Check out some of the papers that were recently published by DMCBH members:
Hee Yeon Im, Deborah Giaschi: Developmental changes in MEG oscillatory activity during visuomotor adaptation: Differential maturation of feedforward and feedback-related mechanisms
Journal: NeuroImage
Visuomotor adaptation is the ability to recalibrate movements with visual feedback, and this adaptation matures throughout childhood. This study investigated the neural mechanisms that dictate this development. Researchers investigated brain scans in children (6-12 years old) and in adults as they performed visual cursor tasks. Results indicated that both child and adult group participants showed adaptation in cursor movements, but older participants were faster and more accurate. The findings show that different aspects of movement adaptation mature at different rates, with brain networks involved in planning and executing movements continuing to develop throughout childhood.
Michael Hayden: Sex-dependent mild cardiac dysfunction and neurometabolic abnormalities in a model of Huntington’s disease
Journal: Disease Models & Mechanisms
Huntington’s disease (HD) is a neurodegenerative disease that affects psychiatric, motor, and cognitive systems, but its impact on other organ systems is poorly understood. In this study, researchers studied cardiac function and brain metabolism in both male and female mice models of HD using ultrasounds and magnetic resonance and found mild cardiac dysfunction and alterations in brain metabolism. Some effects were similar in male and females, while some differed by sex or region. These findings are consistent with clinical observations in human HD and support the use of mice models to investigate Huntington’s disease’s effects on multiple organ systems.
Fidel Vila-Rodriguez: Dorsolateral Prefrontal rTMS Symptom Cluster Response Trajectories for Depression
Journal: JAMA Network Open
Repetitive transcranial magnetic stimulation (rTMS) is a treatment for depression that has not responded to other therapies, but patients experience varying levels of benefit. In this study, researchers analyzed data from 388 adults who received rTMS to identify patterns in how different depression symptoms changed during treatment. They identified four response groups: those who experienced substantial improvement, those with partial improvement and either higher or lower anxiety, and those with minimal improvement. Participants’ age, initial anxiety and mood symptoms, and use of benzodiazepines were associated with their treatment response. The findings suggest that looking at individual symptom patterns, rather than overall depression scores alone, may help identify which patients are more likely to benefit from rTMS and support more personalized treatment approaches. Further research is needed to confirm these associations.
Tim Murphy: Real-time closed-loop feedback system for mouse mesoscale cortical signal and movement control
Journal: eLife
Researchers developed an open-source system that allows mice to learn to control specific brain activity or movements through real-time feedback and rewards. The system includes two approaches: closed-loop neurofeedback (CLNF), which monitors activity in targeted brain regions and provides sound cues to help mice learn to increase or decrease that activity, and closed-loop movement feedback (CLMF), which tracks specific body movements and provides sound cues and rewards when mice reach movement targets. In experiments, both male and female mice learned to modify their brain activity and improved their ability to perform targeted movements over several days. They also adapted quickly when task requirements changed. The findings demonstrate a new tool for studying how the brain learns and adapts, with potential applications in understanding motor learning and recovery after brain injury.
Brian Christie, Jodie Gawryluk: Impaired Synaptic Plasticity in a Rodent Model of Intimate Partner Violence-Related Brain Injury
Journal: Hippocampus
Intimate partner violence mainly affects women and can cause brain injuries through physical trauma, such as a concussion, as well as reduced oxygen and blood flow to the brain during non-fatal strangulation. Both types of injury may affect learning and memory. In this study, researchers examined these effects in female rats, comparing the impact of concussion, strangulation-related oxygen deprivation, and a combination of both. They found that each type of injury impaired a process in the hippocampus, a brain region important for learning and memory. Although the researchers expected the combined injuries to cause greater impairment, they found that even a single injury was enough to disrupt normal brain processes involved in learning and memory. The findings highlight the potential neurological consequences of intimate partner violence and the importance of understanding its effects on brain health.
Mypinder Sekhon, Cheryl Wellington: Quantification of blood-based neurovascular unit biomarkers: an analytical platform comparison study
Journal: Resuscitation Plus
After cardiac arrest, reduced blood flow and oxygen can damage the brain, causing hypoxic-ischemic brain injury (HIBI). Blood-based biomarkers can help doctors assess brain cell damage and predict patient outcomes, but results may vary depending on the testing technology used. In this study, researchers compared four biomarkers of brain injury—glial fibrillary acidic protein (GFAP), neurofilament-light (Nf-L), tau and ubiquitin carboxyl hydrolase L-1 (UCH-L1)—across three testing platforms: the Simoa HD-X, ARGO HT and i-STAT Alinity. The Simoa HD-X and ARGO HT laboratory platforms showed very strong agreement across all four biomarkers, while the i-STAT Alinity point-of-care device showed less consistent agreement for GFAP and UCH-L1. These findings highlight the importance of validating each testing platform and establishing device-specific reference thresholds to ensure blood biomarker results are interpreted accurately when assessing brain injury following cardiac arrest.
