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The Effects of the Inhalant Toluene on Cognitive Function and Behavioral Flexibility: A Review of Recent Findings. ADDICTION NEUROSCIENCE 2023; 5:100059. [PMID: 36798693 PMCID: PMC9928149 DOI: 10.1016/j.addicn.2022.100059] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Substance use disorder (SUD) is characterized, in part, by lack of control over drug seeking and taking. The prefrontal cortex (PFC) is highly involved in control of behavior and deficits in PFC structure and function have been demonstrated in clinical and preclinical studies of SUD. Of the various classes of drugs associated with the development of SUD, inhalants are among the least studied despite their widespread use among adolescents and children. In this work, we review what is currently known regarding the sites and mechanisms of action of inhalants with a focus on the volatile solvent toluene that is contained in a wide variety of legal and easily obtained products. We then describe how inhalants including toluene affect various behaviors with an emphasis on those associated with PFC function and how chronic use of inhalants alters brain structure and neuronal signaling. Findings from these studies highlight advances made in recent years that have expanded our understanding of the effects of inhalants on brain structure and reinforce the need for continued work in this field.
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The Abused Inhalant Toluene Impairs Medial Prefrontal Cortex Activity and Risk/Reward Decision-Making during a Probabilistic Discounting Task. J Neurosci 2019; 39:9207-9220. [PMID: 31548237 DOI: 10.1523/jneurosci.1674-19.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/11/2019] [Accepted: 09/17/2019] [Indexed: 12/29/2022] Open
Abstract
Inhalant (e.g., toluene) misuse is linked to behavioral and cognitive deficits in humans, yet preclinical studies of the effect of inhalants on higher-order cognition are limited. We addressed this gap in the literature by examining the effect of toluene vapor exposure on risk/reward decision-making in male and female Sprague-Dawley rats using a probabilistic discounting task. In this task, rodents chose a risky/large reward or a safe/small reward, with the odds of risky reinforcement descending or ascending throughout the test session. We observed a dose-dependent, sex-independent deficit in behavioral flexibility during probabilistic discounting caused by acute toluene exposure. Rats exposed to toluene vapor during adolescence and tested as adults performed comparably to air-treated controls and were susceptible to the effects of an acute toluene challenge. These behavioral flexibility deficits observed suggests dysfunctional medial prefrontal cortex (mPFC) activity. To address this hypothesis, we virally expressed the genetically encoded calcium sensor GCaMP6f in glutamatergic mPFC neurons and monitored calcium transients in real-time using in vivo fiber photometry. mPFC activity peaked before either lever press during free-choice trials in toluene- and air-treated animals. During forced-choice trials, GCaMP6f transients shifted from pre-risky to pre-safe choice, an effect mitigated by acute toluene exposure. mPFC activity decreased during rewarded trials, with larger decreases following risky/large wins compared with safe/small wins. Toluene-treated animals also had decreased mPFC activity during rewarded trials, but there was no distinction between risky/large wins and safe/small wins. These results provide physiological evidence for mPFC-dependent behavioral deficits caused by toluene.SIGNIFICANCE STATEMENT Inhalants (e.g., toluene) are an understudied class of drugs of abuse that cause devastating behavioral and cognitive deficits in humans. Understanding the neurobiological interactions of toluene vapor using animal models is important for developing effective treatment strategies for inhalant addicts. Here we find that toluene vapor reduces behavioral flexibility in rodents making risk/reward-based decisions. The medial prefrontal cortex (mPFC) drives behavioral flexibility during this type of decision-making and we show that toluene reduces the ability of mPFC neurons to track optimal choices as reward probabilities change. Toluene also reduces these neurons' ability to distinguish between small and large rewards. A combination of these factors likely leads to the impaired performance in probabilistic discounting following acute toluene exposure.
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Marín-Navarrete R, Toledo-Fernández A, Villalobos-Gallegos L, Pérez-López A, Medina-Mora ME. Neuropsychiatric characterization of individuals with inhalant use disorder and polysubstance use according to latent profiles of executive functioning. Drug Alcohol Depend 2018; 190:104-111. [PMID: 30005309 DOI: 10.1016/j.drugalcdep.2018.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/29/2018] [Accepted: 06/05/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND Inhalant use disorder (IUD) is associated with deficits in executive functions (EFs). We described latent profiles of EFs and distribution of neuropsychiatric disorders and patterns of severity of use across these profiles. METHODS Individuals with IUD were recruited at community-based residential facilities for substance use treatment in Mexico City. Latent profile analysis was conducted with the following tasks: self-ordered pointing, Stroop, Iowa gambling, Wisconsin Card Sorting and Tower of Hanoi. RESULTS Three latent profiles were extracted from n = 165: lowest performances of inhibition of response and processing speed; lowest performance of self-monitoring, intermediate performance of inhibition of response and relatively spared processing speed; and intermediate performance of processing speed and self-monitoring, and relatively spared inhibition of response. CONCLUSION Between-group differences were observed mainly for antisocial personality disorder and lifetime suicidal. Findings remark the need for identifying distinct profiles of EFs within these populations to better understand the transdiagnostic heterogeneity of EFs.
