Article Figures & Data
Figures
- Figure 1.
PCL task and control task. In the PCL task, participants were presented one, two, or three cards per trial and asked to predict the weather (“rain” or “sunshine”) based on these cards. Feedback about the correct outcome was given after each trial. The control task had similar motor and perceptual characteristics as the PCL task but no learning demands; here, participants were asked to indicate if two less than two cards were presented.
- Figure 2.
Behavioral results in the PCL task. A, B, Percentage correct responses increased (A) and reaction times decreased (B) similarly in the stress and control groups across training, indicating successful classification learning in both groups. C, Although stress did not affect participants' learning curves in the PCL task, it reduced declarative knowledge about the task. D, Furthermore, stress changed the strategies used during classification learning: stressed participants, compared with nonstressed controls, significantly more often used complex strategies associated with the procedural system and significantly less often used simple strategies associated with the declarative system. Asterisks indicate significant differences between the stress and control groups (p < 0.05). Data represent mean ± SEM.
- Figure 3.
Stress effect on hippocampal activity during classification learning. A, During the PCL task, the right hippocampus was significantly less activated in the stress group than in the control group (pcorr < 0.05, FWE corrected). Coronal and sagittal sections are shown, superimposed on a T1-template image. L, left. B, Parameter estimates of the peak voxel for the control and stress groups in the PCL and control task, respectively. Data represent mean ± SEM (*p < 0.05).
- Figure 4.
Correlations between performance (across all PCL trials) and brain activity (PCL minus control task) in the control group. Performance in the PCL task was significantly correlated with activity in the left hippocampus. Coronal and sagittal sections are shown, superimposed on a T1-template image. Each data point represents a single participant. The scatter plot illustrates the association between brain activity and performance. The analysis, however, was conducted at the whole-brain level. L, left.
- Figure 5.
Correlations between performance (across all PCL trials) and brain activity (PCL minus control task) in the stress group. A, B, Under stress, there was a positive correlation between the performance in the PCL task and activity in the right caudate and the left putamen. C, Activity in the left hippocampus, however, correlated negatively with classification learning in stressed participants. Coronal and sagittal sections are shown, superimposed on a T1-template image. Each data point represents a single participant. The scatter plots illustrate the association between brain activity and performance. The analyses, however, were conducted at the whole-brain level. L, left.
Tables
Control Stress Subjective assessments Stressful 1.00 ± 0.56 57.00 ± 5.41** Painful 0.33 ± 0.33 59.00 ± 4.97** Unpleasant 6.00 ± 3.82 42.33 ± 5.65** Systolic blood pressure Before treatment 117.59 ± 2.66 122.08 ± 2.89 During treatment 116.50 ± 2.56 138.05 ± 2.70** After treatment 113.01 ± 2.53 115.54 ± 2.72 Diastolic blood pressure Before treatment 68.51 ± 1.76 69.94 ± 2.57 During treatment 67.01 ± 2.10 81.96 ± 1.69** After treatment 66.26 ± 1.62 65.49 ± 1.37 Salivary cortisol Before treatment 11.17 ± 1.42 9.28 ± 0.78 1 min after treatment 10.36 ± 1.26 8.42 ± 0.63 25 min after treatment 7.90 ± 0.88 14.52 ± 1.84** 90 min after treatment 6.12 ± 0.93 8.05 ± 0.83 Subjective assessments were given on a scale from 0 to 100.
↵**Control group versus stress group, p <0.01, Bonferroni corrected. Data represent mean ± SEM.
- Table 2.
