Threat of shock increases excitability and connectivity of the intraparietal sulcus

17 figures, 3 tables and 2 additional files

Figures

Schematic of experimental paradigm.

(A) Subjects underwent alternating blocks of threat and safety. (B) Visual display present on the screen during the experiment. During the experiment subjects saw two circles. The color of the outer circle indicated the block type. The color of the inner circle was controlled by the subject, and reflected the subject’s then-current anxiety level.

https://doi.org/10.7554/eLife.23608.003
Behavioral results from both experiments.

(A) Anxiety ratings during the MEG study. (B) Startle magnitude during the MEG study. (C) Anxiety ratings during the fMRI study. Bars represent the mean ± within-subject SEM (Cousineau, 2005). (D) Correlations between anxiety potentiated startle (APS) and differential anxiety ratings. The black squares represent the correlation between APS and ratings during the MEG session. The red dots represent the correlation between APS during the MEG study and anxiety ratings during the fMRI study in the subset of subjects who participated in both studies.

https://doi.org/10.7554/eLife.23608.005
Overview of global brain connectivity (GBC) measure.

(A) Map showing average GBC across all safe and threat TRs. (B) Cartoon schematic of a correlation matrix. The 43204 voxel x 43204 voxel cross correlation matrix was calculated separately for each subject and each condition. Correlations were averaged across rows for the entire grey matter mask, to create a single map reflecting the average correlation between each voxel and all other voxels in the mask. (C) Graph representing the mean GBC following the Fisher’s Z transformation for safe and threat averaged across the entire grey matter mask. Bars represent the mean ± within-subject SEM (Cousineau, 2005).

https://doi.org/10.7554/eLife.23608.007
Results from voxelwise global brain connectivity (GBC) analysis.

(A) Statistical map showing results from a threat vs. safe paired-sample t-test. (B) Graph representing average GBC values after applying the Fisher’s Z transformation for clusters shown in panel A. Bars represent the mean ± within-subject SEM (Cousineau, 2005).

https://doi.org/10.7554/eLife.23608.010
Results from bilateral IPS seed-based connectivity analysis.

(A) Statistical map showing results from a threat vs. safe paired-sample t-test. (B) Graph representing average IPS connectivity values for clusters shown in panel A. Bars represent the mean ± within-subject SEM (Cousineau, 2005).

https://doi.org/10.7554/eLife.23608.013
Overview of MEG analyses.

(A) Spectrogram representing power averaged across all subjects and all sensors with peak in the alpha frequency band. (B) Graph showing the frequency of peak alpha (individual alpha frequency) averaged across subjects. Bars represent the mean ± SEM. (C) Example of single subject alignment with sensors (black dots) source grid (green dots) and headmodel (surface) plotted together.

https://doi.org/10.7554/eLife.23608.015
Alpha results from threat vs. safe t-test.

(A) Statistical map in sensor space showing a significant reduction in alpha power. Black symbols represent clusters of sensors showing significant threat vs. safe differences. (B) Graph showing average alpha power for safe and threat conditions in the largest cluster of sensors in panel A. (C) Statistical map in source space showing a significant reduction in alpha power. (D) Graph showing average alpha power for safe and threat conditions in the cluster in panel C. Bars represent the mean ± within-subject SEM (Cousineau, 2005).

https://doi.org/10.7554/eLife.23608.017
Conjunction map from voxelwise fMRI GBC analysis and MEG alpha power differences.

Colors represent significant safe vs. threat differences from the fMRI analysis (yellow), MEG analysis (blue), and both analyses (green).

https://doi.org/10.7554/eLife.23608.019
Author response image 4
Α connectivity across AAL regions during 2 second baseline prior to startle probe.

A) Mean α connectivity across AAL regions during safe periods. B) Mean α connectivity across AAL regions during threat periods. C) Unthresholded T-test results comparing α connectivity during safe and threat conditions. Thresholded T-test results comparing α connectivity during safe and threat conditions. Labels on Y-axis correspond to regions of the AAL axis. Labels on the X-axis correspond to groups from AAL atlas (frontal, limbic, occipital, parietal, subcortical, temporal, cerebellum). Boxes in A and B represent α connectivity in the occipital cortices.

https://doi.org/10.7554/eLife.23608.025
Author response image 5
Β connectivity across AAL regions during 2 second baseline prior to startle probe.

