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Geiger M, Hurewitz SR, Pawlowski K, Baumer NT, Wilkinson CL. Alterations in aperiodic and periodic EEG activity in young children with Down syndrome. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.01.24306729. [PMID: 38746335 PMCID: PMC11092732 DOI: 10.1101/2024.05.01.24306729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Down syndrome is the most common cause of intellectual disability, yet little is known about the neurobiological pathways leading to cognitive impairments. Electroencephalographic (EEG) measures are commonly used to study neurodevelopmental disorders, but few studies have focused on young children with DS. Here we assess resting state EEG data collected from toddlers/preschoolers with DS (n=29, age 13-48 months old) and compare their aperiodic and periodic EEG features with both age-matched (n=29) and cognitive-matched (n=58) comparison groups. DS participants exhibited significantly reduced aperiodic slope, increased periodic theta power, and decreased alpha peak amplitude. A majority of DS participants displayed a prominent peak in the theta range, whereas a theta peak was not present in age-matched participants. Overall, similar findings were also observed when comparing DS and cognitive-matched groups, suggesting that EEG differences are not explained by delayed cognitive ability.
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Chmiel J, Rybakowski F, Leszek J. EEG in Down Syndrome-A Review and Insights into Potential Neural Mechanisms. Brain Sci 2024; 14:136. [PMID: 38391711 PMCID: PMC10886507 DOI: 10.3390/brainsci14020136] [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: 12/17/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
Introduction: Down syndrome (DS) stands out as one of the most prevalent genetic disorders, imposing a significant burden on both society and the healthcare system. Scientists are making efforts to understand the neural mechanisms behind the pathophysiology of this disorder. Among the valuable methods for studying these mechanisms is electroencephalography (EEG), a non-invasive technique that measures the brain's electrical activity, characterised by its excellent temporal resolution. This review aims to consolidate studies examining EEG usage in individuals with DS. The objective was to identify shared elements of disrupted EEG activity and, crucially, to elucidate the neural mechanisms underpinning these deviations. Searches were conducted on Pubmed/Medline, Research Gate, and Cochrane databases. Results: The literature search yielded 17 relevant articles. Despite the significant time span, small sample size, and overall heterogeneity of the included studies, three common features of aberrant EEG activity in people with DS were found. Potential mechanisms for this altered activity were delineated. Conclusions: The studies included in this review show altered EEG activity in people with DS compared to the control group. To bolster these current findings, future investigations with larger sample sizes are imperative.
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Affiliation(s)
- James Chmiel
- Institute of Neurofeedback and tDCS Poland, 70-393 Szczecin, Poland
| | - Filip Rybakowski
- Department and Clinic of Psychiatry, Poznan University of Medical Sciences, 61-701 Poznań, Poland
| | - Jerzy Leszek
- Department and Clinic of Psychiatry, Wrocław Medical University, 54-235 Wrocław, Poland
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3
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Victorino DB, Faber J, Pinheiro DJLL, Scorza FA, Almeida ACG, Costa ACS, Scorza CA. Toward the Identification of Neurophysiological Biomarkers for Alzheimer's Disease in Down Syndrome: A Potential Role for Cross-Frequency Phase-Amplitude Coupling Analysis. Aging Dis 2023; 14:428-449. [PMID: 37008053 PMCID: PMC10017148 DOI: 10.14336/ad.2022.0906] [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: 06/17/2022] [Accepted: 09/06/2022] [Indexed: 11/18/2022] Open
Abstract
Cross-frequency coupling (CFC) mechanisms play a central role in brain activity. Pathophysiological mechanisms leading to many brain disorders, such as Alzheimer's disease (AD), may produce unique patterns of brain activity detectable by electroencephalography (EEG). Identifying biomarkers for AD diagnosis is also an ambition among research teams working in Down syndrome (DS), given the increased susceptibility of people with DS to develop early-onset AD (DS-AD). Here, we review accumulating evidence that altered theta-gamma phase-amplitude coupling (PAC) may be one of the earliest EEG signatures of AD, and therefore may serve as an adjuvant tool for detecting cognitive decline in DS-AD. We suggest that this field of research could potentially provide clues to the biophysical mechanisms underlying cognitive dysfunction in DS-AD and generate opportunities for identifying EEG-based biomarkers with diagnostic and prognostic utility in DS-AD.
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Affiliation(s)
- Daniella B Victorino
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Jean Faber
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Daniel J. L. L Pinheiro
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Fulvio A Scorza
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Antônio C. G Almeida
- Department of Biosystems Engineering, Federal University of São João Del Rei, Minas Gerais, MG, Brazil.
| | - Alberto C. S Costa
- Division of Psychiatry, Case Western Reserve University, Cleveland, OH, United States.
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, United States.
| | - Carla A Scorza
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
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Fernández A, Ramírez-Toraño F, Bruña R, Zuluaga P, Esteba-Castillo S, Abásolo D, Moldenhauer F, Shumbayawonda E, Maestú F, García-Alba J. Brain signal complexity in adults with Down syndrome: Potential application in the detection of mild cognitive impairment. Front Aging Neurosci 2022; 14:988540. [PMID: 36337705 PMCID: PMC9631477 DOI: 10.3389/fnagi.2022.988540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/27/2022] [Indexed: 11/13/2022] Open
Abstract
Background Down syndrome (DS) is considered the most frequent cause of early-onset Alzheimer’s disease (AD), and the typical pathophysiological signs are present in almost all individuals with DS by the age of 40. Despite of this evidence, the investigation on the pre-dementia stages in DS is scarce. In the present study we analyzed the complexity of brain oscillatory patterns and neuropsychological performance for the characterization of mild cognitive impairment (MCI) in DS. Materials and methods Lempel-Ziv complexity (LZC) values from resting-state magnetoencephalography recordings and the neuropsychological performance in 28 patients with DS [control DS group (CN-DS) (n = 14), MCI group (MCI-DS) (n = 14)] and 14 individuals with typical neurodevelopment (CN-no-DS) were analyzed. Results Lempel-Ziv complexity was lowest in the frontal region within the MCI-DS group, while the CN-DS group showed reduced values in parietal areas when compared with the CN-no-DS group. Also, the CN-no-DS group exhibited the expected pattern of significant increase of LZC as a function of age, while MCI-DS cases showed a decrease. The combination of reduced LZC values and a divergent trajectory of complexity evolution with age, allowed the discrimination of CN-DS vs. MCI-DS patients with a 92.9% of sensitivity and 85.7% of specificity. Finally, a pattern of mnestic and praxic impairment was significantly associated in MCI-DS cases with the significant reduction of LZC values in frontal and parietal regions (p = 0.01). Conclusion Brain signal complexity measured with LZC is reduced in DS and its development with age is also disrupted. The combination of both features might assist in the detection of MCI within this population.
