Publications by authors named "Bouret S"
Article Synopsis
- - The study investigates how ecology and social factors influence cognitive skills in primates by examining the size of specific brain regions related to metacognition and working memory in 16 primate species.
- - Researchers found the volume of the frontal pole (FP) and dorso-lateral prefrontal cortex (DLPFC) is significantly related to body size, daily travel distance, and population density, indicating both ecological and social constraints play a role in cognitive evolution.
- - The results suggest that ecological factors primarily drive brain region size, while social factors more strongly affect the FP, highlighting the importance of foraging and social interactions in the cognitive development of primates.
Article Synopsis
- The study investigates the role of intestinal gluconeogenesis (IGN) in regulating energy balance and the development of feeding circuits in the hypothalamus, particularly during the neonatal period.
- Researchers induced IGN in newborn mice by overexpressing the enzyme G6pc1 and studied the impact on hypothalamic feeding circuit development and sympathetic innervation of adipose tissues.
- Results showed that inducing IGN at birth led to changes in key hypothalamic circuits and better protection against metabolic issues from a high-fat diet, while later induction had no effect on these parameters.
Article Synopsis
- The brain manages mental effort during difficult decisions by balancing cognitive resources used against the expected costs and benefits of those decisions.
- A proposed computational model called online metacognitive control of decisions (oMCD) represents this resource allocation problem as a Markov Decision Process, allowing for optimal decision-making strategies.
- oMCD effectively explains key aspects of decision-making like choice, confidence, and response time, while aligning with existing research on value-based decision-making and related neurocognitive theories.
Article Synopsis
- The arcuate nucleus (ARH) in the hypothalamus is crucial for energy balance, as it detects metabolic hormones in the blood, but only a few neurons in this area can sense these signals due to a barrier involving the median eminence (ME).
- The study found that the proteoglycan aggrecan, produced by certain ARH neurons, establishes a diffusion gradient that limits the entry of these metabolic signals into the ARH, particularly during fasting when more aggrecan is deposited.
- Disrupting aggrecan deposits allows more blood-borne molecules to enter the ARH, leading to uncontrolled food intake, highlighting the importance of this diffusion barrier in the brain's metabolism regulation.
Article Synopsis
- - The rise in obesity and type 2 diabetes is notably affecting pregnant women, leading to increased use of low-calorie sweeteners (LCSs) to reduce calorie intake while still providing sweetness.
- - Research using a mouse model showed that male offspring from mothers consuming LCSs developed high body fat and glucose intolerance, with significant changes in brain circuits and pancreatic function.
- - A metabolite called phenylacetylglycine (PAG) was found to be elevated in the milk of LCS-fed mothers and their offspring, suggesting it may play a role in the negative metabolic and neurodevelopmental effects observed from maternal LCS consumption.
Article Synopsis
- Litter size significantly affects adult physiology in rodents, influencing their metabolism and overall health.
- Despite its importance, this variable is often underreported in scientific research, leading to gaps in understanding.
- The authors provide recommendations for researchers, funding bodies, journal editors, and animal suppliers to ensure litter size is consistently noted in studies.
Article Synopsis
- Humans and primates are thought to engage in strategic exploration, but the strategies used and the brain mechanisms behind this in monkeys are not well understood.
- A study was conducted using a sequential choice task to see if monkeys adjust their exploratory behavior based on potential future benefits from gathering information, especially when given counterfactual feedback about unchosen options.
- Results indicate that monkeys reduced their reliance on expected value in situations where exploration was advantageous, showing brain activity in specific regions (ACC/MCC and dlPFC) that help balance expected values against the benefits of exploring less favorable options and also involved a different circuitry (OFC) when learning from counterfactual outcomes.
Molecular control of the development of hypothalamic neurons involved in metabolic regulation.
J Chem Neuroanat
September 2022
Article Synopsis
- The hypothalamus is a key brain region that regulates behaviors and physiological processes, particularly through the arcuate nucleus (ARH) and lateral hypothalamic area (LHA) which are crucial for feeding and glucose management.
