1
|
Jeon S, Lee YJ, Park I, Kim N, Kim S, Jun JY, Yoo SY, Lee SH, Kim SJ. Resting State Functional Connectivity of the Thalamus in North Korean Refugees with and without Posttraumatic Stress Disorder. Sci Rep 2020; 10:3194. [PMID: 32081883 PMCID: PMC7035375 DOI: 10.1038/s41598-020-59815-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 01/29/2020] [Indexed: 02/07/2023] Open
Abstract
In posttraumatic stress disorder (PTSD), functional connectivity (FC) between the thalamus and other brain areas has yet to be comprehensively investigated. The present study explored resting state FC (rsFC) of thalamus and its associations with trauma-related features. The included subjects were North Korean refugees with PTSD (n = 23), trauma-exposed North Korean refugees without PTSD (trauma-exposed control [TEC] group, n = 22), and South Korean healthy controls (HCs) without traumatic experiences (HC group, n = 40). All participants underwent psychiatric evaluation and functional magnetic resonance imaging (fMRI) procedures using the bilateral thalamus as seeds. In the TEC group, the negative rsFC between each thalamus and its contralateral postcentral cortex was stronger relative to the PTSD and HC groups, while positive rsFC between the left thalamus and left precentral cortex was stronger in the HC group compared to the PTSD and TEC groups. Thalamo-postcentral rsFC was positively correlated with the CAPS total score in the TEC group, and with the number of traumatic experiences in the PTSD group. The present study identified the difference of thalamic rsFC alterations among traumatized refugees and HCs. Negative rsFC between the thalamus and somatosensory cortices might be compensatory changes after multiple traumatic events in refugees.
Collapse
Affiliation(s)
- Sehyun Jeon
- Department of Psychiatry, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Yu Jin Lee
- Department of Psychiatry and Center for Sleep and Chronobiology, Seoul National University College of Medicine and Seoul National University Hospital, Seoul, Republic of Korea
| | - Inkyung Park
- Department of Psychiatry and Center for Sleep and Chronobiology, Seoul National University College of Medicine and Seoul National University Hospital, Seoul, Republic of Korea
| | - Nambeom Kim
- Department of Biomedical Engineering Research Center, Gachon University, Incheon, Republic of Korea
| | - Soohyun Kim
- Department of Neurology, Gangneung Asan Hospital, Gangwon-do, Republic of Korea
| | - Jin Yong Jun
- National Center for Mental Health, Seoul, Republic of Korea
| | - So Young Yoo
- Department of Psychiatry, National Medical Center, Seoul, Republic of Korea
| | - So Hee Lee
- Department of Psychiatry, National Medical Center, Seoul, Republic of Korea
| | - Seog Ju Kim
- Department of Psychiatry, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea.
| |
Collapse
|
2
|
Mukta KN, Gao X, Robinson PA. Neural field theory of evoked response potentials in a spherical brain geometry. Phys Rev E 2019; 99:062304. [PMID: 31330724 DOI: 10.1103/physreve.99.062304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Indexed: 11/07/2022]
Abstract
Evoked response potentials (ERPs) are calculated in spherical and planar geometries using neural field theory of the corticothalamic system. The ERP is modeled as an impulse response and the resulting modal effects of spherical corticothalamic dynamics are explored, showing that results for spherical and planar geometries converge in the limit of large brain size. Cortical modal effects can lead to a double-peak structure in the ERP time series. It is found that the main difference between infinite planar geometry and spherical geometry is that the ERP peak is sharper and stronger in the spherical geometry. It is also found that the magnitude of the response decreases with increasing spatial width of the stimulus at the cortex. The peak is slightly delayed at large angles from the stimulus point, corresponding to group velocities of 6-10 m s^{-1}. Strong modal effects are found in the spherical geometry, with the lowest few modes sufficing to describe the main features of ERPs, except very near to spatially narrow stimuli.