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Affiliation(s)
- Alberto Fernández
- Department of Legal Medicine, Psychiatry and Pathology, Universidad Complutense de Madrid, Madrid, Spain
- Institute of Sanitary Investigation (IdISSC), Hospital Universitario San Carlos, Madrid, Spain
- Center for Cognitive and Computational Neuroscience, Universidad Complutense de Madrid, Madrid, Spain
| | - Federico Ramírez-Toraño
- Center for Cognitive and Computational Neuroscience, Universidad Complutense de Madrid, Madrid, Spain
- Department of Experimental Psychology, Cognitive Processes and Speech Therapy, Universidad Complutense de Madrid, Madrid, Spain
| | - Ricardo Bruña
- Center for Cognitive and Computational Neuroscience, Universidad Complutense de Madrid, Madrid, Spain
- Department of Radiology, Universidad Complutense de Madrid, Madrid, Spain
- Department of Industrial Engineering & IUNE & ITB, Universidad de La Laguna, San Cristóbal de La Laguna, Spain
| | - Pilar Zuluaga
- Statistics & Operations Research Department, Faculty of Medicine, Universidad Complutense de Madrid, Madrid, Spain
| | - Susanna Esteba-Castillo
- Neurodevelopmental Group, Girona Biomedical Research Institute-IDIBGI, Institute of Health Assistance (IAS), Parc Hospitalari Martí i Julià, Girona, Spain
| | - Daniel Abásolo
- Centre for Biomedical Engineering, School of Mechanical Engineering Sciences, University of Surrey, Guildford, United Kingdom
| | - Fernando Moldenhauer
- Adult Down Syndrome Unit, Internal Medicine Department, Health Research Institute, Hospital Universitario de La Princesa, Madrid, Spain
| | - Elizabeth Shumbayawonda
- Centre for Biomedical Engineering, School of Mechanical Engineering Sciences, University of Surrey, Guildford, United Kingdom
| | - Fernando Maestú
- Center for Cognitive and Computational Neuroscience, Universidad Complutense de Madrid, Madrid, Spain
- Department of Experimental Psychology, Cognitive Processes and Speech Therapy, Universidad Complutense de Madrid, Madrid, Spain
| | - Javier García-Alba
- Department of Research and Psychology in Education, Universidad Complutense de Madrid, Madrid, Spain
- *Correspondence: Javier García-Alba,
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5
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Bartesaghi R. Brain circuit pathology in Down syndrome: from neurons to neural networks. Rev Neurosci 2022; 34:365-423. [PMID: 36170842 DOI: 10.1515/revneuro-2022-0067] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/28/2022] [Indexed: 11/15/2022]
Abstract
Down syndrome (DS), a genetic pathology caused by triplication of chromosome 21, is characterized by brain hypotrophy and impairment of cognition starting from infancy. While studies in mouse models of DS have elucidated the major neuroanatomical and neurochemical defects of DS, comparatively fewer investigations have focused on the electrophysiology of the DS brain. Electrical activity is at the basis of brain functioning. Therefore, knowledge of the way in which brain circuits operate in DS is fundamental to understand the causes of behavioral impairment and devise targeted interventions. This review summarizes the state of the art regarding the electrical properties of the DS brain, starting from individual neurons and culminating in signal processing in whole neuronal networks. The reported evidence derives from mouse models of DS and from brain tissues and neurons derived from individuals with DS. EEG data recorded in individuals with DS are also provided as a key tool to understand the impact of brain circuit alterations on global brain activity.
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Affiliation(s)
- Renata Bartesaghi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
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6
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Sibarani CR, Walter LM, Davey MJ, Nixon GM, Horne RSC. Sleep-disordered breathing and sleep macro- and micro-architecture in children with Down syndrome. Pediatr Res 2022; 91:1248-1256. [PMID: 34230620 DOI: 10.1038/s41390-021-01642-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND Children with Down syndrome (DS) are at increased risk of sleep-disordered breathing (SDB), which is associated with intermittent hypoxia and sleep disruption affecting daytime functioning. We aimed to compare the impact of SDB on sleep quality in children with DS compared to typically developing (TD) children with and without SDB. METHODS Children with DS and SDB (n = 44) were age- and sex-matched with TD children without SDB (TD-) and also for SDB severity with TD children with SDB (TD+). Children underwent overnight polysomnography with sleep macro- and micro-architecture assessed using electroencephalogram (EEG) spectral analysis, including slow-wave activity (SWA, an indicator of sleep propensity). RESULTS Children with DS had greater hypoxic exposure, more respiratory events during REM sleep, higher total, delta, sigma, and beta EEG power in REM than TD+ children, despite the same overall frequency of obstructive events. Compared to TD- children, they also had more wake after sleep-onset and lower sigma power in N2 and N3. The DS group had reduced SWA, indicating reduced sleep drive, compared to both TD groups. CONCLUSIONS Our findings suggest that SDB has a greater impact on sleep quality in children with DS compared to TD children. IMPACT SDB in children with DS exacerbates disruption of sleep quality, compared to TD children. The prevalence of SDB is very high in children with DS; however, studies on the effects of SDB on sleep quality are limited in this population. Our findings suggest that SDB has a greater impact on sleep quality in children with DS compared to TD children, and should be screened for and treated as soon as possible.
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Affiliation(s)
- Christy R Sibarani
- Department of Paediatrics and The Ritchie Centre, Monash University, Melbourne, VIC, Australia
| | - Lisa M Walter
- Department of Paediatrics and The Ritchie Centre, Monash University, Melbourne, VIC, Australia
| | - Margot J Davey
- Department of Paediatrics and The Ritchie Centre, Monash University, Melbourne, VIC, Australia.,Melbourne Children's Sleep Centre, Monash Children's Hospital, Melbourne, VIC, Australia
| | - Gillian M Nixon
- Department of Paediatrics and The Ritchie Centre, Monash University, Melbourne, VIC, Australia.,Melbourne Children's Sleep Centre, Monash Children's Hospital, Melbourne, VIC, Australia
| | - Rosemary S C Horne
- Department of Paediatrics and The Ritchie Centre, Monash University, Melbourne, VIC, Australia.
