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Animal camouflage: Sculpting with light.
The three-dimensional nanostructure of butterfly and moth wing scales produces directional reflections that are impossible with an artist's brush. Here, we compare the visual effects used by a moth that masquerades as a dead leaf with those of computer graphics.
Disrupted visual attention relates to cognitive development in infants with Neurofibromatosis Type 1.
BACKGROUND: Neurofibromatosis Type 1 is a genetic condition diagnosed in infancy that substantially increases the likelihood of a child experiencing cognitive and developmental difficulties, including Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). Children with NF1 show clear differences in attention, but whether these differences emerge in early development and how they relate to broader difficulties with cognitive and learning skills is unclear. To address this question requires longitudinal prospective studies from infancy, where the relation between domains of visual attention (including exogenous and endogenous shifting) and cognitive development can be mapped over time. METHODS: We report data from 28 infants with NF1 tested longitudinally at 5, 10 and 14 months compared to cohorts of 29 typical likelihood infants (with no history of NF1 or ASD and/or ADHD), and 123 infants with a family history of ASD and/or ADHD. We used an eyetracking battery to measure both exogenous and endogenous control of visual attention. RESULTS: Infants with NF1 demonstrated intact social orienting, but slower development of endogenous visual foraging. This slower development presented as prolonged engagement with a salient stimulus in a static display relative to typically developing infants. In terms of exogenous attention shifting, NF1 infants showed faster saccadic reaction times than typical likelihood infants. However, the NF1 group demonstrated a slower developmental improvement from 5 to 14 months of age. Individual differences in foraging and saccade times were concurrently related to visual reception abilities within the full infant cohort (NF1, typical likelihood and those with a family history of ASD/ADHD). CONCLUSIONS: Our results provide preliminary evidence that alterations in saccadic reaction time and visual foraging may contribute to learning difficulties in infants with NF1.
Psychedelics as moral bioenhancers: Protocol for a scoping review of ethical arguments for and against.
BACKGROUND: Moral bioenhancement typically refers to the deliberate use of drugs or biotechnologies, potentially alongside other practices, to attempt to improve oneself morally. In addition to general concerns regarding moral self-bioenhancement, the possibility of using psychedelic substances for such purposes raises distinct ethical questions. As a first step in analysing these questions, we intend to perform a scoping review of the existing arguments for and against the use of psychedelics as moral bioenhancers. We will focus primarily on voluntary use by individuals, although voluntary use by couples or small groups will be considered. The present contribution is a protocol for this scoping review. METHODS: Our scoping review will adhere to the Joanna Briggs Institute methodology, which involves five stages: (1) identifying the research question, (2) developing the search strategy, (3) setting inclusion criteria, (4) extracting data, and (5) presenting and analysing the results. We will include both published and unpublished sources if they explicitly present ethical arguments for or against the voluntary use of psychedelics as intentional moral bioenhancers in adults. We will search for relevant studies in Embase, MEDLINE, Web of Science, Google Scholar, The National Library of Medicine, the Cumulated Index to Nursing and Allied Health Literature, Philosopher's Index, the Bioethics Literature Database, EthxWeb, PhilPapers, Stanford Encyclopedia of Philosophy, Philosopher's Index, EBSCO, BASE, and WorldCat. Sources will be excluded if (a) the full text is inaccessible, (b) the main text is in a language other than English, or (c) the focus is not primarily on ethical arguments (for example, focusing primarily on the clinical use of psychedelics for treatment). Two raters will independently assess all articles for eligibility, with disagreements to be resolved with a third reviewer. Data from eligible articles will be charted using a standardised data extraction form. The data will be analysed following PRISMA-ScR guidelines.
Altercentric Memory Error at 9 Months But Correct Object Memory by 18 Months Revealed in Infants' Pupil.
