Mindwandering by Moshe Bar

Author:Moshe Bar [Bar, Moshe]
Language: eng
Format: epub
Publisher: Hachette Books
Published: 2022-02-08T00:00:00+00:00

The rumination score of an individual is simply the sum of her numeric responses to all the questions above.

Our analysis showed that the neuronal volume of the hippocampus, a brain complex that is key for both memory and mood, was directly correlated with the extent of rumination. Within the subfields of the hippocampus, we found increased or decreased structural volume depending on the individual level of ruminative tendencies. It is worth noting that beyond neuronal cell bodies, the gray matter consists also of dendrites and axons, synapses, glial cells, and capillaries, so a change in volume can involve a change in more than one component. To put it simply, thinking style affects not only our mood but also the structure of our brains. It was already known that depression diminishes the volume of the hippocampus and that various therapies for mood disorder, such as selective serotonin reuptake inhibitors (SSRI, like Prozac), psychotherapy, aerobic exercise, and meditation can help regain hippocampal volume. But showing that this volume corresponds to how much we tend to ruminate solidifies the link between thinking and feeling.

For decades, depression has been taken as a disorder of chemical imbalance. Our approach shows that it is just as much a disorder of thought imbalance. There is a cascade of influence in the cortex. Medications aim to regulate the levels of neurotransmitters such as serotonin, and these levels then affect upward all the way to mood and thinking style. Our approach, as cognitive neuroscientists, is instead to address the top level, thought, with the hope that untangling ruminations will not only improve mood but also trickle down in that cascade to normalize levels of the neurotransmitters. A bidirectional cascade with multiple entry points will potentially alleviate the overall symptoms of mood disorders.

Our memory consists of a giant web of representations that are connected to each other with several degrees of separation (chair ➙ table ➙ wood ➙ forest ➙ hiking ➙ vacation ➙ relax ➙ piña colada). While this makes for an efficient framework for memory encoding and retrieval, we would not want our brain to activate the cortical representation of piña colada every time we see a chair. It is crucial that the activation of one mental representation would activate associated representations so that we can generate predictions about what to expect but in doing so activate only the associations that are relevant in the specific context and not beyond. To curb the extent of the representations that are activated simultaneously, the brain exerts inhibition like brakes. In normal levels of inhibition, our mind is still given the mental space to be sufficiently associative. In negative mood and in depression, however, there is excessive inhibition, and as a result the extent of associative activation is severely constrained. In other words, overinhibition diminishes our ability to disengage from cyclical thinking and debilitating rumination. Underinhibition, on the other hand, can cause hallucinations in its extreme because of activation of superfluous associations, as in schizophrenia. Inhibition has to be just right.

This link between breadth of mental activation and mood leads to some counterintuitive possibilities.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.