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Affiliation(s)
- Rodrigo Marín-Navarrete
- Clinical Trials Unit on Addiction and Mental Health, National Institute of Psychiatry Ramón de la Fuente Muñiz, México-Xochimilco 101, Tlalpan, 14370, Mexico City, Mexico; National Institute of Psychiatry Ramón de la Fuente Muñiz, México-Xochimilco 101, Tlalpan, 14370, Mexico City, Mexico.
| | - Aldebarán Toledo-Fernández
- Clinical Trials Unit on Addiction and Mental Health, National Institute of Psychiatry Ramón de la Fuente Muñiz, México-Xochimilco 101, Tlalpan, 14370, Mexico City, Mexico
| | - Luis Villalobos-Gallegos
- Clinical Trials Unit on Addiction and Mental Health, National Institute of Psychiatry Ramón de la Fuente Muñiz, México-Xochimilco 101, Tlalpan, 14370, Mexico City, Mexico
| | - Alejandro Pérez-López
- Clinical Trials Unit on Addiction and Mental Health, National Institute of Psychiatry Ramón de la Fuente Muñiz, México-Xochimilco 101, Tlalpan, 14370, Mexico City, Mexico
| | - María Elena Medina-Mora
- National Institute of Psychiatry Ramón de la Fuente Muñiz, México-Xochimilco 101, Tlalpan, 14370, Mexico City, Mexico
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Tamnes CK, Roalf DR, Goddings AL, Lebel C. Diffusion MRI of white matter microstructure development in childhood and adolescence: Methods, challenges and progress. Dev Cogn Neurosci 2017; 33:161-175. [PMID: 29229299 PMCID: PMC6969268 DOI: 10.1016/j.dcn.2017.12.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/18/2017] [Accepted: 12/04/2017] [Indexed: 12/13/2022] Open
Abstract
Diffusion magnetic resonance imaging (dMRI) continues to grow in popularity as a useful neuroimaging method to study brain development, and longitudinal studies that track the same individuals over time are emerging. Over the last decade, seminal work using dMRI has provided new insights into the development of brain white matter (WM) microstructure, connections and networks throughout childhood and adolescence. This review provides an introduction to dMRI, both diffusion tensor imaging (DTI) and other dMRI models, as well as common acquisition and analysis approaches. We highlight the difficulties associated with ascribing these imaging measurements and their changes over time to specific underlying cellular and molecular events. We also discuss selected methodological challenges that are of particular relevance for studies of development, including critical choices related to image acquisition, image analysis, quality control assessment, and the within-subject and longitudinal reliability of dMRI measurements. Next, we review the exciting progress in the characterization and understanding of brain development that has resulted from dMRI studies in childhood and adolescence, including brief overviews and discussions of studies focusing on sex and individual differences. Finally, we outline future directions that will be beneficial to the field.
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Affiliation(s)
| | - David R Roalf
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Catherine Lebel
- Department of Radiology, Cumming School of Medicine, and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
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Braunscheidel KM, Gass JT, Mulholland PJ, Floresco SB, Woodward JJ. Persistent cognitive and morphological alterations induced by repeated exposure of adolescent rats to the abused inhalant toluene. Neurobiol Learn Mem 2017; 144:136-146. [PMID: 28720405 PMCID: PMC5583007 DOI: 10.1016/j.nlm.2017.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 07/07/2017] [Accepted: 07/14/2017] [Indexed: 12/20/2022]
Abstract
While thepsychoactive inhalant toluene causes behavioral effects similarto those produced by other drugs of abuse, the persistent behavioral and anatomical abnormalities induced by toluene exposure are not well known. To mimic human "binge-like" inhalant intoxication, adolescent, male Sprague-Dawley rats were exposed to toluene vapor (5700ppm) twice daily for five consecutive days. These rats remained in their home cages until adulthood (P60), when they were trained in operant boxes to respond to a palatable food reward and then challenged with several different cognitive tasks. Rats that experienced chronic exposure to toluene plus abstinence ("CTA") showed enhanced performance in a strategy set-shifting task using a between-session, but not a within-session test design. CTA also blunted operant and classical conditioning without affecting responding during a progressive ratio task. While CTA rats displayed normal latent inhibition, previous exposure to a non-reinforced cue enhanced extinction of classically conditioned approach behavior of these animals compared to air controls. To determine whether CTA alters the structural plasticity of brain areas involved in set-shifting and appetitive behaviors, we quantified basal dendritic spine morphology in DiI-labeled pyramidal neurons in layer 5 of the medial prefrontal cortex (mPFC) and medium spiny neurons in the nucleus accumbens (NAc). There were no changes in dendritic spine density or subtype in the mPFC of CTA rats while NAc spine density was significantly increased due to an enhanced prevalence of long-thin spines. Together, these findings suggest that the persistent effects of CTA on cognition are related to learning and memory consolidation/recall, but not mPFC-dependent behavioral flexibility.
