Ancestral Neuroscience Practices in South America: Historical Legacy and Neurobiological Glimpses

Long before the advent of modern neurosurgery and psychiatry, indigenous South American societies engaged in complex interventions targeting the brain and mind. From cranial trepanation in the Andes to ayahuasca rituals in the Amazon, these practices reveal a profound empirical knowledge of neuroanatomy, consciousness, and healing, even though these topics had other names. As contemporary science revisits the therapeutic potential of psychedelics and neuroplastic interventions, it is increasingly relevant to examine the roots of these traditions and their possible contributions to modern neuroscience.

Trepanation in Pre-Columbian South America

Trepanation, the removal of a portion of the cranial vault, was practiced extensively in the Central Andes, especially in present-day Peru. Cultures such as the Paracas (800 BCE–100 CE), Nazca, Wari, and Inca left behind hundreds of trepanned skulls, with survival rates estimated at over 60%, evidenced by significant osteological healing. Using tools made from obsidian or bronze, pre-Columbian surgeons performed scraping, cutting, or boring techniques. These procedures were likely used to treat cranial trauma, reduce intracranial pressure, or relieve symptoms associated with mental and neurological disturbances—often within ritual or spiritual contexts. These findings suggest a sophisticated empirical understanding of cranial anatomy, localized brain trauma, and healing processes, predating Hippocratic medicine. The localization of surgical sites away from vascular zones and the use of antiseptic herbal remedies reflect principles now known to minimize surgical complications.

Psychoactive Plant Use in Amazonian Traditions

Ayahuasca and the Neurobiology of Consciousness

The Amazonian decoction ayahuasca, a combination of Banisteriopsis caapi (monoamine oxidase, or MAO, inhibitor) and Psychotria viridis (dimethyltryptamine, or DMT, source), induces altered states of consciousness. Used by numerous ethnic groups (e.g., Huni Kuin, Ashaninka, Yawanawá), ayahuasca rituals serve diagnostic, therapeutic, and spiritual purposes. DMT is a 5-HT2A receptor agonist associated with increased neuronal plasticity, emotional processing, and disruption of the default mode network (DMN). Harmine and harmaline inhibit MAO-A, allowing oral DMT activation, and also stimulate adult neurogenesis and BDNF (brain-derived neurotrophic factor) expression.

Other Psychoactive Practices

• Rapé (snuff): Tobacco-based mixtures used nasally to clear mental and physical blockages, often with mild psychoactive effects. 
• Sananga: Eye drops from Tabernaemontana undulata, used to sharpen vision and awareness.
• Yopo: A DMT-containing snuff (Virola spp. or Anadenanthera spp.), used by Yanomami and other groups for divination and healing.

Integrative Analysis: Neuroscience Meets Ancestral Knowledge

Both trepanation and the ritual use of entheogens suggest a pre-scientific but functional model of neuromodulation:

These practices reflect an intuitive neurobiological wisdom, where healing is both a physiological and spiritual event. Today, clinical trials on psychedelics for depression, PTSD, and addiction show that their therapeutic success depends not only on pharmacology, but also on setting, guidance, and integration—elements central to Amazonian traditions.

5. Conclusion

Pre-Columbian South America developed extraordinary neurotherapeutic practices, both surgical and psychospiritual. By revisiting these traditions through a neuroscientific lens, we uncover valuable insights into human neurobiology, consciousness, and integrative healing. Far from being obsolete, these ancestral interventions may inform the development of more holistic, culturally respectful and neurobiologically sound approaches to mental and neurological health.

References

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2. Espino PH, Toro-Perez JE, Shkrum S, Burneo JG. Cranial trepanation in pre-Columbian Peruvian cultures: was it an option to treat epilepsy? Brain. 2022 Oct 21;145(10):3335-3338. doi: 10.1093/brain/awac277. PMID: 35895509.
3. Brito-da-Costa AM, Dias-da-Silva D, Gomes NGM, Dinis-Oliveira RJ, Madureira-Carvalho Á. Toxicokinetics and Toxicodynamics of Ayahuasca Alkaloids N,N-Dimethyltryptamine (DMT), Harmine, Harmaline and Tetrahydroharmine: Clinical and Forensic Impact. Pharmaceuticals (Basel). 2020 Oct 23;13(11):334. doi: 10.3390/ph13110334. PMID: 33114119; PMCID: PMC7690791.

About the Contributors

Valéria Marques Figueira Muoio, MD, PhD

Valéria Marques Figueira Muoio, MD, PhD, is a neurosurgeon based in São Paulo, Brazil. She did her doctorate at the University of São Paulo, with a period at Johns Hopkins University and also worked as a scientist at Charite University in Berlin, Germany.

Hugo Sánchez-Castillo

Hugo Sánchez-Castillo is a professor/researcher from the National Autonomus University of Mexico (UNAM). His major field is in the cognitive neurosciences particularly in the neurobiology of stress and related disorders.