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Goeldner C, Kishnani PS, Skotko BG, Casero JL, Hipp JF, Derks M, Hernandez MC, Khwaja O, Lennon-Chrimes S, Noeldeke J, Pellicer S, Squassante L, Visootsak J, Wandel C, Fontoura P, d’Ardhuy XL, De La Torre Fornell R, Glue P, Hoover-Fong J, Uhlmann S, Malagón Valdez J, Marshall A, Martinón-Torres F, Redondo-Collazo L, Rodriguez-Tenreiro C, Marquez Chin V, Michel Reynoso AG, Mitchell EA, Slykerman RF, Wouldes T, Loveday S, Moldenhauer F, Novell R, Ochoa C, Rafii MS, Rebillat AS, Sanlaville D, Sarda P, Shankar R, Pulsifer M, Evans CL, Silva AM, McDonough ME, Stanley M, McCary LM, Vicari S, Wilcox W, Zampino G, Zuddas A. A randomized, double-blind, placebo-controlled phase II trial to explore the effects of a GABAA-α5 NAM (basmisanil) on intellectual disability associated with Down syndrome. J Neurodev Disord 2022; 14:10. [PMID: 35123401 PMCID: PMC8903644 DOI: 10.1186/s11689-022-09418-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 01/12/2022] [Indexed: 11/23/2022] Open
Abstract
Background There are currently no pharmacological therapies to address the intellectual disability associated with Down syndrome. Excitatory/inhibitory imbalance has been hypothesized to contribute to impairments in cognitive functioning in Down syndrome. Negative modulation of the GABAA-α5 receptor is proposed as a mechanism to attenuate GABAergic function and restore the excitatory/inhibitory balance. Methods Basmisanil, a selective GABAA-α5 negative allosteric modulator, was evaluated at 120 mg or 240 mg BID (80 or 160 mg for 12–13 years) in a 6-month, randomized, double-blind, placebo-controlled phase II trial (Clematis) for efficacy and safety in adolescents and young adults with Down syndrome. The primary endpoint was based on a composite analysis of working memory (Repeatable Battery for the Assessment of Neuropsychological Scale [RBANS]) and independent functioning and adaptive behavior (Vineland Adaptive Behavior Scales [VABS-II] or the Clinical Global Impression-Improvement [CGI-I]). Secondary measures included the Behavior Rating Inventory of Executive Functioning-Preschool (BRIEF-P), Clinical Evaluation of Language Fundamentals (CELF-4), and Pediatric Quality of Life Inventory (Peds-QL). EEG was conducted for safety monitoring and quantitatively analyzed in adolescents. Results Basmisanil was safe and well-tolerated; the frequency and nature of adverse events were similar in basmisanil and placebo arms. EEG revealed treatment-related changes in spectral power (increase in low ~ 4-Hz and decrease in high ~ 20-Hz frequencies) providing evidence of functional target engagement. All treatment arms had a similar proportion of participants showing above-threshold improvement on the primary composite endpoint, evaluating concomitant responses in cognition and independent functioning (29% in placebo, 20% in low dose, and 25% in high dose). Further analysis of the individual measures contributing to the primary endpoint revealed no difference between placebo and basmisanil-treated groups in either adolescents or adults. There were also no differences across the secondary endpoints assessing changes in executive function, language, or quality of life. Conclusions Basmisanil did not meet the primary efficacy objective of concomitant improvement on cognition and adaptive functioning after 6 months of treatment, despite evidence for target engagement. This study provides key learnings for future clinical trials in Down syndrome. Trial registration The study was registered on December 31, 2013, at clinicaltrials.gov as NCT02024789. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-022-09418-0.
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8
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Hamburg S, Bush D, Strydom A, Startin CM. Comparison of resting-state EEG between adults with Down syndrome and typically developing controls. J Neurodev Disord 2021; 13:48. [PMID: 34649497 PMCID: PMC8518326 DOI: 10.1186/s11689-021-09392-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/01/2021] [Indexed: 12/01/2022] Open
Abstract
Background Down syndrome (DS) is the most common genetic cause of intellectual disability (ID) worldwide. Understanding electrophysiological characteristics associated with DS provides potential mechanistic insights into ID, helping inform biomarkers and targets for intervention. Currently, electrophysiological characteristics associated with DS remain unclear due to methodological differences between studies and inadequate controls for cognitive decline as a potential cofounder. Methods Eyes-closed resting-state EEG measures (specifically delta, theta, alpha, and beta absolute and relative powers, and alpha peak amplitude, frequency and frequency variance) in occipital and frontal regions were compared between adults with DS (with no diagnosis of dementia or evidence of cognitive decline) and typically developing (TD) matched controls (n = 25 per group). Results We report an overall ‘slower’ EEG spectrum, characterised by higher delta and theta power, and lower alpha and beta power, for both regions in people with DS. Alpha activity in particular showed strong group differences, including lower power, lower peak amplitude and greater peak frequency variance in people with DS. Conclusions Such EEG ‘slowing’ has previously been associated with cognitive decline in both DS and TD populations. These findings indicate the potential existence of a universal EEG signature of cognitive impairment, regardless of origin (neurodevelopmental or neurodegenerative), warranting further exploration. Supplementary Information The online version contains supplementary material available at 10.1186/s11689-021-09392-z.
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Affiliation(s)
- Sarah Hamburg
- The London Down Syndrome Consortium (LonDownS), London, UK.
