@Article{info:doi/10.2196/68519, author="Peroutka, Markie and Rivero Covelo, Ignacio", title="Effects of Ventral Pallidum--Nucleus Accumbens Shell Neural Pathway Modulation on Sucrose Consumption and Motivation in Female Rats: Chemogenetic Manipulation", journal="JMIRx Bio", year="2025", month="Mar", day="8", volume="3", pages="e68519", keywords="ventral pallidum", keywords="nucleus accumbens shell", keywords="chemogenetics", keywords="sucrose", keywords="feeding behavior", keywords="food motivation", keywords="palatable food", keywords="DREADD", keywords="designer receptors exclusively activated by designer drugs", abstract="Background: The neural control of food intake involves interactions between homeostatic and nonhomeostatic systems. The nucleus accumbens shell (AcbSh) and ventral pallidum (VP) play key roles in regulating ingestive behavior and project to each other. Previous studies have shown that these projections influence food consumption, with sex differences reported in the modulation of sucrose intake by VP projections. Objective: This study aimed to investigate the effects of chemogenetic activation or inhibition of projections from the VP to the AcbSh on sucrose consumption and the motivation to work for sucrose in female rats. Methods: Chemogenetic tools (DREADD [designer receptors exclusively activated by designer drugs]) were used to selectively activate or inhibit VP projections to the AcbSh in female Sprague-Dawley rats (Gi [inhibitory G protein] DREADD: n=11; Gq [excitatory G protein] DREADD: n=10; and no DREADD: n=12). Rats were trained on a progressive ratio operant task to assess motivation to work for sucrose. Additionally, free-access sucrose consumption tests were conducted using a 20\% sucrose solution. The effects of chemogenetic modulation were analyzed using two-way ANOVA. Results: Chemogenetic manipulation of VP projections to the AcbSh did not significantly affect the motivation to work for sucrose in the progressive ratio task (F2,31=1.780; P=.18). However, a significant interaction between DREADD type and drug administration was observed in the sucrose consumption test. Activation of the VP-AcbSh projection (using Gq DREADD) decreased sucrose intake, while inhibition (using Gi DREADD) increased sucrose intake (F2,31=18.891; P=.001). No significant changes in sucrose consumption were observed in the control group without DREADD expression (P=.50). Conclusions: This study shows that projections from the VP to the AcbSh modulate sucrose intake but do not affect the motivation to work for sucrose. Chemogenetic activation reduced sucrose consumption, while inhibition increased it, suggesting that distinct neural circuits within the VP-AcbSh pathway may differentially regulate feeding behaviors. These findings highlight the role of this pathway in the consumption of palatable foods and indicate that future research should consider factors such as sex, food macronutrient composition, and specific neural subpopulations to better understand their role in feeding behavior. ", doi="10.2196/68519", url="https://bio.jmirx.org/2025/1/e68519" } @Article{info:doi/10.2196/44384, author="Degen, Isabella and Robson Brown, Kate and Reeve, J. Henry W. and Abdallah, S. Zahraa", title="Beyond Expected Patterns in Insulin Needs of People With Type 1 Diabetes: Temporal Analysis of Automated Insulin Delivery Data", journal="JMIRx Med", year="2024", month="Nov", day="27", volume="5", pages="e44384", keywords="multivariate time series", keywords="k-means", keywords="clustering", keywords="machine learning", keywords="temporal patterns", keywords="data-driven", keywords="OpenAPS", keywords="open dataset", keywords="type 1 diabetes", keywords="insulin needs", abstract="Background: Type 1 diabetes (T1D) is a chronic condition in which the body produces too little insulin, a hormone needed to regulate blood glucose. Various factors such as carbohydrates, exercise, and hormones impact insulin needs. Beyond carbohydrates, most factors remain underexplored. Regulating insulin is a complex control task that can go wrong and cause blood glucose levels to fall outside a range that protects people from adverse health effects. Automated insulin delivery (AID) has been shown to maintain blood glucose levels within a narrow range. Beyond clinical outcomes, data from AID systems are little researched; such systems can provide data-driven insights to improve the understanding and treatment of T1D. Objective: The aim is to discover unexpected temporal patterns in insulin needs and to analyze how frequently these occur. Unexpected patterns are situations where increased insulin does not result in lower glucose or where increased carbohydrate intake does not raise glucose levels. Such situations suggest that factors beyond carbohydrates influence insulin needs. Methods: We analyzed time series data on insulin on board (IOB), carbohydrates on board (COB), and interstitial glucose (IG) from 29 participants using the OpenAPS AID system. Pattern frequency in hours, days (grouped via k-means clustering), weekdays, and months were determined by comparing the 95\% CI of the mean differences between temporal units. Associations between pattern frequency and demographic variables were examined. Significant differences in IOB, COB, and IG across temporal dichotomies were assessed using Mann-Whitney U tests. Effect sizes and Euclidean distances between variables were calculated. Finally, the forecastability of IOB, COB, and IG for the clustered days was analyzed using Granger causality. Results: On average, 13.5 participants had unexpected patterns and 9.9 had expected patterns. The patterns were more pronounced (d>0.94) when comparing hours of the day and similar days than when comparing days of the week or months (0.3