Pub Date : 2024-03-30DOI: 10.1101/2023.07.01.547331
Liv Engel, Amy R Wolff, Madelyn Blake, Val L Collins, Sonal Sinha, Benjamin T Saunders
Environmental cues, through Pavlovian learning, become conditioned stimuli that invigorate and guide animals toward acquisition of rewards. Dopamine neurons in the ventral tegmental area (VTA) and substantia nigra (SNC) are crucial for this process. Dopamine neurons are embedded in a reciprocally connected network with their striatal targets, the functional organization of which remains poorly understood. Here, we investigated how learning during optogenetic Pavlovian cue conditioning of VTA or SNC dopamine neurons directs cue-evoked behavior and shapes subregion-specific striatal dopamine dynamics. We used a fluorescent dopamine biosensor to monitor dopamine in the nucleus accumbens (NAc) core and shell, dorsomedial striatum (DMS), and dorsolateral striatum (DLS). We demonstrate spatially heterogeneous, learning-dependent dopamine changes across striatal regions. While VTA stimulation evoked robust dopamine release in NAc core, shell, and DMS, cues predictive of this activation preferentially recruited dopamine release in NAc core, starting early in training, and DMS, late in training. Corresponding negative prediction error signals, reflecting a violation in the expectation of dopamine neuron activation, only emerged in the NAc core and DMS, and not the shell. Despite development of vigorous movement late in training, conditioned dopamine signals did not similarly emerge in the DLS, even during Pavlovian conditioning with SNC dopamine neuron activation, which elicited robust DLS dopamine release. Together, our studies show broad dissociation in the fundamental prediction and reward-related information generated by different dopamine neuron populations and signaled by dopamine across the striatum. Further, they offer new insight into how larger-scale plasticity across the striatal network emerges during Pavlovian learning to coordinate behavior.
{"title":"Dopamine neurons drive spatiotemporally heterogeneous striatal dopamine signals during learning.","authors":"Liv Engel, Amy R Wolff, Madelyn Blake, Val L Collins, Sonal Sinha, Benjamin T Saunders","doi":"10.1101/2023.07.01.547331","DOIUrl":"10.1101/2023.07.01.547331","url":null,"abstract":"<p><p>Environmental cues, through Pavlovian learning, become conditioned stimuli that invigorate and guide animals toward acquisition of rewards. Dopamine neurons in the ventral tegmental area (VTA) and substantia nigra (SNC) are crucial for this process. Dopamine neurons are embedded in a reciprocally connected network with their striatal targets, the functional organization of which remains poorly understood. Here, we investigated how learning during optogenetic Pavlovian cue conditioning of VTA or SNC dopamine neurons directs cue-evoked behavior and shapes subregion-specific striatal dopamine dynamics. We used a fluorescent dopamine biosensor to monitor dopamine in the nucleus accumbens (NAc) core and shell, dorsomedial striatum (DMS), and dorsolateral striatum (DLS). We demonstrate spatially heterogeneous, learning-dependent dopamine changes across striatal regions. While VTA stimulation evoked robust dopamine release in NAc core, shell, and DMS, cues predictive of this activation preferentially recruited dopamine release in NAc core, starting early in training, and DMS, late in training. Corresponding negative prediction error signals, reflecting a violation in the expectation of dopamine neuron activation, only emerged in the NAc core and DMS, and not the shell. Despite development of vigorous movement late in training, conditioned dopamine signals did not similarly emerge in the DLS, even during Pavlovian conditioning with SNC dopamine neuron activation, which elicited robust DLS dopamine release. Together, our studies show broad dissociation in the fundamental prediction and reward-related information generated by different dopamine neuron populations and signaled by dopamine across the striatum. Further, they offer new insight into how larger-scale plasticity across the striatal network emerges during Pavlovian learning to coordinate behavior.</p>","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10996462/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81425126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-03DOI: 10.1101/2023.06.12.544663
Wei L Ng, E Hesper Rego
Antibiotic resistance in M. tuberculosis exclusively originates from chromosomal mutations, either during normal DNA replication or under stress, when the expression of error-prone DNA polymerases increases to repair damaged DNA. To bypass DNA lesions and catalyze error-prone DNA synthesis, translesion polymerases must be able to access the DNA, temporarily replacing the high-fidelity replicative polymerase. The mechanisms that govern polymerase exchange are not well understood, especially in mycobacteria. Here, using a suite of quantitative fluorescence imaging techniques, we discover that, as in other bacterial species, in M. smegmatis, the replicative polymerase, DnaE1, exchanges at a timescale much faster than that of DNA replication. Interestingly, this fast exchange rate depends on an actinobacteria-specific nucleoid-associated protein (NAP), Lsr2. In cells missing lsr2, DnaE1 exchanges less frequently, and the chromosome is replicated more faithfully. Additionally, in conditions that damage DNA, cells lacking lsr2 load the complex needed to bypass DNA lesions less effectively and, consistently, replicate with higher fidelity but exhibit growth defects. Together, our results show that Lsr2 promotes dynamic flexibility of the mycobacterial replisome, which is critical for robust cell growth and lesion repair in conditions that damage DNA.
