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Aquili L. The Role of Tryptophan and Tyrosine in Executive Function and Reward Processing. Int J Tryptophan Res 2020; 13:1178646920964825. [PMID: 33149600 PMCID: PMC7586026 DOI: 10.1177/1178646920964825] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/10/2020] [Indexed: 01/31/2023] Open
Abstract
The serotonergic precursor tryptophan and the dopaminergic precursor tyrosine have been shown to be important modulators of mood, behaviour and cognition. Specifically, research on the function of tryptophan has characterised this molecule as particularly relevant in the context of pathological disorders such as depression. Moreover, a large body of evidence has now been accumulated to suggest that tryptophan may also be involved in executive function and reward processing. Despite some clear differentiation with tryptophan, the data reviewed in this paper illustrates that tyrosine shares similar functions with tryptophan in the regulation of executive function and reward, and that these processes in turn, rather than acting in isolation, causally influence each other.
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Affiliation(s)
- Luca Aquili
- College of Health & Human Sciences, Charles Darwin University, Darwin, Northern Territory, Australia
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Stewart RM, Wong JWY, Mahfouda S, Morandini HAE, Rao P, Runions KC, Zepf FD. Acute Tryptophan Depletion Moja-De: A Method to Study Central Nervous Serotonin Function in Children and Adolescents. Front Psychiatry 2020; 10:1007. [PMID: 32210845 PMCID: PMC7067742 DOI: 10.3389/fpsyt.2019.01007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 12/20/2019] [Indexed: 11/13/2022] Open
Abstract
Serotonin (5-HT) is widely implicated as a key neurotransmitter relevant to a range of psychiatric disorders and psychological processes. The role of central nervous 5-HT function underlying these processes can be examined through serotonergic challenge methodologies. Acute tryptophan depletion (ATD) is a key challenge method whereby a diminished dietary intake of tryptophan-the amino acid precursor to brain 5-HT synthesis-results in temporary diminished central nervous 5-HT synthesis. While this particular methodology has been used in adult populations, it was only recently that modifications were made to enable the use of ATD in child and adolescent populations. Additionally, the Moja-De modification of the ATD challenge methodology has demonstrated benefits over other ATD techniques used previously. The aim of this protocol paper is to describe the ATD Moja-De methodology in detail, its benefits, as well as studies that have been conducted to validate the procedure in child and adolescent samples. The ATD Moja-De protocol provides a potential methodology for investigating the role of central nervous 5-HT via manipulation of brain tryptophan availability in human psychopathology from a developmental viewpoint.
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Affiliation(s)
- Richard M. Stewart
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Janice W. Y. Wong
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- Specialised Child and Adolescent Mental Health Services, Department of Health, Perth, WA, Australia
| | - Simone Mahfouda
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- School of Psychological Sciences, Faculty of Science, The University of Western Australia, Perth, WA, Australia
| | - Hugo A. E. Morandini
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Pradeep Rao
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Community Child and Adolescent Mental Health Services, Department of Health, Perth, WA, Australia
| | - Kevin C. Runions
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- Community Child and Adolescent Mental Health Services, Department of Health, Perth, WA, Australia
| | - Florian D. Zepf
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- Department of Child and Adolescent Psychiatry, Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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Hildebrandt CS, Helmbold K, Linden M, Langen KJ, Filss CP, Runions KC, Stewart RM, Rao P, Moore JK, Mahfouda S, Morandini HAE, Wong JWY, Rink L, Zepf FD. No detectable effects of acute tryptophan depletion on short-term immune system cytokine levels in healthy adults. World J Biol Psychiatry 2019; 20:416-423. [PMID: 29353534 DOI: 10.1080/15622975.2018.1428357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Objectives: Recent research suggested an influence of diminished central nervous serotonin (5-HT) synthesis on the leptin axis via immunological mechanisms in healthy adult females. However, studies assessing immunological parameters in combination with dietary challenge techniques that impact brain 5-HT synthesis in humans are lacking. Methods: In the present trial, a pilot analysis was conducted on data obtained in healthy adult humans receiving either different dietary acute tryptophan depletion (ATD) challenge or tryptophan (TRP)-balanced control conditions (BAL) to study the effects of reduced central nervous 5-HT synthesis on serum tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β) and IL-6 concentrations. The data of N = 35 healthy adults were analysed who were randomly subjected to one of the following two dietary conditions in a double-blind between-subject approach: (1) The Moja-De ATD challenge (ATD), or (2) TRP-balanced control condition for ATD Moja-De (BAL). Serum concentrations for the assessment of relevant parameters (TNF-α, IL-1β and IL-6) and relevant TRP-related characteristics after the respective challenge procedures were assessed at baseline (T0) and in hourly intervals after administration over a period of 6 h (T1-T6). Results: The ATD condition did not result in significant changes to cytokine concentrations for the entire study sample, or in male and female subgroups. Depletion of CNS 5-HT via dietary TRP depletion appears to have no statistically significant short-term impact on cytokine concentrations in healthy adults. Conclusions: Future research on immunological stressors in combination with challenge techniques will be of value in order to further disentangle the complex interplay between brain 5-HT synthesis and immunological pathways.
