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Impulsivity relates to striatal gray matter volumes in humans: evidence from a delay discounting paradigm.

Tschernegg M, Pletzer B, Schwartenbeck P, Ludersdorfer P, Hoffmann U, Kronbichler M - Front Hum Neurosci (2015)

Bottom Line: Cortical structural changes in prefrontal regions have been found for introspective impulsivity measures.Behaviorally, we found strong evidence in favor of a discounting utility model compared to a standard hyperbolic model of choice valuation.Taken together, our study provides strong evidence for a structural manifestation of time-stable trait impulsivity in the human brain.

View Article: PubMed Central - PubMed

Affiliation: Centre for Cognitive Neuroscience, University of Salzburg Salzburg, Austria.

ABSTRACT
Time-stable personality traits, such as impulsivity and its relationship with functional and structural brain alterations, have gained much attention in the recent literature. Evidence from functional neuroimaging data implies an association between impulsivity and cortical as well as subcortical areas of the reward system. Discounting future rewards during impulsive decisions can be related to activation in the orbitofrontal cortex and striatum. Cortical structural changes in prefrontal regions have been found for introspective impulsivity measures. The present study focuses on brain regions associated with delay discounting to investigate structural manifestations of trait impulsivity. To test this, seventy subjects underwent structural magnetic resonance imaging (MRI) followed by a behavioral delay discounting task outside of the scanner to measure impulsivity with questions like: "Would you like to have 3€ immediately or 10€ in 5 days?". The amount of smaller-but-sooner decisions was calculated and used as a measure of behavioral impulsivity. Furthermore, we estimated subject's individual delay discounting parameter K reflecting the tendency to discount future rewards. Behaviorally, we found strong evidence in favor of a discounting utility model compared to a standard hyperbolic model of choice valuation. Neuronally, we focused on cortical and subcortical brain structure and investigated the association of behavioral impulsivity with delay discounting tendencies and gray matter volume. Voxel-based morphometric analyses showed positive correlations between delay discounting and gray matter volume in the striatum. Additional analyses using Freesurfer provided evidence for a positive correlation between delay discounting and gray matter volume of the caudate. Taken together, our study provides strong evidence for a structural manifestation of time-stable trait impulsivity in the human brain.

No MeSH data available.


Related in: MedlinePlus

Voxel-based morphometry (VBM) Results. The top panel shows cluster with significant correlations between the delay discounting parameter SbS and gray matter volumes (controlled for gender and age) in the voxel-wise analysis (in red), superimposed by the anatomical mask for the caudate (in white); 1507 voxel in the right hemisphere, peak at [9 8 12]; According to the Harvard-Oxford Subcortical Structural Atlas [as implemented in FSL, http://www.fmrib.ox.ac.uk/fsl) thresholded at 25%] this cluster correspond to the right caudate (p < 0.001 cluster level FWE correction, p < 0.05 peak level FWE correction). The bottom panel shows the scatterplot of the correlation between gray matter density (VBM) and delay discounting.
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Figure 2: Voxel-based morphometry (VBM) Results. The top panel shows cluster with significant correlations between the delay discounting parameter SbS and gray matter volumes (controlled for gender and age) in the voxel-wise analysis (in red), superimposed by the anatomical mask for the caudate (in white); 1507 voxel in the right hemisphere, peak at [9 8 12]; According to the Harvard-Oxford Subcortical Structural Atlas [as implemented in FSL, http://www.fmrib.ox.ac.uk/fsl) thresholded at 25%] this cluster correspond to the right caudate (p < 0.001 cluster level FWE correction, p < 0.05 peak level FWE correction). The bottom panel shows the scatterplot of the correlation between gray matter density (VBM) and delay discounting.

Mentions: Figure 2 shows the significant cluster for voxel-wise whole brain correlations with SbS decisions, controlled for age and gender. After controlling for gender and age, a similar cluster emerged consisting of 1507 voxels on the right hemisphere (at [9 8 12], peak t = 4.70, with an additional cluster extent threshold of p < 0.05, FWE corrected). According to the Harvard Oxford Subcortical Structural Atlas, this cluster compromises the right caudate. As can be seen in the lower panel of Figure 2, outliers did clearly not drive the relation between gray matter volumes and SbS decisions.


