Talairach coordinates and voxel cluster size values for face loads 4 minus 1, 3 minus 1, and 2 minus 1 contrasts (FDR<.05).

<p>Talairach coordinates and voxel cluster size values for face loads 4 minus 1, 3 minus 1, and 2 minus 1 contrasts (FDR<.05).</p

Here is an example trial procedure (load 3 shown as illustration).

<p>Between one and four faces (all expressing either angry, happy, or neutral emotion) were shown for encoding for 2000 ms, followed by a 1000 ms blank retention/maintenance phase, and a 2000 ms retrieval phase in which participants stated whether a single probe face had been present or not in the previous display. All faces in any one trial (i.e., at encoding and retrieval) displayed the same emotion. A jittered inter-trial interval (ITI) of between 4000 ms and 6500 ms separated each trial.</p

Correlation between STM capacity estimates (K) and related beta values in load-sensitive regions. r² values are provided with <i>p</i> values in brackets.

<p>Correlation between STM capacity estimates (K) and related beta values in load-sensitive regions. r² values are provided with <i>p</i> values in brackets.</p

Coronal view shows bilateral fusiform activity obtained from the angry minus neutral contrast (regions outlined by black squares).

<p>Activity is greater for angry compared to neutral faces. Bars represent±1 standard error.</p

Talairach coordinates and voxel cluster size values for specific emotion contrasts (FDR<.05).

<p>The happy minus neutral contrast did not yield any regions of activation at this threshold.</p

Figure 6

<p>(A) Face loads 4 (blue), 3 (green), and 2 (red) were contrasted with face load 1. Several regions of the PFC, the frontal eye fields (FEF), inferior parietal sulcus (IPS), fusiform gyrus, and occipital cortex, in both left and right hemispheres, showed greater activity when multiple faces were to be remembered compared to just one face. Brain regions modulated by emotion in the right hemisphere (pink = emotion main effect; white = angry minus neutral contrast; brown = angry minus happy contrast) are overlain to illustrate the anatomical distinction between emotional expression and face load effects. Some anatomical landmarks are provided to aid navigation: superior frontal sulcus (SFS); inferior frontal sulcus (IFS); silvian fissure (SF); inferior parietal sulcus (IPS); occipito-temporal sulcus (OTS). (B) Beta values from each load condition (averaged across emotions) illustrate the contrast between a monotonic increase of activity with load in right PFC (x = 41, y = 29, z = 26) and peaked activation at load 3 in right parietal cortex (x = 18, y = −69, z = 43). Bars represent±1 standard error.</p

Behavioural performance on angry, happy, and neutral trials for all four face loads are displayed as d' (dprime) values.

<p>A maximum d' value of 4.66 indicates 100% performance, while a d' value of zero indicates performance at chance (50%). Participants performed significantly better on the VSTM task when the identities of angry faces were to be remembered, compared to happy or neutral faces. VSTM performance declined as face load increased for all emotional expression conditions. Bars represent±1 standard error.</p

Figure 3

<p>(A) Three coronal brain slices show modulation of brain activity by emotional expression of faces in the VSTM task in the superior temporal sulcus (STS), prefrontal cortex (PFC) along the inferior frontal sulcus (IFS), and globus pallidus internus (GPi), all in the right hemisphere. (B) Beta values for each emotion and face load condition are plotted for the STS, PFC, and GPi. Activity is greater for angry vs. happy and neutral face expression conditions in all three brain regions. Bars represent±1 standard error.</p

Neurofeedback protocol.

<p>During the neurofeedback runs (3 in each of the 4 sessions), participants alternated between 20 s periods of rest and 20 s periods where they had to upregulate activity in the target area. The level of activation was fed back in real time (updated for each TR of 2 s) through the thermometer display.</p

Network activation and deactivation during neurofeedback.

<p>a) Activation of the insular cortex (INS) bilaterally and the right ventral striatum (VS) supported the neurofeedback task, whereas the temporoparietal junctions (TPJ) of both hemispheres were deactivated. The TPJ is recognised as part of the brain’s “default mode network” that is deactivated during effortful tasks. For a full documentation of the activated and deactivated networks see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038115#pone-0038115-t003" target="_blank">Table 3</a>. View from the front and above. The right side of the brain is on the observer’s left (Talairach coordinates of virtual cuts: y = 25, z = −2). b) Successive training sessions produced further increases of activation during upregulation periods in the VS bilaterally (coronal view at y = 7, the right side of the brain is on the observer’s left).</p