early developmental stress and is dense with cannabinoid receptors. Following limited bedding at postnatal days 2-9, adult (postnatal day 70) cerebellar and hippocampal endocannabinoids, related lipids, and mRNA were assessed, and behavioral performance evaluated. Regional and sex-specific effects were present at baseline and following early-life stress. Limited bedding impaired peripherally-measured basal corticosterone in adult males only. In the CNS, early-life stress (1) decreased 2-arachidonoyl glycerol and arachidonic acid in the cerebellar interpositus nucleus in males only; (2) decreased 2-arachidonoyl glycerol in females only in cerebellar Crus I; and (3) increased dorsal hippocampus prostaglandins in males only. Cerebellar interpositus transcriptomics revealed substantial sex effects, with minimal stress effects. Stress did impair novel object recognition in both sexes and social preference in females. Accordingly, the cerebellar endocannabinoid system exhibits robust sex-specific differences, malleable through early-life stress, suggesting the role of endocannabinoids and stress to sexual differentiation of the brain and cerebellar-related dysfunctions.
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Affiliation(s)
- Alexandra B Moussa-Tooks
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
| | - Eric R Larson
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Alex F Gimeno
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Emma Leishman
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
| | - Lisa A Bartolomeo
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Heather B Bradshaw
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
| | - John T Green
- Department of Psychological Science, University of Vermont, Burlington, VT, USA
| | - Brian F O'Donnell
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ken Mackie
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Linda and Jack Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - William P Hetrick
- Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, USA.
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.
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6
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Steinmetz AB, Freeman JH. Intracerebellar cannabinoid administration impairs delay but not trace eyeblink conditioning. Behav Brain Res 2019; 378:112258. [PMID: 31560921 DOI: 10.1016/j.bbr.2019.112258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/22/2019] [Accepted: 09/22/2019] [Indexed: 10/26/2022]
Abstract
Intracerebellar administration of cannabinoid agonists impairs cerebellum-dependent delay eyeblink conditioning (EBC) in rats. It is not known whether the cannabinoid-induced impairment in EBC is found with shorter interstimulus intervals (ISI), longer ISIs, or with trace EBC. Moreover, systemic administration of cannabinoid agonists does not impair trace EBC, suggesting that cannabinoid receptors within the cerebellum are not involved in trace EBC. To more precisely assess the effects of cannabinoids on cerebellar learning mechanisms the current study examined the effects of the cannabinoid agonist WIN55,212-2 (WIN) infusion into the area of the cerebellar cortex necessary for EBC (the eyeblink microzone) in rats during short delay (250 ms CS), long delay (750 ms CS), and trace (250 ms CS, 500 ms trace interval) EBC. WIN was infused into the eyeblink microzone 30 min before pretraining sessions and five EBC training sessions, followed by five EBC training sessions without infusions to assess recovery from drug effects and savings. WIN had no effect on spontaneous blinks or non-associative responses to the CS or US during the pretraining sessions. Short and long delay EBC were impaired by WIN but trace EBC was unaffected. The results indicate that trace EBC is mediated by mechanisms that are resistant to cannabinoid agonists.
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Affiliation(s)
- Adam B Steinmetz
- Department of Psychological and Brain Sciences, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242 USA
| | - John H Freeman
- Department of Psychological and Brain Sciences, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242 USA.
