Divergence of fMRI and neural signals in V1 during perceptual suppression in the awake monkey

Abstract

The role of primary visual cortex (V1) in determining the contents of perception is controversial. Human functional imaging (fMRI) studies of perceptual suppression have revealed a robust drop in V1 activity when a stimulus is subjectively invisible. In contrast, monkey single unit recordings have failed to demonstrate such perception locked changes in V1. To investigate the basis of this discrepancy, we measured both the blood oxygenation level-dependent (BOLD) response and several electrophysiological signals in two behaving monkeys. We found that during conventional stimulus presentation, all signals were in good agreement, showing strong visual modulation to presentation and removal of a stimulus. However, during perceptual suppression, only the BOLD response and low frequency local field potential (LFP) signals exhibited decreases, while the spiking and high frequency LFP signals were unaffected. These results demonstrate that the coupling between the BOLD and electrophysiological signals in V1 is context dependent, with a marked dissociation occurring during perceptual suppression.

Neurophysiologic correlates of fMRI in human motor cortex

“…This high frequency spectral power change has been shown to correlate directly with firing rate [Manning et al, 2009;Miller et al, 2009a;Whittingstall and Logothetis, 2009], and has been demonstrated to reflect broadspectral change across all frequencies Miller et al, 2009b]. Previous studies examined the relationship between spectral power change and BOLD change within a specific region [Logothetis et al, 2001;Maier et al, 2008;Mukamel et al, 2005;Niessing et al, 2005]. We extend this relationship found at the neuronal population volumes sampled by microelectrodes [<500 lm (Katzner et al, 2009)] to a widespread network of movement-related regions on the cortical surface.…”

“…Since ECoG is sampled relatively sparse with 1 cm inter electrode spacing, it should be considered that the part of BOLD signal change explained by low frequency changes is actually due to missed high frequency activity. On motor cortex however, responses for individual fingers can be captured with 1 cm spaced ECoG electrodes [Miller et al, 2009b] and previous studies sampling at smaller scales in 1 area of cortex have also reported low frequency correlation with BOLD when no spiking or high frequency LFP power change could be found [Maier et al, 2008]. This possibility should however be further explored in other studies using higher resolution spatial sampling.…”

“…Because previous studies focused on the BOLD peaks, it is unclear whether the BOLD change in these surrounding areas has a neurophysiological correlate. Fourth, BOLD changes correlate with synaptic processing reflected in local field potentials (LFPs) [Lauritzen, 2005;Logothetis 2008] and in addition to high frequency power changes in the LFP behavior is also associated with power changes in low frequency oscillations in the LFP [Maier et al, 2008;Murthy and Fetz, 1996]. High frequency power change thus may not reflect the complete neurophysiology related to BOLD change.…”

Neural basis of global resting-state fMRI activity

“…Our findings demonstrate that neurovascular coupling is itself dynamic and subject to behavioral state (see also ref. 53). This adds to recent work showing that correlation patterns in both fMRI (22,26) and neural (42,54) signals vary as a function of behavioral state.…”

Mapping of functional brain activity in freely behaving rats during voluntary running using manganese-enhanced MRI: Implication for longitudinal studies

“…Such studies are now becoming feasible for non-human primates (Conway et al, 2007;Goense et al, 2008;Kayser et al, 2007;Maier et al, 2008;Op de Beeck et al, 2008), but still remain a challenge for application in alert and behaving rodents, the most commonly used experimental animals. One reason for that is that the majority of behavioral paradigms developed for rodents often require active locomotion as a behavioral expression of a particular cognitive function.…”