Frontiers in Pharmacology
September 29, 2021
João Castelhano, Gisela Lima, Marta Teixeira et al.
34 citations
Tryptamine psychedelics such as LSD, psilocybin, DMT, and ayahuasca alter brain activation and connectivity in regions that match the distribution of 5HT2A and 5HT1A receptors, including visual cortex, cingulate cortex, medial prefrontal cortex, temporal cortex, and the right amygdala. These effects involve areas supporting mental imagery, theory of mind, and emotional regulation, suggesting potential therapeutic applications. The analysis confirms that changes occur in regions with high 5HT2A receptor density, but also in other areas like the dorsolateral prefrontal cortex. However, too few PET studies exist to meta-analyze receptor occupancy directly.
Frontiers in pharmacology
January 1, 2024
Carla Soares, Gisela Lima, Marta Lapo Pais et al.
13 citations
A pharmacoimaging study in eleven healthy experienced users found that inhaled DMT increases functional connectivity between brain regions involved in social cognition and emotional processing. Specifically, DMT strengthened connections between the supramarginal gyrus and the precuneus, posterior cingulate gyrus, amygdala, and orbitofrontal cortex, as well as between the amygdala and orbitofrontal cortex. These changes occurred in socio-emotional and affective-value circuits, offering insight into how psychedelics may alter brain function and potentially contribute to therapeutic effects in disorders involving social and reward processing deficits.
NeuroImage
August 15, 2024
Marta Lapo Pais, Marta Teixeira, Carla Soares et al.
8 citations
Inhaled DMT, a psychedelic acting on 5-HT2A serotonin receptors, increases the size of neural population receptive fields (pRFs) in the peripheral visual field of the primary visual cortex (V1). This change, measured with MRI and pRF mapping in a within-subject design, occurred during visual effects documented by the Hallucinogen Rating Scale and was not explained by differences in eye or head movements. The enlarged pRFs may underlie perceptual distortions such as field blurring, tunnel vision, and enlargement of nearby visual space. The findings suggest that 5-HT2A receptor activation controls gain in visual cortex, linking neural population responses to psychedelic visual phenomena.
British journal of clinical pharmacology
December 1, 2024
Gisela Lima, Carla Soares, Marta Teixeira et al.
4 citations
Psychedelics are being explored for physical and mental health applications beyond psychiatry, including chronic pain, palliative care, and neuroprotection in ischemia. This article reviews dimethyltryptamine (DMT) and ayahuasca pharmacology, effects, safety, and toxicity, and details the anaesthetist's role in clinical and experimental research—covering participant screening, dosing sessions, adverse effect management, and toxicity treatment. It draws on a current neuroimaging study protocol. The authors argue that anaesthetists are uniquely positioned to manage psychedelic therapy in medically complex, polymedicated patients, but note that non-mental medical applications remain underexplored.
Social cognitive and affective neuroscience
January 31, 2026
Carla Soares, Gisela Lima, Marta Teixeira et al.
1 citation
A pharmacoimaging study examined how ayahuasca affects a brain region involved in social perception, the posterior superior temporal sulcus (pSTS), which is part of the third visual pathway. Twelve healthy volunteers received two doses of ayahuasca (0.5 mg/kg and 0.8 mg/kg DMT) or a placebo in a crossover design. The higher dose increased connectivity of the right pSTS with visual and mirror-neuron brain regions. This enhanced connectivity correlated with stronger perspective-taking experiences. Participants also reported improved social relationships one week later, even though acute effects were minimal. The findings suggest ayahuasca strengthens early social information processing through the third visual pathway and mirror-neuron systems, offering a basis for its prosocial therapeutic effects.
Scientific Reports
December 12, 2025
Gisela Lima, Carla Soares, Marta Teixeira et al.
Reward processing involves learning, liking, and wanting, and its disruption in mesolimbic and mesocortical pathways underlies many disorders. In a preliminary pharmacoimaging study, 11 healthy participants with prior psychedelic experience self-administered inhaled DMT immediately before MRI scanning, with a no-administration control condition. DMT decreased connectivity between the right nucleus accumbens and left ventral tegmental area, increased connectivity between the right nucleus accumbens and anterior cingulate cortex, and increased connectivity between medial prefrontal cortex and anterior cingulate cortex. These connectivity changes correlated with altered volition and perception. Reduced midbrain-NAc connectivity, often increased in addiction, suggests potential therapeutic value for reward-related disorders.
Research Square
September 17, 2025
Gisela Lima, Carla Soares, Marta Teixeira et al.
Reward processing involves learning, liking, and wanting, and its disruption in mesolimbic and mesocortical pathways underlies many disorders. In a within-subject pharmacoimaging study with 11 healthy participants experienced with psychedelics, inhaled N,N-dimethyltryptamine (DMT) altered connectivity within the mesocorticolimbic circuitry. Connectivity decreased between the right nucleus accumbens and left ventral tegmental area, while it increased between the right nucleus accumbens and anterior cingulate cortex, and between the medial prefrontal cortex and anterior cingulate cortex. These changes correlated with shifts in volition and perception. The findings suggest DMT may have therapeutic potential for disorders affecting reward processing.