It was recently proposed that infants have a memory bias for events witnessed together with others. This may allow infants to prioritize relevant information and to predict others' actions, despite limited processing capacities. However, when events occur in the absence of others, for example, an object changes location, this would create altercentric memory errors where infants misremember the object's location where others last saw it. Pupillometry presents a powerful tool to examine the temporal dynamics of such memory biases as they unfold. Here, we showed infants aged 9 (N = 97) and 18 months (N = 79) videos of an agent watching an object move to one of two hiding locations. The object then moved from location A to B, which the agent either missed (leading to her false belief) or witnessed (true belief). The object subsequently reappeared either at its actual or, surprisingly, its initial location. As predicted by the altercentric theory, 9-month-old infants expected the object where the agent falsely believed it to be and not where it really was, as indicated in their pupil dilation. In contrast, 18-month-old infants seemed to remember the object's actual location. Infants' memory errors did not predict correct action anticipation when the agent reached into one of the locations to retrieve the object. This indicates that infants show altercentric memory errors at a young age, which vanish in the second year of life. We suggest that this bias helps young infants to learn from others, but recedes as they become more capable of acting on the world themselves.
Scoping review: potential harm from school-based group mental health interventions.
BACKGROUND: A growing body of evidence demonstrates that school-based mental health interventions may be potentially harmful. We define potential harm as any negative outcome or adverse event that could plausibly be linked to an intervention. In this scoping review, we examine three areas: the types of potential harms and adverse events reported in school-based mental health interventions; the subgroups of children and adolescents at heightened risk; and the proposed explanations for these potential harms. METHODS: We searched eight databases (1960-2023), performed an author search and hand-searched for published and unpublished studies that evaluated controlled trials of school-based group mental health interventions based on cognitive-behavioural therapy and/or mindfulness techniques, with the aim of reducing or preventing internalising symptoms or increasing wellbeing. Two independent raters screened studies for eligibility and assessed study quality using Cochrane tools. From eligible studies, we reviewed those that reported at least one negative outcome. RESULTS: Ten out of 112 (8.93%) interventions (described in 120 studies) reported at least one negative outcome such as a decrease in wellbeing or an increase in depression or anxiety. Three out of 112 interventions (2.68%) reported the occurrence of specific adverse events, none of which were linked to the intervention. Of the 15/120 studies rated as high quality (i.e. those with low risk of bias), 5/15 (33.33%) reported at least one negative outcome. Negative outcomes were found for a number of subgroups including individuals deemed at high risk of mental health problems, male participants, younger children and children eligible for free school meals. About half (54.5%) of the studies acknowledged that the content of the intervention itself might have led to the negative outcome. CONCLUSION: To design and implement effective school-based mental health interventions, the issues of potential harm and their related measurement and reporting challenges must be addressed.
Evaluating CBT for health anxiety and obsessive compulsive disorder adapted for online delivery in the context of COVID-19.
BACKGROUND: The COVID-19 pandemic has had a negative impact on the population's mental health, particularly for individuals with health anxiety (HA) and obsessive compulsive disorder (OCD). This is in conjunction with a significant change in accessibility of face-to-face psychological services which have had to rapidly adapt to the remote delivery of therapy. AIMS: Using a single-arm open trial design, the study aimed to evaluate the effectiveness of evidence-based CBT interventions for HA and OCD delivered via a blend of online therapist consultations interspersed with self-study reading materials. A secondary aim was to evaluate remote training workshops provided to therapists. METHOD: Therapists attended three half-day remote workshops after which consecutive participants with HA or OCD were assigned to therapists for treatment. Monthly expert supervision was provided. Patients completed routine outcome measures at each session and an idiosyncratic measure of pre-occupation with COVID-19 at pre- and post-treatment. RESULTS: Significant and comparable improvements were observed on measures of anxiety, depression and social adjustment from pre- to post-treatment in both the HA (n=14) and OCD (n=20) groups. Disorder-specific measures also showed significant improvements after treatment. The HA group showed greater levels of change on the COVID-19-specific questionnaire. The training workshops were well received by therapists, who valued the monthly supervision sessions. CONCLUSIONS: The study provides support for the effectiveness of the online delivery of CBT for HA and OCD supported by the inclusion of additional self-study booklets.
