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1.
PLoS Comput Biol ; 15(12): e1007550, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31856162

RESUMO

Most objects and vegetation making up the habitats of echolocating bats return a multitude of overlapping echoes. Recent evidence suggests that the limited temporal and spatial resolution of bio-sonar prevents bats from separately perceiving the objects giving rise to these overlapping echoes. Therefore, bats often operate under conditions where their ability to localize obstacles is severely limited. Nevertheless, bats excel at avoiding complex obstacles. In this paper, we present a robotic model of bat obstacle avoidance using interaural level differences and distance to the nearest obstacle as the minimal set of cues. In contrast to previous robotic models of bats, the current robot does not attempt to localize obstacles. We evaluate two obstacle avoidance strategies. First, the Fixed Head Strategy keeps the acoustic gaze direction aligned with the direction of flight. Second, the Delayed Linear Adaptive Law (DLAL) Strategy uses acoustic gaze scanning, as observed in hunting bats. Acoustic gaze scanning has been suggested to aid the bat in hunting for prey. Here, we evaluate its adaptive value for obstacle avoidance when obstacles can not be localized. The robot's obstacle avoidance performance is assessed in two environments mimicking (highly cluttered) experimental setups commonly used in behavioral experiments: a rectangular arena containing multiple complex cylindrical reflecting surfaces and a corridor lined with complex reflecting surfaces. The results indicate that distance to the nearest object and interaural level differences allows steering the robot clear of obstacles in environments that return non-localizable echoes. Furthermore, we found that using acoustic gaze scanning reduced performance, suggesting that gaze scanning might not be beneficial under conditions where the animal has limited access to angular information, which is in line with behavioral evidence.


Assuntos
Quirópteros/fisiologia , Ecolocação/fisiologia , Modelos Biológicos , Robótica/instrumentação , Acústica , Algoritmos , Animais , Aprendizagem da Esquiva/fisiologia , Comportamento Animal/fisiologia , Quirópteros/psicologia , Biologia Computacional , Simulação por Computador , Sinais (Psicologia) , Voo Animal/fisiologia , Robótica/estatística & dados numéricos
2.
Bratisl Lek Listy ; 120(12): 881-886, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31855045

RESUMO

BACKGROUND: Galangin, a flavonoid compound with acetylcholinesterase inhibitory activity, may improve cognitive functions by enhancing cholinergic transmission. OBJECTIVES: We aimed to investigate the effects of galangin on spatial memory impairment in rats. METHODS: The effects of galangin (50 and 100 mg/kg) and reference anti-dementia drug donepezil (1mg/kg) administrations were examined on memory impairment induced by the muscarinic cholinergic receptor antagonist scopolamine or the nicotinic cholinergic receptor antagonist mecamylamine in the Morris water maze (MWM) test. Hippocampal acetylcholine concentrations were also determined. RESULTS: Galangin 50 and 100 mg/kg significantly decreased the mean distance to platform and increased the time spent in the escape platform quadrant in scopolamine-treated rats. Galangin 100 mg/kg significantly decreased the mean distance to platform and increased the time spent in the escape platform quadrant in mecamylamine-treated rats. The effects of galangin in the MWM were comparable with donepezil. Scopolamine and mecamylamine decreased acetylcholine concentrations, whereas galangin both alone and with mecamylamine or scopolamine administration increased acetylcholine concentrations. CONCLUSION: Galangin improved memory impairment comparable to donepezil and nicotinic and muscarinic receptors may be involved in this effect. Galangin may be considered as a promising flavonoid in the prevention and treatment of memory impairment in Alzheimer's disease and other dementias (Fig. 7,Ref. 37).


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Flavonoides/farmacologia , Aprendizagem em Labirinto/efeitos dos fármacos , Mecamilamina/toxicidade , Escopolamina/toxicidade , Memória Espacial/efeitos dos fármacos , Animais , Aprendizagem da Esquiva/fisiologia , Inibidores da Colinesterase , Donepezila , Flavonoides/administração & dosagem , Aprendizagem em Labirinto/fisiologia , Mecamilamina/efeitos adversos , Ratos , Ratos Sprague-Dawley , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia , Escopolamina/efeitos adversos
3.
Acta Psychol (Amst) ; 201: 102942, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31706179

RESUMO

Among the great variety of approach/avoidance tasks, the Visual Approach/Avoidance by the Self Task (VAAST, Rougier et al., 2018) appears to be a promising tool. Previous work showed that the VAAST leads to large and replicable compatibility effects (e.g., faster response time to approach positive stimuli and avoid negative stimuli than the reverse). In the present contribution, we provide an online and easy-to-use version of the VAAST (namely, the online-VAAST). Across four experiments, we show that the online-VAAST produces effects that are of similar magnitude to those of the lab version of this task. Specifically, we obtained compatibility effects when using positive/negative words (Experiment 1), positive/negative images (Experiment 2), French/North-African first names (Experiment 3), and European American/African American first names (Experiment 4). Moreover, these effects emerged with culturally different populations (i.e., Americans in Experiments 1, 2, and 4, French in Experiment 3). Overall, the online-VAAST could be of great interest for all researchers interested in measuring approach/avoidance tendencies: Its specificities allow reaching large samples both offline and online with no accessibility constraints regarding programming abilities or program copyright.


