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Peptides Aug 2024The neuropeptide relaxin-3 and its cognate receptor, relaxin family peptide-3 receptors (RXFP3), have been implicated in modulating learning and memory processes, but...
The neuropeptide relaxin-3 and its cognate receptor, relaxin family peptide-3 receptors (RXFP3), have been implicated in modulating learning and memory processes, but their specific roles remain unclear. This study utilized behavioral and molecular approaches to investigate the effects of putatively reversible blockade of RXFP3 in the ventral dentate gyrus (vDG) of the hippocampus on spatial and fear memory formation in rats. Male Wistar rats received bilateral vDG cannula implantation and injections of the RXFP3 antagonist, R3(BΔ23-27)R/I5 (400 ng/0.5 μL per side), or vehicle at specific time points before acquisition, consolidation, or retrieval phases of the Morris water maze and passive avoidance learning tasks. RXFP3 inhibition impaired acquisition in the passive avoidance task but not the spatial learning task. However, both memory consolidation and retrieval were disrupted in both tasks following RXFP3 antagonism. Ventral hippocampal levels of the consolidation-related kinase p70-S6 kinase (p70S6K) were reduced RXFP3 blockade. These findings highlight a key role for ventral hippocampal RXFP3 signaling in the acquisition, consolidation, and retrieval of spatial and emotional memories, extending previous work implicating this neuropeptide system in hippocampal memory processing.
Topics: Animals; Dentate Gyrus; Rats; Receptors, G-Protein-Coupled; Male; Fear; Rats, Wistar; Avoidance Learning; Memory; Relaxin; Spatial Memory; Maze Learning; Hippocampus; Receptors, Peptide
PubMed: 38788901
DOI: 10.1016/j.peptides.2024.171244 -
Journal of the Experimental Analysis of... Jul 2024Hyperbolic relations between independent and dependent variables are ubiquitous in the experimental analysis of behavior, mentioned in over 150 articles in the Journal...
Hyperbolic relations between independent and dependent variables are ubiquitous in the experimental analysis of behavior, mentioned in over 150 articles in the Journal of the Experimental Analysis of Behavior. There are two principal forms of hyperbolae: The first describes the relation between response rate and reinforcement rate on variable-interval schedules of reinforcement; it rises asymptotically toward a maximum. The second describes the relation between the current equivalent value of an incentive and its delay or (im)probability; it falls from a maximum toward an asymptote of 0. Where do these come from? What do their parameters mean? How are they related? This article answers the first two questions and addresses the last.
Topics: Reinforcement, Psychology; Reinforcement Schedule; Animals; Humans; Conditioning, Operant
PubMed: 38785258
DOI: 10.1002/jeab.916 -
Neuropsychology Jul 2024Psychometrically sound measures of catastrophizing about symptoms and fear avoidance behavior are needed to further applications of the fear-avoidance model in mild...
OBJECTIVE
Psychometrically sound measures of catastrophizing about symptoms and fear avoidance behavior are needed to further applications of the fear-avoidance model in mild traumatic brain injury (mTBI) for research and clinical purposes. To this end, two questionnaires were adapted (minor), the Postconcussion Symptom Catastrophizing Scale (PCS-CS) and the Fear of Mental Activity Scale (FMA). This study aimed to investigate the factor structure, internal consistency, test-retest reliability, and concurrent and construct validity of two adapted questionnaires in a sample of participants with mTBI compared to participants with orthopedic injury and healthy adults.
METHOD
One hundred eighty-five mTBI participants (40% female), 180 participants with orthopedic injury (55% female), and 116 healthy adults (55% female) participated in the study. All participants were assessed at two time points (2 weeks postinjury and 3 months) using self-reported questionnaires. Data were collected using online questionnaires.
RESULTS
Findings indicated a three-factor model (magnification, rumination, helplessness) with a higher order factor (catastrophizing) for the PCS-CS and a two-factor model (activity avoidance and somatic focus) for the FMA. The results showed strong internal consistency, good test-retest reliability, and good concurrent and convergent validity for the PCS-CS and FMA across all samples.
