-
Philosophical Transactions of the Royal... Jul 2024Decisions to disperse from a habitat stand out among organismal behaviours as pivotal drivers of ecosystem dynamics across scales. Encounters with other species are an...
Decisions to disperse from a habitat stand out among organismal behaviours as pivotal drivers of ecosystem dynamics across scales. Encounters with other species are an important component of adaptive decision-making in dispersal, resulting in widespread behaviours like tracking resources or avoiding consumers in space. Despite this, metacommunity models often treat dispersal as a function of intraspecific density alone. We show, focusing initially on three-species network motifs, that interspecific dispersal rules generally drive a transition in metacommunities from homogeneous steady states to self-organized heterogeneous spatial patterns. However, when ecologically realistic constraints reflecting adaptive behaviours are imposed-prey tracking and predator avoidance-a pronounced homogenizing effect emerges where spatial pattern formation is suppressed. We demonstrate this effect for each motif by computing master stability functions that separate the contributions of local and spatial interactions to pattern formation. We extend this result to species-rich food webs using a random matrix approach, where we find that eventually, webs become large enough to override the homogenizing effect of adaptive dispersal behaviours, leading once again to predominately pattern-forming dynamics. Our results emphasize the critical role of interspecific dispersal rules in shaping spatial patterns across landscapes, highlighting the need to incorporate adaptive behavioural constraints in efforts to link local species interactions and metacommunity structure. This article is part of the theme issue 'Diversity-dependence of dispersal: interspecific interactions determine spatial dynamics'.
Topics: Food Chain; Animals; Animal Distribution; Models, Biological; Ecosystem; Population Dynamics; Predatory Behavior
PubMed: 38913053
DOI: 10.1098/rstb.2023.0136 -
Biology Open Jun 2024Myxomycetes are multinucleate unicellular organisms. They form a plasmodium that moves by protoplasmic flow and prey on microorganisms. When encountering intraspecifics,...
Myxomycetes are multinucleate unicellular organisms. They form a plasmodium that moves by protoplasmic flow and prey on microorganisms. When encountering intraspecifics, the plasmodium has the capacity for 'fusion,' actively approaching and fusing its cells, or 'avoidance,' altering its direction to avoid the other individual. This is an allorecognition ability. However, it remains unclear whether the range of allorecognition extends to other species, and its ecological significance is also obscure. Here, we conducted a quantitative evaluation of contact responses from closely related species of plasmodium to clarify the range of allorecognition behaviors in Myxomycetes. Behavioral assays demonstrated that allorecognition behaviors are specifically observed within individuals of the same species, indicating that these behaviors are a phenomenon unique to intraspecies interactions. Myxomycetes allorecognition is an extremely narrow and inward-focused behavior, suggesting for a highly specialized mechanism.
PubMed: 38912557
DOI: 10.1242/bio.060358 -
Addiction Neuroscience Jun 2024Adolescence marks a sensitive period for neurodevelopment wherein exposure to drugs of abuse may disrupt maturation and induce persistent changes in neurophysiology...
Adolescence marks a sensitive period for neurodevelopment wherein exposure to drugs of abuse may disrupt maturation and induce persistent changes in neurophysiology which may exacerbate the risk for developing substance use disorders in adulthood. Adolescent nicotine exposure (ANE) enhances motivation to obtain drugs of abuse, particularly opioids, and increases vulnerability for the development of opioid use disorder (OUD). Here, we characterized ANE effects on learning about the adverse consequences of opioid consumption in adulthood in the absence of further nicotine administration. First, we show that ANE engenders punishment resistant fentanyl self-administration in a heterogenous seeking-taking chain schedule of reinforcement at least at the tested dose of fentanyl (0.75 μg/kg). We found that ANE rats consumed significantly more fentanyl and contingent foot shock punishment was less efficacious in limiting fentanyl seeking in ANE rats, relative to nicotine-naïve controls. Next, we demonstrated that ANE limits learning about the deleterious consequences of acute opioid intoxication in adulthood. In a combined conditioned taste avoidance and place preference paradigm we found that ANE resulted in significant reductions in the strength of morphine-induced CTA, and a simultaneous enhancement of CPP at a higher dose that was less capable of driving reinforcement in naïve controls. Finally, we examined the expression of perineuronal nets (PNNs) within insular cortex (IC) and found ANE rats to have increased density of PNNs across the anterior IC and significantly more parvalbumin-labeled IC cells relative to naïve controls. Together, these data lay the framework for a mechanistic explanation of the extreme comorbidity between nicotine use and development of OUDs.