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7
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Yang Y, Kreko-Pierce T, Howell R, Pugh JR. Long-term depression of presynaptic cannabinoid receptor function at parallel fibre synapses. J Physiol 2019; 597:3167-3181. [PMID: 31020998 DOI: 10.1113/jp277727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 04/18/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Inhibition of synaptic responses by activation of presynaptic cannabinoid type-1 (Cb1) receptors is reduced at parallel fibre synapses in the cerebellum following 4 Hz stimulation. Activation of adenylyl cyclase is necessary and sufficient for down-regulation of Cb1 receptors induced by 4 Hz stimulation. 4 Hz stimulation reduces Cb1 receptor function by (i) increasing the rate of endocannabinoid clearance from the synapse and (ii) decreasing expression of Cb1 receptors. ABSTRACT Cannabinoid type-1 receptors (Cb1R) are expressed in the presynaptic membrane of many synapses, including parallel fibre-Purkinje cell synapses in the cerebellum, where they are involved in short- and long-term plasticity of synaptic responses. We show that Cb1R expression itself is a plastic property of the synapse regulated by physiological activity patterns. We made patch clamp recordings from Purkinje cells in cerebellar slices and assessed Cb1R activity by measuring depolarization-induced suppression of excitation (DSE). We find that DSE is normally stable at parallel fibre synapses but, following 4 Hz stimulation, DSE is persistently reduced and recovers more rapidly. Using a combination of electrophysiology, pharmacology and biochemistry, we show that changes in DSE are a result of the reduced expression of Cb1Rs and increased degradation of endocannabinoids by monoacylglycerol lipase. Long-term changes in presynaptic Cb1R expression may alter other forms of Cb1R-dependent plasticity at parallel fibre synapses, priming or inhibiting the circuit for associative learning.
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Affiliation(s)
- Ying Yang
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA.,Xiangya School of Medicine, Department of Pain, The Third Xiangya Hospital and Institute of Pain Medicine, Central South University, Changsha, Hunan Province, China
| | - Tabita Kreko-Pierce
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA
| | - Rebecca Howell
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA.,Present address: Oklahoma Medical Research Foundation & University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Jason R Pugh
- University of Texas Health Science Center at San Antonio, Department of Cellular and Integrative Physiology, San Antonio, TX, USA.,Center for Biomedical Neuroscience, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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8
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Steinmetz AB, Freeman JH. Cannabinoid agonist administration within the cerebellar cortex impairs motor learning. Neurobiol Learn Mem 2018; 170:106896. [PMID: 29964164 DOI: 10.1016/j.nlm.2018.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/12/2018] [Accepted: 06/27/2018] [Indexed: 02/01/2023]
Abstract
Systemic administration of cannabinoid agonists impairs cerebellum-dependent motor learning. The cannabinoid-induced impairment of motor learning has been hypothesized to be due to disruption of Purkinje cell plasticity within the cerebellar cortex. In the current study, we tested this hypothesis in rats with localized microinfusions of cannabinoid agonists and antagonists into the cerebellar cortex during eyeblink conditioning, a type of cerebellum-dependent motor learning. Infusions of the cannabinoid agonists WIN55,212-2 or ACEA directly into the eyeblink conditioning microzone of the cerebellar cortex severely impaired acquisition of eyeblink conditioning, whereas the CB1R antagonist SR141716A did not produce a significant impairment. Infusions of WIN55,212-2 outside of the eyeblink conditioning microzone did not impair motor learning, establishing anatomical specificity for the agonist effects. The motor learning impairment caused by WIN55,212-2 and ACEA was rescued by SR141716A, indicating that the learning deficit was produced through CB1Rs. The current findings demonstrate that the effects of cannabinoid receptor agonists on motor learning are localized to CB1Rs within a discrete microzone of the cerebellar cortex.
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Affiliation(s)
- Adam B Steinmetz
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, IA 52242, USA
| | - John H Freeman
- Department of Psychological and Brain Sciences, The University of Iowa, Iowa City, IA 52242, USA.
