The role of orbitofrontal cortex in processing empathy stories in 4- to 8-year-old children

Abstract

This study investigates the neuronal correlates of empathic processing in children aged 4-8 years, an age range discussed to be crucial for the development of empathy. Empathy, defined as the ability to understand and share another person's inner life, consists of two components: affective (emotion-sharing) and cognitive empathy (Theory of Mind). We examined the hemodynamic responses of preschool and school children (N = 48), while they processed verbal (auditory) and non-verbal (cartoons) empathy stories in a passive following paradigm, using functional Near-Infrared Spectroscopy. To control for the two types of empathy, children were presented blocks of stories eliciting either affective or cognitive empathy, or neutral scenes which relied on the understanding of physical causalities. By contrasting the activations of the younger and older children, we expected to observe developmental changes in brain activations when children process stories eliciting empathy in either stimulus modality toward a greater involvement of anterior frontal brain regions. Our results indicate that children's processing of stories eliciting affective and cognitive empathy is associated with medial and bilateral orbitofrontal cortex (OFC) activation. In contrast to what is known from studies using adult participants, no additional recruitment of posterior brain regions was observed, often associated with the processing of stories eliciting empathy. Developmental changes were found only for stories eliciting affective empathy with increased activation, in older children, in medial OFC, left inferior frontal gyrus, and the left dorsolateral prefrontal cortex. Activations for the two modalities differ only little, with non-verbal presentation of the stimuli having a greater impact on empathy processing in children, showing more similarities to adult processing than the verbal one. This might be caused by the fact that non-verbal processing develops earlier in life and is more familiar.

Keywords: OFC; affective empathy; children; cognitive empathy; fNIRS; non-verbal; verbal.

Figure 1

(A) Example of a cartoon stimulus from the negative affective empathy condition. (B) Example of a cartoon stimulus from the positive affective empathy condition. (C) Example of a cartoon stimulus from the logical cognitive empathy condition. (D) Example of a cartoon stimulus from the non-logical cognitive empathy condition. (E) Examples of auditory stimuli: negative affective and logical cognitive story, in German and English.

Figure 2

Design.

Figure 3

(A) Optode positions on an equidistant 88-channel EEG cap. Note that the EEG cap was turned by 180° to place optodes on the forehead to be able to record orbitofrontal activation; green: sources, orange: detectors; (B) location of the channels superimposed on a equidistant 88-channel EEG cap together with the approximate location of the selected regions of interest.

Figure 4

(A) Example time course of the predictors used for GLM-analysis of block-averaged fNIRS-data in the interval between −10 to +20 s around onset of the fourth picture (sentence) of one subject. Displayed are the delta functions and the two predictors that model hemodynamic responses induced by the first three or the fourth picture (sentence) of the story presented at t = 0s. (B) Example time course of [oxy-Hb] and [deoxy-Hb] concentration changes for left OFC for the visual affective empathy condition averaged over all block repetitions and over subject population, overlaid with corresponding GLM-model. Note that the time courses show a relative deactivation for the visual affective empathy condition with decreasing [oxy-Hb] and increasing [deoxy-Hb] due to the superposition of the first three and the fourth cartoon slides. The relative deactivation of the lateral orbitofrontal regions during processing of the stories is in agreement with fMRI results on similar material (Hynes et al., , Figure 2). Besides this overall deactivation during the processing of the empathy stories, activation was revealed for the respective contrasts (see results, Table 2).

Figure 5

Activations for the visual condition; [oxy-Hb] and [deoxy-Hb] results across all four main contrasts in the sagittal and a frontal view.

Figure 6

Activations for the auditory condition; [oxy-Hb] and [deoxy-Hb] results across all four main contrasts in the sagittal and a frontal view.