Independent Sources of Spontaneous BOLD Fluctuation Along the Visual Pathway

Jacco A. de Zwart¹, Peter van Gelderen¹, Zhongming Liu¹, Jeff H. Duyn¹

BOLD fMRI experiments of spontaneous brain activity in humans have found inter-hemispheric correlation between homologous regions, and suggested involvement of a direct callosal connection. We studied spontaneous activity in human Lateral Geniculate Nuclei (LGN), with no direct commissural connections. High-resolution 7 T fMRI was performed during visual stimulation and rest. Correlation analysis was performed between left and right LGN, and left and right visual cortex. Substantial specific left-right LGN correlation was found, which was not merely driven by visual cortex, or the result of global fluctuations. Strong signal coherence was thus found not indicative of a direct neuronal connection.