New research suggests depression impacts emotional responses to autobiographical memories

New research from the journal Cognitive Behaviour Therapy points to a cognitive bias that might be involved in the maintenance of negative mood among people with depression. When compared to healthy controls, individuals with major depressive disorder (MDD) reported less happiness when recalling positive memories but more sadness when recalling bad memories.

by Beth Ellwood via PsyPost

Beck’s cognitive model of depression — one of the most prominent theories of depression — proposes that people with depression show a bias toward the processing of negative information about themselves over positive information about themselves.

Study authors Dahyeon Kim and K. Lira Yoon sought to build on a previous study that showed that people with elevated depressive symptoms differed in their emotional responses to personal memories compared to healthy individuals. For healthy subjects, the intensity of their positive feelings when remembering pleasant memories outdid the intensity of their negative feelings when remembering unpleasant memories. For individuals with depressive symptoms, the intensity of their emotional responses was the same whether they were remembering happy or unhappy memories from their personal histories.

In other words, healthy subjects’ emotional responses to memories faded more strongly for unpleasant (vs. pleasant) memories, while this was not true for those with depressive symptomology.

Kim and Yoon were motivated to re-explore this effect among a clinical sample. The researchers conducted interviews among 30 individuals with MDD and 46 control participants. During the interviews, subjects were asked to recall three events from their past: their happiest, saddest, and most anxious moments. After describing each memory, the participants answered two key questions. For the happy memory, they were asked to rate how happy they were when the event originally took place, and then how happy they are now reflecting on it. Similarly, for the sad memory, they rated how sad they were then and now. For the anxious memory, they rated how nervous they felt then and now.

Notably, the two groups did not differ in the intensity of their emotions experienced at the time of the event — this was true whether it was a happy, sad, or anxious memory. This finding implies that the two groups were recalling events of comparable emotional intensity. Nevertheless, in line with previous findings, ratings of happiness “now” were significantly lower among the MDD group compared to the control group. This was true even after controlling for how much time had passed since the event.

In short, the MDD group experienced less happiness when reflecting on happy memories and more sadness when reflecting on sad memories compared to the control group. The same effect was not found when it came to the anxious memories, suggesting that this differential fading of emotional responses to memories was specific to sad memories.

“Given their negative schemas (Beck, 2002), the saddest autobiographical memories (AMs) may align with the current worldview of individuals with MDD,” Kim and Yoon discuss. “Thus, these AMs may seem more relevant, resulting in more intense emotional responses in the MDD group. In contrast, the happiest AMs may contradict their current negative worldview, impeding the experience of more intense happiness in individuals with MDD.”

Kim and Yoon point out that previous studies have shown that recalling positive memories does not improve low mood among individuals with depression. The authors say that their findings offer insight into this effect. “Applied to treatment,” they say, “restructuring positive AMs, with the goal of increasing the happiness experienced from the recall, may be beneficial.”

The study, “Emotional response to autobiographical memories in depression: less happiness to positive and more sadness to negative memories”, was authored by Dahyeon Kim and K. Lira Yoon.

A man who lost all movement below the neck after a spinal cord injury in 2007 was finally able to write again – After researchers implanted microchips into his brain, a paralyzed man was able to write with his mind

By ADRIANNA RODRIGUEZ via USA TODAY 

Stanford University researchers used artificial intelligence software and a brain-computer interface to help the man with immobilized limbs to communicate by text, according to a study published Wednesday in the peer-reviewed journal Nature. 

Dr. Jaimie Henderson, professor of neurosurgery at Stanford, implanted two microchips the size of baby aspirin about 1 millimeter into the man’s brain in 2017. The chips have electrodes that record neurons in the motor cortex, the part of the brain that controls hand movement.

When the man imagined he was using his hand to write on a notepad, the computer converted his thoughts into text on a computer screen.

“This approach allowed a person with paralysis to compose sentences at speeds nearly comparable to those of able-bodied adults of the same age typing on a smartphone,” Henderson said. “The goal is to restore the ability to communicate by text.”

The man – referred to in the study only as T5 – texted at a rate of about 18 words per minute. A person of the same agewith full use of their hands can text an average of 23 words per minute on a smartphone.

His error rate was about one mistake every 18 or 19 attempted characters. When researchers used an autocorrect function, similar to most smartphones, error rates plummeted below 1% when he was asked to copy text and slightly more than 2% when he was asked to write something original.

“It’s exciting to improve the speed of these kinds of devices to approach a level where I think it could be very useful for someone who’s severely paralyzed,” said Dr. Frank Willett, study author and neuroscientist at Stanford. “It’s comparable to writing on a notepad or typing on a smartphone.

Study authors are excited not only about the breakthrough technology but about what their discovery means for future research.

Until now, scientists weren’t sure how long a person could retain motor skills without putting them into practice.

“We had no idea someone who had never moved his hands for 10 years, if you asked him to write, what his brain would do,” Willett said. “It shows these fine dexterous (movements) still evoke rich patterns of brain activity that we can use.”

Researchers hope the technology could be adapted to allow people who can’t talk to simulate conversation through writing.

“While handwriting can approach 20 words per minute, we tend to speak around 125 words per minute, and this is another exciting direction that complements handwriting,” said Krishna Shenoy, professor of electrical engineering at Stanford University.

More work needs to be done before the study’s results can be successfully transferred into real-world applications such as a tablet, smartphone or computer.

“The immediate next step would be refining and streamlining the algorithm, so it’s easier to get up and running quickly,” Willett said. “Every brain is unique, and you get different neurons that do different things, so there’s always a calibration.”

Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT. 

https://www.usatoday.com/story/news/health/2021/05/13/stanford-researchers-implant-microchip-paralyzed-man-communicate/5070495001/