Synaptic Sunday #11 – Adolescence and Anxiety Edition
Compared to younger and older individuals of their species, both adolescent humans and mice on average have a stronger tendency to keep exhibiting a fear response to a threat even when the danger is gone.
In the human experiment, the fear response was initially elicited by pairing a visual stimulus (one of a sequence of yellow or blue images on a computer screen) with a harsh startling sound; in subsequent trials the same images appeared without any startling noise – leading to an extinction of the fear response in children and adults, but not in the adolescents, who kept showing a fear response to whatever image had once been paired with the noise.
As for the animal experiment, the article reports that the experimenters “used standard fear conditioning common in these types of animal studies.” (This is vaguely worded… did they use loud noises? Or pain?) The experimenters also measured neuronal activity in the mice:
… the research team found that the prelimbic region in the prefrontal cortex, the brain region that processes emotion, is activated during acquisition of fear, and the infralimbic prefrontal cortex is used to extinguish this fear association.
When compared to younger and older mice, adolescent mice didn’t exhibit the kinds of neuronal activity associated with fear extinction (this corresponded to their behavior – they continued to show a fear response over time, regardless of the fact that the danger/unpleasantness was no longer present). Even as they got older, the adolescent mice didn’t lose their fear response.
Related data from other studies with humans:
It is estimated that over 75 percent of adults with fear-related disorders can trace the roots of their anxiety to earlier ages.
It’s not clear how the persistent fear response in this experiment fits into the complex puzzle of excessive anxiety and its sources, people’s predispositions towards it, the reasons it persists (or doesn’t) into adulthood, and the ways in which it disrupts mental and physical functioning (also, adolescents with anxiety disorders have often reported that their symptoms started in childhood). And how do these results tie into other findings with teens that show a greater tendency for them to do something dangerous even if they understand the risks?
An overview of different types of anxiety that can become excessive and interfere with daily life (e.g. social anxiety, post-traumatic stress disorder, etc.)
Most of the study participants were girls (though the experimenters reported that the results for the boys weren’t significantly different).
Maintaining a blog had a stronger positive effect on troubled students’ well-being than merely expressing their social anxieties and concerns in a private diary, according to the article published online in the APA journal Psychological Services. Opening the blog up to comments from the online community intensified those effects.
Maybe the effects were stronger for a public blog because the teens felt less isolated with their problems and felt relief that they could be heard; it turns out that when they opened the blogs up to comments, the response from other Internet users was almost always positive and encouraging (few to no trolls). I’m assuming the blogs were anonymous, making the teens less vulnerable to disruption in their lives offline and maybe helping them write more freely about their worries.
Incidentally, the photo at the top of the post links to a relevant write-up on “stressed out lab rats” – how rats living in chronic stress tend to make decisions out of habit, as if their constant stress doesn’t allow them to be more mentally flexible. There are definitely parallels to stressed out humans.
Posted on 09/30/2012, in Neuroscience, Psychology, Research, Synaptic Sunday and tagged adolescence, animal experiments, animal psychology, anxiety, childhood, conditioning, fear, fear extinction, stress. Bookmark the permalink. Leave a Comment.