- Neuronal populations in these areas, including pro-opiomelanocortin (POMC) and agouti-related peptide (AgRP), develop from specific germinative cells during embryonic life and are influenced by various proteins and factors.
- Their development continues through specific signaling cues and processes, which help establish important neural connections necessary for regulating hunger and energy balance.
Article Synopsis
- The melanocortin system is essential for regulating food intake and energy balance, involving key components like pro-opiomelanocortin (POMC), melanocortin receptors (MC4Rs), and agouti-related peptide (AgRP).
- Deficiencies in POMC and MC4R lead to obesity, while a lack of AgRP is linked to leanness, highlighting the system's importance in managing body weight.
- The system's development starts during embryonic life and requires precise regulation of molecular and cellular factors; disruptions in this process can result in metabolic issues and chronic diseases later in life.
Article Synopsis
- Understanding the role of the locus coeruleus (LC) is important for studying behaviors like stress and vigilance, and cognitive processes like attention and decision making.
- Recent advancements in viral tools have improved our ability to study brain functions in rodents, but similar tools for primate research, especially in monkeys, are necessary for effective translational applications.
- The described pharmacogenetics approach using DREADD allows for selective and adjustable inactivation of LC neurons, enabling researchers to explore varying effects on cognitive functions and vigilance by modifying dosages of the DREADD activator, deschloroclozapine (DCZ).
Article Synopsis
- Early postnatal nutrition significantly affects the risk of developing metabolic diseases later in life, with leptin being a key hormone involved in growth.
- In a study using mice, researchers found that those overnourished after birth gained weight rapidly and struggled with metabolic issues as adults, but administering a leptin antagonist during early life helped normalize their fat and insulin levels.
- The findings suggest that reducing leptin's effects in neonatal mice can improve metabolic health long-term, highlighting a potential intervention for tackling obesity-related diseases.
Article Synopsis
- The locus coeruleus (LC), a brain stem noradrenergic nucleus, is linked to processes such as arousal, stress, attention, and recently, physical and cognitive effort.
- * Researchers studied LC activity in monkeys performing various tasks to understand the relationship between effort production, difficulty, and LC activation.
- * Findings reveal that LC neurons are activated during action initiation and force exertion, with activation levels correlating with the difficulty of tasks and the amount of effort required, highlighting the role of the noradrenergic system in how we manage effort in both physical and cognitive challenges.
Article Synopsis
- Dopamine (DA) is crucial for motivation, but the specific roles of D1-like (D1R) and D2-like (D2R) receptors in decision-making involving rewards versus costs are not fully understood.
- Research using drug manipulation and PET imaging on macaque monkeys revealed that blocking D1R or D2R impairs motivation related to rewards and increases the tendency to devalue rewards over time (delay discounting).
- The study found that blocking both receptors had a combined impact on delay discounting, indicating different mechanisms of DA that affect motivation, which could be relevant for understanding neurological and psychiatric conditions.
The survival of the species depends on two closely interlinked processes: the correct functioning of the reproductive system, and the balance between the energy needs of an individual and the supply of energy sources through feeding. These two processes are regulated in the hypothalamus, which produces neurohormones that control various physiological functions. Among these neurohormones, GnRH controls not only the maturation and function of the reproductive organs, including the ovaries and the testes, during puberty and in adulthood, but also sexual attraction.
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- The ventromedial nucleus of the hypothalamus (VMH) is essential for regulating energy balance and responds to fasting, but the underlying processes are not fully understood.
- Researchers focused on the role of autophagy, specifically the gene Atg7, in neurons of the VMH during fasting conditions.