Collapse
Affiliation(s)
- K N Mukta
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
| | - Xiao Gao
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
| | - P A Robinson
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
| |
Collapse
|
3
|
Pang J, Robinson P. Neural mechanisms of the EEG alpha-BOLD anticorrelation. Neuroimage 2018; 181:461-470. [DOI: 10.1016/j.neuroimage.2018.07.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 07/02/2018] [Accepted: 07/12/2018] [Indexed: 12/22/2022] Open
|
4
|
Outpatient rehabilitation resources and medical expenditure in children with attention-deficit hyperactivity disorder in Taiwan. PLoS One 2018; 13:e0199877. [PMID: 29953532 PMCID: PMC6023132 DOI: 10.1371/journal.pone.0199877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 06/15/2018] [Indexed: 11/19/2022] Open
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder in children. This study investigated the use of rehabilitation treatment in Taiwan. We selected children aged 3-12 years from the National Health Insurance Research Database from 2008 to 2012 and included them in the analysis. The children who received a diagnosis according to the International Classification of Diseases, Ninth Revision, Clinical Modification were divided into two groups: ADHD and non-ADHD. We used the chi-squared test, independent sample t test, and multiple regression analysis to conduct the analysis. The utilisation of rehabilitation resources was higher in the ADHD group than in the non-ADHD group. The number of school-aged children with ADHD was higher than the number of preschool-aged children (p < 0.001). The highest utilisation of rehabilitation resources was observed in clinics (p < 0.001). In terms of region, Taipei exhibited the highest utilisation of rehabilitation resources, and the East exhibited the lowest resource utilisation (p < 0.001). Prediction of the use of rehabilitation resources, average cost, average frequency of visits, and total annual cost was affected by factors such as the average frequency of rehabilitation use, demographic characteristics, and the hospital characteristics and location (p < 0.001). The number of children with ADHD and rehabilitation use are increasing yearly; however, limitations in payment restrict the growth of rehabilitation resource use in hospitals. Supplementation of rehabilitation resources at clinics accounts for more than 60%, however, the total annual cost is less than what is observed for hospitals (p < 0.001). Policies should be established to aid in the early detection and treatment of children with ADHD to improve treatment outcomes and reduce the family burden and treatment expenditure in the future.
Collapse
|
5
|
Mukta KN, MacLaurin JN, Robinson PA. Theory of corticothalamic brain activity in a spherical geometry: Spectra, coherence, and correlation. Phys Rev E 2017; 96:052410. [PMID: 29347754 DOI: 10.1103/physreve.96.052410] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Indexed: 11/07/2022]
Abstract
Corticothalamic neural field theory is applied to a spherical geometry to better model neural activity in the human brain and is also compared with planar approximations. The frequency power spectrum, correlation, and coherence functions are computed analytically and numerically. The effects of cortical boundary conditions and resulting modal aspects of spherical corticothalamic dynamics are explored, showing that the results of spherical and finite planar geometries converge to those for the infinite planar geometry in the limit of large brain size. Estimates are made of the point at which modal series can be truncated and it is found that for physiologically plausible parameters only the lowest few spatial eigenmodes are needed for an accurate representation of macroscopic brain activity. A difference between the geometries is that there is a low-frequency 1/f spectrum in the infinite planar geometry, whereas in the spherical geometry it is 1/f^{2}. Another difference is that the alpha peak in the spherical geometry is sharper and stronger than in the planar geometry. Cortical modal effects can lead to a double alpha peak structure in the power spectrum, although the main determinant of the alpha peak is corticothalamic feedback. In the spherical geometry, the cross spectrum between two points is found to only depend on their relative distance apart. At small spatial separations the low-frequency cross spectrum is stronger than for an infinite planar geometry and the alpha peak is sharper and stronger due to the partitioning of the energy into discrete modes. In the spherical geometry, the coherence function between points decays monotonically as their separation increases at a fixed frequency, but persists further at resonant frequencies. The correlation between two points is found to be positive, regardless of the time lag and spatial separation, but decays monotonically as the separation increases at fixed time lag. At fixed distance the correlation has peaks at multiples of the period of the dominant frequency of system activity.
