Unlike the sensory thalamus, studies on the functional organization of the midline and intralaminar nuclei are scarce, and this has hindered the establishment of conceptual models of the function of ...this brain region. We investigated the functional organization of the paraventricular nucleus of the thalamus (PVT), a midline thalamic structure that is increasingly being recognized as a critical node in the control of diverse processes such as arousal, stress, emotional memory and motivation, in mice. We identify two major classes of PVT neurons-termed type I and type II-that differ in terms of gene expression, anatomy and function. In addition, we demonstrate that type II neurons belong to a previously neglected class of PVT neurons that convey arousal-related information to corticothalamic neurons of the infralimbic cortex. Our results uncover the existence of an arousal-modulated thalamo-corticothalamic loop that links the PVT and the ventromedial prefrontal cortex.
Motivated behaviors are often studied in isolation to assess labeled lines of neural connections underlying innate actions. However, in nature, multiple systems compete for expression of ...goal-directed behaviors via complex neural networks. Here, we examined flexible survival decisions in animals tasked with food seeking under predation threat. We found that predator exposure rapidly induced physiological, neuronal, and behavioral adaptations in mice highlighted by reduced food seeking and consumption contingent on current threat level. Diminishing conflict via internal state or external environment perturbations shifted feeding strategies. Predator introduction and/or selective manipulation of danger-responsive cholecystokinin (Cck) cells of the dorsal premammilary nucleus (PMd) suppressed hunger-sensitive Agouti-related peptide (AgRP) neurons, providing a mechanism for threat-evoked hypophagia. Increased caloric need enhanced food seeking under duress through AgRP pathways to the bed nucleus of the stria terminalis (BNST) and/or lateral hypothalamus (LH). Our results suggest oscillating interactions between systems underlying self-preservation and food seeking to promote optimal behavior.
•Predator exposure induced physiological/behavioral changes contingent on threat level•Diminishing conflict via internal or external perturbations shifted feeding strategies•Predator addition or PMdCck activation inhibited AgRP neurons, resulting in hypophagia•Increased caloric need via AgRP → BNST and/or LH enhanced food seeking under predation
Motivated behaviors are often studied in a behavioral vacuum for experimental simplicity. However, in nature, systems compete in real time for expression of goal-directed behaviors via complex neural networks. Here, de Araujo Salgado et al. examine flexible behaviors used by animals tasked with food seeking under predation threat and uncover a neural mechanism of how these systems interact to maximize survival.
Marked deficits in glucose availability, or glucoprivation, elicit organism-wide counter-regulatory responses whose purpose is to restore glucose homeostasis. However, while catecholamine neurons of ...the ventrolateral medulla (VLM
) are thought to orchestrate these responses, the circuit and cellular mechanisms underlying specific counter-regulatory responses are largely unknown. Here, we combined anatomical, imaging, optogenetic and behavioral approaches to interrogate the circuit mechanisms by which VLM
neurons orchestrate glucoprivation-induced food seeking behavior. Using these approaches, we found that VLM
neurons form functional connections with nucleus accumbens (NAc)-projecting neurons of the posterior portion of the paraventricular nucleus of the thalamus (pPVT). Importantly, optogenetic manipulations revealed that while activation of VLM
projections to the pPVT was sufficient to elicit robust feeding behavior in well fed mice, inhibition of VLM
-pPVT communication significantly impaired glucoprivation-induced feeding while leaving other major counterregulatory responses intact. Collectively our findings identify the VLM
-pPVT-NAc pathway as a previously-neglected node selectively controlling glucoprivation-induced food seeking. Moreover, by identifying the ventrolateral medulla as a direct source of metabolic information to the midline thalamus, our results support a growing body of literature on the role of the PVT in homeostatic regulation.
The successful pursuit of goals requires the coordinated execution and termination of actions that lead to positive outcomes. This process relies on motivational states that are guided by internal ...drivers, such as hunger or fear. However, the mechanisms by which the brain tracks motivational states to shape instrumental actions are not fully understood. The paraventricular nucleus of the thalamus (PVT) is a midline thalamic nucleus that shapes motivated behaviors via its projections to the nucleus accumbens (NAc)1,2,3,4,5,6,7,8 and monitors internal state via interoceptive inputs from the hypothalamus and brainstem.3,9,10,11,12,13,14 Recent studies indicate that the PVT can be subdivided into two major neuronal subpopulations, namely PVTD2(+) and PVTD2(−), which differ in genetic identity, functionality, and anatomical connectivity to other brain regions, including the NAc.4,15,16 In this study, we used fiber photometry to investigate the in vivo dynamics of these two distinct PVT neuronal types in mice performing a foraging-like behavioral task. We discovered that PVTD2(+) and PVTD2(−) neurons encode the execution and termination of goal-oriented actions, respectively. Furthermore, activity in the PVTD2(+) neuronal population mirrored motivation parameters such as vigor and satiety. Similarly, PVTD2(−) neurons also mirrored some of these parameters, but to a much lesser extent. Importantly, these features were largely preserved when activity in PVT projections to the NAc was selectively assessed. Collectively, our results highlight the existence of two parallel thalamo-striatal projections that participate in the dynamic regulation of goal pursuits and provide insight into the mechanisms by which the brain tracks motivational states to shape instrumental actions.
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•PVTD2(+)-NAc pathway encodes the execution of goal-oriented actions•PVTD2(−)-NAc pathway encodes the termination of goal-oriented actions•The activity of PVTD2(+) neurons correlated with motivation parameters•PVTD2(−) neuronal activity correlated with motivation, but to a lesser degree
Beas et al. identify two thalamo-striatal pathways, PVTD2(+)-NAc and PVTD2(−)-NAc, that display distinct in vivo dynamics throughout different times of a foraging-like task. These two pathways act synergistically, enabling the execution of specific elements needed to engage, track, and terminate rewarded goal-oriented behavior.
In view of the rising incidence and prevalence of mental disorders, and the stigma often attached to persons with these pathologies, the question of specific, appropriate training for nursing ...students is one of great importance. Objective structured clinical examination (OSCE) and clinical simulation may provide a useful means of introducing the student to this environment.
To examine the perceptions and satisfaction of nursing students after their participation in a targeted mental health course in which the main specialist skills were acquired via clinical simulation.
A quantitative, descriptive, transversal study was conducted, in which the participants in a mental health course completed a questionnaire on their satisfaction with the experience.
The study population consisted of 141 nursing students enrolled in a mental health course and currently in the third year of their Nursing Degree studies at the University of Málaga (Spain).
The overall satisfaction expressed was more than 8 out of 10 (mean score = 8.43, SD = 1.25) and the students' satisfaction with specific aspects of the procedure exceeded 4 out of 5. The study results show that these nursing students considered the methodology in question to be useful preparation for clinical practice (mean score = 4.78, SD = 0.45), that they appreciated the participation of an expert (mean score = 4.72, SD = 0.60) and that receiving the opinions of their peers about their performance was an enriching part of the experience (mean score = 4.54, SD = 0.64).
The participants reported a high degree of satisfaction with the OSCE procedure and observed that this method should be implemented more frequently. Debriefing is viewed as a vital contribution to the learning process and to the participants' satisfaction. However, further research is needed to study the impact of stress and anxiety on the acquisition of skills via OSCEs.
•A high degree of satisfaction with the OSCE method was expressed by the students who took part in a mental health course;•These nursing students believe that OSCEs should be implemented more frequently;•Further research should be undertaken to study the impact of stress and anxiety from acting in front of classmates at OSCEs.
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