CONCLUSIONS
This study has shown that the PCS-CS and FMA are psychometrically sound instruments and can be considered for valid and reliable assessment of catastrophizing about postconcussion like symptoms and fear-avoidance beliefs about mental activities. These instruments can be used in research and clinical practice applications of the fear-avoidance model and add to explanations of prolonged recovery after mTBI. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
Topics: Humans; Female; Male; Adult; Catastrophization; Psychometrics; Brain Concussion; Fear; Middle Aged; Reproducibility of Results; Avoidance Learning; Young Adult; Surveys and Questionnaires; Self Report
PubMed: 38780594
DOI: 10.1037/neu0000954 -
AMPA and NMDA receptors in dentate gyrus mediate memory for sucrose in two port discrimination task.Hippocampus Jul 2024Although the phenomenon of memory formation and recall associated with the use of psychotropic drugs has been extensively studied, mechanisms underlying memories for...
Although the phenomenon of memory formation and recall associated with the use of psychotropic drugs has been extensively studied, mechanisms underlying memories for natural reward have not been clarified. Herein, we test the hypothesis that glutamatergic receptors in the dentate gyrus play a role in memories associated with sucrose. We used pellet self-administration protocol to generate memories in two-port nose-poke discrimination task using male Wistar rats. During non-rewarded probe trial, the conditioned animals readily discriminated the active port versus inactive port and showed massive increase in mRNA expression of AMPA receptor subunit genes (gria2, gria3) as well as c-Fos protein in the DG. Access to sweet pellet further enhanced c-Fos expression in the DG. However, animals pre-treated with AMPA receptor antagonist CNQX (intra-DG), on exposure to operant chamber (no pellet), showed decreased discrimination as well as c-Fos expression. We suggest that AMPA receptors in DG mediate recall and consolidation of memories associated with sucrose consumption. CNQX pre-treated animals, if presented with sweet pellet on nose poke, exhibited high discrimination index coupled with increased c-Fos expression. In these CNQX treated rats, the DI was again decreased following administration of NMDA receptor antagonist AP5. We suggest that, although AMPA receptors are blocked, the access to sweet pellet may induce surge of glutamate in the DG, which in turn may reinstate memories via activation of erstwhile silent synapses in NMDA dependant manner.
Topics: Animals; Male; Receptors, AMPA; Rats, Wistar; Sucrose; Dentate Gyrus; Receptors, N-Methyl-D-Aspartate; Excitatory Amino Acid Antagonists; Proto-Oncogene Proteins c-fos; Rats; 6-Cyano-7-nitroquinoxaline-2,3-dione; Memory; Conditioning, Operant; Discrimination, Psychological; Self Administration; RNA, Messenger; Discrimination Learning
PubMed: 38780087
DOI: 10.1002/hipo.23609 -
Nature Communications May 2024Neural circuits with specific structures and diverse neuronal firing features are the foundation for supporting intelligent tasks in biology and are regarded as the...
Neural circuits with specific structures and diverse neuronal firing features are the foundation for supporting intelligent tasks in biology and are regarded as the driver for catalyzing next-generation artificial intelligence. Emulating neural circuits in hardware underpins engineering highly efficient neuromorphic chips, however, implementing a firing features-driven functional neural circuit is still an open question. In this work, inspired by avoidance neural circuits of crickets, we construct a spiking feature-driven sensorimotor control neural circuit consisting of three memristive Hodgkin-Huxley neurons. The ascending neurons exhibit mixed tonic spiking and bursting features, which are used for encoding sensing input. Additionally, we innovatively introduce a selective communication scheme in biology to decode mixed firing features using two descending neurons. We proceed to integrate such a neural circuit with a robot for avoidance control and achieve lower latency than conventional platforms. These results provide a foundation for implementing real brain-like systems driven by firing features with memristive neurons and put constructing high-order intelligent machines on the agenda.
Topics: Robotics; Neurons; Animals; Neural Networks, Computer; Action Potentials; Models, Neurological; Gryllidae; Nerve Net; Artificial Intelligence; Avoidance Learning
PubMed: 38773067
DOI: 10.1038/s41467-024-48399-7 -
PloS One 2024The following paper describes a steady-state model of concurrent choice, termed the active time model (ATM). ATM is derived from maximization principles and is...
