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1.
Nat Commun ; 15(1): 8238, 2024 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-39300106

RESUMO

A general mathematical description of how the brain sequentially encodes knowledge remains elusive. We propose a linear solution for serial learning tasks, based on the concept of mixed selectivity in high-dimensional neural state spaces. In our framework, neural representations of items in a sequence are projected along a "geometric" mental line learned through classical conditioning. The model successfully solves serial position tasks and explains behaviors observed in humans and animals during transitive inference tasks amidst noisy sensory input and stochastic neural activity. This approach extends to recurrent neural networks performing motor decision tasks, where the same geometric mental line correlates with motor plans and modulates network activity according to the symbolic distance between items. Serial ordering is thus predicted to emerge as a monotonic mapping between sensory input and behavioral output, highlighting a possible pivotal role for motor-related associative cortices in transitive inference tasks.


Assuntos
Modelos Neurológicos , Humanos , Animais , Encéfalo/fisiologia , Aprendizagem/fisiologia , Redes Neurais de Computação , Rede Nervosa/fisiologia , Condicionamento Clássico/fisiologia
2.
Sci Rep ; 14(1): 21578, 2024 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-39285228

RESUMO

Survival relies on an organism's intrinsic ability to instinctively react to stimuli such as food, water, and threats, ensuring the fundamental ability to feed, drink, and avoid danger even in the absence of prior experience. These natural, unconditioned stimuli can also facilitate associative learning, where pairing them consistently with neutral cues will elicit responses to these cues. Threat conditioning, a well-explored form of associative learning, commonly employs painful electric shocks, mimicking injury, as unconditioned stimuli. It remains elusive whether actual injury or pain is necessary for effective learning, or whether the threat of harm is sufficient. Approaching predators create looming shadows and sounds, triggering strong innate defensive responses like escape and freezing. This study investigates whether visual looming stimuli can induce learned freezing or learned escape responses to a conditioned stimulus in male rats. Surprisingly, pairing a neutral tone with a looming stimulus only weakly evokes learned defensive responses, in contrast to the strong responses observed when the looming stimulus is replaced by a shock. This dissociation sheds light on the boundaries for learned defensive responses thereby impacting our comprehension of learning processes and defensive strategies.


Assuntos
Condicionamento Clássico , Animais , Masculino , Ratos , Condicionamento Clássico/fisiologia , Reação de Fuga/fisiologia , Medo/fisiologia , Eletrochoque , Comportamento Animal/fisiologia , Sinais (Psicologia)
3.
Nat Commun ; 15(1): 7728, 2024 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-39231981

RESUMO

To ensure survival, animals must sometimes suppress fear responses triggered by potential threats during feeding. However, the mechanisms underlying this process remain poorly understood. In the current study, we demonstrated that when fear-conditioned stimuli (CS) were presented during food consumption, a neural projection from lateral hypothalamic (LH) GAD2 neurons to nucleus incertus (NI) relaxin-3 (RLN3)-expressing neurons was activated, leading to a reduction in CS-induced freezing behavior in male mice. LHGAD2 neurons established excitatory connections with the NI. The activity of this neural circuit, including NIRLN3 neurons, attenuated CS-induced freezing responses during food consumption. Additionally, the lateral mammillary nucleus (LM), which received NIRLN3 projections, along with RLN3 signaling in the LM, mediated the decrease in freezing behavior. Collectively, this study identified an LHGAD2-NIRLN3-LM circuit involved in modulating fear responses during feeding, thereby enhancing our understanding of how animals coordinate nutrient intake with threat avoidance.


Assuntos
Medo , Animais , Medo/fisiologia , Masculino , Camundongos , Hipotálamo/fisiologia , Hipotálamo/metabolismo , Relaxina/metabolismo , Neurônios/fisiologia , Neurônios/metabolismo , Camundongos Endogâmicos C57BL , Vias Neurais/fisiologia , Ingestão de Alimentos/fisiologia , Condicionamento Clássico/fisiologia , Região Hipotalâmica Lateral/fisiologia , Região Hipotalâmica Lateral/metabolismo
4.
Learn Mem ; 31(8)2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39284619

