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1.
Nat Neurosci ; 23(3): 398-410, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32066984

RESUMO

In humans and rodents, the perception of control during stressful events has lasting behavioral consequences. These consequences are apparent even in situations that are distinct from the stress context, but how the brain links prior stressful experience to subsequent behaviors remains poorly understood. By assessing innate defensive behavior in a looming-shadow task, we show that the initiation of an escape response is preceded by an increase in the activity of corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus (PVN) of the hypothalamus (CRHPVN neurons). This anticipatory increase is sensitive to stressful stimuli that have high or low levels of outcome control. Specifically, experimental stress with high outcome control increases CRHPVN neuron anticipatory activity, which increases escape behavior in an unrelated context. By contrast, stress with no outcome control prevents the emergence of this anticipatory activity and decreases subsequent escape behavior. These observations indicate that CRHPVN neurons encode stress controllability and contribute to shifts between active and passive innate defensive strategies.


Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Reação de Fuga/fisiologia , Neurônios/fisiologia , Núcleo Hipotalâmico Paraventricular/fisiologia , Estresse Psicológico , Acelerometria , Animais , Antecipação Psicológica/fisiologia , Sinais (Psicologia) , Fenômenos Eletrofisiológicos , Elevação dos Membros Posteriores , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Optogenética , Núcleo Hipotalâmico Paraventricular/citologia , Estimulação Luminosa
2.
Proc Natl Acad Sci U S A ; 117(6): 3254-3260, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-32001507

RESUMO

The giant Mauthner (M) cell is the largest neuron known in the vertebrate brain. It has enabled major breakthroughs in neuroscience but its ultimate function remains surprisingly unclear: An actual survival value of M cell-mediated escapes has never been supported experimentally and ablating the cell repeatedly failed to eliminate all rapid escapes, suggesting that escapes can equally well be driven by smaller neurons. Here we applied techniques to simultaneously measure escape performance and the state of the giant M axon over an extended period following ablation of its soma. We discovered that the axon survives remarkably long and remains still fully capable of driving rapid escape behavior. By unilaterally removing one of the two M axons and comparing escapes in the same individual that could or could not recruit an M axon, we show that the giant M axon is essential for rapid escapes and that its loss means that rapid escapes are also lost forever. This allowed us to directly test the survival value of the M cell-mediated escapes and to show that the absence of this giant neuron directly affects survival in encounters with a natural predator. These findings not only offer a surprising solution to an old puzzle but demonstrate that even complex brains can trust vital functions to individual neurons. Our findings suggest that mechanisms must have evolved in parallel with the unique significance of these neurons to keep their axons alive and connected.


Assuntos
Reação de Fuga/fisiologia , Sistema Nervoso/crescimento & desenvolvimento , Neurônios/citologia , Neurônios/fisiologia , Animais , Axônios/fisiologia , Embrião não Mamífero/fisiologia , Larva/fisiologia , Peixe-Zebra
3.
Proc Natl Acad Sci U S A ; 117(1): 472-478, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31871184

RESUMO

The unique engulfment filtration strategy of microphagous rorqual whales has evolved relatively recently (<5 Ma) and exploits extreme predator/prey size ratios to overcome the maneuverability advantages of swarms of small prey, such as krill. Forage fish, in contrast, have been engaged in evolutionary arms races with their predators for more than 100 million years and have performance capabilities that suggest they should easily evade whale-sized predators, yet they are regularly hunted by some species of rorqual whales. To explore this phenomenon, we determined, in a laboratory setting, when individual anchovies initiated escape from virtually approaching whales, then used these results along with in situ humpback whale attack data to model how predator speed and engulfment timing affected capture rates. Anchovies were found to respond to approaching visual looming stimuli at expansion rates that give ample chance to escape from a sea lion-sized predator, but humpback whales could capture as much as 30-60% of a school at once because the increase in their apparent (visual) size does not cross their prey's response threshold until after rapid jaw expansion. Humpback whales are, thus, incentivized to delay engulfment until they are very close to a prey school, even if this results in higher hydrodynamic drag. This potential exaptation of a microphagous filter feeding strategy for fish foraging enables humpback whales to achieve 7× the energetic efficiency (per lunge) of krill foraging, allowing for flexible foraging strategies that may underlie their ecological success in fluctuating oceanic conditions.


