Facial emotion and the brain – insights from the clinic to Ex. Ed.

August 8, 2010 at 10:18 PM

Facial emotion and the brain – insights from the clinic to Ex. Ed.

 

Vanessa Castro UMD ‘11 and Jim Stellar

 

Vanessa was a student at Northeastern and an advisee of mine outside my field (I was on her undergraduate thesis committee).  We wrote a blog post together out of that thesis, and now we are back with another one that also involves non-verbal communication.  She is now looking at face-processing deficits found in autism spectrum disorders (ASD) as related to structural and functional differences in the amygdala.  Some time ago, I made a short post about a NYTimes article on a Harvard study on the amygdala-prefrontal cortex interaction in the development of anxiety [link here]. So, first, let’s find out what Vanessa is doing now that she is finishing her first year of graduate school at U. Massachusetts Dartmouth.

 

Early research has suggested that increased activation of the fusiform face area (FFA) is associated with face perception impairment in autistic samples.  However, recent research suggests something different.  Research now points to abnormal amygdala activation (more specifically, hyperactivation) as a function related to the perceptual deficits in autism.  I would like to investigate how the amygdala differs structurally in autistic populations and as a result the function the amygdala may play in the  face-processing deficits found in ASD (Autistic Spectrum Disorder).  Specifically, I intend to do a literature review of research that utilizes fMRI methods to look at amygdala function.

 

This is terrific and badly needed.  But let’s turn the conversation back to another topic we share and that is experiential education.  One of the roles of nonverbal communication is to pace human interaction, but there we have to go back to facial emotion. 

 

In order to exist comfortably and successfully as social beings, humans must correctly perceive the behaviors, personalities, and intentions of other people. From an evolutionary perspective, it is important if not crucial for man to perceive whether the face of someone approaching is happy (and thus non threatening) or mad (and thus threatening). While the ability to infer another’s state may seem automatic, certain populations are impaired in this ability, as is seen in ASD. What this means is that the lifestyles of individuals with ASD may be severely impaired because of an inability to accurately process and perceive other people. Nonverbal communication exists not only in static images such as facial expressions, but also in more dynamic channels such as body movements, gestures, voice intonations, and spatial cues. When perceiving another person’s behavior we also change our behavior as a result of what we have perceived; in other words we know how to behave in a situation by responding to the ways in which other people behave. In order to know how others are truly behaving, we pick up on these nonverbal cues in the various channels that they exist, often simultaneously. An inability to accurately perceive these cues may result in an inability to form and maintain relationships, which would result in an inability to form and maintain social networks. This could cause isolation, which is not necessarily the way in which humans best exist.

 

This is terrific.  The amygdala has long been associated with fear.  Are we talking now about some kind of fear or anxiety role in ASD that then makes it harder for these patients to see the face or is the amygdale more directly involved?

 

It seems that the role of the amygdala in processing faces is both direct and indirect. While the FFA is believed to be the cortical area where face processing occurs, research has found structural differences in the pathways connecting the FFA to the amygdala (Conturo, Williams, Smith, Gultepe, Akbudak, and Minshew, 2008). MRI diffusion tensor tracking (DTT) was used to trace neuronal fiber pathways in an autistic sample of high functioning adolescents and adults as compared to controls. Hippocampo-fusiform and amygdalo-fusiform pathways were normal in size and shape but abnormal in microstructure in the ASD group.  Similarly, Kleinhans, Richards, Sterling, Stegbauer, Mahurin, Johnson, Greenson, Dawson, and Aylward (2008) found abnormalities in functional connectivity within the amygdala in ASD individuals. Greater connectivity was found in the control group as compared to ASD subjects. Furthermore, connectivity was related to clinical severity in ASD.  Higher levels of social impairment were associated with reduced FFA-amygdala connectivity and increased FFA-right inferior frontal connectivity. These results exemplify the indirect role of the amygdala in face processing deficits found in ASD.

 

It does not appear that the amygdala functions by means of fear or anxiety, but rather has a more direct role in the face processing deficits found in ASD.  One hypothesis is that individuals with ASD spend less time gazing with their eyes at faces, resulting in the hypoactivation of the amygdala and FFA and thus a face processing deficit. Both the eyes and the mouth are said to be indicative of expressing emotion and other nonverbal cues, and therefore may be used in recognizing faces in TD populations. Avoidance of these cues by means of averting eye gaze may result in an inability to correctly process faces. The amygdala has been hypothesized as being related to preferential eye gaze in ASD individuals. Results found that amygdala activation was significantly positively correlated with eye region gaze preference for fearful faces only (Gamer & Buchel, 2009). This is an interesting finding give that the amygdala is believed to be associated with fear. Other studies in this area have found emotion specific findings. Ashwin, Chapman, Colle, and Baron-Cohen (2006) found a significant group by emotion interaction where ASD participants differed from control participants only on the perception of negative basic emotions (e.g. fear, disgust, anger, and sadness). It may be that the role of the amygdala in regulating and processing fear extends not only to the experience of fear but also to the perception of fear in others. This makes sense given the theory of empathy that often emerges in social science, where one’s ability to accurately perceive other people is related to their ability to take on the feelings they perceive. Individuals with ASD are often thought of as lacking an ability to accurately empathize, which may be related both to abnormal amygdala functioning as well as impaired face processing.

 

This is a very technical answer and shows the impressive depth of the thinking in this field in regard to this syndrome.  Let’s take it back to the theme of experiential education and you.  You went to Northeastern, a co-op school.  You did a serious undergraduate thesis.  Now you are in graduate school and have had those shaping experiences too in and out of the classroom.  In all experiential situations, you worked in groups, interacted with people, and presumably used your FFA and amygdala (and other areas) to learn to manage those interactions which helped to give meaning and value to the data/theories you were also gaining.  Of course, you also grew as a scholar.  Reflect on yourself as a subject of this Ex Ed learning and comment on how these interactions outside of the classroom shaped you in your field.

 

As a researcher in the social sciences, particularly within the area of interpersonal perception, possessing the ability to accurately perceive others is not only pertinent to my social success but also my academic success. As a graduate student, I am one of a small cohort; all of whom are essentially competing with each another for academic acclaim. My interpersonal sensitivity has helped me to identify relationships that have resulted in collaborations on several interesting research topics. I have built several strong relationships with my professors and feel comfortable going to them for direction and guidance, a comfort I attribute to having interpersonal sensitivity. The ability to accurately perceive the behavior and intentions of others allows an individual to appropriately manage his or her behavior and intentions. Therefore, by understanding other people I feel that I understand myself more as well.

 

Prefect. Thank you.

NEXT
A view on student diversity and STEM education from someone raised in Jamaica
0 Comments

Leave a Reply