Background: Basic science knowledge is essential for understanding clinical studies and enhancing clinical reasoning in medical practice. However, medical students retain only a portion of the knowledge gained during the early years of medical school. We aimed to examine medical students’ knowledge retention of repeated and recently learned topics in physiology and microbiology with additional analysis of individual variability. Given that prior studies have raised concerns about the validity of retention rate as an indicator of stable knowledge, we also explored alternative measures of retention. Methods: Nineteen third- and 22 fourth-year medical students volunteered to repeat the written examinations in physiology and microbiology, respectively, in September 2022 at the University of Pécs. Students previously completed a summative test in the fall semester and another test in the spring semester. Both examinations consisted of multiple-choice questions and the second test included questions from both semesters introducing a unique form of spaced repetition. In our study, students repeated the complete second test after a 16-week non-use retention interval. Besides retention rates, we calculated the percentage of consistently correct and incorrect answers as retention measures. Correlations between retention measures and students’ grade point averages (GPAs) were examined. Results: Significant declines in test scores were observed, with physiology scores dropping from 70.4 to 53.5% and microbiology scores from 72.1 to 57.3%. Retention rates varied significantly, with values ranging from 54.5 to 97.2%. Microbiology revealed better results of first-semester content compared to the second semester in some of the retention measures, while physiology showed no difference between semesters. Retention rates did not correlate with GPA, however, the percentage of consistently correct answers showed moderate positive correlations, while the consistently incorrect answers showed moderate negative correlations with GPA. Conclusions: There was a substantial knowledge loss among medical students with high individual variability indicating the need to explore factors affecting long-term knowledge retention in real-life educational settings more deeply. Previously acquired knowledge in microbiology demonstrated superior retention, potentially attributable to the beneficial effects of spaced repetition. The lack of correlation between retention rates and GPA suggests that other measures may better reflect stable knowledge.

The nucleus accumbens (NAcc), part of the forebrain limbic circuitry, plays integrative role in the central regulation of feeding. The glucose-monitoring (GM) neurons are important constituents of this neural network. Our main goal was to characterize the endogenous and exogenous chemical sensitivities of these cells. In the present study, extracellular single neuron activity was recorded in the NAcc of the rat by means of multibarreled glass microelectrodes, during 1) microelectrophoretic administration of various chemicals, 2) intraoral taste stimulations, and 3) intragastric infusion of monosodium-L-glutamate (MSG), D-glucose, and NaCl. One fourth of all neurons tested changed their activity in response to the microelectrophoretic administration of D-glucose. Appx. 40% of these GM neurons changed in firing rate during gustatory stimulations. In case of intragastric infusions, short and long term effects have also been recorded. Intraorally applied sucrose or MSG has altered the neuronal responsiveness to intragastric stimulation by glucose or MSG in a few cells. Our data demonstrate that the NAcc is a key structure in the integration of chemical (and other) signals arising from the endogenous and exogenous environments. The GM neurons here possess multiple functional attributes to play a crucial role in the organization of feeding.

Background: The anterior cingulate cortex (ACC) is known for its involvement in various regulatory functions, including in the central control of feeding. Activation of local elements of the central glucose-monitoring (GM) neuronal network appears to be indispensable in these regulatory processes. Destruction of these type 2 glucose transporter protein (GLUT2)-equipped chemosensory cells results in multiple feeding-associated functional alterations. Methods: In order to examine this complex symptomatology, (1) dopamine sensitivity was studied in laboratory rats by means of the single-neuron-recording multibarreled microelectrophoretic technique, and (2) after local bilateral microinjection of the selective type 2 glucose transporter proteindemolishing streptozotocin (STZ), open-field, elevated plus maze, two-bottle and taste reactivity tests were performed. Results: A high proportion of the anterior cingulate cortical neurons changed their firing rate in response to microelectrophoretic administration of D-glucose, thus verifying them as local elements of the central glucose-monitoring network. Approximately 20% of the recorded cells displayed activity changes in response to microelectrophoretic application of dopamine, and almost 50% of the glucose-monitoring units here proved to be dopamine-sensitive. Moreover, taste stimulation experiments revealed even higher (80%) gustatory sensitivity dominance of these chemosensory cells. The anterior cingulate cortical STZ microinjections resulted in extensive behavioral and taste-associated functional deficits. Conclusions: The present findings provided evidence for the selective loss of glucose-monitoring neurons in the anterior cingulate cortex leading to motivated behavioral and gustatory alterations. This complex dataset also underlines the varied significance of the type 2 glucose transporter protein-equipped, dopamine-sensitive glucose-monitoring neurons as potential therapeutic targets. These units appear to be indispensable in adaptive control mechanisms of the homeostatic–motivational–emotional–cognitive balance for the overall well-being of the organism.