Assuntos
Reação de Fuga/fisiologia , Comportamento Alimentar , Peixes/fisiologia , Jubarte/fisiologia , Comportamento Predatório/fisiologia , Animais , Evolução Biológica , Euphausiacea/fisiologia , Filtração , Jubarte/anatomia & histologia , Hidrodinâmica , Arcada Osseodentária/anatomia & histologia , Locomoção/fisiologia , Modelos Biológicos , Tamanho do Órgão/fisiologia , Fatores de Tempo
4.
PLoS Biol ; 17(10): e3000480, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31613896

RESUMO

Many species execute ballistic escape reactions to avoid imminent danger. Despite fast reaction times, responses are often highly regulated, reflecting a trade-off between costly motor actions and perceived threat level. However, how sensory cues are integrated within premotor escape circuits remains poorly understood. Here, we show that in zebrafish, less precipitous threats elicit a delayed escape, characterized by flexible trajectories, which are driven by a cluster of 38 prepontine neurons that are completely separate from the fast escape pathway. Whereas neurons that initiate rapid escapes receive direct auditory input and drive motor neurons, input and output pathways for delayed escapes are indirect, facilitating integration of cross-modal sensory information. These results show that rapid decision-making in the escape system is enabled by parallel pathways for ballistic responses and flexible delayed actions and defines a neuronal substrate for hierarchical choice in the vertebrate nervous system.


Assuntos
Reação de Fuga/fisiologia , Córtex Motor/fisiologia , Neurônios Motores/fisiologia , Reconhecimento Fisiológico de Modelo/fisiologia , Ponte/fisiologia , Peixe-Zebra/fisiologia , Animais , Tomada de Decisões/fisiologia , Larva/fisiologia , Córtex Motor/citologia , Neurônios Motores/citologia , Ponte/citologia , Tempo de Reação/fisiologia
5.
PLoS Biol ; 17(8): e3000417, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31469831

RESUMO

Threatening sounds can elicit a series of defensive behavioral reactions in animals for survival, but the underlying neural substrates are not fully understood. Here, we demonstrate a previously unexplored neural pathway in mice that projects directly from the auditory cortex (ACx) to the lateral periaqueductal gray (lPAG) and controls noise-evoked defensive behaviors. Electrophysiological recordings showed that the lPAG could be excited by a loud noise that induced an escape-like behavior. Trans-synaptic viral tracing showed that a great number of glutamatergic neurons, rather than GABAergic neurons, in the lPAG were directly innervated by those in layer V of the ACx. Activation of this pathway by optogenetic manipulations produced a behavior in mice that mimicked the noise-evoked escape, whereas inhibition of the pathway reduced this behavior. Therefore, our newly identified descending pathway is a novel neural substrate for noise-evoked escape and is involved in controlling the threat-related behavior.


Assuntos
Córtex Auditivo/fisiologia , Reação de Fuga/fisiologia , Substância Cinzenta Periaquedutal/metabolismo , Animais , Córtex Auditivo/metabolismo , Percepção Auditiva/fisiologia , Comportamento Animal/fisiologia , Mecanismos de Defesa , Aminoácidos Excitatórios/fisiologia , Neurônios GABAérgicos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Vias Neurais/fisiologia , Optogenética/métodos , Substância Cinzenta Periaquedutal/fisiologia , Som
6.
Nat Neurosci ; 22(7): 1132-1139, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31182867

RESUMO

An approaching predator and self-motion toward an object can generate similar looming patterns on the retina, but these situations demand different rapid responses. How central circuits flexibly process visual cues to activate appropriate, fast motor pathways remains unclear. Here we identify two descending neuron (DN) types that control landing and contribute to visuomotor flexibility in Drosophila. For each, silencing impairs visually evoked landing, activation drives landing, and spike rate determines leg extension amplitude. Critically, visual responses of both DNs are severely attenuated during non-flight periods, effectively decoupling visual stimuli from the landing motor pathway when landing is inappropriate. The flight-dependence mechanism differs between DN types. Octopamine exposure mimics flight effects in one, whereas the other probably receives neuronal feedback from flight motor circuits. Thus, this sensorimotor flexibility arises from distinct mechanisms for gating action-specific descending pathways, such that sensory and motor networks are coupled or decoupled according to the behavioral state.


