1
|
Nejati V, Peyvandi A, Nazari N, Dehghan M. Cognitive Correlates of Risky Decision-Making in Individuals with and without ADHD: A Meta-analysis. Neuropsychol Rev 2024:10.1007/s11065-024-09646-2. [PMID: 38902592 DOI: 10.1007/s11065-024-09646-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 05/27/2024] [Indexed: 06/22/2024]
Abstract
This meta-analytic study aims to investigate the cognitive correlates of risky decision-making in individuals with attention-deficit/hyperactivity disorder (ADHD) and typically developing (TD) individuals. A systematic analysis of existing literature was conducted, encompassing 38 studies (496 ADHD and 1493 TD). Findings revealed a consistent propensity for riskier decision-making in individuals with ADHD, supported by significant correlations with attention, cognitive flexibility, inhibitory control, time perception, and working memory. The study underscores the relevance of these cognitive functions in shaping decision-making tendencies, with nuanced patterns observed within the ADHD and TD subgroups. Individuals with ADHD often demonstrate altered patterns of correlation, reflecting the specific cognitive challenges characteristic of the disorder.
Collapse
Affiliation(s)
- Vahid Nejati
- Department of Psychology, Shahid Beheshti University, PO Box 1983969411, Tehran, Iran.
| | - Aida Peyvandi
- Department of Psychology, Shahid Beheshti University, PO Box 1983969411, Tehran, Iran
| | - Nasim Nazari
- Department of Psychology, Shahid Beheshti University, PO Box 1983969411, Tehran, Iran
| | - Mahshid Dehghan
- Department of Psychology, Shahid Beheshti University, PO Box 1983969411, Tehran, Iran
| |
Collapse
|
2
|
Aster HC, Waltmann M, Busch A, Romanos M, Gamer M, Maria van Noort B, Beck A, Kappel V, Deserno L. Impaired flexible reward learning in ADHD patients is associated with blunted reinforcement sensitivity and neural signals in ventral striatum and parietal cortex. Neuroimage Clin 2024; 42:103588. [PMID: 38471434 PMCID: PMC10943992 DOI: 10.1016/j.nicl.2024.103588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 02/06/2024] [Accepted: 02/28/2024] [Indexed: 03/14/2024]
Abstract
Reward-based learning and decision-making are prime candidates to understand symptoms of attention deficit hyperactivity disorder (ADHD). However, only limited evidence is available regarding the neurocomputational underpinnings of the alterations seen in ADHD. This concerns flexible behavioral adaption in dynamically changing environments, which is challenging for individuals with ADHD. One previous study points to elevated choice switching in adolescent ADHD, which was accompanied by disrupted learning signals in medial prefrontal cortex. Here, we investigated young adults with ADHD (n = 17) as compared to age- and sex-matched controls (n = 17) using a probabilistic reversal learning experiment during functional magnetic resonance imaging (fMRI). The task requires continuous learning to guide flexible behavioral adaptation to changing reward contingencies. To disentangle the neurocomputational underpinnings of the behavioral data, we used reinforcement learning (RL) models, which informed the analysis of fMRI data. ADHD patients performed worse than controls particularly in trials before reversals, i.e., when reward contingencies were stable. This pattern resulted from 'noisy' choice switching regardless of previous feedback. RL modelling showed decreased reinforcement sensitivity and enhanced learning rates for negative feedback in ADHD patients. At the neural level, this was reflected in a diminished representation of choice probability in the left posterior parietal cortex in ADHD. Moreover, modelling showed a marginal reduction of learning about the unchosen option, which was paralleled by a marginal reduction in learning signals incorporating the unchosen option in the left ventral striatum. Taken together, we show that impaired flexible behavior in ADHD is due to excessive choice switching ('hyper-flexibility'), which can be detrimental or beneficial depending on the learning environment. Computationally, this resulted from blunted sensitivity to reinforcement of which we detected neural correlates in the attention-control network, specifically in the parietal cortex. These neurocomputational findings remain preliminary due to the relatively small sample size.