Collapse
Affiliation(s)
- K N Mukta
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
| | - J N MacLaurin
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
| | - P A Robinson
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
| |
Collapse
|
6
|
Kameneva T, Ying T, Guo B, Freestone DR. Neural mass models as a tool to investigate neural dynamics during seizures. J Comput Neurosci 2017; 42:203-215. [PMID: 28102460 DOI: 10.1007/s10827-017-0636-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 09/14/2016] [Accepted: 01/02/2017] [Indexed: 11/30/2022]
Abstract
Epilepsy is one of the most common neurological disorders and is characterized by recurrent seizures. We use theoretical neuroscience tools to study brain dynamics during seizures. We derive and simulate a computational model of a network of hippocampal neuronal populations. Each population within the network is based on a model that has been shown to replicate the electrophysiological dynamics observed during seizures. The results provide insights into possible mechanisms for seizure spread. We observe that epileptiform activity remains localized to a pathological region when a global connectivity parameter is less than a critical value. After establishing the critical value for seizure spread, we explored how to correct the effect by altering particular synaptic gains. The spreading of seizures is quantified using numerical methods for seizure detection. The results from this study provide a new avenue of exploration for seizure control.
Collapse
Affiliation(s)
- Tatiana Kameneva
- Department of Electrical and Electronic Engineering, The University of Melbourne, Melbourne, Australia.
| | - Tianlin Ying
- Department of Electrical and Electronic Engineering, The University of Melbourne, Melbourne, Australia
| | - Ben Guo
- Department of Electrical and Electronic Engineering, The University of Melbourne, Melbourne, Australia
| | - Dean R Freestone
- Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Melbourne, Australia
| |
Collapse
|
7
|
Abeysuriya RG, Robinson PA. Real-time automated EEG tracking of brain states using neural field theory. J Neurosci Methods 2015; 258:28-45. [PMID: 26523766 DOI: 10.1016/j.jneumeth.2015.09.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/13/2015] [Accepted: 09/16/2015] [Indexed: 12/01/2022]
Abstract
A real-time fitting system is developed and used to fit the predictions of an established physiologically-based neural field model to electroencephalographic spectra, yielding a trajectory in a physiological parameter space that parametrizes intracortical, intrathalamic, and corticothalamic feedbacks as the arousal state evolves continuously over time. This avoids traditional sleep/wake staging (e.g., using Rechtschaffen-Kales stages), which is fundamentally limited because it forces classification of continuous dynamics into a few discrete categories that are neither physiologically informative nor individualized. The classification is also subject to substantial interobserver disagreement because traditional staging relies in part on subjective evaluations. The fitting routine objectively and robustly tracks arousal parameters over the course of a full night of sleep, and runs in real-time on a desktop computer. The system developed here supersedes discrete staging systems by representing arousal states in terms of physiology, and provides an objective measure of arousal state which solves the problem of interobserver disagreement. Discrete stages from traditional schemes can be expressed in terms of model parameters for backward compatibility with prior studies.
Collapse
Affiliation(s)
- R G Abeysuriya
- School of Physics, University of Sydney, New South Wales 2006, Australia; Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia; Neurosleep, 431 Glebe Point Rd, Glebe, New South Wales 2037, Australia; Brain Dynamics Center, Sydney Medical School - Western, University of Sydney, Westmead, New South Wales 2145, Australia.