| | - Daniel Bush
- Institute of Cognitive Neuroscience, University College London, London, UK.,Queen Square Institute of Neurology, University College London, London, UK
| | - Andre Strydom
- The London Down Syndrome Consortium (LonDownS), London, UK.,Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK
| | - Carla M Startin
- The London Down Syndrome Consortium (LonDownS), London, UK.,Department of Psychology, University of Roehampton, London, UK
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Greer JMH, Riby DM, McMullon MEG, Hamilton C, Riby LM. An EEG investigation of alpha and beta activity during resting states in adults with Williams syndrome. BMC Psychol 2021; 9:72. [PMID: 33952354 PMCID: PMC8097943 DOI: 10.1186/s40359-021-00575-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 04/27/2021] [Indexed: 11/10/2022] Open
Abstract
Background Williams syndrome (WS) is neurodevelopmental disorder characterised by executive deficits of attention and inhibitory processing. The current study examined the neural mechanisms during resting states in adults with WS in order to investigate how this subserves the attention and inhibitory deficits associated with the syndrome. Method Adopting electroencephalography (EEG) methodology, cortical electrical activity was recorded from eleven adults with WS aged 35 + years during Eyes Closed (EC) and Eyes Open (EO) resting states, and compared to that of thirteen typically developing adults matched for chronological age (CA) and ten typically developing children matched for verbal mental ability (MA). Using mixed-design analyses of variance (ANOVA), analyses focused on the full alpha (8–12.5 Hz), low-alpha (8–10 Hz), upper-alpha (10–12.5 Hz), and beta (13–29.5 Hz) bands, as these are thought to have functional significance with attentional and inhibitory processes. Results No significant difference in alpha power were found between the WS and CA groups across all analyses, however a trend for numerically lower alpha power was observed in the WS group, consistent with other developmental disorders characterised by attentional/inhibitory deficits such as Attention Deficit Hyperactivity Disorder (ADHD). In contrast, comparable beta power between the WS and CA groups during both EC/EO conditions suggests that their baseline EEG signature is commensurate with successful attentional processing, though this needs to be interpreted with caution due to the small sample size. Analyses also revealed an unusual trend for low variability in the EEG signature of the WS group, which contradicts the heterogeneity typically observed behaviourally. Conclusions This novel finding of low variability in the EEG spectra in the WS group has been previously associated with poor behavioural performance in ADHD and is highly informative, highlighting future research needs to also consider how the role of low variability in the EEG profile of WS manifests in relation to their behavioural and cognitive profiles.
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Affiliation(s)
- Joanna M H Greer
- Department of Psychology, Northumbria University, Newcastle upon Tyne, UK.
| | - Deborah M Riby
- Department of Psychology, Durham University, Durham, UK.,Centre for Developmental Disorders, Durham University, Durham, UK
| | | | - Colin Hamilton
- Department of Psychology, Northumbria University, Newcastle upon Tyne, UK
| | - Leigh M Riby
- Department of Psychology, Northumbria University, Newcastle upon Tyne, UK
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Anagnostopoulou A, Styliadis C, Kartsidis P, Romanopoulou E, Zilidou V, Karali C, Karagianni M, Klados M, Paraskevopoulos E, Bamidis PD. Computerized physical and cognitive training improves the functional architecture of the brain in adults with Down syndrome: A network science EEG study. Netw Neurosci 2021; 5:274-294. [PMID: 33688615 PMCID: PMC7935030 DOI: 10.1162/netn_a_00177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 12/01/2020] [Indexed: 01/31/2023] Open
Abstract
Understanding the neuroplastic capacity of people with Down syndrome (PwDS) can potentially reveal the causal relationship between aberrant brain organization and phenotypic characteristics. We used resting-state EEG recordings to identify how a neuroplasticity-triggering training protocol relates to changes in the functional connectivity of the brain's intrinsic cortical networks. Brain activity of 12 PwDS before and after a 10-week protocol of combined physical and cognitive training was statistically compared to quantify changes in directed functional connectivity in conjunction with psychosomatometric assessments. PwDS showed increased connectivity within the left hemisphere and from left-to-right hemisphere, as well as increased physical and cognitive performance. Our findings reveal a strong adaptive neuroplastic reorganization as a result of the training that leads to a less-random network with a more pronounced hierarchical organization. Our results go beyond previous findings by indicating a transition to a healthier, more efficient, and flexible network architecture, with improved integration and segregation abilities in the brain of PwDS. Resting-state electrophysiological brain activity is used here for the first time to display meaningful relationships to underlying Down syndrome processes and outcomes of importance in a translational inquiry. This trial is registered with ClinicalTrials.gov Identifier NCT04390321.
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Affiliation(s)
- Alexandra Anagnostopoulou
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Charis Styliadis
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Panagiotis Kartsidis
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Evangelia Romanopoulou
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Vasiliki Zilidou
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Chrysi Karali
- School of Biology, Faculty of Science, Aristotle University of Thessaloniki, Greece
| | - Maria Karagianni
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Manousos Klados
- Department of Psychology, The University of Sheffield International Faculty, City College, Thessaloniki, Greece
| | - Evangelos Paraskevopoulos
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
| | - Panagiotis D Bamidis
- Medical Physics Laboratory, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece
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11
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Hamburg S, Rosch R, Startin CM, Friston KJ, Strydom A. Dynamic Causal Modeling of the Relationship between Cognition and Theta-alpha Oscillations in Adults with Down Syndrome. Cereb Cortex 2020; 29:2279-2290. [PMID: 30877793 PMCID: PMC6458903 DOI: 10.1093/cercor/bhz043] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 02/09/2019] [Indexed: 01/17/2023] Open
Abstract
Individuals with Down syndrome (DS) show high inter-subject variability in cognitive ability and have an ultra-high risk of developing dementia (90% lifetime prevalence). Elucidating factors underlying variability in cognitive function can inform us about intellectual disability (ID) and may improve our understanding of factors associated with later cognitive decline. Increased neuronal inhibition has been posited to contribute to ID in DS. Combining electroencephalography (EEG) with dynamic causal modeling (DCM) provides a non-invasive method for investigating excitatory/inhibitory mechanisms. Resting-state EEG recordings were obtained from 36 adults with DS with no evidence of cognitive decline. Theta–alpha activity (4–13 Hz) was characterized in relation to general cognitive ability (raw Kaufmann’s Brief Intelligence Test second Edition (KBIT-2) score). Higher KBIT-2 was associated with higher frontal alpha peak amplitude and higher theta–alpha band power across distributed regions. Modeling this association with DCM revealed intrinsic self-inhibition was the key network parameter underlying observed differences in 4–13 Hz power in relation to KBIT-2 and age. In particular, intrinsic self-inhibition in right V1 was negatively correlated with KBIT-2. Results suggest intrinsic self-inhibition within the alpha network is associated with individual differences in cognitive ability in adults with DS, and may provide a potential therapeutic target for cognitive enhancement.
