1,721,100 research outputs found
Multivariate brain prediction of heart rate and skin conductance responses to social threat
No full textThe challenges of forecasting resilience
No full textDeveloping prospective models of resilience using the translational and transdiagnostic framework proposed in the target article is a challenging endeavor and will require large-scale data sets with dense intraindividual temporal sampling and innovative analytic methods
Placebo Effects on the Neurologic Pain Signature: A Meta-analysis of Individual Participant Functional Magnetic Resonance Imaging Data
No full textImportance: Placebo effects reduce pain and contribute to clinical analgesia, but after decades of research, it remains unclear whether placebo treatments mainly affect nociceptive processes or other processes associated with pain evaluation. Objective: We conducted a systematic, participant-level meta-analysis to test the effect of placebo treatments on pain-associated functional neuroimaging responses in the neurologic pain signature (NPS), a multivariate brain pattern tracking nociceptive pain. Data Sources: Medline (PubMed) was searched from inception to May 2015; the search was augmented with results from previous meta-analyses and expert recommendations. Study Selection: Eligible studies were original investigations that were published in English in peer-reviewed journals and that involved functional neuroimaging of the human brain with evoked pain delivered under stimulus intensity-matched placebo and control conditions. The authors of all eligible studies were contacted and asked to provide single-participant data. Data Extraction and Synthesis: Data were collected between December 2015 and November 2017 following the Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data guidelines. Results were summarized across participants and studies in a random-effects model. Main Outcomes and Measures: The main, a priori outcome was NPS response; pain reports were assessed as a secondary outcome. Results: We obtained data from 20 of 28 identified eligible studies, resulting in a total sample size of 603 healthy individuals. The NPS responses to painful stimulation compared with baseline conditions were positive in 575 participants (95.4%), with a very large effect size (g = 2.30 [95% CI, 1.92 to 2.69]), confirming its sensitivity to nociceptive pain in this sample. Placebo treatments showed significant behavioral outcomes on pain ratings in 17 of 20 studies (85%) and in the combined sample (g = -0.66 [95% CI, -0.80 to -0.53]). However, placebo effects on the NPS response were significant in only 3 of 20 studies (15%) and were very small in the combined sample (g = -0.08 [95% CI, -0.15 to -0.01]). Similarly, analyses restricted to studies with low risk of bias (g = -0.07 [95% CI, -0.15 to 0.00]) indicated very small effects, and analyses of just placebo responders (g = -0.22 [95% CI, -0.34 to -0.11]) indicated small effects, as well. Conclusions and Relevance: Placebo treatments have moderate analgesic effects on pain reports. The very small effects on NPS, a validated measure that tracks levels of nociceptive pain, indicate that placebo treatments affect pain via brain mechanisms largely independent of effects on bottom-up nociceptive processing
The Neural Embodiment of Human Emotion
Get PDFColloquially, we describe emotion as something we feel, but it remains unknown whether emotional experiences and bodily sensations share representational space in the human brain. Does the neural basis of emotion include activation in cortex specialized to represent bodily sensation and action? There is growing evidence that emotions are ‘embodied,’ or grounded in simulations of some modality, such as perception and action. However, a causal link between reports of bodily sensations and discrete emotional states has not been established. This investigation aims to bridge bodily sensations of emotion with its neural construction by analyzing the representational similarity between self-reported topographical maps of emotion-induced bodily activation and neural activity in select sensorimotor and perceptual regions of interest. This exploratory investigation shows that: (1) Emotional images induce subjective sensations of bodily activation, (2) Self-reports of embodiment are correlated with physiological arousal, (3) Self-reported bodily representations of emotion are most similar to neural representations in the visual cortex, indicating that saliency, not somatization, may influence reports of embodiment. This investigation establishes a link between embodiment and physiological responding, but fails to establish a neural link between embodiment and sensorimotor representations. In summary, the relationship between emotion and the body is not purely conceptual: It is supported by physiological responses. Emotion-related bodily representations may serve to ready an organism for social or survival-related action. Knowledge of these representations may contribute to the biomarker initiative and provide neural targets for emotion regulation in the clinic
The Neural Embodiment of Human Emotion
Get PDFColloquially, we describe emotion as something we feel, but it remains unknown whether emotional experiences and bodily sensations share representational space in the human brain. Does the neural basis of emotion include activation in cortex specialized to represent bodily sensation and action? There is growing evidence that emotions are ‘embodied,’ or grounded in simulations of some modality, such as perception and action. However, a causal link between reports of bodily sensations and discrete emotional states has not been established. This investigation aims to bridge bodily sensations of emotion with its neural construction by analyzing the representational similarity between self-reported topographical maps of emotion-induced bodily activation and neural activity in select sensorimotor and perceptual regions of interest. This exploratory investigation shows that: (1) Emotional images induce subjective sensations of bodily activation, (2) Self-reports of embodiment are correlated with physiological arousal, (3) Self-reported bodily representations of emotion are most similar to neural representations in the visual cortex, indicating that saliency, not somatization, may influence reports of embodiment. This investigation establishes a link between embodiment and physiological responding, but fails to establish a neural link between embodiment and sensorimotor representations. In summary, the relationship between emotion and the body is not purely conceptual: It is supported by physiological responses. Emotion-related bodily representations may serve to ready an organism for social or survival-related action. Knowledge of these representations may contribute to the biomarker initiative and provide neural targets for emotion regulation in the clinic
