•The dorsal dentate gyrus supports conjunctive encoding of multiple sensory inputs and memory based spatial pattern separation.•The dorsal dentate gyrus supports memory based spatial context.•Dentate ...gyrus neurogenesis supports remote time-based memory.•The ventral dentate gyrus supports memory based odor pattern separation.•The ventral dentate gyrus supports reward value and social recognition.
In this review there will be a description of the dentate gyrus (DG) neural circuitry that mediates the operation of a variety of mnemonic processes associated with dorsal and ventral DG function in rats. Dysfunction of the dorsal DG can be shown to mediate mnemonic processing of spatially based information including a) the operation of conjunctive encoding of multiple sensory inputs to determine spatial representations, b) pattern separation based on reducing interference between similar spatial locations and spatial contexts for horizontal distance between objects, vertical distance for height of objects, slope or angle of motor movements, c) importance of spatial context in object recognition and processing of shades of grey associated with the walls of the box d) temporal integration in the creation of remote memory based in part on DG neurogenesis and function of the CA3 subregion of the hippocampus. Dysfunction of the ventral DG can be shown to mediate mnemonic processing of odor and reward value based information including a) pattern separation for odors and reward value, and b) social recognition.
The aims of the paper are to update Rolls' quantitative computational theory of hippocampal function and the predictions it makes about the different subregions (dentate gyrus, CA3 and CA1), and to ...examine behavioral and electrophysiological data that address the functions of the hippocampus and particularly its subregions. Based on the computational proposal that the dentate gyrus produces sparse representations by competitive learning and via the mossy fiber pathway forces new representations on the CA3 during learning (encoding), it has been shown behaviorally that the dentate gyrus supports spatial pattern separation during learning. Based on the computational proposal that CA3-CA3 autoassociative networks are important for episodic memory, it has been shown behaviorally that the CA3 supports spatial rapid one-trial learning, learning of arbitrary associations where space is a component, pattern completion, spatial short-term memory, and spatial sequence learning by associations formed between successive items. The concept that the CA1 recodes information from CA3 and sets up associatively learned backprojections to neocortex to allow subsequent retrieval of information to neocortex, is consistent with findings on consolidation. Behaviorally, the CA1 is implicated in processing temporal information as shown by investigations requiring temporal order pattern separation and associations across time; and computationally this could involve associations in CA1 between object and timing information that have their origins in the lateral and medial entorhinal cortex respectively. The perforant path input from the entorhinal cortex to DG is implicated in learning, to CA3 in retrieval from CA3, and to CA1 in retrieval after longer time intervals ("intermediate-term memory") and in the temporal sequence memory for objects.
Monkeypox virus (MPXV), which causes disease in humans, has for many years been restricted to the African continent, with only a handful of sporadic cases in other parts of the world. However, ...unprecedented outbreaks of monkeypox in non-endemic regions have recently taken the world by surprise. In less than 4 months, the number of detected MPXV infections has soared to more than 48,000 cases, recording a total of 13 deaths. In this Review, we discuss the clinical, epidemiological and immunological features of MPXV infections. We also highlight important research questions and new opportunities to tackle the ongoing monkeypox outbreak.
► The dorsal dentate gyrus supports conjunctive encoding processes. ► The dorsal dentate gyrus supports spatial pattern separation. ► The dorsal dentate gyrus supports context pattern separation. ► ...The dorsal dentate gyrus supports remote memory associated with neurogenesis. ► The ventral dentate gyrus supports odor pattern separation.
In this review article the emphasis will be on the role of the DG (dorsal and ventral) in supporting memory based on the operation of specific processes. Based on the development of computational models of dorsal dentate gyrus (dDG) and behavioral evidence based on dysfunction of dDG, this review will show that the dDG mediates mnemonic processing of spatial information. The processes subserved by dDG include (a) the operation of conjunctive encoding of multiple sensory inputs, implying an integration of sensory inputs to determine a spatial representation, and (b) pattern separation of spatial (especially metric) information, involving the reduction of interference between similar spatial locations (c) pattern separation of context (d) importance of context in object recognition, and (e) temporal integration and remote memory and spatial pattern separation based in part on neurogenesis. In addition the ventral dentate gyrus (vDG) mediates mnemonic processing of odor information as indicated by odor pattern separation.
Introduction
Light elicits a range of non‐visual responses in humans. Driven predominantly by intrinsically photosensitive retinal ganglion cells (ipRGCs), but also by rods and/or cones, these ...responses include melatonin suppression. A sigmoidal relationship has been established between melatonin suppression and light intensity; however, photoreceptoral involvement remains unclear.
Methods and Results
In this study, we first modelled the relationships between alpha‐opic illuminances and melatonin suppression using an extensive dataset by Brainard and colleagues. Our results show that (a) melatonin suppression is better predicted by melanopic illuminance compared to other alpha‐opic illuminances, (b) melatonin suppression is predicted to occur at levels as low as ~1.5 melanopic lux (melanopsin‐weighted irradiance 0.2 µW/cm2), (c) saturation occurs at 305 melanopic lux (melanopsin‐weighted irradiance 36.6 µW/cm2). We then tested this melanopsin‐weighted illuminance‐response model derived from Brainard and colleagues' data and show that it predicts equally well melatonin suppression data from our laboratory, although obtained using different intensities and exposure duration.
Discussion
Together, our findings suggest that melatonin suppression by monochromatic lights is predominantly driven by melanopsin and that it can be initiated at extremely low melanopic lux levels in experimental conditions. This emphasizes the concern of the non‐visual impacts of low light intensities in lighting design and light‐emitting devices.