Assuntos
Aprendizagem da Esquiva/fisiologia , Estimulação Luminosa/métodos , Tempo de Reação/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória
4.
Nat Neurosci ; 22(10): 1586-1597, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31551602

RESUMO

Emotional learning and memory are functionally and dysfunctionally regulated by the neuromodulatory state of the brain. While the role of excitatory and inhibitory neural circuits mediating emotional learning and its control have been the focus of much research, we are only now beginning to understand the more diffuse role of neuromodulation in these processes. Recent experimental studies of the acetylcholine, noradrenaline and dopamine systems in fear learning and extinction of fear responding provide surprising answers to key questions in neuromodulation. One area of research has revealed how modular organization, coupled with context-dependent coding modes, allows for flexible brain-wide or targeted neuromodulation. Other work has shown how these neuromodulators act in downstream targets to enhance signal-to-noise ratios and gain, as well as to bind distributed circuits through neuronal oscillations. These studies elucidate how different neuromodulatory systems regulate aversive emotional processing and reveal fundamental principles of neuromodulatory function.


Assuntos
Aprendizagem da Esquiva/fisiologia , Emoções/fisiologia , Rede Nervosa/fisiologia , Animais , Medo/fisiologia , Medo/psicologia , Humanos , Aprendizagem/fisiologia , Memória/fisiologia , Neurotransmissores/fisiologia
5.
Nat Commun ; 10(1): 3970, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31481701

RESUMO

Gamma is a ubiquitous brain rhythm hypothesized to support cognitive, perceptual, and mnemonic functions by coordinating neuronal interactions. While much correlational evidence supports this hypothesis, direct experimental tests have been lacking. Since gamma occurs as brief bursts of varying frequencies and durations, most existing approaches to manipulate gamma are either too slow, delivered irrespective of the rhythm's presence, not spectrally specific, or unsuitable for bidirectional modulation. Here, we overcome these limitations with an approach that accurately detects and modulates endogenous gamma oscillations, using closed-loop signal processing and optogenetic stimulation. We first show that the rat basolateral amygdala (BLA) exhibits prominent gamma oscillations during the consolidation of contextual memories. We then boost or diminish gamma during consolidation, in turn enhancing or impairing subsequent memory strength. Overall, our study establishes the role of gamma oscillations in memory consolidation and introduces a versatile method for studying fast network rhythms in vivo.


Assuntos
Complexo Nuclear Basolateral da Amígdala/fisiologia , Ritmo Gama/fisiologia , Memória Espacial/fisiologia , Animais , Comportamento Apetitivo/fisiologia , Aprendizagem da Esquiva/fisiologia , Masculino , Consolidação da Memória/fisiologia , Optogenética , Ratos Long-Evans
6.
Int J Neurosci ; 129(12): 1203-1212, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31393204

RESUMO

Purpose of the study: Kaempferol (KM) is a flavonoid found in plant-derived foods and medicinal plants. Recently, it is well established that KM plays a protective role to develop Alzheimer's disease. The current study aimed at evaluating the effect of intracerebroventricular micro-injection of KM on memory retention of passive avoidance learning (MRPAM) and identifying the potentially related cholinergic mechanisms (ChMs) in rats. Materials and methods: In the current study, male Wistar rats randomly divided into control, vehicle and KM (10, 20 and 40 µg/rat) groups. Moreover, MRPAM was evaluated by shuttle box test. The role of ChM was studied using non-selective and selective acetylcholine antagonists (scopolamine [SCN], 4-DAMP and methoctramine [MN], respectively) as well as pirenzepine (PZ) in combination with KM. Results: The employment of KM (40 µg/rat) improved the SCN-induced memory impairment in MRPAM. Co-treatment with KM (40 µg/rat) plus 4-DAMP significantly increased the step-through latency (STL, P < 0.05; 167 ± 28 s) and decreased the total dark chamber (TDC, P < 0.05; 121 ± 31 s) compared with those of the 4-DAMP group (STL: 75 ± 13 s; TDC: 178 ± 46 s). Co-treatment with KM (40 µg/rat) plus PZ attenuated STL, and also increased TDC (P < 0.01; 220 ± 28 s) compared with those of the PZ group. Co-treatment with KM (10 and 20 µg/rat) and MN increased STL (P < 0.05), and deceased TDC compared with those of the MN group (P < 0.01). Conclusions: Totally, the results of the present study showed that cholinergic system may be involved in improving effect of KM on SCN-induced memory impairment.