RESUMO

"Pavlovian" or "motivational" biases are the phenomenon that the valence of prospective outcomes modulates action invigoration: the prospect of reward invigorates actions, while the prospect of punishment suppresses actions. Effects of the valence of prospective outcomes are well established, but it remains unclear how the magnitude of outcomes ("stake magnitude") modulates these biases. In this preregistered study (N = 55), we manipulated stake magnitude (high vs. low) in an orthogonalized Motivational Go/NoGo Task. We tested whether higher stakes (a) strengthen biases or (b) elicit cognitive control recruitment, enhancing the suppression of biases in motivationally incongruent conditions. Confirmatory tests showed that high stakes slowed down responding, especially in motivationally incongruent conditions. However, high stakes did not affect whether a response was made or not, and did not change the magnitude of Pavlovian biases. Reinforcement-learning drift-diffusion models (RL-DDMs) fit to the data suggested that response slowing was best captured by stakes prolonging the non-decision time. There was no effect of the stakes on the response threshold (as in typical speed-accuracy trade-offs). In sum, these results suggest that high stakes slow down responses without affecting the expression of Pavlovian biases in behavior. We speculate that this slowing under high stakes might reflect heightened cognitive control, which is however ineffectively used, or reflect positive conditioned suppression, i.e., the interference between goal-directed and consummatory behaviors, a phenomenon previously observed in rodents that might also exist in humans. Pavlovian biases and slowing under high stakes may arise in parallel to each other.


Assuntos
Condicionamento Clássico , Motivação , Recompensa , Humanos , Masculino , Motivação/fisiologia , Adulto Jovem , Feminino , Condicionamento Clássico/fisiologia , Adulto , Tempo de Reação/fisiologia , Adolescente , Punição , Reforço Psicológico , Desempenho Psicomotor/fisiologia
5.
Artigo em Inglês | MEDLINE | ID: mdl-39094926

RESUMO

Foot-shock paradigms have provided valuable insights into the neurobiology of stress and fear conditioning. An extensive body of literature indicates that shock exposure can elicit both conditioned and unconditioned effects, although delineating between the two is a challenging task. This distinction holds crucial implications not only for the theoretical interpretation of fear conditioning, but also for properly evaluating putative preclinical models of post-traumatic stress disorder (PTSD) involving shock exposure. The characteristics of shocks (intensity and number) affect the strength of learning, but how these characteristics interact to influence conditioned and unconditioned consequences of shocks are poorly known. In this study, we aimed to investigate in adult male rats the impact of varying shock number and intensity on the endocrine and behavioral response to contextual fear conditioning and fear generalization to a novel environment markedly distinct from the shock context (i.e., fear generalization). Classical biological markers of stress (i.e., ACTH, corticosterone, and prolactin) were sensitive to manipulations of shock parameters, whereas these parameters had a limited effect on contextual fear conditioning (evaluated by freezing and distance traveled). In contrast, behavior in different novel contexts (fear generalization) was specifically sensitive to shock intensity. Notably, altered behavior in novel contexts markedly improved, but not completely normalized after fear extinction, hypoactivity apparently being the result of both conditioned and unconditioned effects of foot-shock exposure. The present results will contribute to a better understanding of shock exposure as a putative animal model of PTSD.


Assuntos
Hormônio Adrenocorticotrópico , Condicionamento Clássico , Corticosterona , Eletrochoque , Medo , Generalização Psicológica , Animais , Masculino , Medo/fisiologia , Medo/psicologia , Generalização Psicológica/fisiologia , Condicionamento Clássico/fisiologia , Corticosterona/sangue , Ratos , Hormônio Adrenocorticotrópico/sangue , Ratos Wistar
6.
Psychoneuroendocrinology ; 169: 107161, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39116520

RESUMO

Difficulties in fear regulation can sometimes result in maladaptive fear responses. To better understand how to improve fear regulation, it is important to determine how known factors, such as sex hormone status and stress, might interact to influence fear memory. Research has shown that women with high estradiol levels (mid-cycle) and men exhibit better extinction retention compared to women with low estradiol levels (women in the early follicular cycle or using oral contraceptives). Stress has also been demonstrated to affect both the learning and retention of extinction. Despite documented interactions between stress and sex hormones, their combined effects have not been thoroughly studied. This study aims to examine the impact of stress as a function of sex hormone status on extinction learning and retention. A total of 168 non-clinical participants were studied, including men (n = 46), women using oral contraceptives (n = 38), women in the early follicular phase (n = 40), and women in mid-cycle (n = 44). On Day 1, fear acquisition training was performed. On day 2, prior to extinction training, half of the participants were exposed to a psychosocial stressor, while the other half performed a non-stressful control task. On day 3, extinction retention was tested. Fear was quantified using skin conductance responses, while stress hormones were quantified through saliva samples. Exposure to stress prior to extinction training did not affect extinction learning, regardless of sex hormone status. In contrast, pre-extinction stress exposure had different effects on extinction retention depending on hormone status. Stressed men showed impairment in extinction retention compared to controls, while the experimental condition had no effect on naturally cycling women. Regardless of stress exposure, early follicular women exhibited a deficit in fear regulation, while mid-cycle women showed effective fear regulation. Among women using oral contraceptives, the stress group demonstrated better extinction retention compared to the control group. These results demonstrate the importance of considering sex hormone status and stress exposure during extinction learning, as both components may modulate extinction retention. These results could help identifying hormonal conditions that may enhance the effectiveness of extinction-based psychological therapies used in the treatment of fear-related disorders.


