Neural Correlates of Facial Expression Recognition in Earthquake Witnesses

Abstract

Major adverse events, like an earthquake, trigger different kinds of emotional dysfunctions or psychiatric disorders in the exposed subjects. Recent literature has also shown that exposure to natural disasters can increase threat detection. In particular, we previously found a selective enhancement in the ability to read emotional facial expressions in L’Aquila earthquake witnesses, suggesting hypervigilance to stimuli signaling a threat. In light of previous neuroimaging data showing that trauma exposure is related to derangement of resting-state brain activity, in the present study we investigated the neurofunctional changes related to the recognition of emotional faces in L’Aquila earthquake witnesses. Specifically, we tested the relationships between accuracy in recognizing facial expressions and activity of the visual network (VN) and of the default-mode network (DMN). Resting-state functional connectivity (FC) with the main hub of the VN (primary, ventral, right-dorsal, and left-dorsal visual cortices) and DMN (posterior cingulate/precuneus, medial prefrontal, and right and left inferior parietal cortices) was investigated through a seed-based functional magnetic resonance imaging (fMRI) analysis in both earthquake-exposed subjects and non-exposed persons who did not live in an earthquake-affected area. The results showed that, in earthquake-exposed subjects, there is a significant reduction in the correlation between accuracy in recognizing facial expressions and the FC of the dorsal seed of the VN with the right inferior occipito-temporal cortex and the left lateral temporal cortex, and of two parietal seeds of DMN, i.e., lower parietal and medial prefrontal cortex, with the precuneus bilaterally. These findings suggest that a functional modification of brain systems involved in detecting and interpreting emotional faces may represent the neurophysiological basis of the specific “emotional expertise” observed in the earthquake witnesses.

Torture exposure and the functional brain: investigating disruptions to intrinsic network connectivity using resting state fMRI

“…While task-based brain imaging studies indicate that PTE exposure may modulate the functional brain in meaningful ways [ 39 , 40 ], the majority of resting-state fMRI (rsfMRI) studies have examined the role of PTSD symptoms, and only a few have considered the specific effects of trauma exposure itself irrespective of PTSD. For example, studies that examined the effects of repeated trauma exposure observed altered functional connectivity between the SN and DMN in firefighters [ 41 ], and DMN and visual networks in earthquake survivors [ 42 ]. In a study of survivors of intimate partner violence, comparisons between those with and without PTSD showed no differences in intrinsic connectivity patterns 3 weeks or 6 months following assault [ 43 ].…”

Multimodal MRI Assessment of Thalamic Structural Changes in Earthquake Survivors

“…This seems particularly interesting here, since our sample of earthquake survivors, although showing signs of maladaptive responses such as sleep disorders and anxiety-related responses [ 11 ], never developed a psychopathological condition. Indeed, the L’Aquila earthquake survivors’ visual systems showed changes relating to enhanced visual processing of threat-related stimuli (i.e., emotional faces), implying hyperarousal and hypervigilance to threat [ 13 ]. Here we could observe structural changes in the left mediodorsal thalamus, a crucial relay station in the processing of relevant, potentially threatening visual stimuli and driving effective emotional regulation responses.…”

“…However, a certain percentage of individuals can develop behavioral and emotional changes representing subclinical pathological conditions [ 9 , 11 , 12 ]. Recently, Pistoia et al [ 13 ] described a selective enhancement in the ability to read emotional facial expressions in L’Aquila 2009 earthquake survivors, suggesting hypervigilance to stimuli signaling a threat.…”

“…Magnetic resonance imaging (MRI) is undoubtedly one of the most useful tools to obtain information on morphological and functional aspects of the brain. Extensive research has shown the validity of blood-oxygen-level-dependent signals derived by fMRI studies to assess brain responsiveness to emotional stimuli [ 13 ]. Moreover, data from several voxel-based morphometry (VBM) studies revealed evidence of structural brain abnormalities associated with trauma [ 14 , 15 , 16 ].…”

Examining the long-term cognitive effects of exposure to the Canterbury earthquakes in a resilient cohort

“…Studies, including our own work following the Canterbury earthquakes, have found that when compared with non-exposed controls, exposed individuals (including those without PTSD) had increased sensitivity for cues of potential threats, including emotional facial expressions, which could help interpret potentially harmful situations rapidly and may therefore, in the short term, be a useful adaptive response. 18–20…”