Assuntos
Acetilcolina/fisiologia , Aprendizagem da Esquiva/efeitos dos fármacos , Antagonistas Colinérgicos/administração & dosagem , Quempferóis/administração & dosagem , Memória/efeitos dos fármacos , Antagonistas Muscarínicos/administração & dosagem , Animais , Aprendizagem da Esquiva/fisiologia , Diaminas/administração & dosagem , Injeções Intraventriculares , Masculino , Memória/fisiologia , Microinjeções , Piperidinas/administração & dosagem , Pirenzepina/administração & dosagem , Ratos Wistar , Escopolamina/administração & dosagem
7.
J Vet Med Sci ; 81(8): 1121-1128, 2019 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-31270283

RESUMO

Wild animals tend to avoid novel objects that do not elicit clear avoidance behaviors in domesticated animals. We previously found that the basolateral complex of the amygdala (BLA) and dorsal bed nucleus of the stria terminalis (dBNST) were larger in trapped wild rats compared with laboratory rats. Based on these findings, we hypothesized that the BLA and/or dBNST would be differentially activated when wild and laboratory rats showed different avoidance behaviors towards novel objects. In this study, we placed novel objects at one end of the home cage. We measured the time spent in that half of the cage and expressed the data as a percentage of the time spent in that region with no object placement. We found that this percentage was lower in the wild rats compared with the laboratory rats. These behavioral differences were accompanied by increased Fos expression in the BLA, but not in the dBNST, of the wild rats. These results suggest that wild rats show greater BLA activation compared with laboratory rats in response to novel objects. We also found increased Fos expression in the paraventricular nucleus of the hypothalamus, ventral BNST, and ventromedial hypothalamus, but not in the central amygdala of wild rats. Taken together, our data represent new information regarding differences in behavioral and neural responses towards novel objects in wild vs. laboratory rats.


Assuntos
Animais Selvagens/psicologia , Aprendizagem da Esquiva/fisiologia , Complexo Nuclear Basolateral da Amígdala/fisiologia , Ratos/psicologia , Animais , Animais Selvagens/anatomia & histologia , Técnica Indireta de Fluorescência para Anticorpo , Hipotálamo/fisiologia , Masculino , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos/anatomia & histologia
8.
Chemosphere ; 235: 126-135, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31255752

RESUMO

As the exposure of organisms to contaminants can provoke harmful effects, some organisms try to avoid a continuous exposure by using different strategies. The aim of the current study was to assess the ability of the shrimp Palaemon varians to detect a triclosan gradient and escape to less contaminated areas. Two multi-compartmented exposure systems (the linear system and the HeMHAS-Heterogeneous Multi-Habitat Assay System) were used and then results were compared. Finally, it was aimed how sensitive the avoidance response is by comparing it with other endpoints through a sensitivity profile by biological groups and the species sensitive distribution. The distribution of the shrimps along the triclosan gradient was dependent on the concentrations, not exceeding 3% for 54 µg/L in the linear system and 7% for 81 µg/L in the HeMHAS; 25% of organisms preferred the compartment with the lowest concentrations in both systems. Half of the population seems to avoid concentrations around 40-50 µg/L. The triclosan concentration that might start (threshold) to trigger an important avoidance (around 20%) was estimated to be of 18 µg/L. The profile of sensitivity to triclosan showed that avoidance by shrimps was less sensitive than microalgae growth and avoidance by guppy; however, it might occur even at concentrations considered safe for more than 95% of the species. In summary, (i) the HeMHAS proved to be a suitable system to simulate heterogeneous contamination scenarios, (ii) triclosan triggered the avoidance response in P. varians, and (iii) the avoidance was very sensitive compared to other ecotoxicological responses.