PubMed: 38911872
DOI: 10.1016/j.addicn.2024.100150 -
JBJS Essential Surgical Techniques 2024A number of techniques have been described to enter the capsule and gain access to the hip joint during hip arthroscopy. Among these, the interportal and T-capsulotomies...
BACKGROUND
A number of techniques have been described to enter the capsule and gain access to the hip joint during hip arthroscopy. Among these, the interportal and T-capsulotomies are the most commonly utilized; however, these approaches transect the iliofemoral ligament, which normally resists anterior subluxation and stabilizes extension. Thus, these approaches may introduce capsuloligamentous instability and have been associated with complications such as dislocation, postoperative pain, microinstability, seroma, and heterotopic ossification. Although prior literature has demonstrated durable mid-term results for patients undergoing capsulotomies with capsular closure, avoidance of iatrogenic injury to the hip capsule altogether is preferable. Thus, the puncture capsulotomy technique we present is minimally invasive, preserves the biomechanics of the hip joint and capsule without disrupting the iliofemoral ligament, and allows for appropriate visualization of the joint through placement of multiple small portals.
DESCRIPTION
Following induction of anesthesia and with the patient supine on a hip traction table, the nonoperative leg is positioned at 45° abduction with support of a well-padded perineal post, and the operative hip is placed into valgus against the post. Intra-articular fluid distention with normal saline solution is utilized to achieve approximately 9 mm of inferior migration of the femoral head and decrease risk of iatrogenic nerve injury. Then, under fluoroscopic guidance, an anterolateral portal is created 1 cm anterior and 1 cm superior to the greater trochanter at an approximately 15° to 20° angle. Second, via arthroscopic visualization, the anterior portal is created 1 cm distal and 1 cm lateral to the intersection of a vertical line drawn at the anterior superior iliac spine and a horizontal line at the level of the anterolateral portal. Third, equidistant between the anterior and anterolateral portals, the mid-anterior portal is created distally. Finally, at one-third of the distance between the anterior superior iliac spine and the anterolateral portal, the Dienst portal is created. Thus, these 4 portals form a quadrilateral arrangement through which puncture capsulotomy can be performed.
ALTERNATIVES
Alternative approaches to the hip capsule include interportal and T-capsulotomies, with or without capsular closure. Although the most frequently utilized, these approaches transect the iliofemoral ligament and thus may introduce capsuloligamentous instability.
RATIONALE
The puncture capsulotomy technique has the advantage of maintaining the integrity of the capsule through the placement of 4 small portals. The technique does not transect the iliofemoral ligament and thus does not introduce capsuloligamentous instability. Furthermore, although good mid-term outcomes have been reported with capsular closure, the present technique avoids creating unnecessary injury to the capsule and complications of an unrepaired capsule or, conversely, of plication.
EXPECTED OUTCOMES
Patients who underwent the puncture capsulotomy technique showed significant improvements in multiple functional outcome scores at a mean follow-up of 30.4 months, including the International Hip Outcome Tool (iHOT-33) (39.6 preoperatively to 76.1 postoperatively), Hip Outcome Score-Activities of Daily Living subscale (HOS-ADL) (70.0 to 89.3), HOS Sport-Specific Subscale (HOS-SSS) (41.8 to 75.7), and modified Harris hip score (mHHS) (60.1 to 84.9). At 2 years postoperatively with respect to iHOT-33, 81.0% of patients achieved the minimal clinically important difference, 62.0% achieved the patient acceptable symptom state, and 58.9% achieved substantial clinical benefit. In addition, mean visual analog scale pain scores improved significantly over the follow-up period (6.3 to 2.2; p < 0.001). Finally, there were zero occurrences of infection, osteonecrosis of the femoral head, dislocation or instability, or femoral neck fracture in patients treated with puncture capsulotomy.