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Affiliation(s)
- Caroline S Hildebrandt
- a Jülich Aachen Research Alliance, JARA Translational Brain Medicine , Aachen , Germany.,b Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy , RWTH Aachen University , Aachen , Germany.,c Clinics of the City Cologne GmbH , Child and Adolescent Psychiatry and Psychotherapy , Cologne , Germany
| | - Katrin Helmbold
- a Jülich Aachen Research Alliance, JARA Translational Brain Medicine , Aachen , Germany.,b Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy , RWTH Aachen University , Aachen , Germany
| | - Maike Linden
- a Jülich Aachen Research Alliance, JARA Translational Brain Medicine , Aachen , Germany.,b Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy , RWTH Aachen University , Aachen , Germany
| | - Karl-Josef Langen
- d Institute of Neuroscience and Medicine (INM-4) Research Centre Jülich , Jülich , Germany.,e Section JARA-Brain , Jülich-Aachen Research Alliance (JARA) , Jülich , Germany.,f Department of Nuclear Medicine , RWTH Aachen University Hospital , Aachen , Germany
| | - C P Filss
- e Section JARA-Brain , Jülich-Aachen Research Alliance (JARA) , Jülich , Germany.,f Department of Nuclear Medicine , RWTH Aachen University Hospital , Aachen , Germany
| | - Kevin C Runions
- g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia.,h Telethon Kids Institute , Perth , Australia
| | - Richard M Stewart
- g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia
| | - Pradeep Rao
- g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia.,i Department of Health , Community Child and Adolescent Mental Health Services (CAMHS) , Perth , Western Australia , Australia
| | - Julie K Moore
- g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia.,j Princess Margaret Hospital, Department of Health , Pediatric Consultation Liason Program, Acute Child and Adolescent Mental Health Services (CAMHS) , Perth , Western Australia , Australia
| | - Simone Mahfouda
- g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia.,h Telethon Kids Institute , Perth , Australia
| | - Hugo A E Morandini
- g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia
| | - Janice W Y Wong
- g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia.,h Telethon Kids Institute , Perth , Australia.,k Department of Health , Specialised Child and Adolescent Mental Health Services (CAMHS) , Perth , Western Australia , Australia
| | - Lothar Rink
- l Department of Immunology , RWTH Aachen University Hospital , Aachen , Germany
| | - Florian D Zepf
- a Jülich Aachen Research Alliance, JARA Translational Brain Medicine , Aachen , Germany.,b Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy , RWTH Aachen University , Aachen , Germany.,g Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy; School of Medicine, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health , The University of Western Australia , Perth , Australia.,h Telethon Kids Institute , Perth , Australia.,k Department of Health , Specialised Child and Adolescent Mental Health Services (CAMHS) , Perth , Western Australia , Australia
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Wolf D, Klasen M, Eisner P, Zepf FD, Zvyagintsev M, Palomero-Gallagher N, Weber R, Eisert A, Mathiak K. Central serotonin modulates neural responses to virtual violent actions in emotion regulation networks. Brain Struct Funct 2018; 223:3327-3345. [PMID: 29948188 PMCID: PMC6698268 DOI: 10.1007/s00429-018-1693-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 06/03/2018] [Indexed: 12/31/2022]
Abstract
Disruptions in the cortico-limbic emotion regulation networks have been linked to depression, anxiety, impulsivity, and aggression. Altered transmission of the central nervous serotonin (5-HT) contributes to dysfunctions in the cognitive control of emotions. To date, studies relating to pharmaco-fMRI challenging of the 5-HT system have focused on emotion processing for facial expressions. We investigated effects of a single-dose selective 5-HT reuptake inhibitor (escitalopram) on emotion regulation during virtual violence. For this purpose, 38 male participants played a violent video game during fMRI scanning. The SSRI reduced neural responses to violent actions in right-hemispheric inferior frontal gyrus and medial prefrontal cortex encompassing the anterior cingulate cortex (ACC), but not to non-violent actions. Within the ACC, the drug effect differentiated areas with high inhibitory 5-HT1A receptor density (subgenual s25) from those with a lower density (pregenual p32, p24). This finding links functional responses during virtual violent actions with 5-HT neurotransmission in emotion regulation networks, underpinning the ecological validity of the 5-HT model in aggressive behavior. Available 5-HT receptor density data suggest that this SSRI effect is only observable when inhibitory and excitatory 5-HT receptors are balanced. The observed early functional changes may impact patient groups receiving SSRI treatment.