Collapse
Affiliation(s)
- Hans-Christoph Aster
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University Hospital Würzburg, Würzburg, Germany.
| | - Maria Waltmann
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University Hospital Würzburg, Würzburg, Germany; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Anika Busch
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University Hospital Würzburg, Würzburg, Germany
| | - Marcel Romanos
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University Hospital Würzburg, Würzburg, Germany
| | - Matthias Gamer
- Department of Psychology, University of Würzburg, Würzburg, Germany
| | - Betteke Maria van Noort
- Department of Child and Adolescent Psychiatry, Charité University Medicine, Campus Virchow Klinikum, Berlin, Germany; MSB Medical School Berlin, Department of Psychology, Germany
| | - Anne Beck
- Department of Psychiatry and Neurosciences, Charité University Medicine, Berlin, Germany; Department of Psychology, Faculty of Health, Health and Medical University, Potsdam, Germany
| | - Viola Kappel
- Department of Child and Adolescent Psychiatry, Charité University Medicine, Campus Virchow Klinikum, Berlin, Germany
| | - Lorenz Deserno
- Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, University Hospital Würzburg, Würzburg, Germany; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Department of Psychiatry and Psychotherapy, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
3
|
Nejati V, Derakhshan Z. Attention Training Improves Executive Functions and Ameliorates Behavioral Symptoms in Children with Attention-Deficit Hyperactivity Disorder: Implication of Tele-Cognitive-Rehabilitation in the Era of Coronavirus Disease. Games Health J 2024; 13:40-49. [PMID: 38300525 DOI: 10.1089/g4h.2023.0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024] Open
Abstract
Background: Children with attention-deficit hyperactivity disorder (ADHD) struggle with impaired attention, leading to impaired executive function and behavioral symptoms. In this study, we aimed to evaluate the effect of attention training on executive functions and behavioral symptoms in children with ADHD, in a tele-cognitive-rehabilitation setting. Methods: Thirty children (mean age: 9.93 ± 1.68 years, 21 boys) with ADHD were randomly assigned to 2 equal groups of attention training and active control group. Attentive Rehabilitation and Improvement of Attention (ARIA) and a class of storytelling were used for intervention in two groups, in an online platform. Continuous performance test, one-back test, Wisconsin card sorting test (WCST), Conner's parent rating scale, and behavioral rating inventory of executive function (BRIEF) were used for assessment in three-baseline, postintervention, and follow-up sessions. Repeated measures analysis of variances were used for analysis. Results: ARIA leads to significant improvement in omission error (P < 0.001), commission error (P = 0.006), and response time (P = 0.005) of continuous performance test, cluster (P = 0.001), but not preservation error (P = 0.110) of WCST, accuracy of NBT (P = 0.004) and the score of Conner's parent rating scale (P < 0.001) and BRIEF (P < 0.001). These results indicate improved attention and executive functions, amelioration of ADHD symptoms, and improved behavioral performance. Conclusion: This study suggests that attention can be trained through tele-cognitive rehabilitation using a remediation program in children with ADHD. The effectiveness of this training can be confirmed by examining the transfer of training effects to other untrained cognitive domains, executive functions, symptoms of ADHD, and behavioral performance.
Collapse
Affiliation(s)
- Vahid Nejati
- Department of Psychology, Shahid Beheshti University, Tehran, Iran
| | - Zahra Derakhshan
- Department of Psychology, Shahid Beheshti University, Tehran, Iran
| |
Collapse
|
4
|
Atkinson-Clement C, Lebreton M, Patsalides L, de Liege A, Klein Y, Roze E, Deniau E, Hartmann A, Palminteri S, Worbe Y. Decision-making under risk and ambiguity in adults with Tourette syndrome. Psychol Med 2023; 53:5256-5266. [PMID: 35899867 DOI: 10.1017/s0033291722002318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Tourette syndrome (TS) as well as its most common comorbidities are associated with a higher propensity for risky behaviour in everyday life. However, it is unclear whether this increased risk propensity in real-life contexts translates into a generally increased attitude towards risk. We aimed to assess decision-making under risk and ambiguity based on prospect theory by considering the effects of comorbidities and medication. METHODS Fifty-four individuals with TS and 32 healthy controls performed risk and ambiguity decision-making tasks under both gains and losses conditions. Behavioural and computational parameters were evaluated using (i) univariate analysis to determine parameters difference taking independently; (ii) supervised multivariate analysis to evaluate whether our parameters could jointly account for between-group differences (iii) unsupervised multivariate analysis to explore the potential presence of sub-groups. RESULTS Except for general 'noisier' (less consistent) decisions in TS, we showed no specific risk-taking behaviour in TS or any relation with tics severity or antipsychotic medication. However, the presence of comorbidities was associated with distortion of decision-making. Specifically, TS with obsessive-compulsive disorder comorbidity was associated with a higher risk-taking profile to increase gain and a higher risk-averse profile to decrease loss. TS with attention-deficit hyperactivity disorder comorbidity was associated with risk-seeking in the ambiguity context to reduce a potential loss. CONCLUSIONS Impaired valuation of risk and ambiguity was not related to TS per se. Our findings are important for clinical practice: the involvement of individuals with TS in real-life risky situations may actually rather result from other factors such as psychiatric comorbidities.