| | - P A Robinson
- School of Physics, University of Sydney, New South Wales 2006, Australia; Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia; Neurosleep, 431 Glebe Point Rd, Glebe, New South Wales 2037, Australia; Brain Dynamics Center, Sydney Medical School - Western, University of Sydney, Westmead, New South Wales 2145, Australia
| |
Collapse
|
8
|
Saggar M, Zanesco AP, King BG, Bridwell DA, MacLean KA, Aichele SR, Jacobs TL, Wallace BA, Saron CD, Miikkulainen R. Mean-field thalamocortical modeling of longitudinal EEG acquired during intensive meditation training. Neuroimage 2015; 114:88-104. [PMID: 25862265 DOI: 10.1016/j.neuroimage.2015.03.073] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 12/10/2014] [Accepted: 03/27/2015] [Indexed: 12/18/2022] Open
Abstract
Meditation training has been shown to enhance attention and improve emotion regulation. However, the brain processes associated with such training are poorly understood and a computational modeling framework is lacking. Modeling approaches that can realistically simulate neurophysiological data while conforming to basic anatomical and physiological constraints can provide a unique opportunity to generate concrete and testable hypotheses about the mechanisms supporting complex cognitive tasks such as meditation. Here we applied the mean-field computational modeling approach using the scalp-recorded electroencephalogram (EEG) collected at three assessment points from meditating participants during two separate 3-month-long shamatha meditation retreats. We modeled cortical, corticothalamic, and intrathalamic interactions to generate a simulation of EEG signals recorded across the scalp. We also present two novel extensions to the mean-field approach that allow for: (a) non-parametric analysis of changes in model parameter values across all channels and assessments; and (b) examination of variation in modeled thalamic reticular nucleus (TRN) connectivity over the retreat period. After successfully fitting whole-brain EEG data across three assessment points within each retreat, two model parameters were found to replicably change across both meditation retreats. First, after training, we observed an increased temporal delay between modeled cortical and thalamic cells. This increase provides a putative neural mechanism for a previously observed reduction in individual alpha frequency in these same participants. Second, we found decreased inhibitory connection strength between the TRN and secondary relay nuclei (SRN) of the modeled thalamus after training. This reduction in inhibitory strength was found to be associated with increased dynamical stability of the model. Altogether, this paper presents the first computational approach, taking core aspects of physiology and anatomy into account, to formally model brain processes associated with intensive meditation training. The observed changes in model parameters inform theoretical accounts of attention training through meditation, and may motivate future study on the use of meditation in a variety of clinical populations.
Collapse
Affiliation(s)
- Manish Saggar
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA; Department of Computer Science, University of Texas at Austin, TX, USA.
| | - Anthony P Zanesco
- Department of Psychology, University of California, Davis, CA, USA; Center for Mind and Brain, University of California, Davis, CA, USA
| | - Brandon G King
- Department of Psychology, University of California, Davis, CA, USA; Center for Mind and Brain, University of California, Davis, CA, USA
| | | | - Katherine A MacLean
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Stephen R Aichele
- Department of Psychology, University of California, Davis, CA, USA; Center for Mind and Brain, University of California, Davis, CA, USA
| | - Tonya L Jacobs
- Center for Mind and Brain, University of California, Davis, CA, USA
| | - B Alan Wallace
- Santa Barbara Institute for Consciousness Studies, Santa Barbara, CA, USA
| | - Clifford D Saron
- Center for Mind and Brain, University of California, Davis, CA, USA; The M.I.N.D. Institute, University of California, Davis, Sacramento, CA, USA
| | | |
Collapse
|
9
|
Abeysuriya RG, Rennie CJ, Robinson PA, Kim JW. Experimental observation of a theoretically predicted nonlinear sleep spindle harmonic in human EEG. Clin Neurophysiol 2014; 125:2016-23. [PMID: 24583091 DOI: 10.1016/j.clinph.2014.01.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/23/2014] [Accepted: 01/24/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To investigate the properties of a sleep spindle harmonic oscillation previously predicted by a theoretical neural field model of the brain. METHODS Spindle oscillations were extracted from EEG data from nine subjects using an automated algorithm. The power and frequency of the spindle oscillation and the harmonic oscillation were compared across subjects. The bicoherence of the EEG was calculated to identify nonlinear coupling. RESULTS All subjects displayed a spindle harmonic at almost exactly twice the frequency of the spindle. The power of the harmonic scaled nonlinearly with that of the spindle peak, consistent with model predictions. Bicoherence was observed at the spindle frequency, confirming the nonlinear origin of the harmonic oscillation. CONCLUSIONS The properties of the sleep spindle harmonic were consistent with the theoretical modeling of the sleep spindle harmonic as a nonlinear phenomenon. SIGNIFICANCE Most models of sleep spindle generation are unable to produce a spindle harmonic oscillation, so the observation and theoretical explanation of the harmonic is a significant step in understanding the mechanisms of sleep spindle generation. Unlike seizures, sleep spindles produce nonlinear effects that can be observed in healthy controls, and unlike the alpha oscillation, there is no linearly generated harmonic that can obscure nonlinear effects. This makes the spindle harmonic a good candidate for future investigation of nonlinearity in the brain.