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Affiliation(s)
- K M Braunscheidel
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
| | - J T Gass
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 67 President Street, Charleston, SC 29425, USA
| | - P J Mulholland
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 67 President Street, Charleston, SC 29425, USA
| | - S B Floresco
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada
| | - J J Woodward
- Department of Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA; Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 67 President Street, Charleston, SC 29425, USA.
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Orthostatic tremor secondary to recreational use of solvents. NEUROLOGÍA (ENGLISH EDITION) 2017. [DOI: 10.1016/j.nrleng.2015.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Abstract
BACKGROUND Since peaking in the 1990s, inhalant abuse has steadily decreased over the past two decades. Concurrently, nearly every state has passed legislation aimed at minimizing inhalant abuse. While males have historically been more likely to abuse inhalants than females, there is no longer a sex effect in self-reported rates of inhalant abuse. OBJECTIVES The objective of the present study is to evaluate the effect of anti-inhalant abuse legislation on self-reported rates of inhalant abuse, in high school age males and females. METHODS Beginning in 1993, the CDC's biannual Youth Risk Behavior Surveillance Survey asked respondents if they have ever used inhalants to get high. Data from these surveys were collected, along with the date of passage of anti-inhalant abuse legislation in 46 of 50 states. ANOVAs were conducted to assess the effect of legislation on self-reported inhalant abuse rates. RESULTS There were no significant main effects or interactions that demonstrated that inhalant abuse rates decreased in males or females following passage of legislation aimed at decreasing inhalant abuse. Conclusion/Importance: To date, 46 of 50 states have passed laws aimed at minimizing inhalant abuse, and while inhalant abuse rates have been decreasing for the past two decades, there is no evidence that this decline is related to enactment of these laws. Further research is needed to determine the cause of the decrease in inhalant abuse. The laws may benefit from amendments to include options for treatment.
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Affiliation(s)
- Jeffery C Batis
- a Psychology , Indiana University Kokomo , Kokomo , Indiana , USA
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Silveri MM, Dager AD, Cohen-Gilbert JE, Sneider JT. Neurobiological signatures associated with alcohol and drug use in the human adolescent brain. Neurosci Biobehav Rev 2016; 70:244-259. [PMID: 27377691 DOI: 10.1016/j.neubiorev.2016.06.042] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/17/2016] [Accepted: 06/30/2016] [Indexed: 01/02/2023]
Abstract
Magnetic resonance (MR) techniques provide opportunities to non-invasively characterize neurobiological milestones of adolescent brain development. Juxtaposed to the critical finalization of brain development is initiation of alcohol and substance use, and increased frequency and quantity of use, patterns that can lead to abuse and addiction. This review provides a comprehensive overview of existing MR studies of adolescent alcohol and drug users. The most common alterations reported across substance used and MR modalities are in the frontal lobe (63% of published studies). This is not surprising, given that this is the last region to reach neurobiological adulthood. Comparatively, evidence is less consistent regarding alterations in regions that mature earlier (e.g., amygdala, hippocampus), however newer techniques now permit investigations beyond regional approaches that are uncovering network-level vulnerabilities. Regardless of whether neurobiological signatures exist prior to the initiation of use, this body of work provides important direction for ongoing prospective investigations of adolescent brain development, and the significant impact of alcohol and substance use on the brain during the second decade of life.
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Affiliation(s)
- Marisa M Silveri
- Neurodevelopmental Laboratory on Addictions and Mental Health, McLean Hospital, Belmont, MA, USA; McLean Imaging Center, McLean Hospital, Belmont, MA, USA; Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
| | - Alecia D Dager
- Olin Neuropsychiatry Research Center, Hartford, CT, USA; Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Julia E Cohen-Gilbert
- Neurodevelopmental Laboratory on Addictions and Mental Health, McLean Hospital, Belmont, MA, USA; McLean Imaging Center, McLean Hospital, Belmont, MA, USA; Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jennifer T Sneider
- Neurodevelopmental Laboratory on Addictions and Mental Health, McLean Hospital, Belmont, MA, USA; McLean Imaging Center, McLean Hospital, Belmont, MA, USA; Department of Psychiatry, Harvard Medical School, Boston, MA, USA
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Cruz Tabuenca H, Camacho Velásquez JL, Rivero Sanz E, Sánchez Valiente S, López Del Val J. Orthostatic tremor secondary to recreational use of solvents. Neurologia 2015; 32:401-403. [PMID: 26699207 DOI: 10.1016/j.nrl.2015.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/23/2015] [Accepted: 10/09/2015] [Indexed: 10/22/2022] Open
Affiliation(s)
- H Cruz Tabuenca
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
| | - J L Camacho Velásquez
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España.
| | - E Rivero Sanz
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
| | - S Sánchez Valiente
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
| | - J López Del Val
- Servicio de Neurología, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España
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