neuroscience

Brain regions involved in ‘mentalizing’ process vocal emotions differently in youth with epilepsy

Previous research has found that youth with epilepsy are at risk for poorer social and relational outcomes. Although this is not true of everyone with epilepsy, many children and adolescents with this neurodevelopmental disorder report having a hard time making and maintaining friendships. Perhaps related to this, youth with epilepsy often also struggle to interpret others’ emotions: they tend to be less accurate than youth without epilepsy on emotion recognition tasks, where people are asked to identify the intended emotion in facial or vocal expressions. Why might this be? Some researchers have suggested that the brains of youth with epilepsy may respond differently to emotional faces, compared to youth without epilepsy. Could something similar be happening with emotional voices?

To answer this question, the current study recruited youth who had been diagnosed with intractable epilepsy (meaning they still experienced seizures despite taking medication to prevent them), and some who had not. Participants were asked to listen to recordings of emotional voices (e.g., angry voices, fearful voices, etc.) while they were in an MRI scanner. After each recording, participants were asked to indicate what emotion they thought was being expressed. We examined how accurate they were at determining the intended emotion in each recording, and how their brains responded to the different types of voices.

We found that youth with epilepsy were less accurate than youth without epilepsy on this vocal emotion recognition task—especially at younger ages. In addition, we found six regions of the brain that responded differently to the emotional voices in youth with vs. without epilepsy. Activation patterns in these areas (including regions like the right temporo-parietal junction, the right hippocampus, and the right medial prefrontal cortex) could actually predict whether any given participant had been diagnosed with epilepsy or not. Interestingly, many of these six regions are often found to be involved in ‘mentalizing tasks’, where participants are asked to make judgments about others’ emotions, thoughts, and beliefs. Our findings suggest that these brain areas might be responding differently when trying to interpret others’ emotions (based on their tone of voice) in youth with epilepsy. We don’t yet know whether these different patterns of activation are actually related to emotion recognition accuracy, or to social difficulties; they could simply reflect an alternative “strategy” when processing vocal emotional cues. Although more research is needed to determine this, our findings contribute to our understanding of how neurodiverse brains process social and emotional information.

Youth with and without epilepsy differ in 'social brain' connectivity during a social cognitive task, but not at rest

Deficits in social cognition are common in people with epilepsy. This means that individuals with epilepsy may struggle to understand others' intentions in social situations, may find it harder to interpret others' facial expressions or tone of voice in social interactions, or may have trouble forming social connections with others. We know that epilepsy is associated with atypical functioning in regions of the brain that are thought to be involved in social cognition, but most existing research has examined patterns of brain connectivity at rest--that is, when nothing is happening. The current study wanted to investigate whether youth with epilepsy showed different brain connectivity patterns in these 'social brain' areas, when participants were completing a social cognition task. To answer this question, we compared brain connectivity within the "mentalizing network" (involved in theory of mind and other social cognitive functions) and within a network centered around the amygdala (involved in processing salient social information) in youth with and without epilepsy, while they were either completing a facial emotion recognition task or were at rest.

Compared to typically-developing youth, youth with epilepsy showed weaker connectivity between the left posterior superior temporal sulcus and the medial prefrontal cortex of the brain when seeing facial expressions in the emotion recognition task. These regions are thought to work together during social cognitive tasks, so decreased connectivity between these areas may indicate that these network nodes aren't communicating as efficiently or as well as they could be in youth with epilepsy. On the flip side, we found that youth with epilepsy had greater connectivity within the temporal lobe (between the left temporo-parietal junction and the anterior temporal cortex, to be precise) compared to typically-developing adolescents. This pattern was associated with poorer accuracy on the facial emotion recognition task. It is possible that youth with epilepsy are using a different 'strategy' in the task that results in different brain connectivity patterns in the temporal lobe, but we would need to test this possibility explicitly in future studies. In contrast to these findings, youth with and without epilepsy did not differ in their connectivity within either social brain network during resting-state scans (i.e., when they weren't doing a task).

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Overall, our findings highlight that there may be important differences in how regions associated with social cognition are connected to one another during social cognitive tasks in youth with and without epilepsy. Although this is only a first step in understanding this phenomenon, our results indicate that looking at neural connectivity patterns during relevant tasks may be important to understanding the association between epilepsy and social cognitive deficits.

Find out more and read the paper here: https://www.sciencedirect.com/science/article/abs/pii/S0028393221001330

Ongoing maturation of neural responses to voices—but not faces—in adolescence

With age, we become better able to understand the meaning behind others’ nonverbal cues. In other words, we become more skilled at identifying others’ emotional states or attitudes based on their facial expressions, postures or gestures, or tone of voice. Previous research has found that the ability to recognize emotions in vocal cues (i.e., the way in which someone says something, beyond their verbal content) follows a more protracted developmental trajectory throughout adolescence than the same ability with facial expressions. Are there similar differences in the maturational trajectory of the neural representation of both types of nonverbal cues?

