The Gamma Motor Neurons: The Silent Directors of Embodied Attention

This article proposes a revolutionary paradigm for understanding the role of gamma motor neurons (γ-MNs) in attention. Traditionally viewed as mere regulators of proprioceptive sensitivity during movement (α-γ coactivation), we suggest that γ-MNs are, in reality, active directors of a brain-controlled sensory "pre-amplification" mechanism. This top-down gamma modulation allows for fine and targeted attentional focus in all its forms: from internal attention (such as bodily awareness and interoception) to external multimodal attention (visual, auditory, tactile, chemical). The classic model of proprioception fails to explain how attention can refine perception in the absence of macroscopic movement. The hypothesis outlined here solves this gap, demonstrating how γ-MNs can make subtle signals salient, derived from basal muscle tone, intrinsic micro-oscillations of the body, or simple motor intention. Through this modulation, muscle spindles become hypersensitive, amplifying proprioceptive feedback and providing a fundamental bodily anchor for the direction and quality of attention. Our approach aligns with theories of predictive control and embodied cognition, while distinguishing itself from and integrating critiques of the premotor theory of attention. While the latter emphasizes the preparation of macroscopic movements (e.g., saccades) for spatial attention, the γ-MN hypothesis proposes a more microscopic and peripheral mechanism that supports attention at a deep level, making the body an active instrument of sensory investigation. This article offers a concrete neurophysiological mechanism for a unified theory of attention as an intrinsically embodied process, suggesting new directions for future research.