Fabiana M. Carvalho

2 papers in the library · 267 citations · publishing 2011-2016

Papers

Seeing with the eyes shut: Neural basis of enhanced imagery following ayahuasca ingestion

Human Brain Mapping September 16, 2011 Dráulio Barros de Araújo, Sidarta Ribeiro, Guillermo Cecchi et al. 241 citations

Ayahuasca, a hallucinogenic brew containing serotonergic agonists and reuptake inhibitors, triggers vivid visual imagery during ceremonies. Using functional magnetic resonance imaging while participants performed a closed-eyes imagery task, the brew produced a robust increase in activation across occipital, temporal, and frontal brain areas. In the primary visual area, activation levels matched those of natural image viewing with eyes open. This effect correlated with individual perceptual changes measured by psychiatric scales. Activity in areas BA30 and BA37, linked to episodic memory and contextual associations, was also potentiated. Modulation of BA10, involved in prospective imagination and working memory, was detected. The findings suggest Ayahuasca seeings arise from an extensive network for vision, memory, and intention, lending a sense of reality to inner experiences.

DOI: 10.1002/hbm.21381 Ayahuasca Hallucinogen Mental image Perception +2

Time-Perception Network and Default Mode Network Are Associated with Temporal Prediction in a Periodic Motion Task

Frontiers in Human Neuroscience June 2, 2016 Fabiana M. Carvalho, Khallil Taverna Chaim, Tiago Arruda Sanchez et al. 26 citations

Updating internal models to predict future events relies on both frontal and parietal brain regions involved in uncertainty-driven updating and a separate network for temporal attention. Using fMRI, this study examined how continuous manipulation of temporal prediction engages these networks. Participants viewed periodic (simple harmonic oscillation) and non-periodic (variable acceleration) motion patterns. Non-periodic motion activated the exogenous temporal orienting network, including ventral premotor and inferior parietal cortices, cerebellum, presupplementary motor area, and motion-sensitive area MT+, with a right-hemisphere bias suggesting explicit timing. Periodic motion activated default-mode network midline areas (left DMPFC, ACC, bilateral PCC/PC), indicating the DMN may process contextually expected information and validate prospective internal models. Findings show continuous temporal prediction engages both temporal expectation representations and task-independent internal model updating.

DOI: 10.3389/fnhum.2016.00268 Default mode network Precuneus Neuroscience Posterior cingulate +11