Asymmetric correlation between experienced parental attachment and event-related potentials evoked in response to parental faces.

This study aims to explore the modulation effects of attachment relationships with parents on the neural correlates that are associated with parental faces. The event-related potentials elicited in 31 college students while viewing facial stimuli of their parents in two single oddball paradigms (father vs. unfamiliar male and mother vs. unfamiliar female) were measured. We found that enhanced P3a and P3b and attenuated N2b were elicited by parental faces; however, the N170 component failed to discriminate parental faces from unfamiliar faces. An experienced attachment relationship with the father was positively correlated to the P3a response associated with the father's face, whereas no correlation was found in the case of mothers. Further exploration in dipole source localization showed that, within the time window of the P300, distinctive brain regions were involved in the processing of parental faces; the father's face was located in the medial frontal gyrus, which might be involved in self effect, and the anterior cingulate gyrus was activated in response to the mother's face. This research is the first to demonstrate that neural mechanisms involved with parents can be modulated differentially by the qualities of the attachments to the parents. In addition, parental faces share a highly similar temporal pattern, but the origins of these neural responses are distinct, which could merit further investigation

Recording procedure and an example of the facial stimuli.

<p>In each trial, the participants were asked to respond as soon as their parents’ faces were presented and to ignore male/female strangers’ faces. All of the participants were asked to finish two single oddball tasks, and the task order was balanced across the participants. The parents whose photographs are presented here have given written informed consent, as outlined in the PLOS consent form, permitting us to publish, reuse and reprint their photographs.</p

The correlations between the paternal attachment scores and P3a amplitudes evoked by a father’s face.

<p>The figure shows that the P3a amplitude was positively correlated to the total attachment score (<i>r</i> = .71, <i>p</i> < .001, Figure 4a), the trust dimension (<i>r</i> = .68, <i>p</i> < .001, Figure 4b) and the communication dimension (<i>r</i> = .60, <i>p</i> < .001, Figure 4c) and negatively correlated with the alienation dimension (<i>r</i> = -.50, <i>p</i> < .005, Figure 4d).</p

The correlations between the maternal attachment scores and the P3a amplitudes evoked by the mother’s face.

<p>Any significant correlations were found in the case of the mother (total score: <i>r</i> = .11, <i>p</i> = .302, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068795#pone-0068795-g005" target="_blank">Figure 5a</a>; trust dimension: <i>r</i> = .10, <i>p</i> = .311, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068795#pone-0068795-g005" target="_blank">Figure 5b</a>; communication dimension: <i>r</i> = .003, <i>p</i> = .495, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068795#pone-0068795-g005" target="_blank">Figure 5c</a>; alienation dimension: <i>r</i> = .04, <i>p</i> = .423, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068795#pone-0068795-g005" target="_blank">Figure 5d)</a>.</p

Dipole source localization images of parental faces versus unfamiliar faces for P300 latency.

<p>The main different brain regions in response to the father’s and mother’s faces were the right medial frontal gyrus (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068795#pone-0068795-g006" target="_blank">Figure 6a)</a> and the left anterior cingulate gyrus (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068795#pone-0068795-g006" target="_blank">Figure 6b)</a>; blue spots signify the different regions. Activation of the both of the parental faces was also located in the regions of the cerebellar tonsil (red spot) and the precuneus (green spot).</p

Grand average ERPs evoked by different face types.

<p>The light gray shaded areas indicate (a) a 250-550 ms time window for the P3a component at the frontal electrode, (b) a 250-650 ms time window for the P3b component at the parietal electrode, (c) and (d) a 130-180 ms time window for the N170 detection and a 200-300 ms time window for the N2b at the bilateral occipito-temporal areas.</p