结核杆菌的抗生素耐药性完全源于染色体突变，要么是在正常 DNA 复制过程中，要么是在应激状态下，此时易出错 DNA 聚合酶的表达增加，以修复受损 DNA。为了绕过 DNA 病变并催化易出错 DNA 的合成，转座聚合酶必须能够进入 DNA，暂时取代高保真复制聚合酶。聚合酶交换的机制尚不十分清楚，尤其是在分枝杆菌中。在这里，我们利用一套定量荧光成像技术发现，与其他细菌物种一样，在烟曲霉菌中，复制聚合酶 DnaE1 的交换时标比 DNA 复制时标快得多。有趣的是，这种快速的交换速度取决于放线菌特异的核糖体相关蛋白（NAP）Lsr2。在缺少lsr2的细胞中，DnaE1的交换频率较低，而染色体的复制则更加可靠。此外，在损伤 DNA 的条件下，缺乏 lsr2 的细胞装载绕过 DNA 病变所需的复合物的效率较低，复制的保真度也较高，但却表现出生长缺陷。我们的研究结果表明，Lsr2促进了分枝杆菌复制体的动态灵活性，这对细胞的稳健生长以及在DNA受损条件下的病变修复至关重要：与许多其他病原体不同，结核杆菌的水平基因转移能力有限，而水平基因转移是产生抗生素耐药性的主要机制。因此，促进染色体诱变的机制在分枝杆菌中尤为重要。在这里，我们发现 Lsr2（一种核糖体相关蛋白）在模式分枝杆菌 M. smegmatis 的 DNA 复制和诱变过程中发挥着新的作用。我们发现，Lsr2能促进复制DNA聚合酶DnaE1在复制分叉处的快速交换率，并对DnaE2-ImuA'-ImuB转座复合物的有效装载非常重要。如果没有lsr2，M. smegmatis会更忠实地复制染色体，并以较低的速度获得对利福平的抗性，但代价是在DNA损伤剂面前生存能力受损。总之，我们的研究成果证明，Lsr2 是导致分枝杆菌产生抗药性的一个潜在因素。
{"title":"A nucleoid-associated protein is involved in the emergence of antibiotic resistance by promoting the frequent exchange of the replicative DNA polymerase in <i>M. smegmatis</i>.","authors":"Wei L Ng, E Hesper Rego","doi":"10.1101/2023.06.12.544663","DOIUrl":"10.1101/2023.06.12.544663","url":null,"abstract":"<p><p>Antibiotic resistance in <i>M. tuberculosis</i> exclusively originates from chromosomal mutations, either during normal DNA replication or under stress, when the expression of error-prone DNA polymerases increases to repair damaged DNA. To bypass DNA lesions and catalyze error-prone DNA synthesis, translesion polymerases must be able to access the DNA, temporarily replacing the high-fidelity replicative polymerase. The mechanisms that govern polymerase exchange are not well understood, especially in mycobacteria. Here, using a suite of quantitative fluorescence imaging techniques, we discover that, as in other bacterial species, in <i>M. smegmatis</i>, the replicative polymerase, DnaE1, exchanges at a timescale much faster than that of DNA replication. Interestingly, this fast exchange rate depends on an actinobacteria-specific nucleoid-associated protein (NAP), Lsr2. In cells missing <i>lsr2</i>, DnaE1 exchanges less frequently, and the chromosome is replicated more faithfully. Additionally, in conditions that damage DNA, cells lacking <i>lsr2</i> load the complex needed to bypass DNA lesions less effectively and, consistently, replicate with higher fidelity but exhibit growth defects. Together, our results show that Lsr2 promotes dynamic flexibility of the mycobacterial replisome, which is critical for robust cell growth and lesion repair in conditions that damage DNA.</p>","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10802252/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86388738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-07DOI: 10.1080/07377363.2023.2222247
Catherine A. Cherrstrom, Carrie J. Boden, Todd Sherron