The following paper describes a steady-state model of concurrent choice, termed the active time model (ATM). ATM is derived from maximization principles and is characterized by a semi-Markov process. The model proposes that the controlling stimulus in concurrent variable-interval (VI) VI schedules of reinforcement is the time interval since the most recent response, termed here "the active interresponse time" or simply "active time." In the model after a response is generated, it is categorized by a function that relates active times to switch/stay probabilities. In the paper the output of ATM is compared with predictions made by three other models of operant conditioning: melioration, a version of scalar expectancy theory (SET), and momentary maximization. Data sets considered include preferences in multiple-concurrent VI VI schedules, molecular choice patterns, correlations between switching and perseveration, and molar choice proportions. It is shown that ATM can account for all of these data sets, while the other models produce more limited fits. However, rather than argue that ATM is the singular model for concurrent VI VI choice, a consideration of its concept space leads to the conclusion that operant choice is multiply-determined, and that an adaptive viewpoint-one that considers experimental procedures both as selecting mechanisms for animal choice as well as tests of the controlling variables of that choice-is warranted.
Topics: Choice Behavior; Animals; Conditioning, Operant; Reinforcement Schedule; Time Factors; Models, Psychological; Reinforcement, Psychology; Markov Chains
PubMed: 38771859
DOI: 10.1371/journal.pone.0301173 -
Environmental Toxicology and... Jun 2024Antiepileptic drugs, such as phenytoin, are often leaked into aquatic systems through sewage facilities due to their low metabolic rate. Fish, such as the Japanese...
Antiepileptic drugs, such as phenytoin, are often leaked into aquatic systems through sewage facilities due to their low metabolic rate. Fish, such as the Japanese medaka (Oryzias latipes), demonstrate abnormal swimming behavior such as equilibrium abnormalities, rotational behavior, and vertical swimming, when exposed to phenytoin. Therefore, it is hypothesized that predator avoidance may be hindered. This study aimed to investigate the effects of phenytoin exposure-induced behavioral abnormalities in predator avoidance in Japanese medaka. The results showed that individuals with behavioral abnormalities had a reduced ability to avoid danger. Furthermore, the fish demonstrated a delayed recognition reaction to approaching predators. Additionally, predatory fish, such as silver pike characin (Ctenolucius hujeta), were more likely to prey upon abnormal individuals. In conclusion, the fish exposed to phenytoin demonstrated behavioral changes that increased its predation risk. This study is the first to determine the effects of behavioral abnormalities in Japanese medaka which was induced after phenytoin exposure on predator risk avoidance.
Topics: Animals; Phenytoin; Oryzias; Anticonvulsants; Water Pollutants, Chemical; Behavior, Animal; Predatory Behavior; Avoidance Learning
PubMed: 38763435
DOI: 10.1016/j.etap.2024.104474 -
Advanced Materials (Deerfield Beach,... May 2024The field of biomimetic electronics that mimic synaptic functions has expanded significantly to overcome the limitations of the von Neumann bottleneck. However,...
The field of biomimetic electronics that mimic synaptic functions has expanded significantly to overcome the limitations of the von Neumann bottleneck. However, the scaling down of the technology has led to an increasingly intricate manufacturing process. To address the issue, this work presents a one-shot integrable electropolymerization (OSIEP) method with remote controllability for the deposition of synaptic elements on a chip by exploiting bipolar electrochemistry. Condensing synthesis, deposition, and patterning into a single fabrication step is achieved by combining alternating-current voltage superimposed on direct-current voltage-bipolar electropolymerization and a specially designed dual source/drain bipolar electrodes. As a result, uniform 6 × 5 arrays of poly(3,4-ethylenedioxythiophene) channels are successfully fabricated on flexible ultrathin parylene substrates in one-shot process. The channels exhibited highly uniform characteristics and are directly used as electrochemical synaptic transistor with synaptic plasticity over 100 s. The synaptic transistors have demonstrated promising performance in an artificial neural network (NN) simulation, achieving a high recognition accuracy of 95.20%. Additionally, the array of synaptic transistor is easily reconfigured to a multi-gate synaptic circuit to implement the principles of operant conditioning. These results provide a compelling fabrication strategy for realizing cost-effective and disposable NN systems with high integration density.
PubMed: 38762775
DOI: 10.1002/adma.202402361 -
Nature Communications May 2024The ventral pallidum (VP) contains GABA and glutamate neurons projecting to ventral tegmental area (VTA) whose stimulation drives approach and avoidance, respectively....