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Affiliation(s)
- Sarah Hamburg
- Division of Psychiatry, Faculty of Brain Sciences, University College London, 149 Tottenham Court Road, London, UK.,Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.,The London Down Syndrome Consortium (LonDownS), London, UK
| | - Richard Rosch
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London, UK
| | - Carla Marie Startin
- Division of Psychiatry, Faculty of Brain Sciences, University College London, 149 Tottenham Court Road, London, UK.,Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.,The London Down Syndrome Consortium (LonDownS), London, UK
| | - Karl John Friston
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London, UK
| | - André Strydom
- Division of Psychiatry, Faculty of Brain Sciences, University College London, 149 Tottenham Court Road, London, UK.,Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.,The London Down Syndrome Consortium (LonDownS), London, UK
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García-Alba J, Ramírez-Toraño F, Esteba-Castillo S, Bruña R, Moldenhauer F, Novell R, Romero-Medina V, Maestú F, Fernández A. Neuropsychological and neurophysiological characterization of mild cognitive impairment and Alzheimer's disease in Down syndrome. Neurobiol Aging 2019; 84:70-79. [PMID: 31518951 DOI: 10.1016/j.neurobiolaging.2019.07.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/03/2019] [Accepted: 07/30/2019] [Indexed: 10/26/2022]
Abstract
Down syndrome (DS) has been considered a unique model for the investigation of Alzheimer's disease (AD) but intermediate stages in the continuum are poorly defined. Considering this, we investigated the neurophysiological (i.e., magnetoencephalography [MEG]) and neuropsychological patterns of mild cognitive impairment (MCI) and AD in middle-aged adults with DS. The sample was composed of four groups: Control-DS (n = 14, mean age 44.64 ± 3.30 years), MCI-DS (n = 14, 51.64 ± 3.95 years), AD-DS (n = 13, 53.54 ± 6.58 years), and Control-no-DS (healthy controls, n = 14, 45.21 ± 4.39 years). DS individuals were studied with neuropsychological tests and MEG, whereas the Control-no-DS group completed only the MEG session. Our results showed that the AD-DS group exhibited a significantly poorer performance as compared with the Control-DS group in all tests. Furthermore, this effect was crucially evident in AD-DS individuals when compared with the MCI-DS group in verbal and working memory abilities. In the neurophysiological domain, the Control-DS group showed a widespread increase of theta activity when compared with the Control-no-DS group. With disease progression, this increased theta was substituted by an augmented delta, accompanied with a reduction of alpha activity. Such spectral pattern-specifically observed in occipital, posterior temporal, cuneus, and precuneus regions-correlated with the performance in cognitive tests. This is the first MEG study in the field incorporating both neuropsychological and neurophysiological information, and demonstrating that this combination of markers is sensitive enough to characterize different stages along the AD continuum in DS.
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Affiliation(s)
- Javier García-Alba
- Research and Psychology in Education Department, Complutense University of Madrid, Madrid, Spain; Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain.
| | - Federico Ramírez-Toraño
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Experimental Psychology, Complutense University of Madrid, Campus de Somosaguas, Pozuelo de Alarcón, Madrid, Spain
| | - Susanna Esteba-Castillo
- Specialized Department in Mental Health and Intellectual Disability, Parc Hospitalari Martí i Julià - Institut d'Assistència Sanitària, Institut d'Assistència Sanitària (IAS), Girona, Spain; Neurodevelopment group [Girona Biomedical Research Institute]-IDIBGI, Institute of Health Assistance (IAS), Parc Hospitalari Martí i Julià, Girona, Spain
| | - Ricardo Bruña
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Experimental Psychology, Complutense University of Madrid, Campus de Somosaguas, Pozuelo de Alarcón, Madrid, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Fernando Moldenhauer
- Internal Medicine Department, Adult Down Syndrome Unit, La Princesa University Hospital, Health Research Institute, Madrid, Spain
| | - Ramón Novell
- Specialized Department in Mental Health and Intellectual Disability, Parc Hospitalari Martí i Julià - Institut d'Assistència Sanitària, Institut d'Assistència Sanitària (IAS), Girona, Spain; Neurodevelopment group [Girona Biomedical Research Institute]-IDIBGI, Institute of Health Assistance (IAS), Parc Hospitalari Martí i Julià, Girona, Spain
| | - Verónica Romero-Medina
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain
| | - Fernando Maestú
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Experimental Psychology, Complutense University of Madrid, Campus de Somosaguas, Pozuelo de Alarcón, Madrid, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Alberto Fernández
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Legal Medicine, Psychiatry and Pathology, Complutense University of Madrid, Spain, Madrid, Spain
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Ruiz-Mejias M. Outer Brain Oscillations in Down Syndrome. Front Syst Neurosci 2019; 13:17. [PMID: 31139056 PMCID: PMC6519307 DOI: 10.3389/fnsys.2019.00017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
The present article reviews the relationship between sleep and oscillatory activity in Down Syndrome (DS), as well as the featuring emergent rhythmic activity across different brain states. A comprehensive discussion of the data from electroencephalographic studies in DS humans and transgenic/trisomic mouse models is provided, as well as data from signals collected from local field potentials (LFP) and intracellular recordings in DS mouse models. The first sections focus specially on the alpha phenotype consistently observed in DS subjects, as well as its description in DS childhood and aging. Subsequently, a review of the data reported in DS mouse models is presented with the aim to deepen on the mechanisms underlying altered rhythmic patterns. Further sections situate the state-of-the-art of the field, with a discussion on the possible circuit alterations that may underlie impaired alpha and gamma oscillatory activity. A further aim is to highlight the importance of studying network oscillatory activity in mouse models to infer alterations in the underlying circuits related to cognition, such as in intellectual disability. In this direction, a view of alpha and gamma rhythms generated by the cerebral cortex as a tool for evaluating an unbalance between excitation and inhibition in DS is claimed, which points out toward an over-inhibited network. A final aim is to situate oscillatory activity as a key phenomenon that may be used as a biomarker for monitoring as well the effect of novel therapeutic strategies.
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Affiliation(s)
- Marcel Ruiz-Mejias
- Systems Neuroscience, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
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Keshmiri S, Sumioka H, Nakanishi J, Ishiguro H. Bodily-Contact Communication Medium Induces Relaxed Mode of Brain Activity While Increasing Its Dynamical Complexity: A Pilot Study. Front Psychol 2018; 9:1192. [PMID: 30050488 PMCID: PMC6052895 DOI: 10.3389/fpsyg.2018.01192] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 06/20/2018] [Indexed: 11/13/2022] Open
Abstract
We present the results of the analysis of the effect of a bodily-contact communication medium on the brain activity of the individuals during verbal communication. Our results suggest that the communicated content that is mediated through such a device induces a significant effect on electroencephalogram (EEG) time series of human subjects. Precisely, we find a significant reduction of overall power of the EEG signals of the individuals. This observation that is supported by the analysis of the permutation entropy (PE) of the EEG time series of brain activity of the participants suggests the positive effect of such a medium on the stress relief and the induced sense of relaxation. Additionally, multiscale entropy (MSE) analysis of our data implies that such a medium increases the level of complexity that is exhibited by EEG time series of our participants, thereby suggesting their sustained sense of involvement in their course of communication. These findings that are in accord with the results reported by cognitive neuroscience research suggests that the use of such a medium can be beneficial as a complementary step in treatment of developmental disorders, attentiveness of schoolchildren and early child development, as well as scenarios where intimate physical interaction over distance is desirable (e.g., distance-parenting).