Assuntos
Drosophila melanogaster/fisiologia , Reação de Fuga/fisiologia , Voo Animal/fisiologia , Atividade Motora/fisiologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Potenciais de Ação , Animais , Vias Eferentes/fisiologia , Octopamina/farmacologia , Técnicas de Patch-Clamp , Estimulação Luminosa
7.
Neuron ; 103(3): 473-488.e6, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31202540

RESUMO

Innate defensive responses are essential for animal survival and are conserved across species. The ventral tegmental area (VTA) plays important roles in learned appetitive and aversive behaviors, but whether it plays a role in mediating or modulating innate defensive responses is currently unknown. We report that VTAGABA+ neurons respond to a looming stimulus. Inhibition of VTAGABA+ neurons reduced looming-evoked defensive flight behavior, and photoactivation of these neurons resulted in defense-like flight behavior. Using viral tracing and electrophysiological recordings, we show that VTAGABA+ neurons receive direct excitatory inputs from the superior colliculus (SC). Furthermore, we show that glutamatergic SC-VTA projections synapse onto VTAGABA+ neurons that project to the central nucleus of the amygdala (CeA) and that the CeA is involved in mediating the defensive behavior. Our findings demonstrate that aerial threat-related visual information is relayed to VTAGABA+ neurons mediating innate behavioral responses, suggesting a more general role of the VTA.


Assuntos
Reação de Fuga/fisiologia , Medo/fisiologia , Neurônios GABAérgicos/fisiologia , Área Tegmentar Ventral/fisiologia , Vias Aferentes/fisiologia , Animais , Sinalização do Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/fisiologia , Núcleo Central da Amígdala/fisiologia , Genes Reporter , Ácido Glutâmico/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas do Tecido Nervoso/fisiologia , Optogenética , Estimulação Luminosa , Proteínas Proto-Oncogênicas c-fos/análise , Ácido gama-Aminobutírico/fisiologia
8.
Nat Hum Behav ; 3(7): 702-708, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31110337

RESUMO

Theoretical models distinguish between neural responses elicited by distal threats and those evoked by more immediate threats1-3. Specifically, slower 'cognitive' fear responses towards distal threats involve a network of brain regions including the ventral hippocampus (vHPC) and medial prefrontal cortex (mPFC), while immediate 'reactive' fear responses rely on regions such as the periaqueductal grey4,5. However, it is unclear how anxiety and its neural substrates relate to these distinct defensive survival circuits. We tested whether individual differences in trait anxiety would impact escape behaviour and neural responses to slow and fast attacking predators: conditions designed to evoke cognitive and reactive fear, respectively. Behaviourally, we found that trait anxiety was not related to escape decisions for fast threats, but individuals with higher trait anxiety escaped earlier during slow threats. Functional magnetic resonance imaging showed that when subjects faced slow threats, trait anxiety positively correlated with activity in the vHPC, mPFC, amygdala and insula. Furthermore, the strength of functional coupling between two components of the cognitive circuit-the vHPC and mPFC-was correlated with the degree of trait anxiety. This suggests that anxiety predominantly affects cognitive fear circuits that are involved in volitional strategic escape.


Assuntos
Ansiedade/fisiopatologia , Encéfalo/diagnóstico por imagem , Tomada de Decisões/fisiologia , Reação de Fuga/fisiologia , Adolescente , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Tonsila do Cerebelo/fisiologia , Tonsila do Cerebelo/fisiopatologia , Ansiedade/psicologia , Encéfalo/fisiologia , Encéfalo/fisiopatologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Córtex Cerebral/fisiopatologia , Cognição/fisiologia , Medo , Feminino , Neuroimagem Funcional , Hipocampo/diagnóstico por imagem , Hipocampo/fisiologia , Hipocampo/fisiopatologia , Humanos , Imagem por Ressonância Magnética , Masculino , Modelos Teóricos , Substância Cinzenta Periaquedutal/diagnóstico por imagem , Substância Cinzenta Periaquedutal/fisiologia , Substância Cinzenta Periaquedutal/fisiopatologia , Personalidade , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiologia , Córtex Pré-Frontal/fisiopatologia , Adulto Jovem
9.
Behav Processes ; 165: 4-8, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31145966

