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An fMRI investigation of cerebellar function during verbal working memory in methadone maintenance patients.
- Source :
-
Cerebellum (London, England) [Cerebellum] 2012 Mar; Vol. 11 (1), pp. 300-10. - Publication Year :
- 2012
-
Abstract
- Working memory is impaired in opioid-dependent individuals, yet the neural underpinnings of working memory in this population are largely unknown. Previous studies in healthy adults have demonstrated that working memory is supported by a network of brain regions that includes a cerebro-cerebellar circuit. The cerebellum, in particular, may be important for inner speech mechanisms that assist verbal working memory. This study used functional magnetic resonance imaging to examine brain activity associated with working memory in five opioid-dependent, methadone-maintained patients and five matched, healthy controls. An item recognition task was administered in two conditions: (1) a low working memory load "match" condition in which participants determined whether target letters presented at the beginning of the trial matched a probe item, and (2) a high working memory load "manipulation" condition in which participants counted two alphabetical letters forward of each of the targets and determined whether either of these new items matched a probe item. Response times and accuracy scores were not significantly different between the groups. FMRI analyses indicated that, in association with higher working memory load ("manipulation" condition), the patient group exhibited hyperactivity in the superior and inferior cerebellum and amygdala relative to that of controls. At a more liberal statistical threshold, patients exhibited hypoactivity in the left prefrontal and medial frontal/pre-SMA regions. These results indicate that verbal working memory in opioid-dependent individuals involves a disrupted cerebro-cerebellar circuit and shed light on the neuroanatomical basis of working memory impairments in this population.
- Subjects :
- Adult
Cerebellar Diseases chemically induced
Cerebellar Diseases diagnosis
Cerebellum anatomy & histology
Cerebellum drug effects
Female
Humans
Magnetic Resonance Imaging methods
Male
Memory Disorders chemically induced
Memory Disorders diagnosis
Memory, Short-Term drug effects
Methadone adverse effects
Middle Aged
Narcotics adverse effects
Narcotics therapeutic use
Opioid-Related Disorders complications
Opioid-Related Disorders drug therapy
Cerebellar Diseases physiopathology
Cerebellum physiopathology
Memory Disorders physiopathology
Memory, Short-Term physiology
Methadone therapeutic use
Opioid-Related Disorders physiopathology
Subjects
Details
- Language :
- English
- ISSN :
- 1473-4230
- Volume :
- 11
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Cerebellum (London, England)
- Publication Type :
- Academic Journal
- Accession number :
- 21892700
- Full Text :
- https://doi.org/10.1007/s12311-011-0311-0