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9
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Steinmetz AB, Freeman JH. Cannabinoid modulation of memory consolidation within the cerebellum. Neurobiol Learn Mem 2016; 136:228-235. [PMID: 27818269 DOI: 10.1016/j.nlm.2016.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/01/2016] [Accepted: 11/02/2016] [Indexed: 10/20/2022]
Abstract
Cannabinoid receptors contribute to learning and synaptic plasticity mechanisms. The cerebellum contains a high density of cannabinoid receptors and manipulations of cannabinoid receptors affect synaptic plasticity within the cerebellar cortex. In vivo studies have found that cannabinoid agonists impair learning of cerebellum-dependent eyeblink conditioning in rodents and humans. However, the role of cannabinoid receptors or endocannabinoids in memory consolidation within the cerebellum has not been examined. In the current study, we examined the role of cannabinoid receptors and endocannabinoids during learning and consolidation of eyeblink conditioning in rats. Administration of the cannabinoid receptor agonist WIN55,212-2 or drugs that increase/decrease endocannabinoid levels directly into the cerebellar cortex before each training session resulted in marked learning impairments. When administered 1 h after each training session, during memory consolidation, the cannabinoid inverse agonist SR141716A or the endocannabinoid suppressor THL impaired memory. In contrast, increasing endocannabinoid levels with JZL-184 or infusion of WIN55,212-2 within the cerebellar cortex facilitated memory consolidation 1h post-training. Intracerebellar manipulations of cannabinoid receptors or endocannabinoid levels had no effect on memory consolidation when administered 3 or 6h after each training session. The results demonstrate that cannabinoids impair cerebellar learning, but facilitate memory consolidation mechanisms within the cerebellar cortex 1-3h after training.
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Affiliation(s)
- Adam B Steinmetz
- Center for Neural Science, New York University, New York, NY, USA
| | - John H Freeman
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA.
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10
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Stephens GJ. Does modulation of the endocannabinoid system have potential therapeutic utility in cerebellar ataxia? J Physiol 2016; 594:4631-41. [PMID: 26970080 PMCID: PMC4983615 DOI: 10.1113/jp271106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 02/04/2016] [Indexed: 12/12/2022] Open
Abstract
Cerebellar ataxias represent a spectrum of disorders which are, however, linked by common symptoms of motor incoordination and typically associated with deficiency in Purkinje cell firing activity and, often, degeneration. Cerebellar ataxias currently lack a curative agent. The endocannabinoid (eCB) system includes eCB compounds and their associated metabolic enzymes, together with cannabinoid receptors, predominantly the cannabinoid CB1 receptor (CB1R) in the cerebellum; activation of this system in the cerebellar cortex is associated with deficits in motor coordination characteristic of ataxia, effects which can be prevented by CB1R antagonists. Of further interest are various findings that CB1R deficits may also induce a progressive ataxic phenotype. Together these studies suggest that motor coordination is reliant on maintaining the correct balance in eCB system signalling. Recent work also demonstrates deficient cannabinoid signalling in the mouse ‘ducky2J’ model of ataxia. In light of these points, the potential mechanisms whereby cannabinoids may modulate the eCB system to ameliorate dysfunction associated with cerebellar ataxias are considered.
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Affiliation(s)
- G J Stephens
- School of Pharmacy, University of Reading, Reading, RG6 6AJ, UK
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11
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Arjmand S, Vaziri Z, Behzadi M, Abbassian H, Stephens GJ, Shabani M. Cannabinoids and Tremor Induced by Motor-related Disorders: Friend or Foe? Neurotherapeutics 2015; 12:778-87. [PMID: 26152606 PMCID: PMC4604184 DOI: 10.1007/s13311-015-0367-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Tremor arises from an involuntary, rhythmic muscle contraction/relaxation cycle and is a common disabling symptom of many motor-related diseases such as Parkinson disease, multiple sclerosis, Huntington disease, and forms of ataxia. In the wake of anecdotal, largely uncontrolled, observations claiming the amelioration of some symptoms among cannabis smokers, and the high density of cannabinoid receptors in the areas responsible for motor function, including basal ganglia and cerebellum, many researchers have pursued the question of whether cannabinoid-based compounds could be used therapeutically to alleviate tremor associated with central nervous system diseases. In this review, we focus on possible effects of cannabinoid-based medicines, in particular on Parkinsonian and multiple sclerosis-related tremors and the common probable molecular mechanisms. While, at present, inconclusive results have been obtained, future investigations should extend preclinical studies with different cannabinoids to controlled clinical trials to determine potential benefits in tremor.