Collapse
Affiliation(s)
- Cyril Atkinson-Clement
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
- School of Medicine, University of Nottingham, Nottingham, UK
| | - Mael Lebreton
- Paris School of Economics, Paris, France
- Swiss Center for Affective Science, University of Geneva, Geneva, Switzerland
- Laboratory for Behavioral Neurology and Imaging of Cognition, Department of Fundamental Neurosciences, University of Geneva, Geneva, Switzerland
| | - Leïla Patsalides
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
| | - Astrid de Liege
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
- National Reference Center for Tourette Syndrome, Assistance Publique des Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, F-75013 Paris, France
| | - Yanica Klein
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
- National Reference Center for Tourette Syndrome, Assistance Publique des Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, F-75013 Paris, France
| | - Emmanuel Roze
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
- Department of Neurology, Assistance Publique des Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, F-75013 Paris, France
| | - Emmanuelle Deniau
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
- National Reference Center for Tourette Syndrome, Assistance Publique des Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, F-75013 Paris, France
| | - Andreas Hartmann
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
- National Reference Center for Tourette Syndrome, Assistance Publique des Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, F-75013 Paris, France
| | - Stefano Palminteri
- Laboratoire de Neurosciences Cognitives et Computationnelles, INSERM, Paris, France
- Département d'Etudes Cognitives, ENS, PSL Research University, Paris, France
- Institute for Cognitive Neuroscience, HSE, Moscow, Russian Federation
| | - Yulia Worbe
- Inserm U1127, CNRS UMR7225, UM75, ICM, F-75013, Sorbonne University, 75005 Paris, France
- Movement Investigation and Therapeutics Team, Paris, France
- National Reference Center for Tourette Syndrome, Assistance Publique des Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, F-75013 Paris, France
- Department of Neurophysiology, Saint Antoine Hospital, Assistance Publique des Hôpitaux de Paris, Paris, France
| |
Collapse
|
5
|
Hua MH, Huang KL, Hsu JW, Bai YM, Su TP, Tsai SJ, Li CT, Lin WC, Chen TJ, Chen MH. Early Pregnancy Risk Among Adolescents With ADHD: A Nationwide Longitudinal Study. J Atten Disord 2021; 25:1199-1206. [PMID: 31971056 DOI: 10.1177/1087054719900232] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Objective: ADHD potentially leads to risky sexual behaviors, and is considered a major risk factor for early pregnancy (EP). However, the association between ADHD and subsequent EP remains unknown. Method: Seven thousand five hundred five adolescents with ADHD and 30,020 age- and sex-matched individuals without ADHD were enrolled from 2001 to 2009 and were followed until the end of 2011. Adolescents who developed any pregnancy (at age ≤30 years) or EP (at age <20 years) during the follow-up period were identified. Results: Adolescents with ADHD were found to be prone to pregnancy (hazard ratio [HR] = 1.27) and EP (HR = 2.30) compared with those without ADHD. Long-term ADHD medication use was related to a lower risk of subsequent any pregnancy (HR = 0.72) and EP (HR = 0.69). Conclusion: Adolescents with ADHD had an increased risk of any pregnancy and EP compared with their non-ADHD counterparts. Long-term ADHD medication use was associated with a lower subsequent EP risk.