Impulsivity relates to striatal gray matter volumes in humans: evidence from a delay discounting paradigm.

Tschernegg M, Pletzer B, Schwartenbeck P, Ludersdorfer P, Hoffmann U, Kronbichler M - Front Hum Neurosci (2015)

Voxel-based morphometry (VBM) Results. The top panel shows cluster with significant correlations between the delay discounting parameter SbS and gray matter volumes (controlled for gender and age) in the voxel-wise analysis (in red), superimposed by the anatomical mask for the caudate (in white); 1507 voxel in the right hemisphere, peak at [9 8 12]; According to the Harvard-Oxford Subcortical Structural Atlas [as implemented in FSL, http://www.fmrib.ox.ac.uk/fsl) thresholded at 25%] this cluster correspond to the right caudate (p < 0.001 cluster level FWE correction, p < 0.05 peak level FWE correction). The bottom panel shows the scatterplot of the correlation between gray matter density (VBM) and delay discounting.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488624&req=5

Figure 2: Voxel-based morphometry (VBM) Results. The top panel shows cluster with significant correlations between the delay discounting parameter SbS and gray matter volumes (controlled for gender and age) in the voxel-wise analysis (in red), superimposed by the anatomical mask for the caudate (in white); 1507 voxel in the right hemisphere, peak at [9 8 12]; According to the Harvard-Oxford Subcortical Structural Atlas [as implemented in FSL, http://www.fmrib.ox.ac.uk/fsl) thresholded at 25%] this cluster correspond to the right caudate (p < 0.001 cluster level FWE correction, p < 0.05 peak level FWE correction). The bottom panel shows the scatterplot of the correlation between gray matter density (VBM) and delay discounting.
Mentions: Figure 2 shows the significant cluster for voxel-wise whole brain correlations with SbS decisions, controlled for age and gender. After controlling for gender and age, a similar cluster emerged consisting of 1507 voxels on the right hemisphere (at [9 8 12], peak t = 4.70, with an additional cluster extent threshold of p < 0.05, FWE corrected). According to the Harvard Oxford Subcortical Structural Atlas, this cluster compromises the right caudate. As can be seen in the lower panel of Figure 2, outliers did clearly not drive the relation between gray matter volumes and SbS decisions.

Bottom Line: Cortical structural changes in prefrontal regions have been found for introspective impulsivity measures.Behaviorally, we found strong evidence in favor of a discounting utility model compared to a standard hyperbolic model of choice valuation.Taken together, our study provides strong evidence for a structural manifestation of time-stable trait impulsivity in the human brain.

View Article: PubMed Central - PubMed

Affiliation: Centre for Cognitive Neuroscience, University of Salzburg Salzburg, Austria.

ABSTRACT
Time-stable personality traits, such as impulsivity and its relationship with functional and structural brain alterations, have gained much attention in the recent literature. Evidence from functional neuroimaging data implies an association between impulsivity and cortical as well as subcortical areas of the reward system. Discounting future rewards during impulsive decisions can be related to activation in the orbitofrontal cortex and striatum. Cortical structural changes in prefrontal regions have been found for introspective impulsivity measures. The present study focuses on brain regions associated with delay discounting to investigate structural manifestations of trait impulsivity. To test this, seventy subjects underwent structural magnetic resonance imaging (MRI) followed by a behavioral delay discounting task outside of the scanner to measure impulsivity with questions like: "Would you like to have 3€ immediately or 10€ in 5 days?". The amount of smaller-but-sooner decisions was calculated and used as a measure of behavioral impulsivity. Furthermore, we estimated subject's individual delay discounting parameter K reflecting the tendency to discount future rewards. Behaviorally, we found strong evidence in favor of a discounting utility model compared to a standard hyperbolic model of choice valuation. Neuronally, we focused on cortical and subcortical brain structure and investigated the association of behavioral impulsivity with delay discounting tendencies and gray matter volume. Voxel-based morphometric analyses showed positive correlations between delay discounting and gray matter volume in the striatum. Additional analyses using Freesurfer provided evidence for a positive correlation between delay discounting and gray matter volume of the caudate. Taken together, our study provides strong evidence for a structural manifestation of time-stable trait impulsivity in the human brain.

No MeSH data available.


Related in: MedlinePlus