Figure 1.
(A) Selected events (2 trials) comprising part of the encoding phase. At the side of each frame, the amount of time for which it was presented is indicated.
(B) Examples of the face and house stimuli employed.
(C) Proportion of responses to old pairs (dark gray bars) and new pairs (light gray bars) falling in each of the five reponse categories (shown on the x-axis: 1 [“sure old”] through 5 [“sure new”]).
(D) Encoding success (the area under the ROC curve, or Ag) averaged across participants for each block. Bars are standard errors. The first three blocks were outliers (in gray). The black line is a fitted linear trend, which was nonsignificant (F < 1).
Figure 2.
Event-Related fMRI Analyses: Sensory Neocortex and MTL
(A) DM effects (voxels for which the response for successfully encoded pairs was greater than that for unsuccessfully encoded pairs) suriving a statistical threshold of p < 0.001 (uncorrected) are rendered onto a single axial slice of the MNI brain (a single slice was chosen for ease of visualization; voxels shown are not maxima). The scale refers to F values. Each cluster is linked with a black line to a plot of the HRFs for later hits (blue), later misses (green), and unsorted retrieval trials (red). HRFs are averaged across participants; bars are standard errors. Lineplots are titled with the name of the relevant brain region. ERC, entorhinal cortex; PRC, perirhinal cortex. Subtitles indicate the Talairach coordinates of the peak voxel for each significant cluster.
(B) Time-to-peak estimates of the HRF for LOC (blue), FFA/PPA (green), rhinal cortices (red), and hippocampal (cyan) ROIs in each subsequent memory condition. Time-to-peak on the y-axis is in seconds.
Figure 3.
Event-Related fMRI Analyses: PFC
(A) Left ventrolateral prefrontal region exhibiting DM effects (Talairach coordinates: −48, 21, −9). The scale refers to F values.
(B) Mean HRFs (averaged across participants, with standard error bars) observed at this region for later hits (blue), later misses (green), and unsorted retrieval trials (red). HRF for later hits peaked at ̃10 s.
(C) Right dorsolateral prefrontal region exhibiting DM effects (Talairach coordinates: 53, 30, 21).
(D) Mean HRFs for this region.
Figure 4.
(A) Voxels exhibiting significant ( p < 0.01, cluster size > 62 5mm3) functional connectivity with the FFA (red) and PPA (blue).
(B) Voxels exhibiting significant ( p < 0.01, cluster size > 625 mm3) functional connectivity with the average of the FFA/PPA ROI. The blue crosshairs mark the peak voxel ( t = 4.57, p < 0.001), and the color scale refers to t values.
(C) Scatterplots of the correlation between connectivity (timeseries correlation r value) and encoding success (Fisher's z score) for the peak voxel in the PFC correlating with the FFA (left panel) and PPA (right panel). Each blue cross is one participant/block; gray lines are the fit of the correlation for each participant.