A) Mean β connectivity across AAL regions during safe periods. B) Mean β connectivity across AAL regions during threat periods. C) Unthresholded T-test results comparing β connectivity during safe and threat conditions. Thresholded T-test results comparing β connectivity during safe and threat conditions. Labels on Y-axis correspond to regions of the AAL axis. Labels on the X-axis correspond to groups from AAL atlas (frontal, limbic, occipital, parietal, subcortical, temporal, cerebellum).

https://doi.org/10.7554/eLife.23608.026
Author response image 6
Adjacency matrices constructed from downsampled timeseries for the α and β bands.
https://doi.org/10.7554/eLife.23608.027
Author response image 7
Adjacency matrices constructed from non-downsampled timeseries for the α and β bands.
https://doi.org/10.7554/eLife.23608.028
Author response image 8
Adjacency matrices constructed from downsampled timeseries that have been converted to z-scores for the α and β bands.
https://doi.org/10.7554/eLife.23608.029
Author response image 9
Adjacency matrices constructed from non-downsampled timeseries that have been converted to z-scores for the α and β bands.
https://doi.org/10.7554/eLife.23608.030

Tables

Table 1

Individual differences for MEG (N = 28) and MRI (N = 25) experiments.

https://doi.org/10.7554/eLife.23608.004
MeasureMEGMRI
STAI
 State26.04 (1.37)23 (0.9)
 Trait27.12 (0.93)28.18 (1.27)
ASI11.59 (1.21)8.64 (1.18)
BAI1.37 (0.42)0.58 (0.26)
BDI0.89 (0.32)0.42 (0.19)
Shock
 Intensity (mA)5.66 (0.66)6.91 (1.01)
 Rating8.51 (0.2)9.09 (0.19)
Anxiety
 Pre2.04 (0.27)1.98 (0.25)
 Safe2.47 (0.31)1.76 (0.21)
 Threat5.41 (0.37)5.97 (0.39)
Fear
 Pre1.41 (0.15)1.5 (0.23)
 Safe1.84 (0.27)1.27 (0.12)
 Threat4.44 (0.39)4.7 (0.42)
  1. Note: Numbers reflect the mean and standard deviation of the results [M (SD)].

Table 2

Results from voxelwise GBC analysis.

https://doi.org/10.7554/eLife.23608.009
LabelVolumet-valuePeak activation (LPI)
xyz
Right Angular Gyrus1583.4548−5127
Right Intraparietal Sulcus833.4221−6066
Left Intraparietal Sulcus813.6−18−6366
Table 3

Results from voxelwise IPS connectivity analysis.

https://doi.org/10.7554/eLife.23608.012
LabelVolumet-valuePeak activation (LPI)
xyz
Left Thalamus3423.92-9612
Right Inferior Parietal Lobule2083.6757−5739
Left Superior Medial Gyrus1843.6533642
Left Precuneus1793.593−6948
Right Middle Frontal Gyrus1373.64331560
Left Angular Gyrus1133.51−57−5430
Left Middle Frontal Gyrus963.69−241560
Left Middle Frontal Gyrus903.48−4551-3

Additional files

Source code 1

Code used to conduct Startle, MEG, and MRI analyses.

This zip file contains shell scripts and matlab functions that were used to analyze the Startle, MEG, and MRI data.

https://doi.org/10.7554/eLife.23608.020
Supplementary file 1

High resolution adjacency matrices for the MEG connectivity analyses.

This zip file contains high resolution images of the adjacency matrices for the MEG connectivity analysis suggested by the editor and reviewers.

https://doi.org/10.7554/eLife.23608.021

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  1. Nicholas L Balderston
  2. Elizabeth Hale
  3. Abigail Hsiung
  4. Salvatore Torrisi
  5. Tom Holroyd
  6. Frederick W Carver
  7. Richard Coppola
  8. Monique Ernst
  9. Christian Grillon
(2017)
Threat of shock increases excitability and connectivity of the intraparietal sulcus
eLife 6:e23608.
https://doi.org/10.7554/eLife.23608