Collapse
Affiliation(s)
- R G Abeysuriya
- School of Physics, University of Sydney, New South Wales 2006, Australia; Brain Dynamics Center, Sydney Medical School - Western, University of Sydney, Westmead, New South Wales 2145, Australia; Center for Integrated Research and Understanding of Sleep, 431 Glebe Point Rd, Glebe, New South Wales 2037, Australia.
| | - C J Rennie
- School of Physics, University of Sydney, New South Wales 2006, Australia; Brain Dynamics Center, Sydney Medical School - Western, University of Sydney, Westmead, New South Wales 2145, Australia
| | - P A Robinson
- School of Physics, University of Sydney, New South Wales 2006, Australia; Brain Dynamics Center, Sydney Medical School - Western, University of Sydney, Westmead, New South Wales 2145, Australia; Center for Integrated Research and Understanding of Sleep, 431 Glebe Point Rd, Glebe, New South Wales 2037, Australia
| | - J W Kim
- School of Physics, University of Sydney, New South Wales 2006, Australia; Brain Dynamics Center, Sydney Medical School - Western, University of Sydney, Westmead, New South Wales 2145, Australia; Center for Integrated Research and Understanding of Sleep, 431 Glebe Point Rd, Glebe, New South Wales 2037, Australia
| |
Collapse
|
10
|
Donev R, Gantert D, Alawam K, Edworthy A, Hässler F, Meyer-Lindenberg A, Dressing H, Thome J. Comorbidity of schizophrenia and adult attention-deficit hyperactivity disorder. World J Biol Psychiatry 2011; 12 Suppl 1:52-6. [PMID: 21905996 DOI: 10.3109/15622975.2011.599212] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES Adult ADHD is characterised by a plethora of comorbid conditions. However, the comorbidity of schizophrenia and ADHD does not seem to be a typical feature and is therefore under-researched. OBJECTIVE To identify adult patients with schizophrenia and comorbid ADHD and compare their symptomatology with schizophrenic patients without ADHD. METHOD Performance in specific neuropsychological tests (set shifting, selective and sustained attention, cognitive performance, and speed of information processing) was determined. Additionally, important demographic data and information about the patients' history such as the number of suicide attempts were gathered. Twenty-seven patients were involved in this study (14 male and 13 female). Fifteen patients were diagnosed with schizophrenia/no ADHD and twelve had both schizophrenia/ADHD. RESULTS We report here an increase in suicidal behaviour of patients with both schizophrenia and ADHD compared to schizophrenia only. A significant underperformance of the patients with ADHD comorbidity compared to patients with schizophrenia only was also determined. CONCLUSIONS The increased suicidal behaviour in patients with schizophrenia and ADHD suggests the need of further studies on mood regulation and suicidal ideations in these patients.
