RESUMEN
Humans and other animals constantly evaluate their decisions in order to learn and behave adaptively. Experimentally, such evaluation processes are accessed using metacognitive reports made after decisions, typically using verbally formulated confidence scales. When subjects report high confidence, it reflects a high certainty of being correct, but a low confidence might signify either low certainty about the outcome, or a high certainty of being incorrect. Hence, metacognitive reports might reflect not only different levels of decision certainty, but also two certainty directions (certainty of being correct and certainty of being incorrect). It is important to test if such bi-directional processing can be measured because, for decision-making under uncertainty, information about being incorrect is as important as information about being correct for guidance of subsequent behavior. We were able to capture implicit bi-directional certainty readouts by asking subjects to bet money on their perceptual decision accuracy using a six-grade wager scale (post-decision wagering, PDW). To isolate trial-specific aspects of metacognitive judgments, we used pre-decision wagering (wagering before the perceptual decision) to subtract, from PDW trials, influences resulting from non-trial-specific assessment of expected difficulty and psychological biases. This novel design allowed independent quantification of certainty of being correct and certainty of being incorrect, showing that subjects were able to read out certainty in a bi-directional manner. Certainty readouts about being incorrect were particularly associated with metacognitive sensitivity exceeding perceptual sensitivity (i.e. meta-d'â¯>â¯d'), suggesting that such enhanced metacognitive efficiency is driven by information about incorrect decisions. Readouts of certainty in both directions increased on easier trials, and both certainty directions were also associated with faster metacognitive reaction times, indicating that certainty of being incorrect was not confounded with low certainty. Finally, both readouts influenced the amount of money subjects earned through PDW, suggesting that bi-directional readouts are important for planning future actions when feedback about previous decisions is unavailable.
Asunto(s)
Toma de Decisiones , Juicio , Metacognición , Percepción Visual , Adulto , Femenino , Juegos Experimentales , Humanos , Masculino , Modelos Psicológicos , Tiempo de Reacción , Adulto JovenRESUMEN
The role of the amygdala in the mediation of fear and anxiety has been extensively investigated. However, how the amygdala functions during the organization of the anxiety-like behaviors generated in the elevated plus maze (EPM) is still under investigation. The basolateral (BLA) and the central (CeA) nuclei are the main input and output stations of the amygdala. In the present study, we ethopharmacologically analyzed the behavior of rats subjected to the EPM and the tissue content of the monoamines dopamine (DA) and serotonin (5-HT) and their metabolites in the nucleus accumbens (NAc), dorsal hippocampus (DH), and dorsal striatum (DS) of animals injected with saline or midazolam (20 and 30 nmol/0.2 µL) into the BLA or CeA. Injections of midazolam into the CeA, but not BLA, caused clear anxiolytic-like effects in the EPM. These treatments did not cause significant changes in 5-HT or DA contents in the NAc, DH, or DS of animals tested in the EPM. The data suggest that the anxiolytic-like effects of midazolam in the EPM also appear to rely on GABA-benzodiazepine mechanisms in the CeA, but not BLA, and do not appear to depend on 5-HT and DA mechanisms prevalent in limbic structures.
Asunto(s)
Amígdala del Cerebelo/efectos de los fármacos , Ansiolíticos/farmacología , Aprendizaje por Laberinto/efectos de los fármacos , Midazolam/farmacología , Amígdala del Cerebelo/fisiología , Animales , Cuerpo Estriado/química , Cuerpo Estriado/efectos de los fármacos , Dopamina/análisis , Hipocampo/química , Hipocampo/efectos de los fármacos , Masculino , Núcleo Accumbens/química , Núcleo Accumbens/efectos de los fármacos , Ratas , Ratas Wistar , Serotonina/análisisRESUMEN
The amygdala has a crucial role in detecting motivationally significant inputs and in communicating relevant information to other limbic structures. Behavioural studies have shown that the central (CeA) and basolateral (BLA) nuclei of amygdala differentially regulate conditioned and unconditioned fear. Indeed, much evidence has accumulated suggesting that regulatory mechanisms in the BLA serve as a filter for unconditioned and conditioned aversive information that ascends to higher structures from the brainstem, whereas the CeA is the main output for the autonomic and somatic components of fear reaction through major projections to other limbic regions. It is still unclear, however, how amygdaloid nuclei function in high and open spaces so as to determine the characteristic exploratory behaviour of rats submitted to the elevated plus-maze test (EPM). In the present study, we carried out an ethopharmacological analysis of the behaviour of rats submitted to the elevated plus-maze test together with analysis of the tissue content of monoamine dopamine (DA) and serotonin (5-HT) and their metabolites in the dorsal hippocampus (DH), nucleus accumbens (NAC) and dorsal striatum (DS) of animals injected with saline or muscimol (1.0 nmol/0.2 microL) into the BLA or CeA. The data obtained show that injections of muscimol into the CeA, but not into the BLA, caused anxiolytic-like effects in the EPM. Such effects of muscimol into the CeA were accompanied by increases in 5-HT content of the DH, whereas corresponding injections into the BLA caused a reduction in the DA content of the NAC. There was no change in the turnover rates of these monoamines. These data suggest that the BLA and CeA have distinct roles in the exploratory behaviour of rodents in the EPM. While BLA appears to be related to the detection and validation of threatening stimuli, the CeA appears to be involved in the expression of fear behaviours in the EPM.