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Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training
Background: Methamphetamine (MA) abuse is a global crisis that exacerbates sociopolitico-economic burdens in South Africa. MA use is associated with a myriad of neural abnormalities of structure and function, with associated neurocognitive deficits, particularly executive function (EF). Working memo...
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| Format: | Thesis |
| Language: | English |
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Department of Psychiatry and Mental Health
2022
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| _version_ | 1867613253473927168 |
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| access_status_str | Open Access |
| author | Banwell, Michelle Jeanne |
| author2 | Ipser, Jonathan |
| author_browse | Banwell, Michelle Jeanne Ipser, Jonathan |
| author_facet | Ipser, Jonathan Banwell, Michelle Jeanne |
| author_sort | Banwell, Michelle Jeanne |
| collection | Thesis |
| description | Background: Methamphetamine (MA) abuse is a global crisis that exacerbates sociopolitico-economic burdens in South Africa. MA use is associated with a myriad of neural abnormalities of structure and function, with associated neurocognitive deficits, particularly executive function (EF). Working memory (WM) training has been identified as a potential adjunct to treatment of substance use disorder (SUD) to improve EF in the hope of reducing relapse rates. Neuroimaging suggests MA alters intrinsic resting state functional connectivity (rsFC), and this may contribute to neuropsychological deficits observed in methamphetamine use disorder (MUD). Methods: This nested study analysed data described in Brooks et al. (2016), in which WM training was used as an adjunct to inpatient treatment of MUD. Healthy controls (HC, N = 25) were compared to two MUD groups, one receiving treatment as usual (TAU, N = 17), and one receiving additional cognitive training (CT, N = 24) in the form of a modified version of the ‘N-back' task (C-Ya). This task was also used to assess WMA in the neural scanner, using conditions of 0-back and 1-back across groups. The current research explored these data in a novel manner through examining rsFC. Hypotheses: It was predicted that: 1) HC and MUD participants would differ on measures of WMA, but WMA would improve in MA groups at follow-up compared to baseline and this would be augmented in the CT group; 2) rsFC networks of neural regions supporting WM would be predictive of ability to perform well and improve on WM tasks; and 3) MA groups would display heightened rsFC activity within and between resting state neural networks of the default mode network (DMN) and canonical cognitive control networks (CCNs). Results: Significant differences were observed between HC and MA groups in race and level of education, but not on WMA as tested in the scanner. The CT group, who completed WMA 3-back conditions, demonstrated significant improvement on this task post- intervention. Exploratory regression models showed the WM rsFC network did not demonstrate significant relationships with any clinical, demographic, or WM variables when controlling for multiple comparisons. Heightened connectivity within and between the DMN and CCNs was observed in the MUD compared to the HC group, which provided support for hypothesis 3. Exploratory multivariate regression models demonstrated race, age, education, duration of drug use, and an interaction of group and abstinence may impact rsFC in these networks. Post-hoc analyses identified pairwise network combinations affected by these variables. Conclusions: Despite limitations of this small study, it offers tentative preliminary insights into the largely unexplored field of rsFC in MA populations. This study supports limited research demonstrating hyperconnectivity within and between CCNs and DMN of MA users. This study also offers support for recent research suggesting that easier conditions of the Nback task may not reliably test all aspects of WM function. Exploratory analyses of covariates potentially affecting rsFC provide a platform for directions of future research. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/35569 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:12.104Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Department of Psychiatry and Mental Health |
| publisherStr | Department of Psychiatry and Mental Health |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/35569 Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training Banwell, Michelle Jeanne Ipser, Jonathan Methamphetamine resting state FMRI resting state functional connectivity working memory working memory training default mode network cognitive control networks Background: Methamphetamine (MA) abuse is a global crisis that exacerbates sociopolitico-economic burdens in South Africa. MA use is associated with a myriad of neural abnormalities of structure and function, with associated neurocognitive deficits, particularly executive function (EF). Working memory (WM) training has been identified as a potential adjunct to treatment of substance use disorder (SUD) to improve EF in the hope of reducing relapse rates. Neuroimaging suggests MA alters intrinsic resting state functional connectivity (rsFC), and this may contribute to neuropsychological deficits observed in methamphetamine use disorder (MUD). Methods: This nested study analysed data described in Brooks et al. (2016), in which WM training was used as an adjunct to inpatient treatment of MUD. Healthy controls (HC, N = 25) were compared to two MUD groups, one receiving treatment as usual (TAU, N = 17), and one receiving additional cognitive training (CT, N = 24) in the form of a modified version of the ‘N-back' task (C-Ya). This task was also used to assess WMA in the neural scanner, using conditions of 0-back and 1-back across groups. The current research explored these data in a novel manner through examining rsFC. Hypotheses: It was predicted that: 1) HC and MUD participants would differ on measures of WMA, but WMA would improve in MA groups at follow-up compared to baseline and this would be augmented in the CT group; 2) rsFC networks of neural regions supporting WM would be predictive of ability to perform well and improve on WM tasks; and 3) MA groups would display heightened rsFC activity within and between resting state neural networks of the default mode network (DMN) and canonical cognitive control networks (CCNs). Results: Significant differences were observed between HC and MA groups in race and level of education, but not on WMA as tested in the scanner. The CT group, who completed WMA 3-back conditions, demonstrated significant improvement on this task post- intervention. Exploratory regression models showed the WM rsFC network did not demonstrate significant relationships with any clinical, demographic, or WM variables when controlling for multiple comparisons. Heightened connectivity within and between the DMN and CCNs was observed in the MUD compared to the HC group, which provided support for hypothesis 3. Exploratory multivariate regression models demonstrated race, age, education, duration of drug use, and an interaction of group and abstinence may impact rsFC in these networks. Post-hoc analyses identified pairwise network combinations affected by these variables. Conclusions: Despite limitations of this small study, it offers tentative preliminary insights into the largely unexplored field of rsFC in MA populations. This study supports limited research demonstrating hyperconnectivity within and between CCNs and DMN of MA users. This study also offers support for recent research suggesting that easier conditions of the Nback task may not reliably test all aspects of WM function. Exploratory analyses of covariates potentially affecting rsFC provide a platform for directions of future research. 2022-01-25T11:31:01Z 2022-01-25T11:31:01Z 2021 2022-01-25T08:55:00Z Master Thesis Masters MSc http://hdl.handle.net/11427/35569 eng application/pdf Department of Psychiatry and Mental Health Faculty of Health Sciences |
| spellingShingle | Methamphetamine resting state FMRI resting state functional connectivity working memory working memory training default mode network cognitive control networks Banwell, Michelle Jeanne Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training |
| thesis_degree_str | Master's |
| title | Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training |
| title_full | Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training |
| title_fullStr | Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training |
| title_full_unstemmed | Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training |
| title_short | Intrinsic functional brain connectivity in South African methamphetamine users undergoing inpatient treatment, with or without additional cognitive training |
| title_sort | intrinsic functional brain connectivity in south african methamphetamine users undergoing inpatient treatment with or without additional cognitive training |
| topic | Methamphetamine resting state FMRI resting state functional connectivity working memory working memory training default mode network cognitive control networks |
| url | http://hdl.handle.net/11427/35569 |
| work_keys_str_mv | AT banwellmichellejeanne intrinsicfunctionalbrainconnectivityinsouthafricanmethamphetamineusersundergoinginpatienttreatmentwithorwithoutadditionalcognitivetraining |