Collapse
Affiliation(s)
- Rossen Donev
- Academic Unit of Psychiatry, College of Medicine, Swansea University, Swansea, UK
| | | | | | | | | | | | | | | |
Collapse
|
11
|
EGELAND JENS, JOHANSEN SUSANNENORDBY, UELAND TORILL. Differentiating between ADHD sub-types on CCPT measures of sustained attention and vigilance. Scand J Psychol 2009; 50:347-54. [DOI: 10.1111/j.1467-9450.2009.00717.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
12
|
CLEARWATER JM, KERR CC, RENNIE CJ, ROBINSON PA. NEURAL MECHANISMS OF ERP CHANGE: COMBINING INSIGHTS FROM ELECTROPHYSIOLOGY AND MATHEMATICAL MODELING. J Integr Neurosci 2008; 7:529-50. [DOI: 10.1142/s0219635208002003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 11/10/2008] [Indexed: 11/18/2022] Open
|
13
|
Van Albada SJ, Rennie CJ, Robinson PA. Variability of model-free and model-based quantitative measures of EEG. J Integr Neurosci 2007; 6:279-307. [PMID: 17622982 DOI: 10.1142/s0219635207001520] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Accepted: 05/17/2007] [Indexed: 11/18/2022] Open
Abstract
Variable contributions of state and trait to the electroencephalographic (EEG) signal affect the stability over time of EEG measures, quite apart from other experimental uncertainties. The extent of intraindividual and interindividual variability is an important factor in determining the statistical, and hence possibly clinical significance of observed differences in the EEG. This study investigates the changes in classical quantitative EEG (qEEG) measures, as well as of parameters obtained by fitting frequency spectra to an existing continuum model of brain electrical activity. These parameters may have extra variability due to model selection and fitting. Besides estimating the levels of intraindividual and interindividual variability, we determined approximate time scales for change in qEEG measures and model parameters. This provides an estimate of the recording length needed to capture a given percentage of the total intraindividual variability. Also, if more precise time scales can be obtained in future, these may aid the characterization of physiological processes underlying various EEG measures. Heterogeneity of the subject group was constrained by testing only healthy males in a narrow age range (mean = 22.3 years, sd = 2.7). Eyes-closed EEGs of 32 subjects were recorded at weekly intervals over an approximately six-week period, of which 13 subjects were followed for a year. QEEG measures, computed from Cz spectra, were powers in five frequency bands, alpha peak frequency, and spectral entropy. Of these, theta, alpha, and beta band powers were most reproducible. Of the nine model parameters obtained by fitting model predictions to experiment, the most reproducible ones quantified the total power and the time delay between cortex and thalamus. About 95% of the maximum change in spectral parameters was reached within minutes of recording time, implying that repeat recordings are not necessary to capture the bulk of the variability in EEG spectra.
Collapse
|
14
|
Rowe DL, Cooper NJ, Liddell BJ, Clark CR, Gordon E, Williams LM. BRAIN STRUCTURE AND FUNCTION CORRELATES OF GENERAL AND SOCIAL COGNITION. J Integr Neurosci 2007; 6:35-74. [PMID: 17472224 DOI: 10.1142/s021963520700143x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 02/28/2007] [Indexed: 11/18/2022] Open
Abstract
AIMS To examine how general (e.g., memory, attention) and social (emotional and interpersonal processes) cognition relate to measures of brain function and structure. METHODS PCA was used to identify general and social cognitive factors from Brain Resource International Database in 1,316 subjects. The identified factors were correlated with each subject's corresponding brain structure (MRI) and function (EEG/ERP) data. RESULTS Seven core cognitive factors were identified for general and three for social. General cognition was correlated with global grey matter, while social cognition was negatively correlated with grey matter in fronto-temporal-somatosensory regions. Executive function, information processing speed and verbal memory performance were correlated with delta-theta qEEG, while most general cognitive factors negatively correlated with beta qEEG. Faster information processing speed was correlated with alpha qEEG. Executive function and information processing speed was correlated with negative-going ERP amplitude and slower ERP latency at frontal sites, but at posterior sites negative correlations were found. DISCUSSION In contrast to general cognition, social cognition is identified by different functional (automated) activity and more localized neural structures. Only general cognition, requiring more effortful, controlled processing is related to brain function measures, particularly in frontal cortices. INTEGRATIVE SIGNIFICANCE Recording measures from multiple modalities including MRI, EEG/ERP, social and general cognition within the same subject provides a method of brain profiling for use in cognitive-neurotherapy and pharmacological studies.