Significant activations for the contrast PCL-control for the entire sample and for the group comparisons
Cluster MNI coordinates (mm) Tmax pcorr x y z Entire sample Left caudate nucleus 314 −10 14 0 10.11 <0.001 Right caudate nucleus 320 8 10 2 10.70 <0.001 Left putamen 59 −14 8 −6 7.45 <0.001 Right putamen 124 16 14 −4 6.65 <0.001 Left hippocampus 36 −22 −32 −6 4.60 0.003 Right hippocampus 18 22 −36 0 3.35 0.056 Left parahippocampal cortex 16 −14 −34 −10 3.77 0.012 Right parahippocampal cortex 12 16 −34 −8 3.29 0.036 Left orbitofrontal cortex 374 −32 24 −6 10.81 <0.001 Right orbitofrontal cortex 336 30 24 −8 10.84 <0.001 Left cingulate cortex 2503 −4 28 36 12.53 <0.001 Right cingulate cortex 2503 6 20 44 15.28 <0.001 Left inferior frontal lobe 2400 −30 22 −4 12.66 <0.001 Right inferior frontal lobe 2400 30 22 −4 12.68 <0.001 Control group greater than stress group Right hippocampus 9 22 −34 4 2.93 0.045 Stress group greater than control group No suprathreshold activations The significance threshold was set at pcorr < 0.05 (FWE corrected according to SPM8; for ROIs: small volume correction).
- Table 3.
Correlations between activity in the PCL task (vs control task) and the engagement of single-cue versus multicue strategies
Cluster MNI coordinates (mm) Tmax pcorr x y z Positive correlation Left hippocampus 31 −20 −38 2 3.00 0.050 Negative correlation Right caudate nucleus 74 16 12 18 3.50 0.070 Left putamen 71 −30 −16 2 3.80 0.050 Right putamen 55 22 14 −10 3.70 0.066 Multicue strategies were coded as 0 and single-cue strategies as 1. Thus, positive correlations indicate areas that correlate with the use of a single-cue strategy and negative correlations indicate areas that correlate with the use of a multicue strategy. The significance threshold was set at pcorr < 0.05 (FWE corrected according to SPM8; for ROIs: small volume correction).
Cluster MNI coordinates (mm) pcorr x y z Tmax Left caudate nucleus 303 −8 10 −2 6.84 <0.001 Right caudate nucleus 303 8 14 0 7.31 <0.001 Left putamen 39 −14 8 −6 4.98 0.006 Right putamen 103 14 10 −6 4.76 0.010 Left hippocampus 17 −20 −34 −6 4.50 0.012 Right hippocampus 20 22 −34 2 5.42 <0.001 Left parahippocampal cortex 16 −16 −32 −10 3.43 0.047 Left orbitofrontal cortex 344 −32 26 −4 7.43 <0.001 Right orbitofrontal cortex 119 34 24 −6 7.87 <0.001 Left cingulate cortex 690 −2 26 34 8.46 <0.001 Right cingulate cortex 690 8 18 46 11.47 <0.001 Right inferior frontal lobe 215 34 18 −2 10.25 <0.001 The significance threshold was set at pcorr < 0.05 (FWE-corrected according to SPM8; for ROIs: small volume correction).
Cluster MNI coordinates (mm) Tmax pcorr x y z Left caudate nucleus 280 −10 14 0 7.66 <0.001 Right caudate nucleus 280 8 10 2 8.85 <0.001 Left putamen 52 −14 8 −6 5.31 0.003 Right putamen 96 16 14 −4 4.83 0.008 Left orbitofrontal cortex 168 −30 26 −6 8.16 <0.001 Right orbitofrontal cortex 103 30 24 −8 7.45 <0.001 Left cingulate cortex 624 −5 25 38 9.97 <0.001 Right cingulate cortex 624 4 22 44 12.94 <0.001 Left inferior frontal lobe 39 −46 22 24 7.53 0.002 Right inferior frontal lobe 456 52 22 32 8.76 <0.001 Left insular cortex 155 −30 22 −2 10.74 <0.001 Right angular gyrus 80 34 −60 50 7.49 0.003 Right precuneus 30 8 −66 44 7.70 0.002 The significance threshold was set at pcorr < 0.05 (FWE corrected according to SPM8; for ROIs: small volume correction).