Imaging the structural connectome with hybrid MRI-microscopy tractography.
Mapping how neurons are structurally wired into whole-brain networks can be challenging, particularly in larger brains where 3D microscopy is not available. Multi-modal datasets combining MRI and microscopy provide a solution, where high resolution but 2D microscopy can be complemented by whole-brain but lowresolution MRI. However, there lacks unified approaches to integrate and jointly analyse these multi-modal data in an insightful way. To address this gap, we introduce a data-fusion method for hybrid MRI-microscopy fibre orientation and connectome reconstruction. Specifically, we complement precise "in-plane" orientations from microscopy with "through-plane" information from MRI to construct 3D hybrid fibre orientations at resolutions far exceeding that of MRI whilst preserving microscopy's myelin specificity, resulting in superior fibre tracking. Our method is openly available, can be deployed on standard 2D microscopy, including different microscopy contrasts, and is species agnostic, facilitating neuroanatomical investigation in both animal models and human brains.
A cellular basis for mapping behavioural structure.
To flexibly adapt to new situations, our brains must understand the regularities in the world, as well as those in our own patterns of behaviour. A wealth of findings is beginning to reveal the algorithms that we use to map the outside world1-6. However, the biological algorithms that map the complex structured behaviours that we compose to reach our goals remain unknown. Here we reveal a neuronal implementation of an algorithm for mapping abstract behavioural structure and transferring it to new scenarios. We trained mice on many tasks that shared a common structure (organizing a sequence of goals) but differed in the specific goal locations. The mice discovered the underlying task structure, enabling zero-shot inferences on the first trial of new tasks. The activity of most neurons in the medial frontal cortex tiled progress to goal, akin to how place cells map physical space. These 'goal-progress cells' generalized, stretching and compressing their tiling to accommodate different goal distances. By contrast, progress along the overall sequence of goals was not encoded explicitly. Instead, a subset of goal-progress cells was further tuned such that individual neurons fired with a fixed task lag from a particular behavioural step. Together, these cells acted as task-structured memory buffers, implementing an algorithm that instantaneously encoded the entire sequence of future behavioural steps, and whose dynamics automatically computed the appropriate action at each step. These dynamics mirrored the abstract task structure both on-task and during offline sleep. Our findings suggest that schemata of complex behavioural structures can be generated by sculpting progress-to-goal tuning into task-structured buffers of individual behavioural steps.
Left-right dissociation of hippocampal memory processes in mice.
Left-right asymmetries have likely evolved to make optimal use of bilaterian nervous systems; however, little is known about the synaptic and circuit mechanisms that support divergence of function between equivalent structures in each hemisphere. Here we examined whether lateralized hippocampal memory processing is present in mice, where hemispheric asymmetry at the CA3-CA1 pyramidal neuron synapse has recently been demonstrated, with different spine morphology, glutamate receptor content, and synaptic plasticity, depending on whether afferents originate in the left or right CA3. To address this question, we used optogenetics to acutely silence CA3 pyramidal neurons in either the left or right dorsal hippocampus while mice performed hippocampus-dependent memory tasks. We found that unilateral silencing of either the left or right CA3 was sufficient to impair short-term memory. However, a striking asymmetry emerged in long-term memory, wherein only left CA3 silencing impaired performance on an associative spatial long-term memory task, whereas right CA3 silencing had no effect. To explore whether synaptic properties intrinsic to the hippocampus might contribute to this left-right behavioral asymmetry, we investigated the expression of hippocampal long-term potentiation. Following the induction of long-term potentiation by high-frequency electrical stimulation, synapses between CA3 and CA1 pyramidal neurons were strengthened only when presynaptic input originated in the left CA3, confirming an asymmetry in synaptic properties. The dissociation of hippocampal long-term memory function between hemispheres suggests that memory is routed via distinct left-right pathways within the mouse hippocampus, and provides a promising approach to help elucidate the synaptic basis of long-term memory.