Assuntos
Aprendizagem da Esquiva/fisiologia , Reação de Fuga/efeitos dos fármacos , Palaemonidae/fisiologia , Triclosan/toxicidade , Poluentes Químicos da Água/análise , Animais , Ecossistema , Ecotoxicologia , Microalgas/fisiologia , Poecilia/fisiologia , Alimentos Marinhos , Natação/fisiologia , Poluentes Químicos da Água/toxicidade
9.
Nat Commun ; 10(1): 3186, 2019 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-31320626

RESUMO

Biogenic amine neurotransmitters play a central role in metazoan biology, and both their chemical structures and cognate receptors are evolutionarily conserved. Their primary roles are in cell-to-cell signaling, as biogenic amines are not normally recruited for communication between separate individuals. Here, we show that in the nematode C. elegans, a neurotransmitter-sensing G protein-coupled receptor, TYRA-2, is required for avoidance responses to osas#9, an ascaroside pheromone that incorporates the neurotransmitter, octopamine. Neuronal ablation, cell-specific genetic rescue, and calcium imaging show that tyra-2 expression in the nociceptive neuron, ASH, is necessary and sufficient to induce osas#9 avoidance. Ectopic expression in the AWA neuron, which is generally associated with attractive responses, reverses the response to osas#9, resulting in attraction instead of avoidance behavior, confirming that TYRA-2 partakes in the sensing of osas#9. The TYRA-2/osas#9 signaling system represents an inter-organismal communication channel that evolved via co-option of a neurotransmitter and its cognate receptor.


Assuntos
Aprendizagem da Esquiva/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Comunicação Celular/fisiologia , Octopamina/metabolismo , Receptores de Amina Biogênica/metabolismo , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Nociceptores/metabolismo , Receptores de Amina Biogênica/genética , Transdução de Sinais
10.
PLoS One ; 14(7): e0219147, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31344045

RESUMO

Skin conductance response (SCR) is used in psychophysiological research to measure the reactions of the autonomic nervous system to reward and punishment. While there is consistent evidence that SCR increases to both aversive and appetitive stimuli, it remains unclear whether SCR simply represents a general index of arousal to motivationally significant outcomes or may also differentiate action or inhibition of action that lead to such outcomes. Furthermore, individual differences in trait sensitivity to reward and punishment can influence physiological arousal during approach and avoidance behaviors. Yet, their inter-relationships have not been examined. To address these gaps, we employed a reward go/no-go task with ⅔ go and ⅓ no-go trials and an individually titrated go response window. Correct go and no-go responses were rewarded while incorrect responses were penalized. We examined whether SCR varied with outcome (win vs. loss), action (go vs. no-go), and individual differences in reward sensitivity (SR) and sex. The results showed greater SCRs to loss vs. win, to go vs. no-go success, and to go success in positive correlation with SR. Further, SCR mediated the relationship between SR and go success rate. In sex differences, men exhibited greater SCR which was more predictive of go success rate relative to women. In contrast, SCR was more predictive of no-go success rate in women. Thus, SCR varies according to behavioral contingency, outcome, sex, and reward sensitivity. These findings add to the literature by characterizing the individual and behavioral factors that may influence physiological arousal in response to salient events.


Assuntos
Resposta Galvânica da Pele/fisiologia , Recompensa , Adulto , Nível de Alerta/fisiologia , Sistema Nervoso Autônomo/fisiologia , Aprendizagem da Esquiva/fisiologia , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Motivação/fisiologia , Personalidade/fisiologia , Psicofisiologia , Punição/psicologia , Fatores Sexuais , Análise e Desempenho de Tarefas , Adulto Jovem
11.
PLoS Genet ; 15(7): e1008297, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31323047

RESUMO

The avoidance of starvation is critical for the survival of most organisms, thus animals change behavior based on past nutritional conditions. Insulin signaling is important for nutritional state-dependent behavioral plasticity, yet the underlying regulatory mechanism at the cellular level remains unclear. Previous studies showed that insulin-like signaling is required for taste avoidance learning, in which the nematode Caenorhabditis elegans avoids salt concentrations encountered under starvation conditions. DAF-2c, a splice isoform of the DAF-2 insulin receptor, functions in the axon of the ASER sensory neuron, which senses changes in salt concentrations. In addition, mutants of a major downstream factor of DAF-2, the forkhead transcription factor O (FOXO) homolog DAF-16, show defects in taste avoidance learning. Interestingly, the defect of the daf-2 mutant is not suppressed by daf-16 mutations in the learning, unlike those in other phenomena, such as longevity and development. Here we show that multiple DAF-16 isoforms function in ASER. By epistasis analysis using a DAF-2c isoform-specific mutant and an activated form of DAF-16, we found that DAF-16 acts in the nucleus in parallel with the DAF-2c-dependent pathway in the axon, indicating that insulin-like signaling acts both in the cell body and axon of a single neuron, ASER. Starvation conditioning induces nuclear translocation of DAF-16 in ASER and degradation of DAF-16 before starvation conditioning causes defects in taste avoidance learning. Forced nuclear localization of DAF-16 in ASER biased chemotaxis towards lower salt concentrtions and this effect required the Gq/PKC pathway and neuropeptide processing enzymes. These data imply that DAF-16/FOXO transmits starvation signals and modulates neuropeptide transmission in the learning.