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Affiliation(s)
- Dhana Wolf
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Martin Klasen
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Patrick Eisner
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Florian D Zepf
- Centre and Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Division of Psychiatry and Clinical Neurosciences and Division of Paediatrics and Child Health, School of Medicine, The University of Western Australia, Perth, Australia
- Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, Australia
| | - Mikhail Zvyagintsev
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
| | - Nicola Palomero-Gallagher
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany
| | - René Weber
- Media Neuroscience Lab, Department of Communication, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Albrecht Eisert
- Department of Pharmacy, RWTH Aachen, Aachen, Germany
- Department of Pharmacology and Toxicology, RWTH Aachen, Aachen, Germany
| | - Klaus Mathiak
- Department of Psychiatry, Psychotherapy, and Psychosomatics, Medical Faculty, RWTH Aachen, Pauwelsstraße 30, 52074, Aachen, Germany
- JARA-Translational Brain Medicine, Aachen, Germany
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da Cunha-Bang S, Hjordt LV, Dam VH, Stenbæk DS, Sestoft D, Knudsen GM. Anterior cingulate serotonin 1B receptor binding is associated with emotional response inhibition. J Psychiatr Res 2017; 92:199-204. [PMID: 28502766 DOI: 10.1016/j.jpsychires.2017.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/02/2017] [Accepted: 05/05/2017] [Indexed: 01/10/2023]
Abstract
Serotonin has a well-established role in emotional processing and is a key neurotransmitter in impulsive aggression, presumably by facilitating response inhibition and regulating subcortical reactivity to aversive stimuli. In this study 44 men, of whom 19 were violent offenders and 25 were non-offender controls, completed an emotional Go/NoGo task requiring inhibition of prepotent motor responses to emotional facial expressions. We also measured cerebral serotonin 1B receptor (5-HT1BR) binding with [11C]AZ10419369 positron emission tomography within regions of the frontal cortex. We hypothesized that 5-HT1BR would be positively associated with false alarms (failures to inhibit nogo responses) in the context of aversive (angry and fearful) facial expressions. Across groups, we found that frontal cortex 5-HT1BR binding was positively correlated with false alarms when angry faces were go stimuli and neutral faces were nogo stimuli (p = 0.05, corrected alpha = 0.0125), but not with false alarms for non-emotional stimuli (failures to inhibit geometric figures). A posthoc analysis revealed the strongest association in anterior cingulate cortex (p = 0.006). In summary, 5-HT1BRs in the anterior cingulate are involved in withholding a prepotent response in the context of angry faces. Our findings suggest that serotonin modulates response inhibition in the context of certain emotional stimuli.
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Affiliation(s)
- Sofi da Cunha-Bang
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark
| | - Liv Vadskjær Hjordt
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Vibeke Høyrup Dam
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Dea Siggaard Stenbæk
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark
| | - Dorte Sestoft
- Ministry of Justice, Clinic of Forensic Psychiatry, Blegdamsvej 6B, DK-2200 Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark.