Assuntos
Extinção Psicológica , Medo , Estresse Psicológico , Humanos , Extinção Psicológica/fisiologia , Feminino , Masculino , Adulto , Medo/fisiologia , Medo/psicologia , Estresse Psicológico/metabolismo , Estresse Psicológico/fisiopatologia , Adulto Jovem , Estradiol/metabolismo , Estradiol/sangue , Estradiol/análise , Caracteres Sexuais , Hormônios Esteroides Gonadais/metabolismo , Hormônios Esteroides Gonadais/análise , Fatores Sexuais , Adolescente , Saliva/química , Saliva/metabolismo , Fase Folicular/fisiologia , Fase Folicular/psicologia , Ciclo Menstrual/fisiologia , Ciclo Menstrual/psicologia , Condicionamento Clássico/fisiologia
7.
J Affect Disord ; 366: 98-105, 2024 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-39187192

RESUMO

BACKGROUND: Dysregulation of fear processing through altered sensitivity to threat is thought to contribute to the development of anxiety disorders and major depressive disorder (MDD). However, fewer studies have examined fear processing in MDD than in anxiety disorders. The current study used propensity matching to examine the hypothesis that comorbid MDD and anxiety (AnxMDD) shows greater neural correlates of fear processing than MDD, suggesting that the co-occurrence of AnxMDD is exemplified by exaggerated defense related processes. METHODS: 195 individuals with MDD (N = 65) or AnxMDD (N = 130) were recruited from the community and completed multi-level assessments, including a Pavlovian fear learning task during functional imaging. Visual images paired with threat (conditioned stimuli: CS+) were compared to stimuli not paired with threat (CS-). RESULTS: MDD and AnxMDD showed significantly different patterns of activation for CS+ vs CS- in the dorsal anterior insula/inferior frontal gyrus (partial eta squared; ηp2 = 0.02), dorsolateral prefrontal cortex (ηp2 = 0.01) and dorsal anterior/mid cingulate cortex (ηp2 = 0.01). These differences were driven by greater activation to the CS+ in AnxMDD versus MDD. LIMITATIONS: Limitations include the cross-sectional design, a scream US rather than shock and half the number of MDD as AnxMDD participants. CONCLUSIONS: AnxMDD showed a pattern of increased activation in regions identified with fear processing. Effects were consistently driven by threat, further suggesting fear signaling as the emergent target process. Differences emerged in regions associated with salience processing, attentional orienting/conflict, self-relevant processing and executive functioning in comorbid anxiety and depression, thereby highlighting potential treatment targets for this prevalent and treatment resistant group.


Assuntos
Transtornos de Ansiedade , Condicionamento Clássico , Transtorno Depressivo Maior , Medo , Giro do Cíngulo , Imageamento por Ressonância Magnética , Humanos , Masculino , Medo/fisiologia , Feminino , Giro do Cíngulo/fisiopatologia , Giro do Cíngulo/diagnóstico por imagem , Adulto , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/diagnóstico por imagem , Condicionamento Clássico/fisiologia , Transtornos de Ansiedade/fisiopatologia , Transtornos de Ansiedade/epidemiologia , Córtex Insular/fisiopatologia , Córtex Insular/diagnóstico por imagem , Pessoa de Meia-Idade , Comorbidade , Lobo Frontal/fisiopatologia , Lobo Frontal/diagnóstico por imagem , Adulto Jovem , Córtex Cerebral/fisiopatologia , Córtex Cerebral/diagnóstico por imagem , Ansiedade/fisiopatologia , Ansiedade/psicologia
8.
ACS Chem Neurosci ; 15(16): 3034-3043, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39087917