The Russian Farm-Fox Experiment is the best known experimental study in animal domestication. By subjecting a population of foxes to selection for tameness alone, Dimitry Belyaev generated foxes that ...possessed a suite of characteristics that mimicked those found across domesticated species. This ‘domestication syndrome’ has been a central focus of research into the biological pathways modified during domestication. Here, we chart the origins of Belyaev’s foxes in eastern Canada and critically assess the appearance of domestication syndrome traits across animal domesticates. Our results suggest that both the conclusions of the Farm-Fox Experiment and the ubiquity of domestication syndrome have been overstated. To understand the process of domestication requires a more comprehensive approach focused on essential adaptations to human-modified environments.
The ‘domestication syndrome’ has been a central focus of research into the biological processes underlying domestication. The Russian Farm-Fox Experiment was the first to test whether there is a causal relationship between selection for tameness and the domestication syndrome.Historical records and genetic analysis show that the foxes used in the Farm-Fox Experiment originated from fur farms in eastern Canada and that most traits attributed to the behavioral selection for tameness predated the experiment, undermining a central pillar of support for the domestication syndrome.The overall weight of evidence, including data from other species, does not unambiguously support the existence of the domestication syndrome in animals. Competing theories to explain domestication syndrome should be reconsidered after the traits themselves are more clearly connected to the early stages of domestication.
► The prefrontal cortex in rats supports executive functions. ► Executive functions include temporal processing and rule learning. ► In terms of executive function there is prefrontal cortex ...subregional specificity.
While it is acknowledged that species specific differences are an implicit condition of comparative studies, rodent models of prefrontal function serve a significant role in the acquisition of converging evidence on prefrontal function across levels of analysis and research techniques. The purpose of the present review is to examine whether the prefrontal cortex (PFC) in rats supports a variety of processes associated with executive function including working memory, temporal processing, planning (prospective coding), flexibility, rule learning, and decision making. Therefore, in this review we examined changes associated with working memory processes for spatial locations, visual objects, odors, tastes, and response domains or attributes, temporal processes including temporal order, sequence learning, prospective coding, behavioral flexibility associated with reversal learning and set shifting, paired associate learning, and decision making based on effort, time discounting, and uncertainty following damage to the PFC in rats. In addition, potential parallel processes of executive function in monkeys and humans based on several theories of subregional differentiation within the PFC will be presented. Specifically, theories based on domain or attribute specificity (
Goldman-Rakic, 1996), level of processing (
Petrides, 1996), rule learning based on complexity (
Wise, Murray, & Gerfen, 1996), executive functions based on connectivity with other brain regions associated with top-down control (
Miller & Cohen, 2001), are presented and applied to PFC function in rats with the aim of understanding subregional specificity in the rat PFC. The data suggest that there is subregional specificity within the PFC of rats, monkey and humans and there are parallel cognitive functions of the different subregions of the PFC in rats, monkeys and humans.
Since December 2019, the novel coronavirus, SARS-CoV-2, has garnered global attention due to its rapid transmission, which has infected more than two million people worldwide. Early detection of ...SARS-CoV-2 is one of the crucial interventions to control virus spread and dissemination. Molecular assays have been the gold standard to directly detect for the presence of viral genetic material in infected individuals. However, insufficient viral RNA at the point of detection may lead to false negative results. As such, it is important to also employ immune-based assays to determine one's exposure to SARS-CoV-2, as well as to assist in the surveillance of individuals with prior exposure to SARS-CoV-2. Within a span of 4 months, extensive studies have been done to develop serological systems to characterize the antibody profiles, as well as to identify and generate potentially neutralizing antibodies during SARS-CoV-2 infection. The vast diversity of novel findings has added value to coronavirus research, and a strategic consolidation is crucial to encompass the latest advances and developments. This review aims to provide a concise yet extensive collation of current immunoassays for SARS-CoV-2, while discussing the strengths, limitations and applications of antibody detection in SARS-CoV-2 research and control.
A theoretical model linking boredom and academic achievement is proposed. Based on Pekrun's (2006) control-value theory of achievement emotions, the model posits that boredom and achievement ...reciprocally influence each other over time. Data from a longitudinal study with college students (N = 424) were used to examine the hypothesized effects. The study involved 5 assessments of students' boredom and test performance during a university course spanning an entire academic year. Structural equation modeling was used to examine effects of boredom on achievement, and vice versa. The results show that boredom had consistently negative effects on subsequent performance, and performance had consistently negative effects on subsequent boredom, while controlling for students' gender, age, interest, intrinsic motivation, and prior achievement. These results provide robust evidence for the proposed links between boredom and achievement and support systems-theoretical perspectives on the dynamics of emotions and achievement. From a broader educational perspective, the findings imply that researchers and practitioners alike should focus attention on boredom as an important, yet often overlooked, academic emotion.
Transgender adults serve in the U.S. military at 2 to 3 times the rate of the general adult population. Unfortunately, transgender veterans die by suicide at twice the rate of their cisgender veteran ...peers and approximately 5.85 times the rate of the general population. This article reviews the literature regarding the prevalence of suicidal thoughts and behaviors in transgender veterans. Suicide risk and resilience factors are reviewed, and future areas of study are detailed that incorporate findings from the broader suicide-prevention literature and research on transgender mental-health disparities. Individual services and broader prevention considerations are discussed, including the adaptation of evidence-based suicide-specific psychological interventions, national transgender health-training resources, and relevant veteran suicide-prevention initiatives. Finally, U.S. Department of Defense and U.S. Department of Veterans Affairs policies regarding transgender service and health care are reviewed. State-level policies relevant to transgender veteran suicide such as firearm ownership and nondiscrimination laws are also reviewed, and their implications for suicide prevention are discussed. The aim of this article is to provide a broad review of research findings from multiple fields of study to assist health-care providers, researchers, and policymakers in their efforts to prevent transgender veteran suicide.
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