Collapse
Affiliation(s)
- Donald L Rowe
- The Brain Dynamics Center, Westmead Millennium Institute, Westmead Hospital and Western Clinical School, University of Sydney, NSW 2145, Australia.
| | | | | | | | | | | |
Collapse
|
15
|
Alexander DM, Arns MW, Paul RH, Rowe DL, Cooper N, Esser AH, Fallahpour K, Stephan BCM, Heesen E, Breteler R, Williams LM, Gordon E. EEG MARKERS FOR COGNITIVE DECLINE IN ELDERLY SUBJECTS WITH SUBJECTIVE MEMORY COMPLAINTS. J Integr Neurosci 2006; 5:49-74. [PMID: 16544366 DOI: 10.1142/s0219635206001021] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 02/02/2006] [Indexed: 11/18/2022] Open
Abstract
New treatments for Alzheimer's disease require early detection of cognitive decline. Most studies seeking to identify markers of early cognitive decline have focused on a limited number of measures. We sought to establish the profile of brain function measures which best define early neuropsychological decline. We compared subjects with subjective memory complaints to normative controls on a wide range of EEG derived measures, including a new measure of event-related spatio-temporal waves and biophysical modeling, which derives anatomical and physiological parameters based on subject's EEG measurements. Measures that distinguished the groups were then related to cognitive performance on a variety of learning and executive function tasks. The EEG measures include standard power measures, peak alpha frequency, EEG desynchronization to eyes-opening, and global phase synchrony. The most prominent differences in subjective memory complaint subjects were elevated alpha power and an increased number of spatio-temporal wave events. Higher alpha power and changes in wave activity related most strongly to a decline in verbal memory performance in subjects with subjective memory complaints, and also declines in maze performance and working memory reaction time. Interestingly, higher alpha power and wave activity were correlated with improved performance in reverse digit span in the subjective memory complaint group. The modeling results suggest that differences in the subjective memory complaint subjects were due to a decrease in cortical and thalamic inhibitory gains and slowed dendritic time-constants. The complementary profile that emerges from the variety of measures and analyses points to a nonlinear progression in electrophysiological changes from early neuropsychological decline to late-stage dementia, and electrophysiological changes in subjective memory complaint that vary in their relationships to a range of memory-related tasks.
Collapse
Affiliation(s)
- David M Alexander
- The Brain Resource Company and the Brain Resource International Database, Ultimo, NSW 2007, Australia.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Robinson PA. Propagator theory of brain dynamics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:011904. [PMID: 16089998 DOI: 10.1103/physreve.72.011904] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Indexed: 05/03/2023]
Abstract
A physiologically based continuum model of brain dynamics is extended to incorporate arbitrary numbers of structures and neural populations, multiple outgoing fields of activity from a single population of neurons to various targets, improved treatment of converging or diverging projections and mesoscopic structure, and generalized connections to quantities observable via electroencephalography and other methods. The results are applied to study the corticothalamic system, predicting an intracortical resonance that leads to enhancements of electroencephalographic activity in the gamma (>30 Hz) range. This resonance involves feedback loops incorporating slow, short-range inhibitory fibers.
Collapse
Affiliation(s)
- P A Robinson
- School of Physics, University of Sydney, New South Wales, Australia
| |
Collapse
|
17
|
Rowe DL, Robinson PA, Gordon E. Stimulant drug action in attention deficit hyperactivity disorder (ADHD): inference of neurophysiological mechanisms via quantitative modelling. Clin Neurophysiol 2005; 116:324-35. [PMID: 15661111 DOI: 10.1016/j.clinph.2004.08.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To infer the neural mechanisms underlying tonic transitions in the electroencephalogram (EEG) in 11 adolescents diagnosed with attention deficit hyperactivity disorder (ADHD) before and after treatment with stimulant medication. METHODS A biophysical model was used to analyse electroencephalographic (EEG) measures of tonic brain activity at multiple scalp sites before and after treatment with medication. RESULTS It was observed that stimulants had the affect of significantly reducing the parameter controlling activation in the intrathalamic pathway involving the thalamic reticular nucleus (TRN) and the parameter controlling excitatory cortical activity. The effect of stimulant medication was also found to be preferentially localized within subcortical nuclei projecting towards frontal and central scalp sites. CONCLUSIONS It is suggested that the action of stimulant medication occurs via suppression of the locus coeruleus, which in turn reduces stimulation of the TRN, and improves cortical arousal. The effects localized to frontal and central sites are consistent with the occurrence of frontal delta-theta EEG abnormalities in ADHD, and existing theories of hypoarousal. SIGNIFICANCE To our knowledge, this is the first study where a detailed biophysical model of the brain has been used to estimate changes in neurophysiological parameters underlying the effects of stimulant medication in ADHD.