RESUMO

Investigating the link between stress and functional cerebral asymmetry (FCA) has been a subject of interest in recent years. The demonstration of this link in the field of veterinary medicine is particularly important as measuring FCA has the potential to be an alternative and non-invasive behavioral method to assess stress in dogs. The present study aimed to investigate whether FCA is affected by different environmental conditions in dogs. The main aim of this study was to investigate the changes in FCA in dogs living under different conditions. To this aim, strength and direction of FCA in 40 urban free-ranging dogs were measured by a Kong test. Dogs were divided into four groups considering their environmental conditions: The dogs in Group 1 (n = 8) were rehabilitated urban free ranging dogs, which were kept in enriched shelter conditions. The dogs in Group 2 (n = 9) were adopted free ranging dogs, which lived in home environment for more than 1 year. The dogs in Group 3 (n = 11) were urban free ranging dogs, which stayed in individual cages in a dog shelter for more than 6 months. The dogs in Group 4 (n = 12) were adopted urban free ranging dogs, which stayed in a dog pension for more than 30 days. Considering the length of their stay in a kennel environment, quality of living condition and emotional states, the dogs in Group 3 and 4 were classified as chronically stressed dogs. Statistically significant differences existed between groups considering strength and direction of lateralization. Most of the dogs in Group 1 (87.5 %) and Group 2 (77.8 %) showed significant paw preferences, whereas most of the dogs in the Group 3 (72.7 %) and Group 4 (75 %) were categorized as ambilateral. Considering the individual level asymmetry in dogs and environmental conditions of dogs in Group 3 and 4, one may suggest that high ambilaterality levels is related with chronic stress. Thus, reduced FCA may not be the reason for stress sensibility, rather it can be an outcome of stressful situations. These results are the first to demonstrate the possible link between chronic stress and ambilaterality in dogs.


Assuntos
Cães/fisiologia , Dominância Cerebral/fisiologia , Meio Social , Agressão/fisiologia , Animais , Nível de Alerta/fisiologia , Encéfalo/fisiopatologia , Emoções/fisiologia , Reação de Fuga/fisiologia , Feminino , Lateralidade Funcional/fisiologia , Masculino , Estresse Psicológico/complicações , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia
10.
Nat Neurosci ; 22(6): 941-949, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31036941

RESUMO

Flight, an active fear response to imminent threat, is dependent on the rapid risk assessment of sensory information processed by the cortex. The thalamic reticular nucleus (TRN) filters information between the cortex and the thalamus, but whether it participates in the regulation of flight behavior remains largely unknown. Here, we report that activation of parvalbumin-expressing neurons in the limbic TRN, but not those in the sensory TRN, mediates flight. Glutamatergic inputs from the cingulate cortex (Cg) selectively activate the limbic TRN, which in turn inhibits the intermediodorsal thalamic nucleus (IMD). Activation of this Cg→limbic TRN→IMD circuit results in inhibition of the IMD and produces flight behavior. Conversely, removal of inhibition onto the IMD results in more freezing and less flight, suggesting that the IMD may function as a pro-freeze center. Overall, these findings reveal a novel corticothalamic circuit through the TRN that controls the flight response.


Assuntos
Córtex Cerebral/fisiologia , Reação de Fuga/fisiologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Núcleos Talâmicos/fisiologia , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL
11.
PLoS One ; 14(4): e0214374, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30946762

RESUMO

Zebrafish larvae have several biological features that make them useful for cellular investigations of the mechanisms underlying learning and memory. Of particular interest in this regard is a rapid escape, or startle, reflex possessed by zebrafish larvae; this reflex, the C-start, is mediated by a relatively simple neuronal circuit and exhibits habituation, a non-associative form of learning. Here we demonstrate a rapid form of habituation of the C-start to touch that resembles the previously reported rapid habituation induced by auditory or vibrational stimuli. We also show that touch-induced habituation exhibits input specificity. This work sets the stage for in vivo optical investigations of the cellular sites of plasticity that mediate habituation of the C-start in the larval zebrafish.