The ventral pallidum (VP) contains GABA and glutamate neurons projecting to ventral tegmental area (VTA) whose stimulation drives approach and avoidance, respectively. Yet little is known about the mechanisms by which VP cell types shape VTA activity and drive behavior. Here, we found that both VP GABA and glutamate neurons were activated during approach to reward or by delivery of an aversive stimulus. Stimulation of VP GABA neurons inhibited VTA GABA, but activated dopamine and glutamate neurons. Remarkably, stimulation-evoked activation was behavior-contingent such that VTA recruitment was inhibited when evoked by the subject's own action. Conversely, VP glutamate neurons activated VTA GABA, as well as dopamine and glutamate neurons, despite driving aversion. However, VP glutamate neurons evoked dopamine in aversion-associated ventromedial nucleus accumbens (NAc), but reduced dopamine release in reward-associated dorsomedial NAc. These findings show how heterogeneous VP projections to VTA can be engaged to shape approach and avoidance behaviors.
Topics: Ventral Tegmental Area; Animals; Glutamic Acid; Basal Forebrain; Male; Reward; GABAergic Neurons; Avoidance Learning; Mice; Dopamine; Nucleus Accumbens; Neurons; gamma-Aminobutyric Acid; Dopaminergic Neurons; Mice, Inbred C57BL; Behavior, Animal
PubMed: 38762463
DOI: 10.1038/s41467-024-48340-y -
Journal of Neuroengineering and... May 2024Individuals with a moderate-to-severe traumatic brain injury (m/sTBI), despite experiencing good locomotor recovery six months post-injury, face challenges in adapting...
BACKGROUND
Individuals with a moderate-to-severe traumatic brain injury (m/sTBI), despite experiencing good locomotor recovery six months post-injury, face challenges in adapting their locomotion to the environment. They also present with altered cognitive functions, which may impact dual-task walking abilities. Whether they present collision avoidance strategies with moving pedestrians that are altered under dual-task conditions, however, remains unclear. This study aimed to compare between individuals with m/sTBI and age-matched control individuals: (1), the locomotor and cognitive costs associated with the concurrent performance of circumventing approaching virtual pedestrians (VRPs) while attending to an auditory-based cognitive task and; (2) gaze behaviour associated with the VRP circumvention task in single and dual-task conditions.
METHODOLOGY
Twelve individuals with m/sTBI (age = 43.3 ± 9.5 yrs; >6 mo. post injury) and 12 healthy controls (CTLs) (age = 41.8 ± 8.3 yrs) were assessed while walking in a virtual subway station viewed in a head-mounted display. They performed a collision avoidance task with VRPs, as well as auditory-based cognitive tasks (pitch discrimination and auditory Stroop), both under single and dual-task conditions. Dual-task cost (DTC) for onset distance of trajectory deviation, minimum distance from the VRP, maximum lateral deviation, walking speed, gaze fixations and cognitive task accuracy were contrasted between groups using generalized estimating equations.
RESULTS
In contrast to CTLs who showed locomotor DTCs only, individuals with m/sTBI displayed both locomotor and cognitive DTCs. While both groups walked slower under dual-task conditions, only individuals with m/sTBI failed to modify their onset distance of trajectory deviation and maintained smaller minimum distances and smaller maximum lateral deviation compared to single-task walking. Both groups showed shorter gaze fixations on the approaching VRP under dual-task conditions, but this reduction was less pronounced in the individuals with m/sTBI. A reduction in cognitive task accuracy under dual-task conditions was found in the m/sTBI group only.
CONCLUSION
Individuals with m/sTBI present altered locomotor and gaze behaviours, as well as altered cognitive performances, when executing a collision avoidance task involving moving pedestrians in dual-task conditions. Potential mechanisms explaining those alterations are discussed. Present findings highlight the compromised complex walking abilities in individuals with m/sTBI who otherwise present a good locomotor recovery.
Topics: Humans; Male; Adult; Female; Pedestrians; Brain Injuries, Traumatic; Middle Aged; Virtual Reality; Psychomotor Performance; Walking; Cognition; Avoidance Learning; Attention
PubMed: 38755606
DOI: 10.1186/s12984-024-01378-x