RESUMO

A variety of classic psychedelics and MDMA have been shown to enhance fear extinction in rodent models. This has translational significance because a standard treatment for post-traumatic stress disorder (PTSD) is prolonged exposure therapy. However, few studies have investigated psilocybin's potential effect on fear learning paradigms. More specifically, the extents to which dose, timing of administration, and serotonin receptors may influence psilocybin's effect on fear extinction are not understood. In this study, we used a delay fear conditioning paradigm to determine the effects of psilocybin on fear extinction, extinction retention, and fear renewal in male and female mice. Psilocybin robustly enhances fear extinction when given acutely prior to testing for all doses tested. Psilocybin also exerts long-term effects to elevate extinction retention and suppress fear renewal in a novel context, although these changes were sensitive to dose. Analysis of sex differences showed that females may respond to a narrower range of doses than males. Administration of psilocybin prior to fear learning or immediately after extinction yielded no change in behavior, indicating that concurrent extinction experience is necessary for the drug's effects. Cotreatment with a 5-HT2A receptor antagonist blocked psilocybin's effects for extinction, extinction retention, and fear renewal, whereas 5-HT1A receptor antagonism attenuated only the effect on fear renewal. Collectively, these results highlight dose, context, and serotonin receptors as crucial factors in psilocybin's ability to facilitate fear extinction. The study provides preclinical evidence to support investigating psilocybin as a pharmacological adjunct for extinction-based therapy for PTSD.


Assuntos
Relação Dose-Resposta a Droga , Extinção Psicológica , Medo , Alucinógenos , Psilocibina , Psilocibina/farmacologia , Medo/efeitos dos fármacos , Animais , Extinção Psicológica/efeitos dos fármacos , Masculino , Feminino , Alucinógenos/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Serotonina/efeitos dos fármacos , Receptores de Serotonina/metabolismo , Condicionamento Clássico/efeitos dos fármacos
9.
Behav Res Ther ; 181: 104598, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39142133

RESUMO

Meta-analyses indicate differences in Pavlovian fear responses between anxious and non-anxious individuals using electrodermal activity (EDA). Recent research, however, has cast doubt on whether these effects are robust to different analytic choices. Using the multiverse approach conceived by Steegen et al. (2016), we surveyed analytic choices typically implemented in clinical fear conditioning research by conducting 1240 analyses reflecting different choice permutations. Only 1.45% of our analyses produced theoretically congruent statistically significant effects, and the strength and direction of the estimated effects varied substantially across EDA processing methods. We conclude that EDA-estimated fear learning differences are vulnerable to researcher degrees of freedom and make recommendations regarding which analytical choices should be approached with a high degree of caution.


Assuntos
Ansiedade , Condicionamento Clássico , Medo , Resposta Galvânica da Pele , Humanos , Resposta Galvânica da Pele/fisiologia , Medo/psicologia , Condicionamento Clássico/fisiologia , Ansiedade/psicologia , Masculino , Feminino , Adulto , Aprendizagem/fisiologia , Adulto Jovem
10.
Appetite ; 202: 107640, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-39173840

RESUMO

Modern living is characterized by easy access to highly palatable energy-dense foods. Environmental cues associated with palatable foods increase seeking of those foods (specific transfer) and other palatable foods (general transfer). We conducted a series of studies testing the boundaries of food cue-reactivity by evaluating the impact of broader flavor associations (i.e. saltiness, sweetness) in eliciting general transfer effects. Experiment 1 was an online experiment with fictive rewards that tested if two actions associated with different food rewards (chip and chocolate points) could be provoked by images of other foods that were either similar or distinct in flavor from the foods associated with these instrumental actions. We observed that response excitation was only elicited by similarly flavored food cues, whereas distinctly flavored food cues inhibited response rates relative to control cues. Experiment 2 confirmed this observation in a classroom setting where real food rewards were contingent on task performance. Experiment 3 was an online study that further confirmed the reliability of the effects with a well powered sample. There were moderate-to-strong associations between specific and general transfer effects across all studies, suggesting overlapping cognitive processes are responsible for both transfer effects. These data improve the mechanistic understanding of how broad category associations can moderate the impact of food cues on food choices. This knowledge could be helpful for improving the precision of psychological interventions that seek to mitigate the impact of food cue-reactivity.