Assuntos
Aprendizagem da Esquiva/fisiologia , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Cloreto de Sódio/análise , Animais , Comportamento Animal , Núcleo Celular/metabolismo , Epistasia Genética , Insulina , Mutação , Isoformas de Proteínas/metabolismo , Receptor de Insulina/genética , Transdução de Sinais
12.
PLoS One ; 14(6): e0217458, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31216290

RESUMO

Rats not only avoid ingesting a substance associated with LiCl toxicosis, but they display rejection reflexes (e.g., gapes) to its taste; this latter response is thought to reflect disgust or taste aversion. Prior work has shown that rats also avoid consuming foods/fluids associated with other adverse gastrointestinal (GI) effects like lactose indigestion but without the concomitant change in oromotor responses (taste reactivity; TR) indicative of aversion. Because of interpretive limitations of the methods used in those studies, we revisited the taste aversion-avoidance distinction with a design that minimized non-treatment differences among groups. Effects on intake and preference (Experiments 1a, 1b, and 2), as well as consummatory (TR, Experiment 1a and 1b) and appetitive (Progressive Ratio, Experiment 2) behaviors to the taste stimulus were assessed after training. In both experiments, rats were trained to associate 0.2% saccharin (CS) with intraduodenal infusions of LiCl, Lactose, or NaCl control. Rats trained with 18% lactose, 0.3 and 1.5 mEq/kg dose of LiCl subsequently avoided the taste CS in post-training single-bottle intake tests and two-bottle choice tests. However, only those trained with 1.5 mEq/kg LiCl displayed post-conditioning increases in taste CS-elicited aversive TR (Experiment 1a and 1b). This dose of LiCl also led to reductions in breakpoint for saccharin. The fact that conditioned avoidance is not always accompanied by changes in other common appetitive and/or consummatory indices of ingestive motivation further supports a functional dissociation between these processes, and highlights the intricacies of visceral influences on taste-guided ingestive motivation.


Assuntos
Aprendizagem da Esquiva/fisiologia , Modelos Biológicos , Percepção Gustatória/fisiologia , Paladar/fisiologia , Animais , Agentes Aversivos/farmacologia , Aprendizagem da Esquiva/efeitos dos fármacos , Cloreto de Lítio/farmacologia , Masculino , Ratos , Ratos Sprague-Dawley , Sacarina/farmacologia , Percepção Gustatória/efeitos dos fármacos
13.
Neuron ; 103(3): 489-505.e7, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31204082

RESUMO

Despite a wealth of clinical and preclinical data implicating the serotonin (5-HT) system in fear-related affective disorders, a precise definition of this neuromodulator's role in fear remains elusive. Using convergent anatomical and functional approaches, we interrogate the contribution to fear of basal amygdala (BA) 5-HT inputs from the dorsal raphe nucleus (DRN). We show the DRN→BA 5-HT pathway is engaged during fear memory formation and retrieval, and activity of these projections facilitates fear and impairs extinction. The DRN→BA 5-HT pathway amplifies fear-associated BA neuronal firing and theta power and phase-locking. Although fear recruits 5-HT and VGluT3 co-expressing DRN neurons, the fear-potentiating influence of the DRN→BA 5-HT pathway requires signaling at BA 5-HT1A/2A receptors. Input-output mapping illustrates how the DRN→BA 5-HT pathway is anatomically distinct and connected with other brain regions that mediate fear. These findings reveal how a discrete 5-HT circuit orchestrates a broader neural network to calibrate aversive memory.


Assuntos
Tonsila do Cerebelo/fisiologia , Aprendizagem da Esquiva/fisiologia , Núcleo Dorsal da Rafe/fisiologia , Vias Neurais/fisiologia , Serotonina/fisiologia , Animais , Condicionamento Clássico/fisiologia , Extinção Psicológica , Medo/fisiologia , Feminino , Genes Reporter , Resposta de Imobilidade Tônica/fisiologia , Masculino , Rememoração Mental/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Optogenética , Sinaptofisina/administração & dosagem , Sinaptofisina/análise , Ritmo Teta/fisiologia
14.
Psychopharmacology (Berl) ; 236(8): 2437-2449, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31254091