- Their findings indicate that autophagy is activated by fasting, and loss of Atg7 disrupts leptin sensitivity and energy regulation, highlighting the importance of VMH autophagy in maintaining energy homeostasis during periods of starvation.*
The discovery of insulin in 1921 was a major breakthrough in medicine and for therapy in patients with diabetes. The dramatic rise in the prevalence of overweight and obesity has been tightly linked to an increased prevalence of gestational diabetes mellitus (GDM), which poses major health concerns. Babies born to GDM mothers are more likely to develop obesity, type 2 diabetes and cardiovascular disease later in life.
View Article and Find Full Text PDFBalancing costs and benefits in primates: ecological and palaeoanthropological views.
Philos Trans R Soc Lond B Biol Sci
March 2021
Article Synopsis
- Balancing costs and benefits is crucial for species like primates, influencing their life history, reproductive strategies, and feeding behaviors in complex environments.
- Decision-making in these species may involve cognitive processes similar to humans, but data on this relationship is limited, particularly in how it relates to socio-ecological challenges.
- The review discusses how modern primates and extinct hominins use cognitive skills to manage resources and navigate competing demands effectively in their social and ecological contexts.
Article Synopsis
- The trade-off between effort and reward significantly influences behavior and is linked to disorders like depression and Parkinson's disease.
- A study with rhesus monkeys showed that lowering noradrenaline levels led to decreased effort exertion, affecting decision-making without impacting reward sensitivity.
- Computational modeling indicated that "effort" could explain resource allocation for actions and decision-making, demonstrating noradrenaline's crucial role in processing effort.
Article Synopsis
- The locus coeruleus (LC), a small but important area in the brainstem, plays a major role in the brain's noradrenergic system, which affects various cognitive and behavioral functions.
- Despite 60 years of research, the LC has remained difficult to fully understand, but recent advancements in neuroscience techniques are leading to new insights into its organization and roles.
- LC neurons not only respond to general autonomic arousal but also have subpopulations that can target specific cognitive processes, indicating a more complex influence on brain networks than previously thought.
Article Synopsis
- Hypothalamic neurons that produce gonadotropin-releasing hormone (GnRH) travel from the nose to the hypothalamus guided by specific signals, including semaphorins and neuropilins.
- Removing neuropilin-1 in these new GnRH neurons improves their survival and migration, leading to an increase in their numbers and unusual clustering in the accessory olfactory bulb.
- In female mice, this alteration causes early weight gain, premature attraction to male scents, and the onset of puberty sooner than normal, indicating that GnRH neurons may influence the timing of puberty by regulating body fat and behavior.
Article Synopsis
- Noradrenaline and dopamine both influence behavior but their specific roles in motivation are not well understood.
- A study analyzed the activity of noradrenergic neurons and dopaminergic neurons in monkeys as they performed tasks for rewards, finding both were linked to task engagement.
- Results showed that noradrenaline neurons not only predicted future engagement after failure but were also more active during new task conditions, highlighting their role in adapting behavior to changing situations.
Sugar-sweetened beverage consumption is a known independent risk factor for nonalcoholic steatohepatitis (NASH). Non-caloric sweeteners (NCS) are food additives providing sweetness without calories and are considered safe and/or not metabolized by the liver. The potential role of newer NCS in the regulation of NASH, however, remain unknown.
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- Obesity triggers cellular responses like endoplasmic reticulum (ER) stress, and this stress occurs early in leptin-deficient mice before they become obese.
- Treating these mice with the drug tauroursodeoxycholic acid (TUDCA) during infancy helps improve their long-term weight, food intake, and glucose regulation.
- ER stress is linked to autophagy activation, and disrupting this process in specific neurons worsens metabolic issues, further emphasizing the critical role of early life ER stress and autophagy in metabolic regulation.
Article Synopsis
- The rise in obesity and type II diabetes, especially in children, is linked to maternal obesity, which negatively affects offspring's metabolism.
- In a study using mice, researchers found that offspring of obese mothers had issues like glucose intolerance, increased weight, and disrupted hormone signaling related to hunger.
- Treatment with tauroursodeoxycholic acid, which alleviates ER stress, showed promise in reversing some metabolic and developmental problems in these offspring.