Assuntos
Sinais (Psicologia) , Preferências Alimentares , Recompensa , Transferência de Experiência , Humanos , Feminino , Masculino , Adulto Jovem , Adulto , Preferências Alimentares/psicologia , Paladar , Adolescente , Condicionamento Clássico , Comportamento de Escolha , Condicionamento Operante
11.
Int J Psychophysiol ; 204: 112425, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39182762

RESUMO

Presenting unpaired unconditional stimuli (US) during extinction training reduces the renewal of conditional fear due to context change and slows re-acquisition. The present study investigated whether this reduced return of fear is mediated by Pavlovian inhibitory conditioning to the conditional stimulus paired with the US during acquisition (CS+) that is acquired when this stimulus is presented without the US in an excitatory extinction context. Using an ABA renewal paradigm that trained extinction in a context different from acquisition and renewal test, participants either received no USs (Standard), five unsignalled US presentations (Unsignalled) or five presentations of the US preceded by a novel, third CS (Signalled) during extinction training. Extinction was followed by tests for renewal and re-acquisition. Replicating previous results, renewal of electrodermal conditional responses was observed in group Standard, but not in group Unsignalled. Signalling the additional USs, and thus reducing context conditioning and the potential for inhibitory conditioning, did not reduce their effect in that renewal was absent in group Signalled. These results are inconsistent with an inhibitory conditioning account of the effects of unpaired US presentations during extinction. A trial sequence learning account or an arousal account may explain the effects of unpaired presentations of the US during extinction.


Assuntos
Condicionamento Clássico , Extinção Psicológica , Medo , Resposta Galvânica da Pele , Extinção Psicológica/fisiologia , Humanos , Medo/fisiologia , Masculino , Resposta Galvânica da Pele/fisiologia , Condicionamento Clássico/fisiologia , Feminino , Adulto , Adulto Jovem , Adolescente , Análise de Variância
12.
J Psychiatr Res ; 178: 59-65, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39121708

RESUMO

Ventral tegmental area (VTA) dopamine (DA) neurons have been found to substantially associate with post-traumatic stress disorder (PTSD) pathology, however, whether and how these DA neurons affect fear memory management in PTSD individuals remains largely unknown. In this study, we utilized auditory conditioned foot-shock to evaluate the fear memory retrieval and retention characteristics in a single prolonged stress-induced PTSD rat model. We employed chemogenetic technology to specifically activate VTA DA neurons to examine the freezing behaviors responding to the conditioned stimuli. In vivo extracellular electrophysiological analyses were used to identify VTA DA neuronal firing alterations due to the chemogenetic activation. The results demonstrated that PTSD model rats showed comparable fear memory retrieval (Day 2 after the conditioned foot-shock), but significant enhancements in fear memory retention (Day 8 after the conditioned foot-shock), compared to normal control rats. Chemogenetic activation of VTA DA neurons markedly diminished the retention of fear memory in PTSD model rats, which appeared concomitantly with increases in the firing activities of the DA neurons. These findings revealed that PTSD induced the persistence of fear memory, which could be attenuated by activation of VTA DA neurons. It is presumed that VTA dopaminergic signals may serve as a prospective option for PTSD treatment.


Assuntos
Modelos Animais de Doenças , Neurônios Dopaminérgicos , Medo , Ratos Sprague-Dawley , Transtornos de Estresse Pós-Traumáticos , Área Tegmentar Ventral , Animais , Área Tegmentar Ventral/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Medo/fisiologia , Neurônios Dopaminérgicos/fisiologia , Masculino , Ratos , Retenção Psicológica/fisiologia , Potenciais de Ação/fisiologia , Eletrochoque/efeitos adversos , Memória/fisiologia , Condicionamento Clássico/fisiologia
13.
J Psychiatr Res ; 178: 50-58, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39121707

RESUMO

Trauma type moderates the impact of trauma exposure on clinical symptomatology; however, the impact of trauma type on the neural correlates of emotion regulation is not as well understood. This study examines how violent and nonviolent trauma differentially influence the neural correlates of conditioned fear and extinction. We aggregated psychophysiological and fMRI data from three studies; we categorized reported trauma as violent or nonviolent, and subdivided violent trauma as sexual or nonsexual. We examined skin conductance responses (SCR) during a fear conditioning and extinction paradigm. For fMRI data analyses, we conducted region-specific and whole-brain analyses. We examined associations between beta weights from specific brain regions and CAPS scores. The group exposed to violent trauma showed significantly higher SCR during extinction recall. Those exposed to nonviolent trauma showed significantly higher functional activation during late extinction learning. The group exposed to violent trauma showed higher functional connectivity within the default mode network (DMN) and between the DMN and frontoparietal control network. For secondary analyses of sexual vs nonsexual trauma, we did not observe any between-group differences in SCR. During late extinction learning, the group exposed to sexual trauma showed significantly higher activation in the prefrontal cortex and precuneus. During extinction recall, the group exposed to nonsexual trauma showed significantly higher activation in the insular cortex. Violent trauma significantly impacts functional brain activations and connectivity in brain areas important for perception and attention with no significant impact on brain areas that modulate emotion regulation. Sexual trauma impacts brain areas important for internal perception.