Collapse
Affiliation(s)
| | - Kai-Lin Huang
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| | - Ju-Wei Hsu
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| | - Ya-Mei Bai
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| | - Tung-Ping Su
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei.,Cheng Hsin General Hospital, Taipei
| | - Shih-Jen Tsai
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| | - Cheng-Ta Li
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| | - Wei-Chen Lin
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| | - Tzeng-Ji Chen
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| | - Mu-Hong Chen
- Taipei Veterans General Hospital, Taipei.,National Yang-Ming University, Taipei
| |
Collapse
|
6
|
Salas-Lucia F, Pacheco-Torres J, González-Granero S, García-Verdugo JM, Berbel P. Transient Hypothyroidism During Lactation Alters the Development of the Corpus Callosum in Rats. An in vivo Magnetic Resonance Image and Electron Microscopy Study. Front Neuroanat 2020; 14:33. [PMID: 32676012 PMCID: PMC7333461 DOI: 10.3389/fnana.2020.00033] [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: 12/07/2019] [Accepted: 05/28/2020] [Indexed: 12/20/2022] Open
Abstract
Magnetic resonance imaging (MRI) data of children with late diagnosed congenital hypothyroidism and cognitive alterations such as abnormal verbal memory processing suggest altered telencephalic commissural connections. The corpus callosum (CC) is the major inter-hemispheric commissure that contra-laterally connects neocortical areas. However, in late diagnosed neonates with congenital hypothyroidism, the possible effect of early transient and chronic postnatal hypothyroidism still remains unknown. We have studied the development of the anterior, middle and posterior CC, using in vivo MRI and electron microscopy in hypothyroid and control male rats. Four groups of methimazole (MMI) treated rats were studied. One group, as a model for early transient hypothyroidism, was MMI-treated from postnatal day (P) 0 to P21; some of these rats were also treated with L-thyroxine (T4) from P15 to 21. Another group modeling chronic hypothyroid, were treated with MMI from P0 to 150 and from embryonic day 10 to P170. The results obtained from these groups were compared with same age control rats. The normalized T2 signal obtained using MRI was higher in MMI-treated rats and correlated with a low number and percentage of myelinated axons. The number and density of myelinated axons decreased in transient and chronic hypothyroid rats at P150. The g-ratio (inner to outer diameter ratio) and the estimated conduction velocity of myelinated axons were similar between MMI-treated and controls, but the conduction delay decreased in the posterior CC of MMI-treated rats compared to controls. These data show that early postnatal transient and chronic hypothyroidism alters CC maturation in a way that may affect the callosal transfer of information. These alterations cannot be reversed after delayed T4-treatment. Our data support the findings of neurocognitive delay in late T4-treated children with congenital hypothyroidism.
Collapse
Affiliation(s)
- Federico Salas-Lucia
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel Hernández (UMH), Sant Joan d’Alacant, Spain
| | - Jesús Pacheco-Torres
- Instituto de Neurociencias de Alicante, UMH – Consejo Superior de Investigaciones Científicas, Sant Joan d’Alacant, Spain
| | - Susana González-Granero
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València - Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - José Manuel García-Verdugo
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universitat de València - Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Valencia, Spain
| | - Pere Berbel
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel Hernández (UMH), Sant Joan d’Alacant, Spain
| |
Collapse
|
7
|
Furukawa E, Alsop B, Shimabukuro S, Tripp G. Is increased sensitivity to punishment a common characteristic of attention deficit/hyperactivity disorder? An experimental study of response allocation in Japanese children. ACTA ACUST UNITED AC 2019; 11:433-443. [PMID: 31098948 DOI: 10.1007/s12402-019-00307-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 05/07/2019] [Indexed: 12/13/2022]
Abstract
Research on motivational processes in attention deficit/hyperactivity disorder (ADHD) focuses on reward. Studies with punishment are limited and findings mixed. This study evaluated the effects of punishment on response allocation in Japanese children with and without ADHD. Thirty-four children meeting DSM-IV criteria for ADHD and 59 typically developing control-group children completed an operant task in which they choose between playing two simultaneously available games. Reward was arranged symmetrically across the games under concurrent variable interval schedules. Asymmetric punishment schedules were superimposed with responses on one game punished four times as often as responses on the other. Children with ADHD showed greater behavioral sensitivity to punishment than controls. They allocated significantly more responses to the less frequently punished alternative and were more likely to play this game on consecutive trials and responded more slowly to the more punished game. Control group children allocated their responses evenly across games. Punishment exerted greater control over the behavior of Japanese children with ADHD than controls, similar to findings with children from Western countries, suggesting this is a common characteristic of the disorder. The behavior of typically developing Japanese children, while demonstrating awareness of punishment, was not controlled by the frequency of its occurrence.