IMPORTANT TIPS
Anterolateral portal placement should be performed using the intra-articular fluid distention technique with fluoroscopy to avoid risk of iatrogenic labral damage and distraction-induced neurapraxia. Subsequent portals must then be placed under direct arthroscopic visualization.On establishment of the anterolateral portal, the scope should be switched to the anterior portal to ensure that the anterolateral portal has not been placed through the labrum and to adjust its placement to better access pathology. This portal, as well as all others, may be subsequently modified by adjusting the angle of the cannula, without making a new skin incision.If a cam lesion is located more anteromedially or posterolaterally, an additional accessory portal may be made distal or proximal to the anterolateral portal, respectively, in order to enhance visualization.Intermittent traction is utilized throughout the surgery. No traction is utilized during preparing and draping, suture tensioning and tie-down, and femoroplasty, with minimal traction during acetabuloplasty; these precautions serve to prevent iatrogenic superficial peroneal nerve injury.There can be a steep learning curve for this technique. In particular, greater surgical experience is required to perform adequate femoral osteoplasty for large cam lesions with this approach.Instrument maneuverability and visualization can be somewhat constrained with this approach.It is more difficult to perform certain procedures with this technique, including segmental and circumferential labral reconstructions, particularly with remote grafts.
ACRONYMS AND ABBREVIATIONS
iHOT-33 = International Hip Outcome Tool-33HOS-ADL = Hip Outcome Score-Activities of Daily Living subscaleHOS-SSS = Hip Outcome Score-Sport-Specific SubscaleAP = anteroposteriorMRA = magnetic resonance arthrogramMRI = magnetic resonance imagingCT = computed tomographyASIS = anterior superior iliac spinemHHS = modified Harris hip score.
PubMed: 38903605
DOI: 10.2106/JBJS.ST.23.00061 -
Frontiers in Neuroscience 2024Reward-seeking behavior is frequently associated with risk of punishment. There are two types of punishment: positive punishment, which is defined as addition of an...
Reward-seeking behavior is frequently associated with risk of punishment. There are two types of punishment: positive punishment, which is defined as addition of an aversive stimulus, and negative punishment, involves the omission of a rewarding outcome. Although the medial prefrontal cortex (mPFC) is important in avoiding punishment, whether it is important for avoiding both positive and negative punishment and how it contributes to such avoidance are not clear. In this study, we trained male mice to perform decision-making tasks under the risks of positive (air-puff stimulus) and negative (reward omission) punishment, and modeled their behavior with reinforcement learning. Following the training, we pharmacologically inhibited the mPFC. We found that pharmacological inactivation of mPFC enhanced the reward-seeking choice under the risk of positive, but not negative, punishment. In reinforcement learning models, this behavioral change was well-explained as an increase in sensitivity to reward, rather than a decrease in the strength of aversion to punishment. Our results suggest that mPFC suppresses reward-seeking behavior by reducing sensitivity to reward under the risk of positive punishment.
PubMed: 38903603
DOI: 10.3389/fnins.2024.1412509 -
Progress in Neuro-psychopharmacology &... Jun 2024The ventral pallidum (VP) receives its primary inputs from the nucleus accumbens (NAC) and the basolateral amygdala (BLA). We demonstrated recently that in the VP, the...
