Resting States Affect Spontaneous BOLD Oscillations in Sensory and Paralimbic Cortex

Abstract

The brain exhibits spontaneous neural activity that depends on the behavioral state of the organism. We asked whether the blood oxygenation level-dependent (BOLD) signal reflects these modulations. BOLD was measured under three steady-state conditions: while subjects kept their eyes closed, kept their eyes open, or while fixating. The BOLD spectral density was calculated across brain voxels and subjects. Visual, sensory-motor, auditory, and retrosplenial cortex showed modulations of the BOLD spectral density by resting state type. All modulated regions showed greater spontaneous BOLD oscillations in the eyes closed than the eyes open or fixation conditions, suggesting that the differences were endogenously driven. Next, we examined the pattern of correlations between regions whose ongoing BOLD signal was modulated by resting state type. Regional neuronal correlations were estimated using an analytic procedure from the comparison of BOLD-BOLD covariances in the fixation and eyes closed conditions. Most regions were highly correlated with one another, with the exception of the primary visual cortices, which showed low correlations with the other regions. In conclusion, changes in resting state were associated with synchronous modulations of spontaneous BOLD oscillations in cortical sensory areas driven by two spatially overlapping, but temporally uncorrelated signals.

Spontaneous blood oxygenation level‐dependent fMRI signal is modulated by behavioral state and correlates with evoked response in sensorimotor cortex: A 7.0‐T fMRI study

“…In a recent quantitative study of the dependence of visual cortex spontaneous BOLD activity on behavioral state, both coherence and amplitude of spontaneous signal were found to be highest in an eyes closed (EC) resting condition and reduced in alternative conditions with the eyes open (EO) [Bianciardi et al, 2009]. Similar observations were observed over a more limited range of behavioral states in visual, sensorimotor, auditory, and retrosplenial cortex [McAvoy et al, 2008]. Using BOLD fMRI in conjunction with measurements of local field potential (LFP) (single cortical site near visual cortex) in awake monkeys at rest, a positive correlation was observed between the baseline fMRI fluctuations in cerebral cortex and the LFP, with the correlation being highest during states of reduced alertness (EC) [Scholvinck et al, 2010].…”

“…Although much is known regarding the origin and synchrony of spontaneous activity between different brain regions [Boly et al, 2008;Chang and Glover, 2009;Cohen et al, 2008;Fukunaga et al, 2008;Murayama et al, 2010;Smith et al, 2009], comparatively less is known quantitatively regarding the role of behavioral state on the synchrony and amplitude of spontaneous activity [Bianciardi et al, 2009;Fox et al, 2006;McAvoy et al, 2008;Yang et al, 2007]. In terms of conventional-evoked BOLD fMRI responses, an understanding of this relationship may be important for accurate quantification of baseline signal fluctuations and for predicting magnitude variations in fMRI response Liu et al, 2010].…”

Lag structure in resting-state fMRI

“…This state contrast is known to modulate the amplitude of intrinsic BOLD activity in visual cortex (Marx et al 2004;McAvoy et al 2008). The latency projection correlates of this experiment are shown in Fig (Bianciardi et al 2009;Marx et al 2004;McAvoy et al 2008). This set of observations is significant in the light of potential relations between latency and perfusion (see below).…”

Functional segmentation of the brain cortex using high model order group PICA

“…The fixation reduces motion artifacts and still offers some cognitive baseline function to reduce some of the variability of free thinking. McAvoy et al [2008] recently presented rather similar spatial distribution of areas where BOLD fluctuation frequency is dependent on whether the subject has eyes open, closed, or is fixating on a cross. We found a similar distribution of areas, and in addition differences in power spectral densities between the visual area sources.…”