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Linden M, Helmbold K, Kempf J, Sippas S, Filss C, Langen KJ, Eisert A, Zepf FD. Dietary tryptophan depletion in humans using a simplified two amino acid formula - a pilot study. Food Nutr Res 2016; 60:29272. [PMID: 27989269 PMCID: PMC5165058 DOI: 10.3402/fnr.v60.29272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 09/26/2016] [Accepted: 11/03/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Acute tryptophan depletion (ATD) is a well-established dietary method in translational brain research used to briefly lower central nervous serotonin (5-hydroxytryptamine (5-HT)) synthesis. A simplified two amino acid ATD formula (ATDPHE/LEU) was developed while reducing the overall amount of amino acids (AAs), with the objective of administration especially in children and adolescents in future studies. OBJECTIVE This study investigated tryptophan (TRP) influx rates across the blood-brain barrier (BBB) after dietary ATDPHE/LEU administration relative to the ATD Moja-De protocol that has been established for use in children and adolescents. DESIGN Seventy-two healthy adults (50% females) were randomized into four groups and administered ATD Moja-De, its TRP-balanced control condition (BAL), ATDPHE/LEU, or its respective control mixture (BALPHE/LEU) in a counterbalanced, double-blind, between-subjects design. Blood samples were collected at baseline and at hourly intervals for 6 h after AA intake. Questionnaires about mood, taste, and challenge tolerance were completed at fixed time points. RESULTS Both challenge mixtures significantly reduced central nervous TRP influx as calculated by Michaelis-Menten kinetics relative to baseline and the respective control conditions with only mild and comparable side effects. A greater decline in TRP influx over the BBB after ATDPHE/LEU administration when compared with ATD Moja-De was detected without group effects for taste, challenge tolerance, and mood. There was unintended initial short increase in plasma TRP concentrations observed after ATDPHE/LEU intake, and a possible redistribution between free and protein-bound TRP triggered by protein synthesis stimulated by the ingested AAs may account for this finding. Moreover, a decline in TRP influx after BALPHE/LEU administration over a 6-h period was observed, and the large amount of PHE in the BALPHE/LEU mixture may be a possible explanation for this particular phenomenon, which could have led to an unexpected increase in displacement of TRP at the BBB in this control condition. CONCLUSIONS This pilot study provides preliminary evidence for the possibility of lowering TRP influx as calculated by Michaelis-Menten kinetics into the brain by using a simplified ATD protocol in humans. The simplified composition of only two AAs, the lower overall AA amount, and the appropriate tolerance are characteristics of the newly developed ATDPHE/LEU protocol. Future studies focusing on the effects of the ATDPHE/LEU protocol and its respective control condition on CSF 5-HIAA concentrations, as well as neurochemical studies in rodents, are needed to further validate this newly developed AA mixture before definite conclusions about its usability in ATD-related research in humans, its specificity, and additional effects can be made.
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Affiliation(s)
- Maike Linden
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany
| | - Katrin Helmbold
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany
| | - Janina Kempf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany.,Faculty of Arts and Social Sciences, Maastricht University, Maastricht, The Netherlands
| | - Shabnam Sippas
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany.,Faculty of Arts and Social Sciences, Maastricht University, Maastricht, The Netherlands
| | - Christian Filss
- Section JARA-Brain, Jülich-Aachen Research Alliance (JARA), Jülich, Germany
| | - Karl-Josef Langen
- Section JARA-Brain, Jülich-Aachen Research Alliance (JARA), Jülich, Germany.,Institute of Neuroscience and Medicine (INM-3, -4, -5), Research Centre Jülich, Jülich, Germany.,Department of Nuclear Medicine, RWTH Aachen University Hospital, Aachen, Germany
| | - Albrecht Eisert
- Department of Pharmacy, RWTH Aachen University, Aachen, Germany
| | - Florian Daniel Zepf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany.,Centre and Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Australia.,Specialised Child and Adolescent Mental Health Services (CAMHS), Department of Health in Western Australia, Perth, Australia;
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7
