Cortical and subcortical signatures of conscious object recognition

Abstract

The neural mechanisms underlying conscious recognition remain unclear, particularly the roles played by the prefrontal cortex, deactivated brain areas and subcortical regions. We investigated neural activity during conscious object recognition using 7 Tesla fMRI while human participants viewed object images presented at liminal contrasts. Here, we show both recognized and unrecognized images recruit widely distributed cortical and subcortical regions; however, recognized images elicit enhanced activation of visual, frontoparietal, and subcortical networks and stronger deactivation of the default-mode network. For recognized images, object category information can be decoded from all of the involved cortical networks but not from subcortical regions. Phase-scrambled images trigger strong involvement of inferior frontal junction, anterior cingulate cortex and default-mode network, implicating these regions in inferential processing under increased uncertainty. Our results indicate that content-specific activity in both activated and deactivated cortical networks and non-content-specific subcortical activity support conscious recognition.

A mesoscale connectome-based model of conscious access in the macaque monkey

“…On some missed trials we could observe transient activity throughout the fronto-parietal network, that died back to baseline. This is consistent with recent reports in humans that the spatial activity pattern for unrecognised and recognised stimuli is similar, and differs mainly by the magnitude of activation (Levinson et al 2021), and monkey physiology studies showing transient prefrontal activity on some miss trials (Van Vugt et al 2018).…”

“…A sufficiently high level of this vigilance signal was critical to enable the model to accurately detect incoming stimuli. Recent evidence in humans suggests that several subcortical structures show increased activation when stimuli are perceived, but may not contain content-specific information (Levinson et al 2021). This is also consistent with our recent work, which suggests that content-independent dopamine release in the cortex enables the engagement of distributed, sustained activity in working memory (Froudist-Walsh et al 2021a).…”

Seeing minds, matter, and meaning: The CEEing model of pre-reflective subjective construal.

“…Indeed, a number of neuroimaging studies using subliminal presentation methods report either FFA activity or N170 electroencephalogram (EEG) effects, which are believed to face specific and emanate from FFA (Jiang & He, 2006;Moutoussis & Zeki, 2002;Sterzer et al, 2008Sterzer et al, , 2009Suzuki & Noguchi, 2013). At the same time, twice as many studies report not finding these effects in FFA (Fisch et al, 2009;Harris et al, 2011Harris et al, , 2013Jiang et al, 2009;Kume et al, 2016;Levinson et al, 2021;Navajas et al, 2013;Reiss & Hoffman, 2007;Rodríguez et al, 2012;Shafto & Pitts, 2015).…”

Hierarchical Fluctuation Shapes a Dynamic Flow Linked to States of Consciousness

“…The default-mode network (DMN) is located on the top of the principal gradient. Although traditionally viewed as a tasknegative network, the DMN is active when making social or self-referential inferences and was recently suggested as carrying rich information related to conscious perception even during BOLD deactivation [64][65][66] . As a conservative system, it is possible that histaminergic regulation of wakefulness evolutionally developed along this hierarchical axis, which also captures dominant variations in synaptic excitation and inhibition 67 , the intrinsic timescale 67 , and gene expression, to optimize hierarchical information processing for advanced cognition.…”