Assuntos
Condicionamento Clássico , Extinção Psicológica , Medo , Resposta Galvânica da Pele , Imageamento por Ressonância Magnética , Trauma Psicológico , Humanos , Extinção Psicológica/fisiologia , Masculino , Medo/fisiologia , Feminino , Adulto , Resposta Galvânica da Pele/fisiologia , Adulto Jovem , Condicionamento Clássico/fisiologia , Trauma Psicológico/fisiopatologia , Trauma Psicológico/diagnóstico por imagem , Rede de Modo Padrão/fisiopatologia , Rede de Modo Padrão/diagnóstico por imagem , Exposição à Violência , Delitos Sexuais , Adolescente , Encéfalo/fisiopatologia , Encéfalo/diagnóstico por imagem , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia
14.
J Anxiety Disord ; 106: 102911, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39128178

RESUMO

Anxiety disorders are common and highly distressing mental health conditions. Exposure therapy is a gold-standard treatment for anxiety disorders. Mechanisms of Pavlovian fear learning, and particularly fear extinction, are central to exposure therapy. A growing body of evidence suggests an important role of reward processes during Pavlovian fear extinction. Nonetheless, predominant models of exposure therapy do not currently incorporate reward processes. Herein, we present a theoretical model of reward processes in relation to Pavlovian mechanisms of exposure therapy, including a focus on dopaminergic prediction error signaling, coinciding positive emotional experiences (i.e., relief), and unexpected positive outcomes. We then highlight avenues for further research and discuss potential strategies to leverage reward processes to maximize exposure therapy response, such as pre-exposure interventions to increase reward sensitivity or post-exposure rehearsal (e.g., savoring, imaginal recounting strategies) to enhance retrieval and retention of learned associations.


Assuntos
Transtornos de Ansiedade , Condicionamento Clássico , Extinção Psicológica , Medo , Terapia Implosiva , Recompensa , Humanos , Extinção Psicológica/fisiologia , Terapia Implosiva/métodos , Medo/fisiologia , Transtornos de Ansiedade/terapia , Condicionamento Clássico/fisiologia
15.
Pharmacol Biochem Behav ; 244: 173863, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-39186953

RESUMO

In addition to cocaine's addictive properties, cocaine use may lead to heightened risk-taking behavior. The disruptive effects of cocaine on aversive memory formation may underlie this behavior. The present study investigated the effects of cocaine on fear memory using a cued fear conditioning paradigm in female Sprague Dawley rats, and further determined the role of D2 receptors in modulating the effect of cocaine on cued fear expression. Animals received six evenly spaced shocks preceded by a tone. The following day, rats were returned to the fear chamber where tones, but no shocks, were delivered. In Experiment 1, separate or concurrent administrations of cocaine (15 mg/kg; i.p.) and the D2 receptor antagonist eticlopride (0.1 mg/kg; i.p.) were given immediately after conditioning trials. It was determined that cocaine administration during the consolidation period diminished the expression of cued fear during the subsequent test day. Concurrent eticlopride administration attenuated this effect, indicating the involvement of D2 receptors in the deleterious effects of cocaine on fear memory consolidation. In Experiment 2, eticlopride (0.05 µg) was infused directly into the ventral hippocampus (VH) after fear conditioning and before cocaine administration. Cocaine continued to disrupt consolidation of cued and contextual fear memory, and concurrent intra-VH eticlopride blocked this effect, thereby demonstrating that VH D2 receptors mediate cocaine-induced impairment of fear memory consolidation. Overall, the present study provides evidence that acute cocaine administration impairs aversive memory formation and establishes a potential circuit through which cocaine induces its detrimental effects on fear memory consolidation.


Assuntos
Cocaína , Sinais (Psicologia) , Medo , Ratos Sprague-Dawley , Receptores de Dopamina D2 , Animais , Feminino , Medo/efeitos dos fármacos , Cocaína/farmacologia , Cocaína/administração & dosagem , Receptores de Dopamina D2/metabolismo , Ratos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Consolidação da Memória/efeitos dos fármacos , Salicilamidas/farmacologia , Memória/efeitos dos fármacos , Antagonistas dos Receptores de Dopamina D2/farmacologia , Antagonistas dos Receptores de Dopamina D2/administração & dosagem , Condicionamento Clássico/efeitos dos fármacos
16.
Elife ; 132024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39088250