{"title":"Nontraditional Students and Credit for Prior Learning—Analytical Thinking, Clout, Drives, and Motives","authors":"Catherine A. Cherrstrom, Carrie J. Boden, Todd Sherron","doi":"10.1080/07377363.2023.2222247","DOIUrl":"https://doi.org/10.1080/07377363.2023.2222247","url":null,"abstract":"","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46453227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.1080/07377363.2023.2218580
Kit W. Cho, Dana Kongo
{"title":"The Relations Among Math Anxiety, Math Self-Construct, and Math Achievement in Older and Underserved Minority Students","authors":"Kit W. Cho, Dana Kongo","doi":"10.1080/07377363.2023.2218580","DOIUrl":"https://doi.org/10.1080/07377363.2023.2218580","url":null,"abstract":"","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43431650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-08DOI: 10.1080/07377363.2023.2196647
Heidi Boldway, Elizabeth Valenti, M. Zafonte
{"title":"Examining the Perception of Military Culture in the Undergraduate University Classroom","authors":"Heidi Boldway, Elizabeth Valenti, M. Zafonte","doi":"10.1080/07377363.2023.2196647","DOIUrl":"https://doi.org/10.1080/07377363.2023.2196647","url":null,"abstract":"","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42545620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-18DOI: 10.1080/07377363.2023.2191303
Leslie Gordon, Emily C. Chen-Bendle
{"title":"The Formation and Benefits of Communal Cohorts in an EdD Program","authors":"Leslie Gordon, Emily C. Chen-Bendle","doi":"10.1080/07377363.2023.2191303","DOIUrl":"https://doi.org/10.1080/07377363.2023.2191303","url":null,"abstract":"","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49409205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-04DOI: 10.1080/07377363.2023.2203072
Mary s. Bonhomme
{"title":"Notes and Trends","authors":"Mary s. Bonhomme","doi":"10.1080/07377363.2023.2203072","DOIUrl":"https://doi.org/10.1080/07377363.2023.2203072","url":null,"abstract":"","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":"71 1","pages":"237 - 240"},"PeriodicalIF":1.2,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42306082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-04DOI: 10.1080/07377363.2021.2023989
Safietou Sagna, Annemarie Vaccaro
Abstract Adult students and are a rapidly growing population in U.S. higher education. Yet limited scholarship has centered on the voices of adult learners and explored the complex roles that family play in their decisions to enroll and their motivations to persist in college. This study begins to fill that gap. In a grounded theory study using individual interviews with 31 adult students at a continuing education campus in the northeast United States, we documented the complicated roles family played in adult student motivation, success, and persistence. Three grounded theory categories emerged from this study: (a) family as a source of motivation, inspiration, and pride; (b) family as a source of tangible support; and (c) family as a challenge. We suggest numerous ways that higher education institutions can use these findings to foster success and persistence for adult students.