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Affiliation(s)
- Soheil Keshmiri
- Hiroshi Ishiguro Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
| | - Hidenobu Sumioka
- Hiroshi Ishiguro Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
| | - Junya Nakanishi
- Graduate School of Engineering Science, Osaka University, Suita, Japan
| | - Hiroshi Ishiguro
- Hiroshi Ishiguro Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
- Graduate School of Engineering Science, Osaka University, Suita, Japan
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Neural synchronization deficits linked to cortical hyper-excitability and auditory hypersensitivity in fragile X syndrome. Mol Autism 2017; 8:22. [PMID: 28596820 PMCID: PMC5463459 DOI: 10.1186/s13229-017-0140-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 05/04/2017] [Indexed: 12/31/2022] Open
Abstract
Background Studies in the fmr1 KO mouse demonstrate hyper-excitability and increased high-frequency neuronal activity in sensory cortex. These abnormalities may contribute to prominent and distressing sensory hypersensitivities in patients with fragile X syndrome (FXS). The current study investigated functional properties of auditory cortex using a sensory entrainment task in FXS. Methods EEG recordings were obtained from 17 adolescents and adults with FXS and 17 age- and sex-matched healthy controls. Participants heard an auditory chirp stimulus generated using a 1000-Hz tone that was amplitude modulated by a sinusoid linearly increasing in frequency from 0–100 Hz over 2 s. Results Single trial time-frequency analyses revealed decreased gamma band phase-locking to the chirp stimulus in FXS, which was strongly coupled with broadband increases in gamma power. Abnormalities in gamma phase-locking and power were also associated with theta-gamma amplitude-amplitude coupling during the pre-stimulus period and with parent reports of heightened sensory sensitivities and social communication deficits. Conclusions This represents the first demonstration of neural entrainment alterations in FXS patients and suggests that fast-spiking interneurons regulating synchronous high-frequency neural activity have reduced functionality. This reduced ability to synchronize high-frequency neural activity was related to the total power of background gamma band activity. These observations extend findings from fmr1 KO models of FXS, characterize a core pathophysiological aspect of FXS, and may provide a translational biomarker strategy for evaluating promising therapeutics. Electronic supplementary material The online version of this article (doi:10.1186/s13229-017-0140-1) contains supplementary material, which is available to authorized users.
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Ruiz-Mejias M, Martinez de Lagran M, Mattia M, Castano-Prat P, Perez-Mendez L, Ciria-Suarez L, Gener T, Sancristobal B, García-Ojalvo J, Gruart A, Delgado-García JM, Sanchez-Vives MV, Dierssen M. Overexpression of Dyrk1A, a Down Syndrome Candidate, Decreases Excitability and Impairs Gamma Oscillations in the Prefrontal Cortex. J Neurosci 2016; 36:3648-59. [PMID: 27030752 PMCID: PMC6601739 DOI: 10.1523/jneurosci.2517-15.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 11/21/2022] Open
Abstract
The dual-specificity tyrosine phosphorylation-regulated kinase DYRK1A is a serine/threonine kinase involved in neuronal differentiation and synaptic plasticity and a major candidate of Down syndrome brain alterations and cognitive deficits. DYRK1A is strongly expressed in the cerebral cortex, and its overexpression leads to defective cortical pyramidal cell morphology, synaptic plasticity deficits, and altered excitation/inhibition balance. These previous observations, however, do not allow predicting how the behavior of the prefrontal cortex (PFC) network and the resulting properties of its emergent activity are affected. Here, we integrate functional, anatomical, and computational data describing the prefrontal network alterations in transgenic mice overexpressingDyrk1A(TgDyrk1A). Usingin vivoextracellular recordings, we show decreased firing rate and gamma frequency power in the prefrontal network of anesthetized and awakeTgDyrk1Amice. Immunohistochemical analysis identified a selective reduction of vesicular GABA transporter punctae on parvalbumin positive neurons, without changes in the number of cortical GABAergic neurons in the PFC ofTgDyrk1Amice, which suggests that selective disinhibition of parvalbumin interneurons would result in an overinhibited functional network. Using a conductance-based computational model, we quantitatively demonstrate that this alteration could explain the observed functional deficits including decreased gamma power and firing rate. Our results suggest that dysfunction of cortical fast-spiking interneurons might be central to the pathophysiology of Down syndrome. SIGNIFICANCE STATEMENT DYRK1Ais a major candidate gene in Down syndrome. Its overexpression results into altered cognitive abilities, explained by defective cortical microarchitecture and excitation/inhibition imbalance. An open question is how these deficits impact the functionality of the prefrontal cortex network. Combining functional, anatomical, and computational approaches, we identified decreased neuronal firing rate and deficits in gamma frequency in the prefrontal cortices of transgenic mice overexpressingDyrk1A We also identified a reduction of vesicular GABA transporter punctae specifically on parvalbumin positive interneurons. Using a conductance-based computational model, we demonstrate that this decreased inhibition on interneurons recapitulates the observed functional deficits, including decreased gamma power and firing rate. Our results suggest that dysfunction of cortical fast-spiking interneurons might be central to the pathophysiology of Down syndrome.