RESUMO

BACKGROUND: Aversive stimuli in the environment influence human actions. This includes valence-dependent influences on action selection, e.g., increased avoidance but decreased approach behavior. However, it is yet unclear how aversive stimuli interact with complex learning and decision-making in the reward and avoidance domain. Moreover, the underlying computational mechanisms of these decision-making biases are unknown. METHODS: To elucidate these mechanisms, 54 healthy young male subjects performed a two-step sequential decision-making task, which allows to computationally model different aspects of learning, e.g., model-free, habitual, and model-based, goal-directed learning. We used a within-subject design, crossing task valence (reward vs. punishment learning) with emotional context (aversive vs. neutral background stimuli). We analyzed choice data, applied a computational model, and performed simulations. RESULTS: Whereas model-based learning was not affected, aversive stimuli interacted with model-free learning in a way that depended on task valence. Thus, aversive stimuli increased model-free avoidance learning but decreased model-free reward learning. The computational model confirmed this effect: the parameter lambda that indicates the influence of reward prediction errors on decision values was increased in the punishment condition but decreased in the reward condition when aversive stimuli were present. Further, by using the inferred computational parameters to simulate choice data, our effects were captured. Exploratory analyses revealed that the observed biases were associated with subclinical depressive symptoms. CONCLUSION: Our data show that aversive environmental stimuli affect complex learning and decision-making, which depends on task valence. Further, we provide a model of the underlying computations of this affective modulation. Finally, our finding of increased decision-making biases in subjects reporting subclinical depressive symptoms matches recent reports of amplified Pavlovian influences on action selection in depression and suggests a potential vulnerability factor for mood disorders. We discuss our findings in the light of the involvement of the neuromodulators serotonin and dopamine.


Assuntos
Aprendizagem da Esquiva/fisiologia , Simulação por Computador , Tomada de Decisões/fisiologia , Depressão/psicologia , Modelos Psicológicos , Recompensa , Afeto/fisiologia , Comportamento de Escolha/fisiologia , Humanos , Masculino , Estimulação Luminosa/métodos , Punição/psicologia , Adulto Jovem
15.
Behav Processes ; 165: 1-3, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31185264

RESUMO

The nematode Phasmarhabditis hermaphrodita can infect and kill many species of slugs and has been formulated into a biological control agent for farmers and gardeners. P. hermaphrodita can manipulate the behaviour of slugs, making those infected move to areas where the nematode is present. Research suggests P. hermaphrodita uses manipulation of biogenic amines to achieve this, however the exact role of serotonin and dopamine needs further elucidation. Here we fed slugs Deroceras invadens (uninfected and infected with P. hermaphrodita) apomorphine, sertraline and haloperidol and observed their behaviour when given a choice between a P. hermaphrodita infested habitat, or a parasite free area of soil. In contrast to their usual P. hermaphrodita avoidance behaviour, uninfected D. invadens fed sertraline were attracted to the nematodes and conversely those fed haloperidol avoided the nematodes. D. invadens fed apomorphine were recorded equally on the control and nematode side. D. invadens pre-infected with P. hermaphrodita fed sertraline and apomorphine were found significantly more on the side with the nematodes. However, suppressing dopaminergic signalling through feeding with haloperidol abrogated this attraction and slugs were found on both sides. These results demonstrate that serotonin and dopamine are potential regulators of behavioural manipulation by P. hermaphrodita.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Agentes de Controle Biológico/farmacologia , Gastrópodes/efeitos dos fármacos , Gastrópodes/parasitologia , Rhabditoidea , Animais , Apomorfina/farmacologia , Aprendizagem da Esquiva/fisiologia , Dopamina/fisiologia , Haloperidol/farmacologia , Serotonina/fisiologia , Sertralina/farmacologia , Solo/parasitologia
16.
Psychopharmacology (Berl) ; 236(12): 3413-3419, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31250073

RESUMO

RATIONALE: The endocannabinoid system (eCS) is an important modulator of social anxiety and social reward, as well as memory functions. OBJECTIVES: The present study evaluated the role of eCS in social interactions and aversive memory extinction in capuchin monkeys (Sapajus spp.) by blocking the cannabinoid type 1 receptor (CB1r). METHODS: In experiment 1, spontaneous social and non-social behaviors of five capuchin males, each one living in triads with two other females, were observed after AM251 treatment (vehicle, 0.3, 1.0, and 3.0 mg/kg; i.m.). In experiment 2, seven male capuchin monkeys were trained to reach for a reward inside a wooden box. After training, they were given either vehicle or a 3.0-mg/kg i.m. dose of AM251 before a single aversive encounter with a live snake in the box. The latency to return to reach the reward inside the box in subsequent trials was measured. RESULTS: The 3.0-mg/kg dose significantly increased the time spent performing self-directed behaviors, while decreasing that of social interactions. No changes were observed in vigilance or locomotion. AM251 increased the latency to reach the reward after the aversive encounter. CONCLUSION: Taken together, these results suggest that CB1r antagonism induces social deficits without increasing anxiety levels and impairs the extinction of aversive memories. This behavioral profile in monkeys underscores the potential involvement of eCS signaling in the deficits observed in autism spectrum disorders.


