A new study in Biological Psychiatry explores the influence of oxytocin

Difficulty in registering and responding to the facial expressions of other people is a hallmark of autism spectrum disorder (ASD). Relatedly, functional imaging studies have shown that individuals with ASD display altered brain activations when processing facial images.

The hormone oxytocin plays a vital role in the social interactions of both animals and humans. In fact, multiple studies conducted with healthy volunteers have provided evidence for beneficial effects of oxytocin in terms of increased trust, improved emotion recognition, and preference for social stimuli.

This combination of scientific work led German researchers to hypothesize about the influence of oxytocin in ASD. Dr. Gregor Domes, from the University of Freiburg and first author of the new study, explained: “In the present study, we were interested in the question of whether a single dose of oxytocin would change brain responses to social compared to non-social stimuli in individuals with autism spectrum disorder.”

They found that oxytocin did show an effect on social processing in the individuals with ASD, “suggesting that oxytocin may help to treat a basic brain function that goes awry in autism spectrum disorders,” commented Dr. John Krystal, Editor of Biological Psychiatry.

To conduct this study, they recruited fourteen individuals with ASD and fourteen control volunteers, all of whom completed a face- and house-matching task while undergoing imaging scans. Each participant completed this task and scanning procedure twice, once after receiving a nasal spray containing oxytocin and once after receiving a nasal spray containing placebo. The order of the sprays was randomized, and the tests were administered one week apart.

Using two sets of stimuli in the matching task, one of faces and one of houses, allowed the researchers to not only compare the effects of the oxytocin and placebo administrations, but also allowed them to discriminate findings between specific effects to only social stimuli and non-specific effects to more general brain processing.

What they found was intriguing. The data indicate that oxytocin specifically increases responses of the amygdala to social stimuli in individuals with ASD. The amygdala, the authors explain, “has been associated with processing of emotional stimuli, threat-related stimuli, face processing, and vigilance for salient stimuli”.

This finding suggests oxytocin might promote the salience of social stimuli in ASD. Increased salience of social stimuli might support behavioral training of social skills in ASD.

These data support the idea that oxytocin may be a promising approach in the treatment of ASD and could stimulate further research, even clinical trials, on the exploration of oxytocin as an add-on treatment for individuals with autism spectrum disorder.

Researchers map neurons in the brain involved with social interactions with others in groups

Meaningful social interactions are critical to an individual’s well-being, and such interactions rely on people’s behaviors towards one another. In research published in Science, investigators at Massachusetts General Hospital (MGH) have mapped the neurons in the brain that allow a monkey to process and remember the interactions and behaviors of another monkey to influence the animal’s own actions. The findings might be used to develop treatment strategies for people with neuropsychiatric conditions.

The study had three Rhesus monkeys sit around a rotary table and take turns to offer an apple slice to one of the other two monkeys. At the same time, the researchers recorded the activity of individual neurons in a brain area known to play a role in social cognition, called the dorsomedial prefrontal cortex (dmPFC).

During these interactions, the monkeys reciprocated past offers of an apple slice and retaliated when they did not receive a slice from another. The researchers’ recordings identified distinct neurons in the dmPFC that responded to the actions of other monkeys in the group. Certain neurons were activated with a particular action and outcome of specific individuals within the group (such as a neighbor monkey offering an apple slice leads to the outcome of receiving the reward). Many of the neurons encoded information not only about the actions and outcomes of specific individuals but also about their past behavior. This information about past interactions with group members influenced an animal’s upcoming decisions to reciprocate or retaliate, and investigators could use the neuronal information to predict which monkey would receive an apple slice from a particular monkey even before it was offered.

“This finding suggested that the dmPFC plays a role in strategic decisions. To test this idea, we disrupted the normal activity in this area and found that the animals were less likely to reciprocate,” says lead author Raymundo Báez-Mendoza, PhD, an investigator in the Department of Neurosurgery at MGH.

The results suggest that the dmPFC plays an important role in mapping out our actions and outcomes as well as the actions of others. “In neuropsychiatric conditions in which this ability is compromised, treatments aimed at improving the functioning of this brain area, either directly or indirectly, might improve peoples’ lives,” says senior author Ziv Williams, MD.

(Photo credit: Karen Huntt / Corbis, TIME.com “Babies Vs. Chimps…”)

Environment, not evolution, might underlie some human-ape differences (ScienceDaily, 15 July 2019)

Apes’ abilities have been unfairly measured, throwing into doubt the assumed belief that human infants are superior to adult chimpanzees, according to a new study (published in Animal Cognition) by leaders in the field of ape cognition.

[Researchers] say it should come as no surprise that apes raised in institutions would not perform well compared with humans raised in western families, especially when tested with western cultural practices, for example, gestures such as pointing…

“Most studies, comparing apes with human children, for instance, have been poorly designed, with different relevant experiences given to each species, testing them at different ages in many cases, and then claiming to have found a difference in social cognition between humans and apes, but the species haven’t been treated similarly before or during the tests.

"These studies suffer from the same type of prejudice that once existed in studies of human intelligence, which started from a biased position of assuming northern Europeans were innately more intelligent than southern Europeans. We argue the same type of bias is apparent in cross-species studies…”

The researchers say it’s vital scientists realise that environmental experiences vary among humans (both between children and adults, and between people with different cultural experiences) and among apes (also from young to old, and between apes with different experiences). 

 "…To truly understand the abilities of each species, research needs to examine specific individual learning histories within specific ecological circumstances for both humans and for apes.

“We urge researchers to stop using fallacious research designs and reasoning in studies of comparative cognition.” (full article)

Story Article:

University of Portsmouth. “Environment, not evolution, might underlie some human-ape differences.” ScienceDaily. ScienceDaily, 15 July 2019. <www.sciencedaily.com/releases/2019/07/190715094847.htm>. 

Journal Reference:

David A. Leavens, Kim A. Bard, William D. Hopkins. The mismeasure of ape social cognition. Animal Cognition, 2017; 22 (4): 487 DOI: 10.1007/s10071-017-1119-1