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Affiliation(s)
- Shokouh Arjmand
- Kerman Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Zohreh Vaziri
- Kerman Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Mina Behzadi
- Kerman Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Hassan Abbassian
- Kerman Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Gary J Stephens
- School of Pharmacy, University of Reading, Whiteknights, P.O. Box 228, Reading, RG6 6AJ, UK.
| | - Mohammad Shabani
- Kerman Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
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12
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Steinmetz AB, Freeman JH. Differential effects of the cannabinoid agonist WIN55,212-2 on delay and trace eyeblink conditioning. Behav Neurosci 2014; 127:694-702. [PMID: 24128358 DOI: 10.1037/a0034210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Central cannabinoid-1 receptors (CB1R) play a role in the acquisition of delay eyeblink conditioning (EBC) but not trace EBC in humans and animals. However, it is not clear why trace conditioning is immune to the effects of cannabinoid receptor compounds. The current study examined the effects of variants of delay and trace conditioning procedures to elucidate the factors that determine the effects of CB1R agonists on EBC. In Experiment 1, rats were administered the cannabinoid agonist WIN55,212-2 during delay, long-delay, or trace conditioning. Rats were impaired during delay and long-delay, but not trace conditioning; the impairment was greater for long-delay than delay conditioning. Trace conditioning was further examined in Experiment 2 by manipulating the trace interval and keeping constant the conditioned stimulus (conditional stimulus [CS]) duration. It was found that when the trace interval was 300 ms or less, WIN55,212-2 administration impaired the rate of learning. Experiment 3 tested whether the trace interval duration or the relative durations of the CS and trace interval were critical parameters influencing the effects of WIN55,212-2 on EBC. Rats were not impaired with a 100-ms CS, 200-ms trace paradigm but were impaired with a 1,000-ms CS, 500-ms trace paradigm, indicating that the duration of the trace interval does not matter, but the proportion of the interstimulus interval occupied by the CS relative to the trace period is critical. Taken together, the results indicate that cannabinoid agonists affect cerebellar learning when the CS is longer than the trace interval.
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13
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Evaluation of bidirectional interstimulus interval (ISI) shift in auditory delay eye-blink conditioning in healthy humans. Learn Behav 2012; 39:358-70. [PMID: 21562779 DOI: 10.3758/s13420-011-0031-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Delay eye-blink conditioning is an associative learning task that can be utilized to probe the functional integrity of the cerebellum and related neural circuits. Typically, a single interstimulus interval (ISI) is utilized, and the amplitude of the conditioned response (CR) is the primary dependent variable. To study the timing of the CR, an ISI shift can be introduced (e.g., shifting the ISI from 350 to 850 ms). In each phase, a conditioned stimulus (e.g., a 400- or 900-ms tone) coterminates with a 50-ms corneal air puff unconditioned stimulus. The ability of a subject to adjust the CR to the changing ISI constitutes a critical timing shift. The feasibility of this procedure was examined in healthy human participants (N = 58) using a bidirectional ISI shift procedure while cortical event-related brain potentials were measured. CR acquisition was faster and the responses better timed when a short ISI was used. After the ISI shift, additional training was necessary to allow asymptotic responding at the new ISI. Interestingly, auditory event-related potentials to the CR were not associated with conditioning measures at either ISI.