{"title":"“I Didn’t Just Do It for Myself”: Exploring the Roles of Family in Adult Learner Persistence","authors":"Safietou Sagna, Annemarie Vaccaro","doi":"10.1080/07377363.2021.2023989","DOIUrl":"https://doi.org/10.1080/07377363.2021.2023989","url":null,"abstract":"Abstract Adult students and are a rapidly growing population in U.S. higher education. Yet limited scholarship has centered on the voices of adult learners and explored the complex roles that family play in their decisions to enroll and their motivations to persist in college. This study begins to fill that gap. In a grounded theory study using individual interviews with 31 adult students at a continuing education campus in the northeast United States, we documented the complicated roles family played in adult student motivation, success, and persistence. Three grounded theory categories emerged from this study: (a) family as a source of motivation, inspiration, and pride; (b) family as a source of tangible support; and (c) family as a challenge. We suggest numerous ways that higher education institutions can use these findings to foster success and persistence for adult students.","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":"71 1","pages":"168 - 182"},"PeriodicalIF":1.2,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44502909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-04DOI: 10.1080/07377363.2021.2024000
Yan Yin Ho, Eun-Young Yeo, Dhaniah Suhana Binte Mohammad Wijaya
Abstract The increasing number of adult learners in higher education is a trend that has been observed in recent years. An impetus for this trend is the need for upskilling and re-skilling in order to stay relevant and employable in today’s world of globalised knowledge. However, finding uninterrupted blocks of time to study in adult learners’ busy schedules may be challenging because of their many other commitments and responsibilities. Bite-sized learning, through the utilisation of micro-learning activities that learners can access anytime and anywhere on their mobile devices, is one method of helping adult learners better manage their studies and learn more effectively. Before adult educators put in the resources to develop bite-sized learning activities, it is nonetheless important to ascertain that adult learners would indeed utilise such provisions. This article discusses the results of a study conducted to investigate the utilisation of bite-sized learning by adult learners enrolled in a part-time undergraduate degree programme. Specifically, the study examined whether adult learners utilised bite-sized learning activities during pockets of “down time” in their busy schedules, especially during the daytime, since adult learners tend to study at night after work or over the weekends. The results showed that adult learners were keen to learn from bite-sized learning activities during these pockets of down time. Implications of the results and directions for future investigation, including the aptness of bite-sized learning in today’s COVID-19 situation, are also discussed.
{"title":"Turning Coffee Time into Teaching Moments Through Bite-Sized Learning for Adult Learners","authors":"Yan Yin Ho, Eun-Young Yeo, Dhaniah Suhana Binte Mohammad Wijaya","doi":"10.1080/07377363.2021.2024000","DOIUrl":"https://doi.org/10.1080/07377363.2021.2024000","url":null,"abstract":"Abstract The increasing number of adult learners in higher education is a trend that has been observed in recent years. An impetus for this trend is the need for upskilling and re-skilling in order to stay relevant and employable in today’s world of globalised knowledge. However, finding uninterrupted blocks of time to study in adult learners’ busy schedules may be challenging because of their many other commitments and responsibilities. Bite-sized learning, through the utilisation of micro-learning activities that learners can access anytime and anywhere on their mobile devices, is one method of helping adult learners better manage their studies and learn more effectively. Before adult educators put in the resources to develop bite-sized learning activities, it is nonetheless important to ascertain that adult learners would indeed utilise such provisions. This article discusses the results of a study conducted to investigate the utilisation of bite-sized learning by adult learners enrolled in a part-time undergraduate degree programme. Specifically, the study examined whether adult learners utilised bite-sized learning activities during pockets of “down time” in their busy schedules, especially during the daytime, since adult learners tend to study at night after work or over the weekends. The results showed that adult learners were keen to learn from bite-sized learning activities during these pockets of down time. Implications of the results and directions for future investigation, including the aptness of bite-sized learning in today’s COVID-19 situation, are also discussed.","PeriodicalId":44549,"journal":{"name":"Journal of Continuing Higher Education","volume":"71 1","pages":"183 - 198"},"PeriodicalIF":1.2,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42331344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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