Assuntos
Reação de Fuga/fisiologia , Habituação Psicofisiológica , Tato/fisiologia , Peixe-Zebra/fisiologia , Animais , Eletrochoque , Reação de Fuga/efeitos dos fármacos , Glicina/farmacologia , Habituação Psicofisiológica/efeitos dos fármacos , Cabeça , Larva/efeitos dos fármacos , Larva/fisiologia , Reflexo de Sobressalto/efeitos dos fármacos , Reflexo de Sobressalto/fisiologia , Estricnina/farmacologia
12.
Proc Natl Acad Sci U S A ; 116(15): 7226-7231, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30902894

RESUMO

The roundworm Caenorhabditis elegans exhibits robust escape behavior in response to rapidly rising temperature. The behavior lasts for a few seconds, shows history dependence, involves both sensory and motor systems, and is too complicated to model mechanistically using currently available knowledge. Instead we model the process phenomenologically, and we use the Sir Isaac dynamical inference platform to infer the model in a fully automated fashion directly from experimental data. The inferred model requires incorporation of an unobserved dynamical variable and is biologically interpretable. The model makes accurate predictions about the dynamics of the worm behavior, and it can be used to characterize the functional logic of the dynamical system underlying the escape response. This work illustrates the power of modern artificial intelligence to aid in discovery of accurate and interpretable models of complex natural systems.


Assuntos
Caenorhabditis elegans/fisiologia , Reação de Fuga/fisiologia , Temperatura Alta , Modelos Biológicos , Animais
13.
Artigo em Inglês | MEDLINE | ID: mdl-30833888

RESUMO

Processing of multimodal information is essential for an organism to respond to environmental events. However, how multimodal integration in neurons translates into behavior is far from clear. Here, we investigate integration of biologically relevant visual and auditory information in the goldfish startle escape system in which paired Mauthner-cells (M-cells) initiate the behavior. Sound pips and visual looms as well as multimodal combinations of these stimuli were tested for their effectiveness of evoking the startle response. Results showed that adding a low intensity sound early during a visual loom (low visual effectiveness) produced a supralinear increase in startle responsiveness as compared to an increase expected from a linear summation of the two unimodal stimuli. In contrast, adding a sound pip late during the loom (high visual effectiveness) increased responsiveness consistent with a linear multimodal integration of the two stimuli. Together the results confirm the Inverse Effectiveness Principle (IEP) of multimodal integration proposed in other species. Given the well-established role of the M-cell as a multimodal integrator, these results suggest that IEP is computed in individual neurons that initiate vital behavioral decisions.


Assuntos
Reação de Fuga/fisiologia , Carpa Dourada/fisiologia , Reflexo de Sobressalto/fisiologia , Estimulação Acústica , Acústica , Animais , Rede Nervosa/fisiologia , Neurônios/fisiologia , Estimulação Luminosa , Tempo de Reação
14.
Artigo em Inglês | MEDLINE | ID: mdl-30742862

RESUMO

Exposure of rats to an environment with low O2 levels evokes a panic-like escape behavior and recruits the dorsal periaqueductal gray (dPAG), which is considered to be a key region in the pathophysiology of panic disorder. The neurochemical basis of this response is, however, currently unknown. We here investigated the role played by nitric oxide (NO) within the dPAG in mediation of the escape reaction induced by hypoxia exposure. The results showed that exposure of male Wistar rats to 7% O2 increased nitrite levels, a NO metabolite, in the dPAG but not in the amygdala or hypothalamus. Nitrite levels in the dPAG were correlated with the number of escape attempts during the hypoxia challenge. Injections of the NO synthesis inhibitor NPA, the NO-scavenger c- PTIO, or the NMDA receptor antagonist AP-7 into the dorsolateral column of the periaqueductal gray (dlPAG) inhibited escape expression during hypoxia, without affecting the rats' locomotion. Intra-dlPAG administration of c-PTIO had no effect on the escape response evoked by the elevated-T maze, a defensive behavior that has also been associated with panic attacks. Altogether, our results suggest that NO plays a critical role in mediation of the panic-like defensive response evoked by exposure to low O2 concentrations.


