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Structural integrity of the substantia nigra and subthalamic nucleus predicts flexibility of instrumental learning in older-age individuals.

Chowdhury R, Guitart-Masip M, Lambert C, Dolan RJ, Düzel E - Neurobiol. Aging (2013)

Bottom Line: Normal aging is associated with a variable loss of dopamine neurons in the SN/VTA.Older, but not younger, participants with greater structural integrity of the SN/VTA and the adjacent subthalamic nucleus could overcome this asymmetry.We show that interindividual variability among healthy older adults of the structural integrity within the SN/VTA and subthalamic nucleus relates to effective acquisition of competing instrumental responses.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience, University College London, London, UK; Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, UK. rumana.chowdhury1979@gmail.com

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Relationship between substantia nigra/ventral tegmental area (SN/VTA) structural integrity and flexibility of instrumental learning. (A) Higher SN/VTA integrity (indexed by magnetization transfer values of SN/VTA) in older adults correlated with both a reduced action bias and reduced interaction between action and valence learning (n = 42). (B) No correlation between SN/VTA integrity and the action bias or the action–valence interaction in younger adults (n = 30). Scatter plots, in which each dot represents an individual. Abbreviations: GAL, go to avoid losing; GW, go to win; NGAL, no-go to avoid losing; NGW, no-go to win.
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fig4: Relationship between substantia nigra/ventral tegmental area (SN/VTA) structural integrity and flexibility of instrumental learning. (A) Higher SN/VTA integrity (indexed by magnetization transfer values of SN/VTA) in older adults correlated with both a reduced action bias and reduced interaction between action and valence learning (n = 42). (B) No correlation between SN/VTA integrity and the action bias or the action–valence interaction in younger adults (n = 30). Scatter plots, in which each dot represents an individual. Abbreviations: GAL, go to avoid losing; GW, go to win; NGAL, no-go to avoid losing; NGW, no-go to win.

Mentions: We next analyzed how SN/VTA integrity related to the ability to overcome response biases. The action bias (go > no-go performance for both wins and losses) was negatively correlated with SN/VTA integrity (r = −0.45, p = 0.003, Fig. 4A; partial correlation controlling for age and SN/VTA volume: r = −0.40, p = 0.011), suggesting that only those individuals with high SN/VTA integrity were able to overcome this action bias. Moreover, the negative correlation between the interaction in task performance (go to win and no-go to avoid losing > no-go to win and go to avoid losing performance) and SN/VTA integrity suggests the action–valence learning asymmetry could also be overcome with higher SN/VTA integrity (r = −0.42, p = 0.006, Fig. 4A; partial correlation controlling for age and SN/VTA volume: r =−0.35, p = 0.028). There was no correlation between SN/TA integrity and the main effect of valence (r = 0.22, p = 0.155; partial correlation controlling for age and SN/VTA volume: r = 0.27, p = 0.091). We found no evidence that working memory capacity contributed to the relationship between SN/VTA integrity and the pattern of task performance among older adults (Supplementary Results).


Structural integrity of the substantia nigra and subthalamic nucleus predicts flexibility of instrumental learning in older-age individuals.

Chowdhury R, Guitart-Masip M, Lambert C, Dolan RJ, Düzel E - Neurobiol. Aging (2013)

Relationship between substantia nigra/ventral tegmental area (SN/VTA) structural integrity and flexibility of instrumental learning. (A) Higher SN/VTA integrity (indexed by magnetization transfer values of SN/VTA) in older adults correlated with both a reduced action bias and reduced interaction between action and valence learning (n = 42). (B) No correlation between SN/VTA integrity and the action bias or the action–valence interaction in younger adults (n = 30). Scatter plots, in which each dot represents an individual. Abbreviations: GAL, go to avoid losing; GW, go to win; NGAL, no-go to avoid losing; NGW, no-go to win.
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fig4: Relationship between substantia nigra/ventral tegmental area (SN/VTA) structural integrity and flexibility of instrumental learning. (A) Higher SN/VTA integrity (indexed by magnetization transfer values of SN/VTA) in older adults correlated with both a reduced action bias and reduced interaction between action and valence learning (n = 42). (B) No correlation between SN/VTA integrity and the action bias or the action–valence interaction in younger adults (n = 30). Scatter plots, in which each dot represents an individual. Abbreviations: GAL, go to avoid losing; GW, go to win; NGAL, no-go to avoid losing; NGW, no-go to win.
Mentions: We next analyzed how SN/VTA integrity related to the ability to overcome response biases. The action bias (go > no-go performance for both wins and losses) was negatively correlated with SN/VTA integrity (r = −0.45, p = 0.003, Fig. 4A; partial correlation controlling for age and SN/VTA volume: r = −0.40, p = 0.011), suggesting that only those individuals with high SN/VTA integrity were able to overcome this action bias. Moreover, the negative correlation between the interaction in task performance (go to win and no-go to avoid losing > no-go to win and go to avoid losing performance) and SN/VTA integrity suggests the action–valence learning asymmetry could also be overcome with higher SN/VTA integrity (r = −0.42, p = 0.006, Fig. 4A; partial correlation controlling for age and SN/VTA volume: r =−0.35, p = 0.028). There was no correlation between SN/TA integrity and the main effect of valence (r = 0.22, p = 0.155; partial correlation controlling for age and SN/VTA volume: r = 0.27, p = 0.091). We found no evidence that working memory capacity contributed to the relationship between SN/VTA integrity and the pattern of task performance among older adults (Supplementary Results).

Bottom Line: Normal aging is associated with a variable loss of dopamine neurons in the SN/VTA.Older, but not younger, participants with greater structural integrity of the SN/VTA and the adjacent subthalamic nucleus could overcome this asymmetry.We show that interindividual variability among healthy older adults of the structural integrity within the SN/VTA and subthalamic nucleus relates to effective acquisition of competing instrumental responses.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience, University College London, London, UK; Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, UK. rumana.chowdhury1979@gmail.com

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