Mark Cembrowski: Spatiotemporal development of sparse excitatory neuronal types within the deep mouse cortex
Journal: iScience
Understanding how different types of brain cells develop and organize themselves is important for learning how the brain forms and functions. In this study, researchers used a technique called single-cell spatial transcriptomics to track more than 1.5 million cells in the developing mouse brain across four stages of development, in both males and females. They focused on two groups of deep cortical neurons, found in regions called the subplate and claustrum, which were previously thought to develop in similar ways. Instead, they discovered that these cells have distinct origins and follow different developmental timelines and patterns of gene activity. The findings reveal important differences in how these brain regions develop and provide a valuable resource for future research into brain development.
Journal: Neuropharmacology
Cognitive difficulties during recovery from alcohol use disorder may make it harder to maintain abstinence, but the lasting effects of alcohol on different thinking abilities are not fully understood. In this study, researchers examined rats with a history of long-term alcohol exposure, testing their ability to adapt to changing rules and remember information during periods of abstinence. While the rats performed similarly to control animals on most tasks, those with a history of alcohol exposure had more difficulty changing their behaviour in response to new feedback and showed reduced working memory accuracy when tasks became more challenging. Researchers also identified changes in the composition of certain neuropeptides, called enkephalins, in the brain’s medial prefrontal cortex, a region involved in decision-making and cognitive control. The findings suggest that long-term alcohol exposure can leave lasting effects on cognitive flexibility and memory, with some individuals potentially more vulnerable than others.
Vesna Sossi, Jon Stoessl: A review of FDG-PET biomarker analysis methods in Parkinson’s disease
Journal: Journal of Parkinson’s Disease
Diagnosing Parkinson’s disease (PD) in its early stages and distinguishing it from other movement disorders can be challenging. Brain imaging using a technique called fluorodeoxyglucose positron emission tomography (FDG-PET) can help by measuring how the brain uses glucose, providing insight into brain activity and function. In this review, researchers examine different ways of analyzing FDG-PET scans to identify patterns of brain activity associated with Parkinson’s disease. They discuss how approaches ranging from measuring activity in individual brain regions to using artificial intelligence and machine learning can help improve diagnosis, distinguish between movement disorders and provide a better understanding of the brain changes underlying the disease.
Mypinder Sekhon, Noah Silverberg, William Panenka, Thalia Field, Cheryl Wellington: Feasibility of multi-domain data acquisition in patients at risk for hypoxic-ischemic brain injury following cardiac arrest: a prospective cohort study
Journal: Resuscitation Plus
Brain injury caused by a lack of oxygen and blood flow following cardiac arrest can lead to lasting neurological complications. Understanding how these injuries affect patients over time requires combining different types of information, including brain imaging, electrical brain activity and blood-based biomarkers. In this study, researchers assessed the feasibility of collecting these data from 30 patients following cardiac arrest, both during their hospital stay and six months after discharge. They successfully collected early blood samples from most participants and obtained brain imaging for all, but faced challenges completing some tests, including ultrasound assessments and longer-term MRI scans. Follow-up was also more successful when patients could participate remotely or with help from caregivers. The findings identify practical challenges and opportunities for tracking brain injury and recovery over time, helping guide the design of future studies to improve understanding and prediction of patient outcomes.
Sarah Kraeutner: Enhanced agonist intermuscular coherence supports improvements in force steadiness driven by motor imagery training during aging
Journal: Behavioural Brain Research
Motor imagery training (MIT), which involves mentally rehearsing a movement without physically performing it, may help improve muscle control, but its benefits in older adults are not well understood. In this study, researchers compared younger and older adults who completed five sessions of mentally rehearsing an everyday arm movement. Both groups showed improved ability to maintain steady muscle force after training, while older adults also showed changes in communication between muscles that may help support better movement control. Improvements also carried over to a different arm movement that participants had not practised. These findings suggest that repeated mental rehearsal can improve motor control in both younger and older adults and may help reduce some age-related declines in movement ability.