Assuntos
Reação de Fuga/fisiologia , Hipóxia/fisiopatologia , Óxido Nítrico/fisiologia , Pânico/fisiologia , Substância Cinzenta Periaquedutal/fisiologia , 2-Amino-5-fosfonovalerato/administração & dosagem , 2-Amino-5-fosfonovalerato/análogos & derivados , 2-Amino-5-fosfonovalerato/farmacologia , Tonsila do Cerebelo/metabolismo , Animais , Arginina/administração & dosagem , Arginina/análogos & derivados , Arginina/farmacologia , Reação de Fuga/efeitos dos fármacos , Hipotálamo/metabolismo , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Microinjeções , Atividade Motora/efeitos dos fármacos , Nitritos/metabolismo , Substância Cinzenta Periaquedutal/metabolismo , Ratos
15.
Behav Brain Res ; 356: 107-119, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30118773

RESUMO

Previous studies showed that chronic treatment with corticosterone facilitates elevated T-maze (ETM) inhibitory avoidance and a step-down avoidance task, responses that have been used to investigate aversive conditioning and memory processes. On the other hand, chronic corticosterone does not alter ETM escape from the open arms. The purpose of the present study was to further investigate the effects of chronic corticosterone treatment (200 mg pellets, 21-day release) in an animal model of anxiety that does not involve aversive conditioning: the light/dark transition model. We also investigated the pattern of ΔFosB immunoreactivity (ΔFosB-ir) in different brain regions. To examine how treatment with chronic corticosterone interferes with CRFR1 expression we measured CRFR1 in the same brain structures that exhibited increased ΔFosB-ir. Results showed that chronic treatment with corticosterone did not alter behavioral measurements performed in the light/dark transition model. On the other hand, ΔFosB-ir was increased in several structures that modulate aversive conditioning: the cingulate cortex, the ventro and dorsolateral septum, the amygdala, the paraventricular, dorsomedial and ventromedial hypothalamus, the periaqueductal grey matter, the dorsal raphe, and the median raphe nucleus. Chronic treatment with corticosterone also increased CRFR1-immunoreactivity in the ventrolateral septum, central amygdala, dorsomedial hypothalamus, ventral region of the dorsal raphe and median raphe. These results contribute to a better understanding of the behavioral and neurobiological alterations induced by chronic exposure to glucocorticoids.


Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-fos/efeitos dos fármacos , Receptores de Hormônio Liberador da Corticotropina/efeitos dos fármacos , Animais , Ansiedade/tratamento farmacológico , Transtornos de Ansiedade/metabolismo , Aprendizagem da Esquiva/fisiologia , Encéfalo/metabolismo , Corticosterona/farmacologia , Modelos Animais de Doenças , Reação de Fuga/fisiologia , Masculino , Memória , Neurônios/metabolismo , Proteínas Proto-Oncogênicas c-fos/imunologia , Ratos , Ratos Wistar , Receptores de Hormônio Liberador da Corticotropina/imunologia , Estresse Psicológico/metabolismo
16.
J Neurosci ; 39(7): 1182-1194, 2019 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-30578342