Collapse
Affiliation(s)
- D L Rowe
- School of Physics, University of Sydney, Camperdown, NSW 2006, Australia.
| | | | | |
Collapse
|
18
|
Rowe DL. A FRAMEWORK FOR INVESTIGATING THALAMOCORTICAL ACTIVITY IN MULTISTAGE INFORMATION PROCESSING. J Integr Neurosci 2005; 4:5-26. [PMID: 16035138 DOI: 10.1142/s0219635205000707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 02/21/2005] [Indexed: 11/18/2022] Open
Abstract
A framework for investigating information processing in cortico-thalamocortical (cortico-TC) networks is presented, that in part can be used to model and interpret individual changes in electroencephalographic spectra and event-related potentials such as those from the Brain Resource International Database. Scientific work covering neurophysiology, TC firing modes, and TC models are explored in the framework to explain how the brain might process complex information in a multistage process. It is proposed that the thalamus and the cortico-TC system have unique ionic properties and transmission delays (in humans), which are suited to the function of taking "snapshots" or samples of complex environmental stimuli, rather than continuous data streams. This leads to careful and sequential coordination of stimulus and response processes, and increases the probability of information transfer and the resulting information complexity in higher cortical regions. Given the scope of this framework, the multidimensional and standardized Brain Resource International Database provides a pertinent set of measures for both testing hypotheses generated from the model, and for fitting the model to experimental data to investigate mechanisms underlying information processing.
Collapse
Affiliation(s)
- Donald L Rowe
- The Brain Dynamics Center, University of Sydney and Westmead Hospital, NSW 2145, Australia.
| |
Collapse
|
19
|
Rowe DL, Robinson PA, Rennie CJ. Estimation of neurophysiological parameters from the waking EEG using a biophysical model of brain dynamics. J Theor Biol 2004; 231:413-33. [PMID: 15501472 DOI: 10.1016/j.jtbi.2004.07.004] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Revised: 06/22/2004] [Accepted: 07/12/2004] [Indexed: 11/20/2022]
Abstract
This paper presents the results from using electroencephalographic (EEG) data to estimate the values of key neurophysiological parameters using a detailed biophysical model of brain activity. The model incorporates spatial and temporal aspects of cortical function including axonal transmission delays, synapto-dendritic rates, range-dependent connectivities, excitatory and inhibitory neural populations, and intrathalamic, intracortical, corticocortical and corticothalamic pathways. Parameter estimates were obtained by fitting the model's theoretical spectrum to EEG spectra from each of 100 healthy human subjects. Statistical analysis was used to infer significant parameter variations occurring between eyes-closed and eyes-open states, and a correlation matrix was used to investigate links between the parameter variations and traditional measures of quantitative EEG (qEEG). Accurate fits to all experimental spectra were observed, and both inter-subject and between-state variability were accounted for by the variance in the fitted biophysical parameters, which were in turn consistent with known independent experimental and theoretical estimates. These values thus provide physiological information regarding the state. transitions (eyes-closed vs. eyes-open) and phenomena including cortical idling and alpha desynchronization. The parameters are also consistent with traditional qEEG, but are more informative, since they provide links to underlying physiological processes. To our knowledge, this is the first study where a detailed biophysical model of the brain is used to estimate neurophysiological parameters underlying the transitions in a broad range (0.25-50 Hz) of EEG spectra obtained from a large set of human data.
Collapse
Affiliation(s)
- Donald L Rowe
- School of Physics, University of Sydney, New South Wales 2006, Australia.
| | | | | |
Collapse
|