Kiran Soma: The parental intestinal microbiome modulates systemic and local glucocorticoid levels in neonatal mice
Journal: PLoS One
The gut microbiome, the community of microorganisms living in the intestines, may influence how the body produces and regulates hormones involved in stress and immune function. In this study, researchers investigated whether differences in gut bacteria could affect levels of glucocorticoids, steroid hormones that help regulate stress and immune responses, during early development. They compared newborn mice whose parents had different gut microbiome compositions and found that even relatively subtle differences in gut bacteria were associated with changes in glucocorticoid levels in the blood and immune organs. Mice with one microbiome profile also had higher levels of several short-chain fatty acids, substances produced by gut bacteria that may influence hormone regulation. These findings suggest that the gut microbiome can shape hormone activity early in life, even without major changes to the overall diversity of gut bacteria.
Kota Mizumoto: LIN-44/Wnt controls developmental neurite pruning via UNC-43/CaMKII and PKC-2/PKC in Caenorhabditis elegans
Journal: PNAS USA
As the brain develops, neurons refine their connections by removing parts of their branches, a process called neurite pruning that helps shape functional neural circuits. However, the molecular signals that control this process are not fully understood. In this study, researchers used the roundworm C. elegans to investigate how specific neurons remove unnecessary branches during development. They identified an important role for Wnt-calcium signalling, a communication pathway that regulates calcium activity inside cells, in controlling neurite pruning. They also found that human CaMKIIA, a protein involved in this pathway, could trigger pruning in the worms, while mutations in human CaMKII genes associated with intellectual disabilities disrupted this function. The findings provide new insight into the molecular mechanisms that guide nervous system development and suggest a potential link between disrupted neurite pruning and neurodevelopmental conditions.
Jessica Rosin: Fetal microglia show region-specific and morphology-dependent sex differences in their responsiveness to prenatal maternal stress
Journal: Journal of Neuroinflammation
Prenatal stress may influence brain development by affecting microglia, immune cells in the brain that help shape developing neural connections. In this study, researchers examined how exposure to cold stress during pregnancy affected microglia in the developing brains of mouse embryos. Using an adapted version of the MicrogliaMorphology analysis tool, they assessed changes in the shape and activity of these cells. They found that maternal stress altered microglia in a specific region of the hypothalamus involved in regulating social behaviours. These changes occurred in male embryos but not females and included increased interactions between microglia and neurons, as well as greater activity in which microglia engulf and remove cellular material. The findings suggest that certain brain regions may be particularly sensitive to stress during pregnancy and provide insight into how prenatal stress may influence brain development differently in males and females.
Journal: Biomolecules
Amyotrophic lateral sclerosis (ALS) is a progressive disease that damages motor neurons and disrupts communication across the nervous system. This review examined possible connections between two processes implicated in ALS: changes in serotonin signalling, which helps regulate brain and nerve activity, and dysfunction of a protein called TDP-43, which is involved in maintaining normal cell function. Reviewing 14 published studies, researchers found evidence that serotonin signalling is disrupted early in ALS and that these changes may be linked to the abnormal accumulation of TDP-43 in nerve cells. The relationship may work in both directions, with TDP-43 dysfunction impairing serotonin signalling and reduced serotonin potentially contributing to TDP-43 abnormalities. Although more research is needed to establish how these processes interact, understanding their relationship could reveal new targets for future ALS treatments.
Sam Fereshtehnejad: Thalamic quantitative susceptibility mapping and susceptibility source separation: a critical narrative review of evidence and interpretation
Journal: Frontiers in Neurology
Quantitative susceptibility mapping (QSM) is an MRI technique that measures magnetic properties of brain tissue, which can provide clues about changes in its composition. This review examines how QSM, including newer methods that separate different sources of magnetic signals, can help researchers study the thalamus in healthy aging and neurological diseases. Findings suggest that overall magnetic susceptibility in the thalamus is often reduced in people with multiple sclerosis, while results in Alzheimer’s and Parkinson’s diseases are less consistent. Separating magnetic signals may reveal changes that conventional QSM measurements miss, but these signals do not directly identify specific substances such as iron, myelin or disease-related proteins. Differences in imaging methods and data analysis also make studies difficult to compare. Although these techniques show promise as research tools, further validation, standardized methods and long-term studies are needed before they can be used reliably to support clinical diagnosis or monitor disease progression.