The shallow cognitive map hypothesis: A hippocampal framework for thought disorder in schizophrenia.
Memories are not formed in isolation. They are associated and organized into relational knowledge structures that allow coherent thought. Failure to express such coherent thought is a key hallmark of Schizophrenia. Here we explore the hypothesis that thought disorder arises from disorganized Hippocampal cognitive maps. In doing so, we combine insights from two key lines of investigation, one concerning the neural signatures of cognitive mapping, and another that seeks to understand lower-level cellular mechanisms of cognition within a dynamical systems framework. Specifically, we propose that multiple distinct pathological pathways converge on the shallowing of Hippocampal attractors, giving rise to disorganized Hippocampal cognitive maps and driving conceptual disorganization. We discuss the available evidence at the computational, behavioural, network, and cellular levels. We also outline testable predictions from this framework, including how it could unify major chemical and psychological theories of schizophrenia and how it can provide a rationale for understanding the aetiology and treatment of the disease.
An emergent neural coactivity code for dynamic memory.
Neural correlates of external variables provide potential internal codes that guide an animal's behavior. Notably, first-order features of neural activity, such as single-neuron firing rates, have been implicated in encoding information. However, the extent to which higher-order features, such as multineuron coactivity, play primary roles in encoding information or secondary roles in supporting single-neuron codes remains unclear. Here, we show that millisecond-timescale coactivity among hippocampal CA1 neurons discriminates distinct, short-lived behavioral contingencies. This contingency discrimination was unrelated to the tuning of individual neurons, but was instead an emergent property of their coactivity. Contingency-discriminating patterns were reactivated offline after learning, and their reinstatement predicted trial-by-trial memory performance. Moreover, optogenetic suppression of inputs from the upstream CA3 region during learning impaired coactivity-based contingency information in the CA1 and subsequent dynamic memory retrieval. These findings identify millisecond-timescale coactivity as a primary feature of neural firing that encodes behaviorally relevant variables and supports memory retrieval.
Integrating new memories into the hippocampal network activity space.
By investigating the topology of neuronal co-activity, we found that mnemonic information spans multiple operational axes in the mouse hippocampus network. High-activity principal cells form the core of each memory along a first axis, segregating spatial contexts and novelty. Low-activity cells join co-activity motifs across behavioral events and enable their crosstalk along two other axes. This reveals an organizational principle for continuous integration and interaction of hippocampal memories.
A Hippocampus-Accumbens Tripartite Neuronal Motif Guides Appetitive Memory in Space.
Retrieving and acting on memories of food-predicting environments are fundamental processes for animal survival. Hippocampal pyramidal cells (PYRs) of the mammalian brain provide mnemonic representations of space. Yet the substrates by which these hippocampal representations support memory-guided behavior remain unknown. Here, we uncover a direct connection from dorsal CA1 (dCA1) hippocampus to nucleus accumbens (NAc) that enables the behavioral manifestation of place-reward memories. By monitoring neuronal ensembles in mouse dCA1→NAc pathway, combined with cell-type selective optogenetic manipulations of input-defined postsynaptic neurons, we show that dCA1 PYRs drive NAc medium spiny neurons and orchestrate their spiking activity using feedforward inhibition mediated by dCA1-connected parvalbumin-expressing fast-spiking interneurons. This tripartite cross-circuit motif supports spatial appetitive memory and associated NAc assemblies, being independent of dorsal subiculum and dispensable for both spatial novelty detection and reward seeking. Our findings demonstrate that the dCA1→NAc pathway instantiates a limbic-motor interface for neuronal representations of space to promote effective appetitive behavior.