RESUMO

The brain's ability to appraise threats and execute appropriate defensive responses is essential for survival in a dynamic environment. Humans studies have implicated the anterior insular cortex (aIC) in subjective fear regulation and its abnormal activity in fear/anxiety disorders. However, the complex aIC connectivity patterns involved in regulating fear remain under investigated. To address this, we recorded single units in the aIC of freely moving male mice that had previously undergone auditory fear conditioning, assessed the effect of optogenetically activating specific aIC output structures in fear, and examined the organization of aIC neurons projecting to the specific structures with retrograde tracing. Single-unit recordings revealed that a balanced number of aIC pyramidal neurons' activity either positively or negatively correlated with a conditioned tone-induced freezing (fear) response. Optogenetic manipulations of aIC pyramidal neuronal activity during conditioned tone presentation altered the expression of conditioned freezing. Neural tracing showed that non-overlapping populations of aIC neurons project to the amygdala or the medial thalamus, and the pathway bidirectionally modulated conditioned fear. Specifically, optogenetic stimulation of the aIC-amygdala pathway increased conditioned freezing, while optogenetic stimulation of the aIC-medial thalamus pathway decreased it. Our findings suggest that the balance of freezing-excited and freezing-inhibited neuronal activity in the aIC and the distinct efferent circuits interact collectively to modulate fear behavior.


Assuntos
Medo , Córtex Insular , Optogenética , Animais , Medo/fisiologia , Masculino , Camundongos , Córtex Insular/fisiologia , Vias Neurais/fisiologia , Tonsila do Cerebelo/fisiologia , Condicionamento Clássico/fisiologia , Camundongos Endogâmicos C57BL , Células Piramidais/fisiologia
17.
J Exp Psychol Anim Learn Cogn ; 50(3): 197-209, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39101917

RESUMO

The ABA renewal effect occurs when behavior is trained in one context (A), extinguished in a second context (B), and the test occurs in the training context (A). Two mechanisms that explain ABA renewal are context summation at the test and contextual modulation of extinction learning, with the former being unlikely if both contexts have a similar associative history. In two experiments, we used within-subjects designs in which participants learned to avoid a loud noise (unconditioned stimulus) signaled by discrete visual stimuli (conditioned stimuli [CSs]), by pressing the space bar on the computer keyboard. The training was conducted in two contexts, with a different pair of CSs (CS+ and CS-) trained in each context. During extinction, CS+ and CS- stimuli were presented in the alternative context from that of training, and participants were allowed to freely respond, but no loud noise was presented. Finally, all CSs were tested in both contexts, resulting in a within-subjects ABA versus ABB comparison. Across experiments, participants increased avoidance responses during training and decreased them during extinction, although Experiment 2 revealed less extinction. During the test, responding was higher when CS+ were tested in the training context (ABA) versus the extinction context (ABB), revealing the renewal of instrumental avoidance. Experiment 2 also measured expectancy after the avoidance test and revealed a remarkable similarity between avoidance responses and expectancy ratings. This study shows the renewal of instrumental avoidance in humans, and the results suggest the operation of a modulatory role for the context in renewal, similar to the occasion setting of extinction learning by the context. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Assuntos
Aprendizagem da Esquiva , Condicionamento Operante , Extinção Psicológica , Humanos , Masculino , Extinção Psicológica/fisiologia , Feminino , Aprendizagem da Esquiva/fisiologia , Adulto Jovem , Adulto , Condicionamento Operante/fisiologia , Adolescente , Condicionamento Clássico/fisiologia
18.
J Behav Ther Exp Psychiatry ; 85: 101984, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39116644

RESUMO

BACKGROUND AND OBJECTIVES: The conditioned-intrusion paradigm was designed to provide insight into the relationship between fear conditioning and intrusive memory formation, which is relevant to understanding posttraumatic stress disorder symptoms and treatment. However, boundary conditions of this new paradigm have not been explored and it is currently not known whether findings from this work are valid in a clinical context. METHODS: In the current study, we explored the relationship between stress reactivity to trauma film clips, usual exposure to violent media, renewal of fear conditioning using skin conductance as well as subjective ratings, and the effect of shock versus film clip during conditioning on the frequency of intrusive memories. An adapted fear conditioning paradigm using trauma clips as unconditional stimuli was used, and participants subsequently reported intrusive memories of the trauma clips. RESULTS: Skin conductance responses to conditioned stimuli paired with shocks and film clips were significantly higher than conditioned stimuli paired with film clips alone. Subjective stress reactivity, previous exposure to violent media, and film valence rating were associated with the frequency of intrusive memories. No aspects of fear conditioning were associated with intrusive memories, and factor analysis suggested the fear conditioning and stress related to film clip viewing were mostly separate constructs. Similarly, content and triggers of intrusive memories were usually film-clip related rather than conditional stimulus related. LIMITATIONS: We did not observe strong conditioning effects of the unconditional stimuli to conditional stimuli, which were shapes rather than high frequency stimuli such as faces. CONCLUSIONS: These findings provide potential boundary conditions for this paradigm and suggest multiple ways in which the validity of the paradigm can be tested in the future.


