Synaptic Sunday #11 – Adolescence and Anxiety Edition

1) Learning to Overcome Fear is Difficult for Teens

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?

2) Anxiety Disorders in Children and Teens

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.)

3) Blogging May Help Teens Deal With Social Distress

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.

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Incidentally, the photo that was at the top of the post linked 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.

Synaptic Sunday #6 – The Dog’s Mind and fMRI Edition

1) How do you train a dog to get into an fMRI scanner and stay there without resorting to restraints and drugs?

2) More importantly, why would you want to get a dog into an fMRI scanner?

Scientists Use Brain Scans to Peek at What Dogs Are Thinking

From the link:

The researchers aim to decode the mental processes of dogs by recording which areas of their brains are activated by various stimuli. Ultimately, they hope to get at questions like: Do dogs have empathy? Do they know when their owners are happy or sad? How much language do they really understand?

An fMRI scan doesn’t give us mind-reading abilities; it shows blood-flow to different areas of the brain (oxygen-rich as compared to deoxygenated blood), and researchers infer brain activity from that. When the dogs were given a signal for “treat,” for instance, there appeared to be increased activity in a part of the brain that in people is associated with rewards. But can we get a real understanding of what the dog is experiencing? If you look at questions of empathy, what is empathy to a dog? Maybe we’d see increased activity in certain parts of the brain that in humans is associated with empathy, which could be interesting, but what does that tell us more deeply about the dog’s mind and subjective experiences? If they know when their owners are happy or sad, what kind of knowledge is this: a reading of facial and behavioral cues, or something deeper than that? This is a limitation of fMRI when it’s used on people as well, though with people we can try to supplement the fMRI scan findings with other measures – various cognitive tasks, including those that ask for verbal input (“woof, woof”).

3) Overall, fMRI studies can be quite problematic, for dogs or humans (or dead salmon) – as detailed in this recent article: Controversial science of brain imaging.