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Richard J. Ortiz

New Mexico State University

4 papers in the library · 13 citations · publishing 2025-2026

Papers

Dose-dependent changes in global brain activity and functional connectivity following exposure to psilocybin: a BOLD MRI study in awake rats

Frontiers in Neuroscience May 1, 2025 Evan Fuini, Arnold Chang, Josh Edwards et al. 6 citations

Psilocybin, a hallucinogen, produces dose-dependent increases in brain activity in awake rats, particularly in the somatosensory cortex, basal ganglia, and thalamus. Female rats showed greater activation than males at the 0.3 mg/kg dose in thalamic and basal ganglia regions. The drug also caused a global increase in functional connectivity, especially hyperconnectivity to the cerebellum. Higher doses activated circuits involved in sensory filtering and motor organization, such as the cortico-striato-thalamo-cortical circuit and claustrum. However, the direction of BOLD signal changes and neural network activity patterns differed from those reported in human studies.

Sex-dependent developmental changes in behavior, brain structure, functional connectivity, and sensory perception following exposure to psilocybin during adolescence

Neuropsychopharmacology February 18, 2026 Itishree Sahoo, Sairam Masadi, Ashwath Maheswari et al. 3 citations

Adolescent mice given psilocybin every other day from postnatal days 40-50 showed long-term changes in brain structure and function when tested in adulthood. Brain imaging revealed reduced volume and altered water diffusivity in several regions, with males more affected than females. Functional connectivity increased globally and regionally, notably between the prefrontal cortex and hypothalamus, thalamus, and midbrain. Mice showed reduced brain sensitivity to rewarding and aversive odors, and males had lower levels of epigenetic and neuroplasticity protein markers in the prefrontal cortex. Behaviorally, female mice showed reduced mobility in the open field test, while no differences appeared in the light/dark box test. These findings indicate that adolescent psilocybin exposure produces lasting developmental consequences, especially in males.

Psilocybin as a Treatment for Repetitive Mild Head Injury: Evidence from Neuroradiology and Molecular Biology

bioRxiv (Cold Spring Harbor Laboratory) February 6, 2025 Bryce Axe, Ashwath Maheswari, Reagan Walhof et al. 3 citations preprint

Repetitive mild head injuries from sports, accidents, or military service cause lasting cognitive, motor, and behavioral problems and raise the risk of dementia, Parkinson's disease, and chronic traumatic encephalopathy, yet no approved treatment exists. Testing the psychedelic psilocybin in adult female rats with mild repetitive head injury, the authors report that psilocybin reduces vasogenic edema, restores normal vascular reactivity and functional connectivity, reduces buildup of phosphorylated tau, increases levels of brain-derived neurotrophic factor and its receptor TrkB, and modulates lipid signaling molecules. These findings suggest psilocybin may have healing effects on head injury-related brain damage.

Beyond the toad's kiss: Mapping acute 5-MeO-DMT effects on brain connectivity across sex and dose using awake rat neuroimaging

Neuropharmacology March 6, 2026 Noah Cavallaro, Priya Rai, David Akins et al. 1 citation

In a first-ever fMRI study of 5-MeO-DMT, a fast-acting psychedelic, brain activity changes were observed that match its quick onset and short peak effects. A previously unknown sex difference in how the brain responds to the drug was also identified. The findings align with the drug's unique pharmacology and clinical reports, offering new insights into its neural effects.