Assuntos
Condicionamento Clássico , Medo , Resposta Galvânica da Pele , Estresse Psicológico , Humanos , Medo/fisiologia , Masculino , Resposta Galvânica da Pele/fisiologia , Feminino , Adulto Jovem , Adulto , Estresse Psicológico/fisiopatologia , Condicionamento Clássico/fisiologia , Adolescente , Memória/fisiologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia
19.
J Neurosci ; 44(38)2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39060174

RESUMO

The presence of valence coding neurons in the basolateral amygdala (BLA) that form distinct projections to other brain regions implies functional opposition between aversion and reward during learning. However, evidence for opponent interactions in fear learning is sparse and may only be apparent under certain conditions. Here we test this possibility by studying the roles of the BLA→central amygdala (CeA) and BLA→nucleus accumbens (Acb) pathways in fear learning in male rats. First, we assessed the organization of these pathways in the rat brain. BLA→CeA and BLA→Acb pathways were largely segregated in the BLA but shared overlapping molecular profiles. Then we assessed activity of the BLA→CeA and BLA→Acb pathways during two different forms of fear learning-fear learning in a neutral context and fear learning in a reward context. BLA→CeA neurons were robustly recruited by footshock regardless of where fear learning occurred, whereas recruitment of BLA→Acb neurons was state-dependent because footshock only recruited this pathway in a reward context. Finally, we assessed the causal roles of activity in these pathways in fear learning. Photoinhibition of the BLA→CeA pathway during the footshock US impaired fear learning, regardless of where fear learning occurred. In contrast, photoinhibition of the BLA→Acb pathway augmented fear learning, but only in the reward context. Taken together, our findings show circuit- and state-dependent opponent processing of fear. Footshock activity in the BLA→Acb pathway limits how much fear is learned.


Assuntos
Medo , Medo/fisiologia , Animais , Masculino , Ratos , Vias Neurais/fisiologia , Complexo Nuclear Basolateral da Amígdala/fisiologia , Núcleo Accumbens/fisiologia , Recompensa , Ratos Sprague-Dawley , Condicionamento Clássico/fisiologia , Tonsila do Cerebelo/fisiologia , Neurônios/fisiologia , Rede Nervosa/fisiologia
20.
Artigo em Inglês | MEDLINE | ID: mdl-39029651

RESUMO

Substance use disorder is conceptualized as a form of maladaptive learning, whereby drug-associated memories, elicited by the presence of stimuli related to drug contexts or cues, contribute to the persistent recurrence of craving and the reinstatement of drug-seeking behavior. Hence, use of pharmacology or non-pharmacology way to disrupt drug-related memory holds promise to prevent relapse. Several studies have shown that memories can be unstable and susceptible to modification during the retrieval reactivation phase, termed the "reconsolidation time window". In this study, we use the classical conditioned place preference (CPP) model to investigate the role of aversive counterconditioning on drug-related memories during reconsolidation. Specifically, we uncovered that reconditioning drug cues through counterconditioning with LiCl-induced aversive outcomes following drug memory retrieval reduces subsequent drug-seeking behavior. Notably, the recall of cocaine- or morphine-CPP was eliminated when LiCl-induced aversive counterconditioning was performed 10 min, but not 6 h (outside the reconsolidation time window) after cocaine or morphine memory retrieval. In addition, the effect of LiCl-induced aversive counterconditioning could last for about 14 days. These results suggest that aversive counterconditioning during the reconsolidation of cocaine or morphine memory can prevent the re-seeking of cocaine or morphine, presumably by updating or replacing cocaine or morphine memories with aversive information.


Assuntos
Cocaína , Condicionamento Clássico , Comportamento de Procura de Droga , Cloreto de Lítio , Morfina , Animais , Cloreto de Lítio/farmacologia , Masculino , Morfina/farmacologia , Cocaína/farmacologia , Comportamento de Procura de Droga/efeitos dos fármacos , Comportamento de Procura de Droga/fisiologia , Condicionamento Clássico/efeitos dos fármacos , Condicionamento Clássico/fisiologia , Rememoração Mental/efeitos dos fármacos , Rememoração Mental/fisiologia , Recidiva , Sinais (Psicologia) , Ratos
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