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14
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Steinmetz AB, Edwards CR, Vollmer JM, Erickson MA, O’Donnell BF, Hetrick WP, Skosnik PD. Examining the effects of former cannabis use on cerebellum-dependent eyeblink conditioning in humans. Psychopharmacology (Berl) 2012; 221:133-41. [PMID: 22134474 PMCID: PMC3517929 DOI: 10.1007/s00213-011-2556-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 10/19/2011] [Indexed: 10/15/2022]
Abstract
RATIONALE Previous work in humans has shown that chronic cannabis users exhibit disruptions in classical eyeblink conditioning (EBC), a form of associative learning that is known to be dependent on the cerebellum. Based upon previous work in animals, it was hypothesized that these learning deficits were related to cannabinoid receptor (CB1R) downregulation. However, it remains unclear whether there is a recovery of cerebellum-dependent learning after the cessation of cannabis use. METHODS Therefore, former cannabis users (n=10), current cannabis users (n=10), and cannabis-naïve controls (n=10), all free of DSM-IV Axis-I or -II disorders, were evaluated. A standard delay EBC procedure was utilized in which paired presentations of a conditioned stimulus (CS; e.g., tone) and a co-terminating unconditioned stimulus (US; e.g., ocular airpuff) were administered, thus eliciting a conditioned eyeblink response (CR). The primary dependent measures were percentage of CRs and CR latency across conditioning blocks. RESULTS Similar to prior studies, current cannabis users exhibited marked impairments in both the acquisition and timing of CRs compared to controls. Although former cannabis users showed intact CR acquisition compared to controls, they exhibited significantly impaired (shorter) CR latencies. In both cannabis groups, UR amplitude did not differ from controls, indicating normal US processing. CONCLUSIONS These data suggest that a recovery of function has occurred for the learning of the CS-US association, while the accurate timing of the CR shows lasting impairments. Taken together, these results suggest that heavy cannabis use can disrupt timing-related synaptic plasticity within the cerebellum, even after the cessation of cannabis use.
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Affiliation(s)
- Adam B. Steinmetz
- Department of Psychology, University of Iowa, Iowa City, IA 52242, USA
| | - Chad R. Edwards
- Department of Psychological and Brain Sciences, Indiana University, 1101 E. 10th St., Bloomington, IN 47405, USA
| | - Jennifer M. Vollmer
- Department of Psychiatry, Yale University School of Medicine, 300 George St., Suite 901, New Haven, CT 06511, USA
| | - Molly A. Erickson
- Department of Psychological and Brain Sciences, Indiana University, 1101 E. 10th St., Bloomington, IN 47405, USA
| | - Brian F. O’Donnell
- Department of Psychological and Brain Sciences, Indiana University, 1101 E. 10th St., Bloomington, IN 47405, USA
| | - William P. Hetrick
- Department of Psychological and Brain Sciences, Indiana University, 1101 E. 10th St., Bloomington, IN 47405, USA
| | - Patrick D. Skosnik
- Department of Psychiatry, Yale University School of Medicine, 300 George St., Suite 901, New Haven, CT 06511, USA. VA Connecticut Healthcare System, Building 1, 950 Campbell Avenue, West Haven, CT 06516, USA
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Retention and extinction of delay eyeblink conditioning are modulated by central cannabinoids. Learn Mem 2011; 18:634-8. [PMID: 21940395 DOI: 10.1101/lm.2254111] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Rats administered the cannabinoid agonist WIN55,212-2 or the antagonist SR141716A exhibit marked deficits during acquisition of delay eyeblink conditioning, as noted by Steinmetz and Freeman in an earlier study. However, the effects of these drugs on retention and extinction of eyeblink conditioning have not been assessed. The present study examined the effects of WIN55,212-2 and SR141716A on retention and extinction of delay eyeblink conditioning in rats. Rats were given acquisition training for five daily sessions followed by one session of retention training with subcutaneous administration of 3 mg/kg of WIN55,212-2 or 5 mg/kg of SR141716A and an additional session with the vehicle. Two sessions of extinction training were then given with WIN55,212-2, SR141716A, or vehicle. Retention and extinction were impaired by WIN55,212-2, whereas SR141716A produced no deficits. The extinction deficit in rats given WIN55,212-2 was observed only during the first session, suggesting a specific impairment in short-term plasticity mechanisms. The current results and previous findings indicate that the cannabinoid system modulates cerebellar contributions to acquisition, retention, and extinction of eyeblink conditioning.
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