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Ma I, van Holstein M, Mies GW, Mennes M, Buitelaar J, Cools R, Cillessen AHN, Krebs RM, Scheres A. Ventral striatal hyperconnectivity during rewarded interference control in adolescents with ADHD. Cortex 2016; 82:225-236. [PMID: 27399612 DOI: 10.1016/j.cortex.2016.05.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/22/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVE Attention-deficit/hyperactivity disorder (ADHD) is characterized by cognitive deficits (e.g., interference control) and altered reward processing. Cognitive control is influenced by incentive motivation and according to current theoretical models, ADHD is associated with abnormal interactions between incentive motivation and cognitive control. However, the neural mechanisms by which reward modulates cognitive control in individuals with ADHD are unknown. METHOD We used event-related functional resonance imaging (fMRI) to study neural responses during a rewarded Stroop color-word task in adolescents (14-17 years) with ADHD (n = 25; 19 boys) and healthy controls (n = 33; 22 boys). RESULTS Adolescents with ADHD showed increased reward signaling within the superior frontal gyrus and ventral striatum (VS) relative to controls. Importantly, functional connectivity analyses revealed a hyperconnectivity between VS and motor control regions in the ADHD group, as a function of reward-cognitive control integration. Connectivity was associated with performance improvement in controls but not in the ADHD group, suggesting inefficient connectivity. CONCLUSION Adolescents with ADHD show increased neural sensitivity to rewards and its interactions with interference control in VS and motor regions, respectively. The findings support theoretical models of altered reward-cognitive control integration in individuals with ADHD.
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Affiliation(s)
- Ili Ma
- Behavioural Science Institute, Radboud University, Nijmegen, The Netherlands.
| | - Mieke van Holstein
- Radboud University, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands
| | - Gabry W Mies
- Behavioural Science Institute, Radboud University, Nijmegen, The Netherlands
| | - Maarten Mennes
- Radboud University, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands
| | - Jan Buitelaar
- Radboud University, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands; Radboud University Medical Center, Department of Cognitive Neuroscience, Nijmegen, The Netherlands; Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, The Netherlands
| | - Roshan Cools
- Radboud University, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands; Radboud University Medical Center, Department of Psychiatry, Nijmegen, The Netherlands
| | | | - Ruth M Krebs
- Ghent University, Department of Experimental Psychology, Ghent, Belgium
| | - Anouk Scheres
- Behavioural Science Institute, Radboud University, Nijmegen, The Netherlands
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8
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Serotonergic modulation of resting state default mode network connectivity in healthy women. Amino Acids 2016; 48:1109-1120. [PMID: 26767373 DOI: 10.1007/s00726-015-2137-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 11/16/2015] [Indexed: 09/29/2022]
Abstract
The default mode network (DMN) plays a central role in intrinsic thought processes. Altered DMN connectivity has been linked to diminished cerebral serotonin synthesis. Diminished brain serotonin synthesis is further associated with a lack of impulse control and various psychiatric disorders. Here, we investigated the serotonergic modulation of intrinsic functional connectivity (FC) within the DMN in healthy adult females, controlling for the menstrual cycle phase. Eighteen healthy women in the follicular phase (aged 20-31 years) participated in a double-blind controlled cross-over study of serotonin depletion. Acute tryptophan depletion (ATD) and a balanced amino acid load (BAL), used as the control condition, were applied on two separate days of assessment. Neural resting state data using functional magnetic resonance imaging (fMRI) and individual trait impulsivity scores were obtained. ATD compared with BAL significantly reduced FC with the DMN in the precuneus (associated with self-referential thinking) and enhanced FC with the DMN in the frontal cortex (associated with cognitive reasoning). Connectivity differences with the DMN between BAL and ATD in the precentral gyrus were significantly correlated with the magnitude of serotonin depletion. Right medial frontal gyrus and left superior frontal gyrus connectivity differences with the DMN were inversely correlated with trait impulsivity. These findings partially deviate from previous findings obtained in males and underline the importance of gender-specific studies and controlling for menstrual cycle to further elucidate the mechanism of ATD-induced changes within intrinsic thought processes.
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Zepf F, Rao P, Moore J, Stewart R, Ladino YM, Hartmann B. Human breast milk and adipokines – A potential role for the soluble leptin receptor (sOb-R) in the regulation of infant energy intake and development. Med Hypotheses 2016; 86:53-5. [DOI: 10.1016/j.mehy.2015.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 11/19/2015] [Indexed: 11/29/2022]
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