Functional Connectivity of Resting Hemodynamic Signals in Submillimeter Orientation Columns of the Visual Cortex

Vasireddi, Anil; Vazquez, Alberto L.; Whitney, David E.; Fukuda, Mitsuhiro; Kim, Seong‐Gi

doi:10.1089/brain.2015.0414

Cited by 7 publications

(5 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At 617nm, the deoxyhemoglobin absorption coefficient is ~10x greater than the oxyhemoglobin absorption coefficient (Kocsis et al, 2006; Steinke and Shepherd, 1992). The sensitivity to deoxyhemoglobin of this IOS signal is thus comparable to BOLD-fMRI, in which deoxyhemoglobin provides the intrinsic contrast (Vasireddi et al, 2016).…”

Section: Methodsmentioning

confidence: 89%

“…In the visual system, on a spatial scale of a few millimeters, spontaneous activity impacts subsequent stimulus-induced activation (Arieli et al, 1996), and the spatial patterns of spontaneous activity closely match stimulus-induced activation patterns (Tsodyks et al, 1999). Spontaneous activity moves through several discrete patterns, many of which match specific responses to visual stimuli at different orientations (Kenet et al, 2003; Vasireddi et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

“…Much evidence exists that spontaneous activity fluctuations in the brain impact subsequent task or stimulus induced activations (Arieli et al, 1996; Hyder and Rothman, 2011; Northoff et al, 2010), but much work remains to link stimulus or task activation to the networks observed in resting state fMRI. Many studies have observed that, over brain regions spanning a few millimeters, spontaneous activities and stimulus-induced activations follow similar spatiotemporal patterns (Kenet et al, 2003; Tsodyks et al, 1999; Vasireddi et al, 2016). On a larger spatial scale, discrete, bilateral patterns are observed in the same regions as stimulus-induced activations (Mohajerani et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Spontaneous activity forms a foundation for odor-evoked activation maps in the rat olfactory bulb

et al. 2018

View full text Add to dashboard Cite

Fluctuations in spontaneous activity have been observed by many neuroimaging techniques, but because these resting-state changes are not evoked by stimuli, it is difficult to determine how they relate to task-evoked activations. We conducted multi-modal neuroimaging scans of the rat olfactory bulb, both with and without odor, to examine interaction between spontaneous and evoked activities. Independent component analysis of spontaneous fluctuations revealed resting-state networks, and odor-evoked changes revealed activation maps. We constructed simulated activation maps using resting-state networks that were highly correlated to evoked activation maps. Simulated activation maps derived by intrinsic optical signal (IOS), which covers the dorsal portion of the glomerular sheet, significantly differentiated one odor's evoked activation map from the other two. To test the hypothesis that spontaneous activity of the entire glomerular sheet is relevant for representing odor-evoked activations, we used functional magnetic resonance imaging (fMRI) to map the entire glomerular sheet. In contrast to the IOS results, the fMRI-derived simulated activation maps significantly differentiated all three odors' evoked activation maps. Importantly, no evoked activation maps could be significantly differentiated using simulated activation maps produced using phase-randomized resting-state networks. Given that some highly organized resting-state networks did not correlate with any odors' evoked activation maps, we posit that these resting-state networks may characterize evoked activation maps associated with odors not studied. These results emphasize that fluctuations in spontaneous activity form a foundation for active processing, signifying the relevance of resting-state mapping to functional neuroimaging.

show abstract

Section: Methodsmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spontaneous activity forms a foundation for odor-evoked activation maps in the rat olfactory bulb

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Multiple signaling pathways have been implicated in coupling neural activity to increases in blood flow [24]. Signals from astrocytes [8,[25][26][27] and neurons [28][29][30][31][32][33] are both thought to contribute to driving neurovascular coupling. One pathway implicated in neurovascular coupling is nitric oxide (NO) [34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal patterns of nitric oxide diffusion and degradation drive emergent cerebrovascular dynamics