Khaled Abdelrahman: Protocol for generating highly enriched sex-specific primary cortical astrocytes from individual mouse pups
Journal: STAR Protocols
Researchers developed a protocol to isolate and grow highly enriched populations of astrocytes (support cells in the brain) from individual newborn mice. The method uses a series of steps to separate astrocytes from other brain cells and confirm each mouse’s sex and genetic makeup. By keeping samples from individual mice separate rather than combining them, researchers can study how sex and genetic differences influence astrocyte function without the potential effects of pooled samples.
Blair Leavitt: A novel minimally humanized mouse model of aniridia for preclinical evaluation of CRISPR gene editing strategies
Journal: Frontiers in Genome Editing
Researchers developed and validated a new genetically modified mouse model of aniridia, a rare inherited condition that causes vision loss and is most often linked to changes in the PAX6 gene. The model carries a version of the gene adapted to include human DNA and a common disease-causing variant, allowing researchers to test potential treatments against the same genetic change found in patients. The mice developed eye abnormalities consistent with aniridia, supporting the model’s validity. As an initial test, researchers used CRISPR-based gene editing, specifically an approach called adenine base editing, to correct a small proportion of the disease-causing variant in laboratory-grown neurons. Although the level of correction was modest, the model provides a new tool for evaluating CRISPR gene-editing therapies and other potential treatments for aniridia and other genetic diseases.
Teresa Liu-Ambrose, Robin Hsiung: Exercise and white matter hyperintensities: a randomized clinical trial
Journal: Brain Communications
A 12-month clinical trial involving 89 adults aged 55 and older with subcortical vascular cognitive impairment (SVCI), a condition that affects thinking and memory and increases dementia risk, examined whether regular strength training could slow changes in the brain. Participants took part in either twice-weekly progressive resistance training or a balance and flexibility program. Overall, strength training did not significantly reduce white matter hyperintensities (WMHs), areas of brain damage associated with small blood vessel disease. However, improvements were seen in specific brain regions, and further analysis found reduced WMH volume across the brain among women in the strength-training group, but not men. Higher levels of vascular endothelial growth factor, a protein involved in blood vessel growth and repair, were also associated with lower WMH volume. These findings suggest that strength training may help slow brain changes associated with vascular cognitive impairment, although further research is needed to confirm the effects.
Jason Snyder, Fidel Vila-Rodriguez: Chronic Electroconvulsive Shock Disrupts Hippocampal Physiology and Impairs Associative Memory in Mice
Journal: Hippocampus
Electroconvulsive therapy (ECT) is an effective treatment for depression, but it can also affect memory. To better understand these effects, researchers studied how repeated electroconvulsive shock (ECS) treatment influences brain activity and memory in male and female mice. They found that ECS altered communication between brain cells in the hippocampus, a region important for learning and memory, and reduced brain activity during exploration. The treated mice also had difficulty remembering the relationship between an object and the place or situation in which they encountered it, although their ability to recognize individual objects and locations remained intact. These findings suggest that ECS can disrupt hippocampal function and certain types of memory, helping researchers better understand the biological mechanisms behind memory difficulties sometimes experienced by patients receiving ECT.
Teresa Liu-Ambrose: Sedentary behavior as a Gut-Brain metabolic state
Journal: Brain, Behavior, and Immunity
This review explores how sedentary behaviour, particularly prolonged periods of uninterrupted sitting, may affect brain health through its interactions with the gut microbiome. Rather than viewing sedentary behaviour simply as a lack of physical activity, the authors highlight it as a distinct metabolic state that may have its own effects on the body. Although research has linked prolonged sitting with poorer cardiometabolic and brain health, its relationship with the gut microbiome is not yet well understood. The authors outline possible pathways involving gut-produced substances, inflammation and communication between the gut and brain that could influence cognition and mood. They emphasize that more research is needed to establish whether sedentary behaviour directly changes the gut microbiome and how these changes might affect brain health. Future studies should examine patterns of sitting alongside physical activity, gut microbiome composition, blood markers and measures of cognitive and emotional health. This work could help inform more targeted lifestyle recommendations to support long-term brain health.
Helen Tremlett: Development and validation of a social vulnerability index for use in Canadians living with multiple sclerosis
Journal: Multiple Sclerosis and Related Disorders
Researchers developed a new tool to measure social vulnerability among people living with multiple sclerosis (MS), recognizing that factors such as income, social support and access to healthcare can influence health outcomes. Using survey responses from 932 people with MS across Canada, they created an index that combines several social and economic factors into a single score. Higher vulnerability scores were associated with poorer general and mental health, greater difficulty maintaining social connections and more severe disability. The findings suggest that this index could help identify people with MS who may face additional social barriers to good health and inform more targeted support and healthcare interventions.