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Affiliation(s)
- Marcel Ruiz-Mejias
- Systems Neuroscience, August Pi i Sunyer Biomedical research Institute (IDIBAPS), 08036 Barcelona, Spain
| | - Maria Martinez de Lagran
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, 08003 Barcelona, Spain, Pompeu Fabra University (UPF), 08003 Barcelona, Spain, Centre for Biomedical Research on Rare Diseases (CIBERER) 08003 Barcelona, Spain
| | | | - Patricia Castano-Prat
- Systems Neuroscience, August Pi i Sunyer Biomedical research Institute (IDIBAPS), 08036 Barcelona, Spain
| | - Lorena Perez-Mendez
- Systems Neuroscience, August Pi i Sunyer Biomedical research Institute (IDIBAPS), 08036 Barcelona, Spain
| | - Laura Ciria-Suarez
- Systems Neuroscience, August Pi i Sunyer Biomedical research Institute (IDIBAPS), 08036 Barcelona, Spain
| | - Thomas Gener
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, 08003 Barcelona, Spain, Pompeu Fabra University (UPF), 08003 Barcelona, Spain, Centre for Biomedical Research on Rare Diseases (CIBERER) 08003 Barcelona, Spain
| | - Belen Sancristobal
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, 08003 Barcelona, Spain, Pompeu Fabra University (UPF), 08003 Barcelona, Spain, Centre for Biomedical Research on Rare Diseases (CIBERER) 08003 Barcelona, Spain
| | | | - Agnès Gruart
- Neuroscience Department, Pablo de Olavide University 41013 Seville, Spain, and
| | | | - Maria V Sanchez-Vives
- Systems Neuroscience, August Pi i Sunyer Biomedical research Institute (IDIBAPS), 08036 Barcelona, Spain, Catalan Institution for Research and Advanced Studies (ICREA) 08010 Barcelona, Spain
| | - Mara Dierssen
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, 08003 Barcelona, Spain, Pompeu Fabra University (UPF), 08003 Barcelona, Spain, Centre for Biomedical Research on Rare Diseases (CIBERER) 08003 Barcelona, Spain,
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Cramer NP, Xu X, F Haydar T, Galdzicki Z. Altered intrinsic and network properties of neocortical neurons in the Ts65Dn mouse model of Down syndrome. Physiol Rep 2015; 3:3/12/e12655. [PMID: 26702072 PMCID: PMC4760451 DOI: 10.14814/phy2.12655] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 11/17/2015] [Indexed: 11/24/2022] Open
Abstract
All individuals with Down syndrome (DS) have a varying but significant degree of cognitive disability. Although hippocampal deficits clearly play an important role, behavioral studies also suggest that deficits within the neocortex contribute to somatosensory deficits and impaired cognition in DS. Using thalamocortical slices from the Ts65Dn mouse model of DS, we investigated the intrinsic and network properties of regular spiking neurons within layer 4 of the somatosensory cortex. In these neurons, the membrane capacitance was increased and specific membrane resistance decreased in slices from Ts65Dn mice. Examination of combined active and passive membrane properties suggests that trisomic layer 4 neurons are less excitable than those from euploid mice. The frequencies of excitatory and inhibitory spontaneous synaptic activities were also reduced in Ts65Dn neurons. With respect to network activity, spontaneous network oscillations (Up states) were shorter and less numerous in the neocortex from Ts65Dn mice when compared to euploid. Up states evoked by electrical stimulation of the ventrobasal nucleus (VBN) of the thalamus were similarly affected in Ts65Dn mice. Additionally, monosynaptic EPSCs and polysynaptic IPSCs evoked by VBN stimulation were significantly delayed in layer 4 regular spiking neurons from Ts65Dn mice. These results indicate that, in the Ts65Dn model of DS, the overall electrophysiological properties of neocortical neurons are altered leading to aberrant network activity within the neocortex. Similar changes in DS individuals may contribute to sensory and cognitive dysfunction and therefore may implicate new targets for cognitive therapies in this developmental disorder.
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Affiliation(s)
- Nathan P Cramer
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Xiufen Xu
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Tarik F Haydar
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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Abstract
The present review describes brain imaging technologies that can be used to assess the effects of nutritional interventions in human subjects. Specifically, we summarise the biological relevance of their outcome measures, practical use and feasibility, and recommended use in short- and long-term nutritional studies. The brain imaging technologies described consist of MRI, including diffusion tensor imaging, magnetic resonance spectroscopy and functional MRI, as well as electroencephalography/magnetoencephalography, near-IR spectroscopy, positron emission tomography and single-photon emission computerised tomography. In nutritional interventions and across the lifespan, brain imaging can detect macro- and microstructural, functional, electrophysiological and metabolic changes linked to broader functional outcomes, such as cognition. Imaging markers can be considered as specific for one or several brain processes and as surrogate instrumental endpoints that may provide sensitive measures of short- and long-term effects. For the majority of imaging measures, little information is available regarding their correlation with functional endpoints in healthy subjects; therefore, imaging markers generally cannot replace clinical endpoints that reflect the overall capacity of the brain to behaviourally respond to specific situations and stimuli. The principal added value of brain imaging measures for human nutritional intervention studies is their ability to provide unique in vivo information on the working mechanism of an intervention in hypothesis-driven research. Selection of brain imaging techniques and target markers within a given technique should mainly depend on the hypothesis regarding the mechanism of action of the intervention, level (structural, metabolic or functional) and anticipated timescale of the intervention's effects, target population, availability and costs of the techniques.
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Hemmati S, Ahmadlou M, Gharib M, Vameghi R, Sajedi F. Down syndrome's brain dynamics: analysis of fractality in resting state. Cogn Neurodyn 2013; 7:333-40. [PMID: 24427209 PMCID: PMC3713204 DOI: 10.1007/s11571-013-9248-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 12/16/2012] [Accepted: 03/14/2013] [Indexed: 11/26/2022] Open
Abstract
To the best knowledge of the authors there is no study on nonlinear brain dynamics of down syndrome (DS) patients, whereas brain is a highly complex and nonlinear system. In this study, fractal dimension of EEG, as a key characteristic of brain dynamics, showing irregularity and complexity of brain dynamics, was used for evaluation of the dynamical changes in the DS brain. The results showed higher fractality of the DS brain in almost all regions compared to the normal brain, which indicates less centrality and higher irregular or random functioning of the DS brain regions. Also, laterality analysis of the frontal lobe showed that the normal brain had a right frontal laterality of complexity whereas the DS brain had an inverse pattern (left frontal laterality). Furthermore, the high accuracy of 95.8 % obtained by enhanced probabilistic neural network classifier showed the potential of nonlinear dynamic analysis of the brain for diagnosis of DS patients. Moreover, the results showed that the higher EEG fractality in DS is associated with the higher fractality in the low frequencies (delta and theta), in broad regions of the brain, and the high frequencies (beta and gamma), majorly in the frontal regions.
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Affiliation(s)
- Sahel Hemmati
- />Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mehran Ahmadlou
- />Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- />Dynamic Brain Research Group, Tehran, Iran
- />Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Masoud Gharib
- />Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Roshanak Vameghi
- />Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Firoozeh Sajedi
- />Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
- />Dynamic Brain Research Group, Tehran, Iran
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Ahmadlou M, Gharib M, Hemmati S, Vameghi R, Sajedi F. Disrupted small-world brain network in children with Down Syndrome. Clin Neurophysiol 2013; 124:1755-64. [PMID: 23583023 DOI: 10.1016/j.clinph.2013.03.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/08/2013] [Accepted: 03/12/2013] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To explore how the global organization or topology of the functional brain connectivity (FBC) is affected in Down Syndrome (DS). METHODS As the brain is a highly complex network including numerous nonlinearly interacted neuronal areas, the FBCs of typically developing (TD) children and DS patients were computed using a nonlinear synchronization method. Then the differences in global organization of the obtained FBCs of the two groups were analyzed, in all electroencephalogram (EEG) frequency bands, in the framework of Small-Worldness Network (a network with optimum balance between segregation and integration of information). RESULTS The topology of the functional connectivity of DS patients is disrupted in the whole brain in alpha and theta bands, and especially in the left intra-hemispheric brain networks in upper alpha band. CONCLUSIONS The global organization of the DS brain does not resemble a Small-World network, but it works as a random network. SIGNIFICANCE It is the first study on global organization of the FBC in DS.
