Article Figures & Data
Figures
- Figure 1.
WM paradigm. The general trial structure shared by all trial types and examples of face stimuli are displayed. A trial starts with the presentation of face cue, which had to be maintained across a delay period to make a match discrimination with the probe face presented at the end of the delay period. This paradigm was designed to allow for the manipulation of specific WM components and the measurement of their effect on task performance. For example, the number of cue faces varied between 1 and 2 faces and the delay period varied between either 1 or 9 s so that we could measure the effect of longer maintenance requirements and memory load on task performance, respectively. In conditions involving distraction, a single face was presented in the middle of the delay period for 1 s. The effect of manipulating WM subcomponents was quantified by contrasting task performance (% correct accuracy) between conditions that differed only in the subcomponent of interest. See text for details on task manipulations in each of the five conditions and planned contrasts between conditions.
- Figure 2.
Task performance results. A, Group means of percentage task accuracy for the five conditions in the WM paradigm. B, Group means of the change in task accuracy with manipulation of the three WM components, ΔL, ΔM, and ΔD. Error bars indicate SEM.
- Figure 3.
GABA spectroscopy. A, Example of the voxel position within the left middle frontal gyrus in a representative subject. The irregular shape of the in-plane section (green lines) of the voxel is the result of having to rotate the voxel obliquely in reference to the slice plane of the structural images. SFS, Superior frontal sulcus; PCS, precentral sulcus. B, Group-averaged edited spectra from the middle frontal gyrus show the characteristic pseudo-doublet peak of the GABA line graph at ∼3.0 ppm and the doublet peak of Glx at ∼3.7 ppm.
- Figure 4.
Specificity of subjects' DLPFC GABA content correlation with task performance sensitivity to memory load. Scatter plot of individual subject's DLPFC GABA content (x-axis) plotted against ΔL (y-axis), change in task accuracy across levels of memory load (A); visual cortex GABA content plotted against ΔL (B); and DLPFC Glx plotted against ΔL (C).