RESUMO

During many behaviors in vertebrates, the CNS generates asymmetric activities between the left and right sides to produce asymmetric body movements. For asymmetrical activations of the CNS, reciprocal inhibition between the left and right sides is believed to play a key role. However, the complexity of the CNS makes it difficult to identify the reciprocal inhibition circuits at the level of individual cells and the contribution of each neuron to the asymmetric activity. Using larval zebrafish, we examined this issue by investigating reciprocal inhibition circuits between a pair of Mauthner (M) cells, giant reticulospinal neurons that trigger fast escapes. Previous studies have shown that a class of excitatory neurons, called cranial relay neurons, is involved in the reciprocal inhibition pathway between the M cells. Using transgenic fish, in which two of the cranial relay neurons (Ta1 and Ta2) expressed GFP, we showed that Ta1 and Ta2 constitute major parts of the pathway. In larvae in which Ta1/Ta2 were laser-ablated, the amplitude of the reciprocal IPSPs dropped to less than one-third. Calcium imaging and electrophysiological recording showed that the occurrence probability of bilateral M-cell activation upon sound/vibration stimuli was greatly increased in the Ta1/Ta2-ablated larvae. Behavioral experiments revealed that the Ta1/Ta2 ablation resulted in shallower body bends during sound/vibration-evoked escapes, which is consistent with the observation that increased occurrence of bilateral M-cell activation impaired escape performance. Our study revealed major components of the reciprocal inhibition circuits in the M cell system and the behavioral importance of the circuits.SIGNIFICANCE STATEMENT Reciprocal inhibition between the left and right side of the CNS is considered imperative for producing asymmetric movements in animals. It has been difficult, however, to identify the circuits at the individual cell level and their role in behavior. Here, we address this problem by examining the reciprocal inhibition circuits of the hindbrain Mauthner (M) cell system in larval zebrafish. We determined that two paired interneurons play a critical role in the reciprocal inhibition between the paired M cells and that the reciprocal inhibition prevents bilateral firing of the M cells and is thus necessary for the full body bend during M cell-initiated escape. Further, we discussed the cooperation of multiple reciprocal inhibitions working in the hindbrain and spinal cord to ensure high-performance escapes.


Assuntos
Reação de Fuga/fisiologia , Vias Neurais/citologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Rombencéfalo/citologia , Rombencéfalo/fisiologia , Medula Espinal/citologia , Medula Espinal/fisiologia , Peixe-Zebra/fisiologia , Estimulação Acústica , Animais , Animais Geneticamente Modificados , Potenciais Pós-Sinápticos Excitadores/fisiologia , Interneurônios/fisiologia , Larva , Desempenho Psicomotor/fisiologia
17.
Behav Processes ; 158: 228-233, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30585168

RESUMO

Observations of the flight response of ungulates are commonly used to test behavioral responses to predation risk. In gregarious ungulates with sexual body-size dimorphism such responses are likely to be stronger in situations where individuals have perceptions of less security as well as among more-sensitive individuals, such as female groups or female groups with offspring which are understood to use safety habitats more often than males do. However, little is known about these behaviors in solitary ungulates with little sexual dimorphism. Therefore, we examined the flight response to human presence and the habitat use of Japanese serow (Capricornis crispus), a solitary ungulate with little sexual dimorphism, in relation to its physical and social environments, based on direct observations conducted over approximately four years. Based on a total of 335 sightings, serows took flight less often when in steep terrain, in closed habitat, or in low-visibility seasons, and they selectively used steep-closed habitat. These findings suggest that steep slopes and low-visibility conditions provide the species with greater security, and that serows select safer habitats to decrease predation risk. There were no significant differences in the flight responses and habitat use of solitary males and solitary females; the absence of differences is likely related to the serow's habit of monogamy and its underdeveloped sexual dimorphism. Females with kids more frequently fled than other group types; this difference is thought to be linked to females' priority to secure the survival of their offspring. This result shows the key role of offspring presence in affecting flight response in the serow. Conversely, there were no differences in habitat use between females with kids and other group types; here, the absence of such differences may be associated with intra-sexual territoriality of the serow, since all types of territory holders (including females with kids) need to continuously use the entire home range to maintain a territory.


Assuntos
Artiodáctilos/fisiologia , Ecossistema , Meio Ambiente , Reação de Fuga/fisiologia , Meio Social , Animais , Feminino , Japão , Masculino , Comportamento Predatório , Estações do Ano , Caracteres Sexuais
18.
J Abnorm Psychol ; 128(2): 106-118, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30589305