The current study examined age-related changes in a) facial and vocal emotion recognition skills, and b) in neural activation to both types of stimuli in adolescence. A group of 8- to 19-year-old participants were asked to complete both a facial and a vocal emotion recognition task—in which they were asked to identify the intended emotion in other teenagers’ facial expressions and voices—while undergoing functional magnetic resonance imaging (fMRI). We found that accuracy on the emotion recognition tasks began to plateau around age 14 for faces, but continued to increase linearly throughout adolescence for voices. At a neural level, a variety of subcortical regions, visual-motor association areas, prefrontal regions, and the right superior temporal gyrus responded to both faces and voices. While there were no age-related changes in activation within these areas when responding to faces, prefrontal regions (specifically, the inferior frontal cortex and dorsomedial prefrontal cortex) were more engaged when hearing voices in older adolescents. These findings suggest that the maturation of vocal emotion recognition skills and associated neural responses in frontal regions of the brain are continuing to develop throughout adolescence, following a more protracted trajectory than other social cognitive skills like the ability to interpret facial emotions. This may make it harder for teenagers to navigate social situations in which they must rely on vocal cues—for instance, when others are wearing masks.

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Emotional faces elicit less activation in face-processing regions of the brain in youth with epilepsy

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Youth with epilepsy sometimes report having a hard time forming and maintaining relationships with others. This may be due to a variety of factors, but some research has suggested that deficits in “emotion recognition’”—or, the ability to interpret emotion in others’ facial expressions or tone of voice—may make it more challenging for youth with epilepsy to navigate social interactions. Difficulties in emotion recognition tend to be more pronounced in adults with childhood-onset epilepsy, suggesting that recurrent seizures may be disrupting the integrity of brain circuits involved in this social-cognitive skill in youth. However, though previous studies had investigated the neural representation of emotional faces in adults, none had examined the neural correlates of emotional face processing in youth with epilepsy. The current study examined whether emotional faces elicited different neural response in the brains of youth with and without epilepsy—and whether such differences were related to deficits in emotion recognition. Participants completed a facial emotion recognition task, in which they were asked to identify the emotion in other teenagers’ facial expressions, while undergoing functional magnetic resonance imaging (fMRI). We found that, compared to typically-developing youth, youth with epilepsy were less accurate in the facial emotion recognition task. In addition, youth with epilepsy showed blunted activation in the fusiform gyrus and right posterior superior temporal sulcus—two regions that play an important role in the processing of faces and social information. Reduced activation in these regions was correlated with poorer accuracy in the facial emotion recognition task. Together, our results suggest that reduced engagement of brain regions involved in processing socio-emotional signals may contribute to difficulties in social cognition experienced by youth with epilepsy.

Read more about the study here.

Brain characteristics associated with symptoms of anxiety/depression in youth with epilepsy

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Compared to the general population or to other groups of people with chronic health conditions, individuals with epilepsy are more likely to also experience internalizing disorders (i.e., depression and/or anxiety) during their lifetime. In adults, these comorbid conditions are thought to be indexed by specific neural biomarkers, including irregularities in the structure and function of frontal and temporal regions of the brain. However, less work has investigated whether similar patterns may be noted in children and adolescents with epilepsy, who are at risk of developing depression and/or anxiety. The current study capitalized on the fact that youth with epilepsy often undergo MRI (magnetic resonance imaging) scans, PET (positron emission tomography) scans, and psychological assessments as part of their clinical evaluations. We examined whether youth with epilepsy who experienced clinically-significant levels of internalizing problems had different patterns of brain structure and/or function than youth who scored in the normal range for such symptoms. We found that 42% of youth in our sample scored in the clinical range for internalizing symptoms on a parent-report of psychological well-being (Child Behavior Checklist; Achenbach, 2001)—suggesting that anxiety and depression may be a common concern for many young patients. Symptoms were not predicted by characteristics of the illness (like age of seizure onset or location of seizure focus) nor of the patient (like age or gender). However, youth in the clinical range showed reduced cortical volume overall, as well as cortical thinning and decreased function (measured via glucose reuptake) in bilateral parietal/occipital lobes and left temporal regions, compared to youth in the normal range. A follow-up classifier analysis demonstrated that these brain characteristics were predictive of internalizing problems at an individual level. Taken together, our findings suggest that children and adolescents with epilepsy who show widespread reductions in cortical thickness and neural function in clinical evaluations may benefit from intensified psychological evaluation and support for possible mood and anxiety symptoms.

Read more at: https://www.ncbi.nlm.nih.gov/pubmed/31882324

Age-related changes in adolescents’ neural connectivity and activation when hearing vocal prosody

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The ability to understand others' emotional state based on their tone of voice (vocal emotional prosody) develops throughout adolescence. Does neural activation to vocal prosody also change with age during the teenage years? We asked 8 to 19 year-old youth to complete a vocal emotion recognition task, in which they had to identify speakers' intended emotion based on their prosody, while in the MRI scanner. Age was associated with greater functional activation in regions of the frontal lobe often associated with language processing and emotional categorization. Further, age was linked to greater structural and functional connectivity between these frontal regions and the temporal-parietal junction, an area crucial for social cognition. These maturational changes were associated with greater accuracy in identifying the intended emotion in others' voices, suggesting that these neurodevelopmental processes may be supporting the growth of vocal emotion recognition skills during adolescence.

Neural responses to teenagers' faces depend on age and relative closeness to peers

In our new paper, we investigated whether the extent of teenagers’ social re-orientation towards peers was associated with their neural response to adolescents’ emotional faces. We asked 8- to 19-year-old youth to report on their closeness to their parents and to their friends, and to identify the emotions in teenage faces while undergoing fMRI. Compared to younger teenagers, older adolescents reported being closer to their peers than to their parents. In addition, responses in the ‘social’ and ‘reward’ related areas of the brain differed depending on teenagers’ age and relative closeness to their peers. Our findings suggest that the formation of close peer relationships during the teenage years may be accompanied by changes in neural response to social information.

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