Deconstructing Pain: Sensory and Cognitive Manipulations of Pain are Mediated by Distinct Systems
Get PDFCognitive strategies can strongly modulate emotion and pain. However, it is unclear whether cognition primarily influences core affective processes or later decision and valuation processes. We combined fMRI imaging with an experimental pain paradigm, and concurrently manipulated both the intensity of noxious input and a cognitive reappraisal of pain. Both manipulations strongly influenced reported pain, but they did so via two distinct brain pathways. The effects of stimulus intensity were mediated by a distributed brain network recently shown to predict physical pain with over 90% sensitivity and specificity across four studies. Cognitive reappraisal had no effect on activity in this network. Instead, cognitive effects on pain were mediated through a pathway connecting the nucleus accumbens and ventromedial prefrontal cortex. This pathway was unresponsive to noxious input, and has been broadly implicated in valuation and emotional appraisal. These findings suggest that sensory and cognitive manipulations influence pain through distinct brain pathways
Does thinking about the past reduce temporal discounting? An investigation into the effects of episodic thought on intertemporal choice
Get PDFHumans show a preference for present rewards over delayed rewards, a phenomenon known as temporal discounting (TD). TD, of perennial interest because of its violation of rational economic theory, is associated with poor outcomes such as drug addiction and perhaps even global warming. Recent research has shown that episodic future thinking can reduce temporal discounting, possibly by modulating subjective valuation processes through imagery-based operations supported by the medial temporal lobe and connecting structures. Interestingly, a growing body of additional research suggests that episodic memory and episodic future thought share similar cognitive processes and neural mechanisms. Given these findings, an immediate question is whether episodic memory can also reduce temporal discounting. To investigate this question, we created a behavioral paradigm whereby participants performed intertemporal choice trials, but each trial was primed by either a brief period of episodic past thought, episodic future thought, or a non-episodic imagery control condition. In line with previous findings, participants discounted future rewards compared to present rewards and showed wide inter-individual variability in their discounting rates. However, when comparing discounting rates between the three conditions, results revealed that episodic memory reduced TD more than episodic future thought and the imagery control condition. In contrast, no differences in TD were observed between the episodic future thought condition and the control condition. Given that the episodic past thought condition was associated with higher self-reported imagery than the episodic future thought condition, these findings suggest that basic episodic imagery processes might play an important role in modulating intertemporal decision-making
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Exploring the Brain Mechanisms Involved in Reward Prediction Errors Using Conditioned Inhibition
Get PDFMany previous studies of the brain areas involved in reward prediction errors have not accounted for the downstream projections of dopamine areas when interpreting these results. We propose that paradigms like conditioned inhibition, which involves pairing a rewarded CS with an inhibitor that always cancels the reward, can reduce this confound and allow for further specification of the computational role different brain regions play into the RPE signal. Further predictions of the role of different brain areas in reward learning and how positive and negative valence learning interact in the brain are inspired by the PVLV model, a more biologically plausible alternative to TD learning that uses two parameters, learned value and primary value, compared to the single RPE parameter used by TD. To test the predictions of the PVLV model and compare activity across different conditions that allowed us to examine the roles of different regions in RPE computation, we ran a conditioned inhibition fMRI study using juice rewards, with a particular focus on examining the brain activity in several regions of interest in the PVLV model, including the ventral striatum, central nucleus of the amygdala and lateral habenula. We found that the rewarded CS activated the VTA/SN, consistent with many other studies of reward learning, as well as several regions in the basal ganglia. There was also overlap between activations for the CS, CS+Inhibitor and Inhibitor in the prefrontal cortex, insula and basal ganglia. Also, better than expected rewards activated the medial OFC; while worse than expected rewards activated the lateral OFC. In the amygdala, we found increased activity for the juice reward compared to the neutral solution, but we did not find increased activity for the rewarded CS as predicted by the PVLV model
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