Assuntos
Aprendizagem da Esquiva/fisiologia , Medo/fisiologia , Relações Interpessoais , Memória/fisiologia , Piperidinas/farmacologia , Pirazóis/farmacologia , Receptor CB1 de Canabinoide/antagonistas & inibidores , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Cebus , Relação Dose-Resposta a Droga , Medo/efeitos dos fármacos , Medo/psicologia , Feminino , Masculino , Memória/efeitos dos fármacos , Distribuição Aleatória , Recompensa
17.
Nat Hum Behav ; 3(7): 733-745, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31110338

RESUMO

Jointly minimizing multiple threats over extended time horizons enhances survival. Consequently, many tests of approach-avoidance conflicts incorporate multiple threats for probing corollaries of animal and human anxiety. To facilitate computations necessary for threat minimization, the human brain may concurrently harness multiple decision policies and associated neural controllers, but it is unclear which. We combine a task that mimics foraging under predation with behavioural modelling and functional neuroimaging. Human choices rely on immediate predator probability-a myopic heuristic policy-and on the optimal policy, which integrates all relevant variables. Predator probability relates positively and the associated choice uncertainty relates negatively to activations in the anterior hippocampus, amygdala and dorsolateral prefrontal cortex. The optimal policy is positively associated with dorsomedial prefrontal cortex activity. We thus provide a decision-theoretic outlook on the role of the human hippocampus, amygdala and prefrontal cortex in resolving approach-avoidance conflicts relevant for anxiety and integral for survival.


Assuntos
Tonsila do Cerebelo/diagnóstico por imagem , Ansiedade/fisiopatologia , Aprendizagem da Esquiva/fisiologia , Comportamento de Escolha/fisiologia , Tomada de Decisões/fisiologia , Hipocampo/diagnóstico por imagem , Córtex Pré-Frontal/diagnóstico por imagem , Adulto , Tonsila do Cerebelo/fisiologia , Comportamento Apetitivo , Feminino , Neuroimagem Funcional , Hipocampo/fisiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Pré-Frontal/fisiologia , Adulto Jovem
18.
Drug Alcohol Depend ; 200: 145-152, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31132681

RESUMO

BACKGROUND: Cognitive Bias Modification (CBM) has garnered interest as a potential addiction treatment. CBM interventions such as Approach Avoidance Training (AAT) are designed to alter automatic tendencies to approach drugs or drug-related cues. In our previous work, the cannabis AAT (CAAT) reduced cannabis approach bias, which was related to reduced cannabis use, among 80 non-treatment-seeking cannabis-using youth (Jacobus et al., 2018). In this preliminary examination, a subsample of these youth underwent neuroimaging to explore CAAT's effect on cannabis cue-related neural activation. METHODS: Sub-study participants were 41 cannabis-using youth ages 17-21 (mean age = 18.83; 47.5% female). Participants completed a cannabis cue-reactivity task during a functional MRI scan pre- and post CAAT-training or CAAT-sham to examine CAAT-related neural changes. RESULTS: Thirty-seven youth completed all six CAAT (n = 19) or CAAT-sham (n = 18) training sessions and had usable neuroimaging data. The group*time interaction on cannabis approach bias reached trend-level significance (p = .055). Change in approach bias slopes from pre-to post-treatment was positive for CAAT-sham (increased approach bias) and negative for CAAT-training (change to avoidance bias), consistent with the larger study. No significant changes emerged for cannabis cue-induced activation following CAAT-training or CAAT-sham in whole brain or region of interest analyses. However, active CAAT-training was associated with small-to-medium decreases in amygdala (Cohen's dz = 0.36) and medial prefrontal cortex (Cohen's dz = 0.48) activation to cannabis cues. CONCLUSIONS: Despite reducing cannabis use in the larger sample, CAAT-training did not alter neural cannabis cue-reactivity in the sub-study compared to CAAT-sham. More research is needed to understand neural mechanisms underlying AAT-related changes in substance use.