The ventral pallidum (VP) receives its primary inputs from the nucleus accumbens (NAC) and the basolateral amygdala (BLA). We demonstrated recently that in the VP, the D2 DA receptor (DR) agonist quinpirole dose-dependently facilitates memory consolidation in inhibitory avoidance and spatial learning. In the VP, DR can be found both on NAC and BLA terminals. According to our hypothesis, quinpirole microinjected into the VP can facilitate memory consolidation via modulation of synaptic plasticity on NAC and/or BLA terminals. The effect of intra-VP quinpirole on BLA-VP and NAC shell-VP synapses was investigated via a high frequency stimulation (HFS) protocol. Quinpirole was administered in three doses into the VP of male Sprague-Dawley rats after HFS; controls received vehicle. To examine whether an interaction between the NAC shell and the BLA at the level of the VP was involved, tetrodotoxin (TTX) was microinjected into one of the nuclei while stimulating the other nucleus. Our results showed that quinpirole dose-dependently modulates BLA-VP and NAC shell-VP synapses, similar to those observed in inhibitory avoidance and spatial learning, respectively. The lower dose inhibits BLA inputs, while the larger doses facilitates NAC shell inputs. The experiments with TTX demonstrates that the two nuclei do not influence each others' evoked responses in the VP. Power spectral density analysis demonstrated that independent from the synaptic facilitation, intra-VP quinpirole increases the amplitude of gamma frequency band after NAC HFS, and BLA tonically suppresses the NAC's HFS-induced gamma facilitation. In contrast, HFS of the BLA results in a delayed, transient increase in the amplitude of the gamma frequency band correlating with the LTP of the P1 component of the VP response to BLA stimulation. Furthermore, our results demonstrate that the BLA plays a prominent role in the generation of the delta oscillations: HFS of the BLA leads to a gradually increasing delta frequency band facilitation over time, while BLA inhibition blocks the NAC's HFS induced strong delta facilitation. These findings demonstrate that there is a complex interaction between the NAC shell region and the VP, as well as the BLA and the VP, and support the important role of VP DRs in the regulation of limbic information flow.
PubMed: 38901759
DOI: 10.1016/j.pnpbp.2024.111059 -
Frontiers in Robotics and AI 2024Soft robots exhibit complex nonlinear dynamics with large degrees of freedom, making their modelling and control challenging. Typically, reduced-order models in time or...
Soft robots exhibit complex nonlinear dynamics with large degrees of freedom, making their modelling and control challenging. Typically, reduced-order models in time or space are used in addressing these challenges, but the resulting simplification limits soft robot control accuracy and restricts their range of motion. In this work, we introduce an end-to-end learning-based approach for fully dynamic modelling of any general robotic system that does not rely on predefined structures, learning dynamic models of the robot directly in the visual space. The generated models possess identical dimensionality to the observation space, resulting in models whose complexity is determined by the sensory system without explicitly decomposing the problem. To validate the effectiveness of our proposed method, we apply it to a fully soft robotic manipulator, and we demonstrate its applicability in controller development through an open-loop optimization-based controller. We achieve a wide range of dynamic control tasks including shape control, trajectory tracking and obstacle avoidance using a model derived from just 90 min of real-world data. Our work thus far provides the most comprehensive strategy for controlling a general soft robotic system, without constraints on the shape, properties, or dimensionality of the system.
PubMed: 38899065
DOI: 10.3389/frobt.2024.1403733 -
BioRxiv : the Preprint Server For... Jun 2024Many psychiatric disorders involve excessive avoidant or defensive behavior, such as avoidance in anxiety and trauma disorders or defensive rituals in...
OBJECTIVE
Many psychiatric disorders involve excessive avoidant or defensive behavior, such as avoidance in anxiety and trauma disorders or defensive rituals in obsessive-compulsive disorders. Developing algorithms to predict these behaviors from local field potentials (LFPs) could serve as foundational technology for closed-loop control of such disorders. A significant challenge is identifying the LFP features that encode these defensive behaviors.
