Spontaneous fMRI Activity Reflects a Dynamic Image of Brain State

Marta Bianciardi¹, Masaki Fukunaga¹, Jacco A. de Zwart¹, Jeff H. Duyn¹

The origin of spontaneous fMRI activity (SA-fMRI) of the human brain is still poorly understood, for example if it represents ongoing sensory processing or homeostatic/cognitive functions that depend on brain state. To investigate this, we measured the amplitude of SA-fMRI in the visual cortex and of fluctuations in amplitude of magnetoencephalographic-MEG activity and electro-oculogram-activity, varying independently the brain-attentive-state (eyes-open/closed) and the visual input (presence/absence of light). Amplitude of SA-fMRI changed dynamically with brain state, and was not modulated by visual input. Our results suggest that the level of SA-fMRI may depend on the level of arousal and oculo-motor activity.