Teresa Liu-Ambrose, Robin Hsiung: Interaction of physical fitness and resting state functional connectivity on global cognitive function in older adults with mild cognitive impairment
Journal: Journal of Alzheimer’s Disease
A study of 95 older adults with mild cognitive impairment (MCI), a condition that can precede Alzheimer’s disease, examined how physical fitness relates to brain activity and cognitive function. Researchers measured participants’ cardiovascular fitness and muscle strength, and used brain scans to assess communication between different brain networks. They found that higher cardiovascular fitness influenced the relationship between brain network connectivity and cognitive performance. In particular, people with better cardiovascular fitness showed better cognitive function in association with stronger connections between the limbic network, which is involved in memory and emotion, and other brain networks. Muscle strength did not show the same relationship. These findings suggest that cardiovascular fitness may help support cognitive function in older adults with MCI, although further research is needed to determine whether improving fitness can help preserve brain health.
Ujendra Kumar: Cannabidiol Regulates Amyloid-β Plaque Deposition and Astrogliosis in the 5xFAD Transgenic Mouse Model
Journal: Journal of molecular neuroscience
Researchers investigated the effects of cannabidiol (CBD), a non-intoxicating compound found in cannabis, in a mouse model of Alzheimer’s disease. The disease is characterized by the buildup of amyloid-beta plaques and inflammation in the brain. In treated mice, CBD reduced the accumulation of amyloid plaques and activated support cells called astrocytes, which can contribute to brain inflammation. The researchers also observed changes in the activity of several cell receptors and improved regulation of a cellular signalling pathway involved in brain function. In particular, increased levels of the CB2 and PPARγ receptors may help explain CBD’s effects. These findings provide insight into how CBD may influence Alzheimer’s-related brain changes, but further research is needed to determine whether these effects could translate into treatments for people.
Sophia Frangou, Liisa Galea: Lifestyle and BrainAGE in adult depression
Journal: Translational Psychiatry
Researchers examined how lifestyle and physical health may influence brain ageing in people with a history of depression. Using health and brain imaging data from more than 37,000 UK adults, including 896 with depression, they identified four lifestyle and fitness profiles among those with depression: active with a balanced diet, health-conscious and active, sedentary with higher metabolic risk, and moderately active but physically frail. Although depression overall was associated with slightly accelerated brain ageing, the effects varied between groups. People in the sedentary, higher-risk group showed additional signs of accelerated ageing in brain regions involved in thinking, memory and emotional processing. They also reported the highest levels of depressive symptoms. The findings highlight that people with depression have different lifestyle and health profiles, which may influence brain ageing, and suggest that tailoring interventions to individual needs could help support long-term brain health.
Jeff Dong: Aging-enhanced accumulation of fibroblasts excludes oligodendrocytes in demyelinated lesions
Journal: Journal of Inflammation
This study found that fibroblasts, cells involved in tissue repair and scar formation, accumulate in areas of myelin damage in the spinal cords of mice. Researchers found that these cells interact with immune cells and oligodendrocyte precursor cells, which are responsible for producing the cells that restore the protective myelin coating around nerve fibres. However, areas with high numbers of fibroblasts had fewer oligodendrocyte precursor cells, suggesting that fibroblast accumulation may interfere with the repair process. This effect became more pronounced with age: older mice had greater fibroblast accumulation and stronger exclusion of repair cells from affected areas. The researchers also identified fibroblasts in multiple sclerosis (MS) lesions using publicly available human tissue data, suggesting that similar processes may occur in people with MS. The findings point to fibroblasts as potential contributors to impaired myelin repair, particularly with aging, and suggest that controlling their activity could help support the brain and spinal cord’s natural repair processes.
Noah Silverberg, William Panenka: Cognitive behavioural therapy compared to compensatory strategy training for persisting memory symptoms after concussion in adults: protocol for a randomised controlled trial
Journal: BMJ Open
This study will compare two approaches to treating persistent memory difficulties after concussion: cognitive behavioural therapy tailored to memory concerns (CBT-Mem) and compensatory strategy training (CST), the current standard approach to cognitive rehabilitation. While CST teaches practical techniques to manage memory challenges, CBT-Mem aims to address psychological factors that may contribute to ongoing symptoms. In this multisite clinical trial, adults aged 18–59 who continue to experience memory problems 6–36 months after a concussion will be randomly assigned to one of the two treatments or a usual-care waitlist group. Both treatments will be delivered through 10 weekly videoconference sessions. Researchers will assess participants’ perceptions of their memory functioning 20 weeks after enrolment to determine whether either approach is effective and how the two compare. As this paper describes the study protocol, results on treatment effectiveness are not yet available.