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Affiliation(s)
- Mehran Ahmadlou
- Netherlands Institute for Neuroscience, Amsterdam, Netherlands
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EEG delta oscillations as a correlate of basic homeostatic and motivational processes. Neurosci Biobehav Rev 2011; 36:677-95. [PMID: 22020231 DOI: 10.1016/j.neubiorev.2011.10.002] [Citation(s) in RCA: 397] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 09/23/2011] [Accepted: 10/08/2011] [Indexed: 10/16/2022]
Abstract
Functional significance of delta oscillations is not fully understood. One way to approach this question would be from an evolutionary perspective. Delta oscillations dominate the EEG of waking reptiles. In humans, they are prominent only in early developmental stages and during slow-wave sleep. Increase of delta power has been documented in a wide array of developmental disorders and pathological conditions. Considerable evidence on the association between delta waves and autonomic and metabolic processes hints that they may be involved in integration of cerebral activity with homeostatic processes. Much evidence suggests the involvement of delta oscillations in motivation. They increase during hunger, sexual arousal, and in substance users. They also increase during panic attacks and sustained pain. In cognitive domain, they are implicated in attention, salience detection, and subliminal perception. This evidence shows that delta oscillations are associated with evolutionary old basic processes, which in waking adults are overshadowed by more advanced processes associated with higher frequency oscillations. The former processes rise in activity, however, when the latter are dysfunctional.
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Albertini G, Galli M, Babiloni C, Onorati P. Informational Digest Bulletin from San Raffaele Foundation and Tosinvest Sanità (No. 22). New Quantitative Approaches in the Evaluation of Neuroanatomical Features, “Tonic” Cortical EEG Rhythms, and Cognitive/Motor Behavior in Individuals With Down Syndro. JOURNAL OF POLICY AND PRACTICE IN INTELLECTUAL DISABILITIES 2010. [DOI: 10.1111/j.1741-1130.2010.00259.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Cognitive deficits and associated neurological complications in individuals with Down's syndrome. Lancet Neurol 2010; 9:623-33. [PMID: 20494326 DOI: 10.1016/s1474-4422(10)70112-5] [Citation(s) in RCA: 289] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Improvements in medical interventions for people with Down's syndrome have led to a substantial increase in their longevity. Diagnosis and treatment of neurological complications are important in maintaining optimal cognitive functioning. The cognitive phenotype in Down's syndrome is characterised by impairments in morphosyntax, verbal short-term memory, and explicit long-term memory. However, visuospatial short-term memory, associative learning, and implicit long-term memory functions are preserved. Seizures are associated with cognitive decline and seem to cause additional decline in cognitive functioning, particularly in people with Down's syndrome and comorbid disorders such as autism. Vision and hearing disorders as well as hypothyroidism can negatively impact cognitive functioning in people with Down's syndrome. Dementia that resembles Alzheimer's disease is common in adults with Down's syndrome. Early-onset dementia in adults with Down's syndrome does not seem to be associated with atherosclerotic complications.
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Cortical sources of EEG rhythms are abnormal in down syndrome. Clin Neurophysiol 2010; 121:1205-12. [PMID: 20362500 DOI: 10.1016/j.clinph.2010.02.155] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 02/05/2010] [Accepted: 02/24/2010] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Previous studies have been inconclusive whether dominant resting state alpha rhythms are greater or lower in amplitude in subjects with Down syndrome (DS) when compared to control subjects, ample resting alpha rhythms being considered as a reflection of good mechanisms of cortical neural synchronization. Here we tested the hypothesis that when the effects of head volume conduction are taken into account by the normalization of the cortical sources of resting alpha rhythms, these sources are lower in amplitude in DS subjects than in controls in line with typical findings in Alzheimer's disease patients. METHODS Eyes-closed resting electroencephalographic (EEG) data were recorded in 45 DS subjects (25 males; mean age of 22.8years+/-0.7 standard error of mean (SEM)) and in 45 age-matched cognitively normal subjects (25 males; mean age of 22.4years+/-0.5 SEM). EEG rhythms of interest were delta (2-4Hz), theta (4-8Hz), alpha 1 (8-10.5Hz), alpha 2 (10.5-13Hz), beta 1 (13-20Hz), beta 2 (20-30Hz), and gamma (30-40Hz). Cortical EEG sources were estimated by low resolution electromagnetic tomography (LORETA) and normalized across all voxels and frequencies. RESULTS Central, parietal, occipital, and temporal cortical sources of resting alpha and beta rhythms were lower in amplitude in the DS than control subjects, whereas the opposite was true for occipital delta cortical sources. A control analysis on absolute source values showed that they were globally larger in amplitude across several frequency bands in DS than control subjects. CONCLUSIONS These results suggest that normalized cortical sources of alpha rhythms are lower in amplitude in DS than control subjects, as it is typically found in Alzheimer's disease. SIGNIFICANCE DS is accompanied by a functional impairment of cortical neuronal synchronization mechanisms in the resting state condition.
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Albertini G, Onorati P, Babiloni C, Pistoia F, Sarà M. Informational Digest Bulletin From San Raffaele Foundation and Tosinvest Sanità (No. 21). A New Quantitative Approach of the Evaluation of “Tonic” Cortical EEG Rhythms in Adults With Down Syndrome and in Adults With an Impairment of Awareness-Persistent Vegetative State (PVS). JOURNAL OF POLICY AND PRACTICE IN INTELLECTUAL DISABILITIES 2010. [DOI: 10.1111/j.1741-1130.2010.00250.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Cramer NP, Best TK, Stoffel M, Siarey RJ, Galdzicki Z. GABAB–GIRK2-Mediated Signaling in Down Syndrome. GABABRECEPTOR PHARMACOLOGY - A TRIBUTE TO NORMAN BOWERY 2010; 58:397-426. [DOI: 10.1016/s1054-3589(10)58015-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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