RESUMO

Suicide is a leading cause of death worldwide. Despite decades of clinical and theoretical accounts that suggest that suicidal thoughts and behaviors are efforts to escape painful emotions, little prior research has examined decision making involved in escaping aversive states. We compared the performance of 85 suicidal participants to 44 nonsuicidal psychiatric patients on a novel reinforcement learning task with choices to make either active (i.e., "go") or passive responses (i.e., "no-go") to either escape or avoid an aversive stimulus. We used a computational cognitive model to isolate decision-making biases. We hypothesized that suicidal participants would exhibit a relatively elevated bias for making active responses to escape an aversive state and would show worse performance when escape required a passive response (i.e., "doing nothing" to escape). Our hypotheses were supported: The computational model revealed that suicidal participants exhibited a higher bias for an active response to escape compared with nonsuicidal psychiatric controls, suggesting that this finding was not just the result of the presence of psychopathology. The bias parameter also accounted for unique variance in predicting group status among several constructs previously related to suicidal thoughts and behaviors. This study provides a new method for testing escape decision making and does so using a computational cognitive model, allowing us to precisely index processes underlying suicidal and related behaviors. Future research examining escape decision making from a computational perspective could help link neural processes or environmental stressors to suicidal thoughts or behaviors. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Tomada de Decisões , Reação de Fuga/fisiologia , Ideação Suicida , Adulto , Afeto/fisiologia , Viés de Atenção/fisiologia , Boston , Emoções/fisiologia , Feminino , Humanos , Masculino , Suicídio/psicologia , Tentativa de Suicídio/psicologia
19.
Artigo em Inglês | MEDLINE | ID: mdl-30353372

RESUMO

Feeding is important to supply the immediate energy needs of animals and starved animals must expend energy in attempting to acquire foods irrespective of the danger of predation risk. Crayfish escape from attack of predators by tailflipping and in response to rostral stimuli crayfish show backward escape swimming following an initial rapid flexion of the abdomen. Since the tailflip is an energetically costly behaviour, the occurrence of a tailflip diminishes if a stimulus is repeatedly applied through habituation. In this study, we have compared the process of this habituation between fed and starved crayfish. We found that in starved animals habituation was enhanced compared to fed animals. The presence of food in the experimental tanks further enhanced habituation of starved animals. Starved crayfish thus showed trade-offs between energy saving and predation risk.


Assuntos
Astacoidea , Reação de Fuga , Habituação Psicofisiológica , Natação , Animais , Astacoidea/fisiologia , Ingestão de Alimentos , Reação de Fuga/fisiologia , Feminino , Alimentos , Habituação Psicofisiológica/fisiologia , Masculino , Atividade Motora/fisiologia , Inanição/fisiopatologia , Natação/fisiologia , Cauda/fisiologia
20.
Anat Rec (Hoboken) ; 301(12): 2164-2176, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30312013

RESUMO

Muscles of the mesopelagic copepod Gaussia princeps (Arthropoda, Crustacea, Calanoida) are responsible for repetitive movements of feeding and swimming appendages that are too fast to be followed by eye. This article provides a comparative functional and ultrastructural description of five muscles that have different contraction speeds and are located within different anatomical sites. All are very fast, as indicated by a thick:thin filament ratio of 3:1 and sarcomere lengths that vary between 1 and 3 µm. Measured lengths of thin and thick filaments indicate classification of the muscles into three distinct groups (short, medium, and long) and predict a difference in speed of up to threefold between fibers with the shortest and longest sarcomeres. Indeed, the kicking movement of the posterior legs (with the shortest sarcomere length) is approximately threefold faster than the simultaneous back-folding of the antennae (with the longest length). Thus, a specific relationship between speed of movement and sarcomere length is established, and we can use the latter to predict the former. Regulatory systems of contraction (sarcoplasmic reticulum [SR] and transverse [T] tubules) match the different contractile properties, varying in frequency of distribution and overall content in parallel to sarcomere variations. All muscles from appendages and body musculature show a unique disposition of contractile material, SR, and T tubules found only in copepod muscles; muscle filaments are grouped in large supermyofibrils that are riddled with frequent cylindrical shafts containing SR and T tubules. This arrangement insures a high spatial frequency of regulatory components. Anat Rec, 301:2164-2176, 2018. © 2018 Wiley Periodicals, Inc.


Assuntos
Reação de Fuga/fisiologia , Contração Muscular/fisiologia , Fibras Musculares de Contração Rápida/fisiologia , Sarcômeros/fisiologia , Animais , Copépodes , Fibras Musculares de Contração Rápida/ultraestrutura , Sarcômeros/ultraestrutura
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