Collapse
Affiliation(s)
- Emi Furukawa
- Human Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan.
| | - Brent Alsop
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | - Shizuka Shimabukuro
- Human Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| | - Gail Tripp
- Human Developmental Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan
| |
Collapse
|
8
|
Lucia FS, Pacheco-Torres J, González-Granero S, Canals S, Obregón MJ, García-Verdugo JM, Berbel P. Transient Hypothyroidism During Lactation Arrests Myelination in the Anterior Commissure of Rats. A Magnetic Resonance Image and Electron Microscope Study. Front Neuroanat 2018; 12:31. [PMID: 29755326 PMCID: PMC5935182 DOI: 10.3389/fnana.2018.00031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 04/09/2018] [Indexed: 12/14/2022] Open
Abstract
Thyroid hormone deficiency at early postnatal ages affects the cytoarchitecture and function of neocortical and telencephalic limbic areas, leading to impaired associative memory and in a wide spectrum of neurological and mental diseases. Neocortical areas project interhemispheric axons mostly through the corpus callosum and to a lesser extent through the anterior commissure (AC), while limbic areas mostly project through the AC and hippocampal commissures. Functional magnetic resonance data from children with late diagnosed congenital hypothyroidism and abnormal verbal memory processing, suggest altered ipsilateral and contralateral telencephalic connections. Gestational hypothyroidism affects AC development but the possible effect of transient and chronic postnatal hypothyroidism, as occurs in late diagnosed neonates with congenital hypothyroidism and in children growing up in iodine deficient areas, still remains unknown. We studied AC development using in vivo magnetic resonance imaging and electron microscopy in hypothyroid and control male rats. Four groups of methimazole (MMI) treated rats were studied. One group was MMI-treated from postnatal day (P) 0 to P21; some of these rats were also treated with L-thyroxine (T4) from P15 to P21, as a model for early transient hypothyroidism. Other rats were MMI-treated from P0 to P150 and from embryonic day (E) 10 to P170, as a chronic hypothyroidism group. The results were compared with age paired control rats. The normalized T2 signal using magnetic resonance image was higher in MMI-treated rats and correlated with the number and percentage of myelinated axons. Using electron microscopy, we observed decreased myelinated axon number and density in transient and chronic hypothyroid rats at P150, unmyelinated axon number increased slightly in chronic hypothyroid rats. In MMI-treated rats, the myelinated axon g-ratio and conduction velocity was similar to control rats, but with a decrease in conduction delays. These data show that early postnatal transient and chronic hypothyroidism alters AC maturation that may affect the transfer of information through the AC. The alterations cannot be recovered after delayed T4-treatment. Our data support the neurocognitive delay found in late T4-treated children with congenital hypothyroidism.
Collapse
Affiliation(s)
- Federico S. Lucia
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel Hernández, Sant Joan d’Alacant, Alicante, Spain
| | - Jesús Pacheco-Torres
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Alicante, Spain
| | - Susana González-Granero
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Universitat de València, Valencia, Spain
| | - Santiago Canals
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Alicante, Spain
| | - María-Jesús Obregón
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - José M. García-Verdugo
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Universitat de València, Valencia, Spain
| | - Pere Berbel
- Departamento de Histología y Anatomía, Facultad de Medicina, Universidad Miguel Hernández, Sant Joan d’Alacant, Alicante, Spain
| |
Collapse
|