Hanson · Brain, behavior and evolution 2025 · Narrative review · n=?

Inhibitory Systems in Brain Evolution: Pathways of Vulnerability in Neurodevelopmental Disorders.

Level 5 - mechanism / opinion, no new human data

Narrative review synthesizing evolutionary neurobiology and mechanistic hypotheses without new empirical human data.

PubMed 39137740 · doi:10.1159/000540865 · record verified 2026-08-26

What was done

This narrative review synthesized literature on primate brain evolution, prefrontal cortex expansion, and cellular adaptations in GABAergic inhibitory interneurons. The authors examined how structural and circuit reorganization—particularly within frontostriatal and frontoamygdalar pathways—relates to primate social behavior, life history traits, and susceptibility to neurodevelopmental conditions such as autism, schizophrenia, and Williams syndrome.

What was found

The abstract reports no empirical numbers or quantitative effect sizes. It qualitatively describes evolutionary increases in the diversity and number of inhibitory GABAergic interneurons, along with frontostriatal and frontoamygdalar reorganization, proposing that the increased complexity of these inhibitory systems provides a biological substrate for excitation-inhibition imbalance and neurodevelopmental disorders.

Why it matters

It offers an evolutionary and comparative neurodevelopmental framework that links specialized primate inhibitory adaptations to modern vulnerabilities in executive function and socioemotional processing.

Limits

The paper is a non-systematic narrative review presenting theoretical frameworks rather than primary experimental data. The abstract provides no quantitative metrics, inclusion criteria, or direct clinical testing of the proposed evolutionary vulnerability mechanisms.

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