Assuntos
Comportamento do Adolescente/psicologia , Aprendizagem da Esquiva , Encéfalo/diagnóstico por imagem , Imagem por Ressonância Magnética/tendências , Fumar Maconha/terapia , Terapia Assistida por Computador/tendências , Adolescente , Aprendizagem da Esquiva/fisiologia , Comportamento Aditivo/diagnóstico por imagem , Comportamento Aditivo/psicologia , Sinais (Psicologia) , Método Duplo-Cego , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Abuso de Maconha/diagnóstico por imagem , Abuso de Maconha/psicologia , Abuso de Maconha/terapia , Fumar Maconha/psicologia , Estimulação Luminosa/métodos , Projetos Piloto , Terapia Assistida por Computador/métodos , Adulto Jovem
19.
Neuroscience ; 410: 305-315, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31026567

RESUMO

Memories are acquired and stored in two forms, short-term memory (STM) and long-term memory (LTM). For the consolidation of LTM, de novo protein synthesis is required, which are also known as plasticity related proteins. Long-term potentiation is a form of synaptic plasticity and it is considered as a cellular model of learning and memory. One of the Long-term potentiation specific plasticity related proteins, PKM-ζ, is required for the formation of LTM as well as for the maintenance of Long-term potentiation. In our study, we have shown that for the consolidation of LTM, in addition to Long-term potentiation -specific plasticity related proteins, synaptic tags are required to interact with each other. In the present study, we investigated the involvement of Long-term potentiation -specific PKM-ζ and learning tags within a critical time window, which are required for the formation of LTM without affecting STM. Behavioral tagging is an established model for the assessment of some forms of learning and memory. Despite being studied for LTM formation for many years, no studies so far have investigated the role of PKM-ζ in Behavioral tagging model. Hence, by using these two different memories based tasks (i.e., Inhibitory avoidance and Novel object recognition tasks), we observed how PKM-ζ activated by exposing a novel arena after a weak training and led to the consolidation of memory. These findings thus show how the process of behavioral tagging activates Long-term potentiation -specific PKM-ζ for the formation of LTM.


Assuntos
Aprendizagem da Esquiva/fisiologia , Regulação Enzimológica da Expressão Gênica , Memória de Longo Prazo/fisiologia , Córtex Pré-Frontal/enzimologia , Proteína Quinase C/biossíntese , /fisiologia , Animais , Masculino , Proteína Quinase C/genética , Ratos , Ratos Wistar
20.
Behav Ther ; 50(3): 594-607, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31030876

RESUMO

Irritable bowel syndrome (IBS) is a functional gastrointestinal syndrome consisting of different bowel pattern subtypes: diarrhea predominant (IBS-D), constipation predominant (IBS-C), and alternating (IBS-A). This paper aimed to identify whether (a) psychological factors implicated in the cognitive behavioral model of IBS were differentially associated with bowel pattern subtypes, (b) whether there were differences in symptom severity and work and social adjustment across the IBS-subtypes. Analysis was conducted on baseline data of 557 individuals with refractory IBS recruited into the Assessing Cognitive Therapy in Irritable Bowel (ACTIB) randomized controlled trial. Correlations assessed the associations between psychological factors, stool patterns, symptom severity, and work and social adjustment. Hierarchical regressions identified whether cognitive and behavioral factors were significantly associated with frequency of loose/watery stools, hard/lumpy stools and symptom severity while controlling for affective (anxiety and depression) and demographic factors (age, gender, symptom duration). One-way ANOVAs were conducted to assess differences across Rome III classified subtypes (IBS-A, D and C) in cognitive, behavioral, affective, symptom severity, and adjustment measures. Psychological factors were significantly associated with symptom severity and work and social adjustment. Increased avoidance behavior and unhelpful gastrointestinal (GI) cognitions were significantly associated with higher frequency of loose/watery stools. Increased control behaviors were associated with higher frequency of hard/lumpy stools. Cognitive and behavioral differences were significant across the Rome III classified IBS subtypes. There were no differences in anxiety, depression, overall symptom severity, or work and social adjustment. The results are discussed in terms of their utility in tailoring cognitive behavioral treatments to IBS subtypes.


Assuntos
Aprendizagem da Esquiva/fisiologia , Cognição/fisiologia , Síndrome do Intestino Irritável/diagnóstico , Síndrome do Intestino Irritável/psicologia , Adulto , Ansiedade/diagnóstico , Ansiedade/psicologia , Ansiedade/terapia , Terapia Cognitivo-Comportamental/métodos , Constipação Intestinal/diagnóstico , Constipação Intestinal/psicologia , Constipação Intestinal/terapia , Estudos Transversais , Depressão/diagnóstico , Depressão/psicologia , Depressão/terapia , Diarreia/diagnóstico , Diarreia/psicologia , Diarreia/terapia , Feminino , Humanos , Síndrome do Intestino Irritável/terapia , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários
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