2020

View full text Add to dashboard Cite

Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in neurovascular coupling. NO produced by neurons diffuses into the smooth muscle surrounding cerebral arterioles, driving vasodilation. However, the rate of NO degradation in hemoglobin is orders of magnitude higher than in brain tissue, though how this might impact NO signaling dynamics is not completely understood. We used simulations to investigate how the spatial and temporal patterns of NO generation and degradation impacted dilation of a penetrating arteriole in cortex. We found that the spatial location of NO production and the size of the vessel both played an important role in determining its responsiveness to NO. The much higher rate of NO degradation and scavenging of NO in the blood relative to the tissue drove emergent vascular dynamics. Large vasodilation events could be followed by post-stimulus constrictions driven by the increased degradation of NO by the blood, and vasomotion-like 0.1-0.3 Hz oscillations could also be generated. We found that these dynamics could be enhanced by elevation of free hemoglobin in the plasma, which occurs in diseases such as malaria and sickle cell anemia, or following blood transfusions. Finally, we show that changes in blood flow during hypoxia or hyperoxia could be explained by altered NO degradation in the parenchyma. Our simulations suggest that many common vascular dynamics may be emergent phenomena generated by NO degradation by the blood or parenchyma.

show abstract

“…The default mode network under resting state was clearly seen across six layers by seed-based functional connectivity analysis after removing depth-dependent physiological noise [ 42 ]. In addition, a recent study showed the existence of temporal correlation of resting state hemodynamic signals derived from optical imaging at sub-millimeter columnar scale in the visual cortex [ 43 ]. These studies suggest that functional connectivity could be a potentially useful method to investigate the laminar connectional architecture at the functional level.…”

Section: Introductionmentioning

confidence: 99%

Resting state fMRI connectivity is sensitive to laminar connectional architecture in the human brain

Deshpande

Wang²,

Robinson³

2022

Brain Inf.

View full text Add to dashboard Cite

Previous invasive studies indicate that human neocortical graymatter contains cytoarchitectonically distinct layers, with notable differences in their structural connectivity with the rest of the brain. Given recent improvements in the spatial resolution of anatomical and functional magnetic resonance imaging (fMRI), we hypothesize that resting state functional connectivity (FC) derived from fMRI is sensitive to layer-specific thalamo-cortical and cortico-cortical microcircuits. Using sub-millimeter resting state fMRI data obtained at 7 T, we found that: (1) FC between the entire thalamus and cortical layers I and VI was significantly stronger than between the thalamus and other layers. Furthermore, FC between somatosensory thalamus (ventral posterolateral nucleus, VPL) and layers IV, VI of the primary somatosensory cortex were stronger than with other layers; (2) Inter-hemispheric cortico-cortical FC between homologous regions in superficial layers (layers I–III) was stronger compared to deep layers (layers V–VI). These findings are in agreement with structural connections inferred from previous invasive studies that showed that: (i) M-type neurons in the entire thalamus project to layer-I; (ii) Pyramidal neurons in layer-VI target all thalamic nuclei, (iii) C-type neurons in the VPL project to layer-IV and receive inputs from layer-VI of the primary somatosensory cortex, and (iv) 80% of collosal projecting neurons between homologous cortical regions connect superficial layers. Our results demonstrate for the first time that resting state fMRI is sensitive to structural connections between cortical layers (previously inferred through invasive studies), specifically in thalamo-cortical and cortico-cortical networks.

show abstract

Functional Connectivity of Resting Hemodynamic Signals in Submillimeter Orientation Columns of the Visual Cortex

Cited by 7 publications

References 45 publications

Spontaneous activity forms a foundation for odor-evoked activation maps in the rat olfactory bulb

Spontaneous activity forms a foundation for odor-evoked activation maps in the rat olfactory bulb

Spatial and temporal patterns of nitric oxide diffusion and degradation drive emergent cerebrovascular dynamics

Resting state fMRI connectivity is sensitive to laminar connectional architecture in the human brain

Contact Info

Product

Resources

About