Over the last month, many online news articles have drawn our attention to neuroscience-related topics and research. If it exists, I prefer to refer to the original research to interpret such news articles' real significance and claims. The themes from the research this month appear to be around diet and eating and also one of our lab's favorite topics: ADHD.
Diet and Eating
The first news article explained how recent research showed a difference between the brain circuits for eating for nourishment versus eating for pleasure, which could have significant implications for the treatment of obesity and eating disorders (Dolan, 2024a). After locating the original research article, I discovered that it was behind a paywall (Liu et al., 2024). So, this information was gathered from the news article. The news article explains how neural mechanisms for hedonic (pleasure-based) versus drive (homeostatic/hunger-based) were uncovered in male mice (Dolan, 2024a). The researchers examined the diagonal band of Broca (DBB) region of their brains, which is rich in proenkephalin (an endogenous opioid), and a region implicated in mouse feeding behaviors (Dolan, 2024a). The researchers employed various techniques (i.e., optogenetics) to excite and inhibit this region and measure resulting feeding behavioral changes with concomitant imaging of these neurons based on various food exposures (Dolan, 2024a). The researchers discovered the different subregions mediate hedonic versus hunger-based eating via different neural circuits (Dolan, 2024a). For hunger-based eating, the circuit emerged from the DBB to the hypothalamus, specifically the paraventricular region which is known to be associated with the homeostatic regulation of food intake (Dolan, 2024a). For hedonic feeding, the circuit emerged from the DBB to a different region of the hypothalamus, the lateral hypothalamus which is associated with this (Dolan, 2024a). Thus, as these two subregions of the hypothalamus are already known to differentiate hedonic versus hunger-based eating, this appears to be a type of replication study.
The second news article related to eating was also about rodents, this time rats, and connecting a high-fat diet to brain functioning and, thus, memory (Hedrih, 2024a). Locating the original study, which imparted that the purpose was to examine limbic structures like the amygdalae and hippocampi, known to be involved with emotion and memory respectively, or specifically emotional memory during the acquisition of a conditioned olfactory aversion on the background of a lifelong high-fat diet in rats (Osorio‐Gómez et al., 2024). The results of the study revealed that rats experienced a metabolic syndrome, as would be seen in humans, and an augmented aversion which was counter to their cognitive loss associated with the diet (Osorio‐Gómez et al., 2024). The authors explained that this aversion was paired with an increase in norepinephrine and glutamate in these limbic structures which remained at basal levels despite the diet (Osorio‐Gómez et al., 2024). The diet modified cognitive functioning, upregulating neurotransmission, and resulted in a strengthened memory trace for the conditioned aversion (Osorio‐Gómez et al., 2024). The takeaway message was that a metabolic syndrome can be detrimental to cognition but may render other processes like conditioning easier.
The last news article in this category was about the relationship between the gut microbiome and cognition (Dolan, 2024b). Locating the original study, I discovered the primary purpose was to examine if a prebiotic could increase muscle function and exercise in older adults (Ni Lochlainn et al., 2024). The authors explained that for their primary hypothesis, there was no evidence of an increase in muscle mass (Ni Lochlainn et al., 2024). However, they discovered an unexpected positive effect of the prebiotic on cognition as revealed by measures derived from the CANTAB cognitive battery and fewer errors on a test of visual memory and learning (Paired Associates Learning test) (Ni Lochlainn et al., 2024). The take-home message from this study was about the influence of the gut microbiome in relation to brain health and cognition.
ADHD
Finally, the last news article for review from the last month was about ADHD, the primary focus of much of our research in this lab. This news study tied mind-wandering in ADHD to mediating anxiety and depression in those with ADHD, perhaps related to ruminating thoughts and lack of mindfulness (Hedrih, 2024). In reading the original study, the research took place at a university clinic in Turkey (Kandeğer et al., 2023). The study employed 175 unmedicated adults with ADHD diagnoses and gave them a series of inventories for ADHD, anxiety, depression, mind wandering, rumination, and mindfulness (Kandeğer et al., 2023). The results of the study divulged correlations across all of these measures, however, there was no direct association between ADHD and anxiety and depression symptom severity in a regression analysis (Kandeğer et al., 2023). Of note, a type of analysis called a mediation analysis revealed a positive relationship between ADHD and anxiety and depression severity via moderators of EMW, rumination, and diminished mindfulness (Kandeğer et al., 2023). The take-home message from this is that those with ADHD should regularly practice regulating their emotions via challenging automatic negative thoughts that cycle through ruminations and practicing mindfulness to avoid mindless mind wandering.