Michael Hayden, Lynn Raymond: Antidopaminergic Medications and Clinical Outcomes in Huntington Disease: Evidence From the PROOF-HD Placebo-Controlled Trial
Journal: Neurology
This study examined whether antidopaminergic medications, including antipsychotics and VMAT2 inhibitors, are associated with faster disease progression in people with Huntington disease (HD). Researchers analysed data from 247 participants in the placebo group of the PROOF-HD clinical trial, comparing those taking these medications with those who were not. Participants taking antidopaminergic medications showed greater worsening over time across several measures of motor function, thinking skills and ability to manage daily activities. These differences were evident from about nine months into the study, with similar patterns seen across different medication types and doses. However, because this was a retrospective analysis rather than a controlled comparison of medication use, the researchers cannot rule out the possibility that people taking these medications had more severe symptoms to begin with. The findings highlight the importance of accounting for medication use when designing and interpreting HD clinical trials and point to the need for further research into how these treatments may relate to disease progression.
Amani Hariri: Spatial decoupling of recognition and signaling in aptamer switches via tri-strand intermolecular competition
Journal: Science Advances
Researchers have developed a new DNA-based biosensor design, called the Competitor Bridge Aptamer (CoBrA), that could provide a more reliable way to detect different types of molecules in biological samples. The system uses specially designed DNA structures called aptamers, which recognize specific target molecules and trigger a predictable change in the position of fluorescent signals. Unlike conventional sensors, which can produce inconsistent signals depending on how the DNA folds, CoBrA separates target recognition from signal generation. Using dopamine and cortisol as test cases, the researchers demonstrated that the system could detect both molecules in buffer solutions, blood serum and artificial cerebrospinal fluid. The design could potentially be adapted to other sensing technologies, including those that use electrical signals rather than fluorescence. This modular approach may help advance the development of more versatile and reliable biosensors for measuring a wider range of molecules in biological samples.
Journal: eClinicalMedicine
This study evaluated whether the Get going After concussIoN (GAIN) program could reduce persistent post-concussion symptoms in adults aged 18–60. The program, which had previously shown promising results in younger people, was tested in 310 adults who received either GAIN alongside enhanced usual care or enhanced usual care alone. After three months, participants who received GAIN showed a slightly greater reduction in concussion symptoms, but the difference between the groups was not statistically significant. The program did, however, reduce unhelpful beliefs and behaviours related to concussion symptoms, and participants reported high satisfaction. It did not lead to greater improvements in psychological distress or overall physical and mental health. No serious adverse events were reported. While the study did not confirm that GAIN reduces persistent symptoms more effectively than usual care alone, the findings suggest it may help people develop healthier ways of understanding and managing their symptoms.
Zach Pennington: An amygdala to anterior hypothalamic circuit gates stress sensitivity
Journal: Nature
This study investigated how previous stressful experiences can make the brain more sensitive to future stress. Using mice, researchers identified a previously overlooked brain region called the anterior hypothalamic nucleus (AHN), which showed increased activity in animals that had experienced earlier stress. They found that the AHN became more responsive to negative experiences and developed stronger connections with brain networks involved in detecting threats. Further experiments showed that reducing activity in the AHN, or blocking signals it receives from the amygdala, weakened the heightened stress response. Increasing AHN activity had the opposite effect. The findings identify a previously unrecognized brain circuit linking the amygdala and AHN that may help explain how earlier adversity changes the brain’s response to later stressful events. This pathway could offer new directions for understanding and developing treatments for stress-related conditions.
Milan Valyear: Dopamine signaling in the medial accumbens shell constrains the duration of reinforced actions
Journal: Cell Reports
This study reveals a previously unrecognized role for dopamine in regulating how long behaviours last. Using optogenetics to activate dopamine-producing nerve fibres in a specific brain region called the medial accumbens shell, researchers found that dopamine not only reinforces rewarding actions but also helps bring them to an end. Mice that received higher-frequency stimulation performed more, but shorter, lever presses to activate the dopamine pathway. They also ended bouts of licking sooner and restarted them more quickly. The researchers found that this effect was driven by dopamine D1 receptors. These findings suggest that dopamine has a dual role: it encourages reward-seeking behaviour while also limiting how long an individual action or bout of behaviour continues. This provides new insight into how the brain regulates the balance between persisting in and disengaging from rewarding activities.
