Browsing by Author "Sousa, L. de"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- Effects of emotional valence and three-dimensionality of visual stimuli on brain activation: an fMRI studPublication . Dores, Artemisa Rocha; Almeida, I.; Barbosa, F.; Castelo-Branco, M.; Guerreiro, S.; Almeida, I.; Reis, M.; Sousa, L. de; Castro Caldas, A.Examining changes in brain activation associated with emotion-inducing stimuli is essential to the study of emotions. Due to the ecological potential of virtual reality in neurocognitive rehabilitation, inspection of whether brain activation in response to emotional stimuli can also be modulated by the three-dimensional properties of the images is now important. This study sought to test whether the activation of brain areas involved in the emotional processing of scenarios of different valences can be modulated by three dimensionality. It focused on the interaction effect among emotion-inducing stimuli of different emotional valences (pleasant, unpleasant and neutral valences) and visualization types (2D, 3D).
- Effects of emotional valence and three-dimensionality of visual stimuli on brain activation: an fMRI studyPublication . Dores, Artemisa Rocha; Almeida, I.; Barbosa, F.; Castelo-Branco, M.; Monteiro, L.; Reis, M.; Sousa, L. de; Caldas, A. CastroExamining changes in brain activation linked with emotion-inducing stimuli is essential to the study of emotions. Due to the ecological potential of techniques such as virtual reality (VR), inspection of whether brain activation in response to emotional stimuli can be modulated by the three-dimensional (3D) properties of the images is important. The current study sought to test whether the activation of brain areas involved in the emotional processing of scenarios of different valences can be modulated by 3D. Therefore, the focus was made on the interaction effect between emotion-inducing stimuli of different emotional valences (pleasant, unpleasant and neutral valences) and visualization types (2D, 3D). However, main effects were also analyzed.METHODS: The effect of emotional valence and visualization types and their interaction were analyzed through a 3x2 repeated measures ANOVA. Post-hoc t-tests were performed under a ROI-analysis approach. The results show increased brain activation for the 3D affective-inducing stimuli in comparison with the same stimuli in 2D scenarios, mostly in cortical and subcortical regions that are related to emotional processing, in addition to visual processing regions. This study has the potential of clarify brain mechanisms involved in the processing of emotional stimuli (scenarios’ valence) and their interaction with three-dimensionality.
- Long-term effects of chronic cocaine exposure throughout adolescence on anxiety and stress responsivity in a wistar rat modelPublication . Alves, C.J.; Magalhães, A.; Melo, P.; Sousa, L. de; Monteiro, Pedro; Summavielle, TeresaAdolescents display increased vulnerability to engage in drug experimentation. This is often considered a risk factor for later drug abuse. In this scenario, the permanent effects of cocaine exposure during adolescence on anxiety levels and stress responsivity, which may result in behavioral phenotypes prone to addiction, are now starting to be unveiled. Thus, the purpose of the present study was to evaluate the long-lasting effects of chronic cocaine administration during adolescence, on anxiety-like behavior and on stress response. Adolescent male Wistar rats were daily administered 45-mg cocaine/kg of body weight in three equal intraperitoneal doses with 1-h interval, from postnatal day (PND) 35 to 50. The effects of cocaine administration on anxiety levels, assessed in the Elevated Plus Maze (EPM), and on social stress response, assessed in the resident-intruder paradigm (R/I), were evaluated 10 days after withdrawal, when rats were reaching the adulthood. The underlying dopaminergic activity, and the corticosterone and testosterone levels were determined. Our results showed that cocaine induced long-lasting alterations in the hypothalamus-pituitary-adrenals (HPA) axis function and in testosterone levels. Such alterations resulted in significant and enduring changes in behavioral responses to environmental challenges, such as the EPM and R/I, including the evaluation of potential threats that may lead to high-risk behavior and low-benefit choices. This was further supported by an altered dopaminergic function in the amygdala and hippocampus. The present findings provide new insights into how the use of cocaine during adolescent development may modulate emotional behavior later in life. Compromised ability to recognize and deal with potential threats is an important risk factor to perpetuate compulsive drug seeking and relapse susceptibility.