APPROACH
We analyzed LFP signals from the infralimbic cortex and basolateral amygdala of rats undergoing tone-shock conditioning and extinction, standard for investigating defensive behaviors. We utilized a comprehensive set of neuro-markers across spectral, temporal, and connectivity domains, employing SHapley Additive exPlanations for feature importance evaluation within Light Gradient-Boosting Machine models. Our goal was to decode three commonly studied avoidance/defensive behaviors: freezing, bar-press suppression, and motion (accelerometry), examining the impact of different features on decoding performance.
MAIN RESULTS
Band power and band power ratio between channels emerged as optimal features across sessions. High-gamma (80-150 Hz) power, power ratios, and inter-regional correlations were more informative than other bands that are more classically linked to defensive behaviors. Focusing on highly informative features enhanced performance. Across 4 recording sessions with 16 subjects, we achieved an average coefficient of determination of 0.5357 and 0.3476, and Pearson correlation coefficients of 0.7579 and 0.6092 for accelerometry jerk and bar press rate, respectively. Utilizing only the most informative features revealed differential encoding between accelerometry and bar press rate, with the former primarily through local spectral power and the latter via inter-regional connectivity. Our methodology demonstrated remarkably low time complexity, requiring 110 ms for training and 1 ms for inference.
SIGNIFICANCE
Our results demonstrate the feasibility of accurately decoding defensive behaviors with minimal latency, using LFP features from neural circuits strongly linked to these behaviors. This methodology holds promise for real-time decoding to identify physiological targets in closed-loop psychiatric neuromodulation.
PubMed: 38895388
DOI: 10.1101/2024.06.06.597165 -
BioRxiv : the Preprint Server For... Jun 2024Social phobia is highly detrimental for social behavior, mental health, and productivity. Despite much previous research, the behavioral and neurobiological mechanisms...
Social phobia is highly detrimental for social behavior, mental health, and productivity. Despite much previous research, the behavioral and neurobiological mechanisms associated with the development of social phobia remain elusive. To investigate these issues, the present study implemented a mouse model of social threat conditioning in which mice received electric shock punishment upon interactions with unfamiliar conspecifics. This resulted in immediate reductions in social behavior and robust increases in defensive mechanisms such as avoidance, freezing, darting, and ambivalent stretched posture. Furthermore, social deficits lasted for prolonged periods and were independent of contextual settings, sex variables, or particular identity of the social stimuli. Shedding new light into the neurobiological factors contributing to this phenomenon, we found that optogenetic silencing of the prelimbic (PL), but not the infralimbic (IL), subregion of the medial prefrontal cortex (mPFC) during training led to subsequent forgetting and development of lasting social phobia. Similarly, pharmacological inhibition of NMDARs in PL also impaired the development of social phobia. These findings are consistent with the notion that social-related trauma is a prominent risk factor for the development of social phobia, and that this phenomenon engages learning-related mechanisms within the prelimbic prefrontal cortex to promote prolonged representations of social threat.
PubMed: 38895224
DOI: 10.1101/2024.06.04.597446 -
Sensors (Basel, Switzerland) Jun 2024Path planning creates the shortest path from the source to the destination based on sensory information obtained from the environment. Within path planning, obstacle... (Review)
Review
Path planning creates the shortest path from the source to the destination based on sensory information obtained from the environment. Within path planning, obstacle avoidance is a crucial task in robotics, as the autonomous operation of robots needs to reach their destination without collisions. Obstacle avoidance algorithms play a key role in robotics and autonomous vehicles. These algorithms enable robots to navigate their environment efficiently, minimizing the risk of collisions and safely avoiding obstacles. This article provides an overview of key obstacle avoidance algorithms, including classic techniques such as the Bug algorithm and Dijkstra's algorithm, and newer developments like genetic algorithms and approaches based on neural networks. It analyzes in detail the advantages, limitations, and application areas of these algorithms and highlights current research directions in obstacle avoidance robotics. This article aims to provide comprehensive insight into the current state and prospects of obstacle avoidance algorithms in robotics applications. It also mentions the use of predictive methods and deep learning strategies.
PubMed: 38894362
DOI: 10.3390/s24113573