Abbreviations in this blog:
ADHD: Attention-Deficit/Hyperactivity Disorder
DBB: Diagonal Band of Broca
EMW: excessive mind-wandering
References
· Dolan, E. W. (2024a, September 4). Scientists uncover brain circuit that balances eating for necessity and eating for pleasure. PsyPost. https://www.psypost.org/scientists-uncover-brain-circuit-that-balances-eating-for-necessity-and-eating-for-pleasure/?utm_source=dlvr.it&utm_medium=facebook&fbclid=IwY2xjawFdCiRleHRuA2FlbQIxMQABHVm4JZXu9fNuqqOqbysiBUQUWjyg5VdDKQ9QIX2PyyXoynru2-rMFyHmnQ_aem_bW4tcRkLXtD7_i3V8aKT6g
· Dolan, E. W. (2024b, September 4). New study shows gut microbiome could play role in preventing cognitive decline. PsyPost. https://www.psypost.org/new-study-shows-gut-microbiome-could-play-role-in-preventing-cognitive-decline/?utm_source=dlvr.it&utm_medium=facebook&fbclid=IwY2xjawFdCnVleHRuA2FlbQIxMQABHRfnwYeexzAvXL5LmYW3qHplIQcztTC6pxcedb2JCRQZm6dDez-7sRRECQ_aem_-YUEfUOsyP4d8RBcnVr-jQ
· Hedrih, V. (2024a, September 5). High-fat diet alters brain function and memory in rats, new study shows. PsyPost. https://www.psypost.org/high-fat-diet-alters-brain-function-and-memory-in-rats-new-study-shows/?utm_source=dlvr.it&utm_medium=facebook&fbclid=IwY2xjawFdCrxleHRuA2FlbQIxMQABHSctPyMDDPcA727gUtowepf5cGrylrFeG8OZn4KwsXxBp6fwNMLrprLk7Q_aem_07pLr4zJ1e0H1zvmYbYgWA
· Hedrih, V. (2024c, September 9). Excessive mind wandering mediates link between ADHD and depression/anxiety, study finds. PsyPost. https://www.psypost.org/excessive-mind-wandering-mediates-link-between-adhd-and-depression-anxiety-study-finds/?utm_source=dlvr.it&utm_medium=facebook&fbclid=IwY2xjawFdCv9leHRuA2FlbQIxMQABHTtyO-Ni6FTbe0lX_HQFcZEPx8RIt0nlQOrVlEbGJFAOlHr9aT6cq48WBA_aem_cb09tSERVcA_vC_FBP5GKw
· Kandeğer, A., Odabaş Ünal, Ş., Ergün, M. T., & Yavuz Ataşlar, E. (2023). Excessive mind wandering, rumination, and mindfulness mediate the relationship between ADHD symptoms and anxiety and depression in adults with ADHD. Clinical Psychology & Psychotherapy, 31(1). https://doi.org/10.1002/cpp.2940
· Liu, H., Bean, J. C., Li, Y., Yu, M., Ginnard, O. Z., Conde, K. M., Wang, M., Fang, X., Liu, H., Tu, L., Yin, N., Han, J., Yang, Y., Tong, Q., Arenkiel, B. R., Wang, C., He, Y., & Xu, Y. (2024). Distinct basal forebrain-originated neural circuits promote homoeostatic feeding and suppress hedonic feeding in male mice. Nature Metabolism. https://doi.org/10.1038/s42255-024-01099-4
· Ni Lochlainn, M., Bowyer, R. C., Moll, J. M., García, M. P., Wadge, S., Baleanu, A.-F., Nessa, A., Sheedy, A., Akdag, G., Hart, D., Raffaele, G., Seed, P. T., Murphy, C., Harridge, S. D., Welch, A. A., Greig, C., Whelan, K., & Steves, C. J. (2024). Effect of gut microbiome modulation on muscle function and cognition: The promote randomised controlled trial. Nature Communications, 15(1). https://doi.org/10.1038/s41467-024-46116-y
· Osorio‐Gómez, D., Perez, C. I., Salcedo‐Tello, P., Hernández‐Matias, A., Hernández‐Ramírez, S., Arroyo, B., Pacheco‐López, G., Gutierrez, R., Bermúdez‐Rattoni, F., & Guzmán‐Ramos, K. (2024). Early‐life and chronic exposure to high‐fat diet alters noradrenergic and glutamatergic neurotransmission in the male rat amygdala and hippocampus under cognitive challenges. Journal of Neuroscience Research, 102(6). https://doi.org/10.1002/jnr.25360
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