Functional MRI impulse response for BOLD and CBV contrast in rat somatosensory cortex

Silva, Afonso C.; Koretsky, Alan P.; Duyn, Jeff H.

doi:10.1002/mrm.21246

Cited by 125 publications

(150 citation statements)

References 39 publications

Supporting

Mentioning

120

Contrasting

Unclassified

Order By: Relevance

“…For the visual cortex data, where a short stimulus was used, we anticipated a narrow HDR (Miezin et al, 2000;Pfeuffer et al, 2003;Zhang et al, 2008). The values measured indicate a fast temporal resolution for the neurovascular coupling mechanism, in line with reports in the rat brain (Silva et al, 2007).…”

Section: Discussionsupporting

confidence: 86%

Cortical Depth-Dependent Temporal Dynamics of the BOLD Response in the Human Brain

Siero

Petridou

Hoogduin

et al. 2011

J Cereb Blood Flow Metab

128

134

View full text Add to dashboard Cite

Recent animal studies at high field have shown that blood oxygen level-dependent (BOLD) contrast can be specific to the laminar vascular architecture of the cortex, by differences in its temporal dynamics in reference to cortical depth. In this study, we characterize the temporal dynamics of the hemodynamic response (HDR) across cortical depth in the human primary motor and visual cortex, at 7 T and using very short stimuli and with high spatial and temporal resolution. We find that the shape and temporal dynamics of the HDR changed in an orderly manner across cortical depth. Compared with the pial vasculature, HDRs in deeper gray matter are significantly faster in onset time (by B0.5 second) and peak time (B2 seconds), and are narrower (by B1 second) and with smaller amplitude, in line with the known vascular organization across cortical depth and the transit of deoxygenated blood through the vasculature. The width of the HDR in deeper gray matter was as short as 2.1 seconds, indicating that neurovascular coupling takes place at a shorter timescale than previously reported in the human brain. These findings open the possibility to probe layer-specific hemodynamics and neurovascular coupling mechanisms in human gray matter.

show abstract

Section: Discussionsupporting

confidence: 86%

Cortical Depth-Dependent Temporal Dynamics of the BOLD Response in the Human Brain

Siero

Petridou

Hoogduin

et al. 2011

J Cereb Blood Flow Metab

128

134

View full text Add to dashboard Cite

show abstract

“…The rapid increase in blood flow to cortex that follows sensory stimulation, which occurs over a period of seconds, is accompanied by an increase in arterial cerebral blood volume. This causes an increase in oxygenation of the venous blood on the time scale of the arterial-venous transit time (16). If the stimulation is prolonged, ≈20 s or more in duration, a slow increase in venous blood volume gradually becomes a significant component of the blood volume change (14,15).…”

Section: Discussionmentioning

confidence: 99%

Fluctuating and sensory-induced vasodynamics in rodent cortex extend arteriole capacity

Drew

Shih

Kleinfeld

2011

Proc. Natl. Acad. Sci. U.S.A.

266

388

View full text Add to dashboard Cite

Neural activity in the brain is followed by localized changes in blood flow and volume. We address the relative change in volume for arteriole vs. venous blood within primary vibrissa cortex of awake, head-fixed mice. Two-photon laser-scanning microscopy was used to measure spontaneous and sensory evoked changes in flow and volume at the level of single vessels. We find that arterioles exhibit slow (<1 Hz) spontaneous increases in their diameter, as well as pronounced dilation in response to both punctate and prolonged stimulation of the contralateral vibrissae. In contrast, venules dilate only in response to prolonged stimulation. We conclude that stimulation that occurs on the time scale of natural stimuli leads to a net increase in the reservoir of arteriole blood. Thus, a "bagpipe" model that highlights arteriole dilation should augment the current "balloon" model of venous distension in the interpretation of fMRI images.ocalized changes in the flow and volume of oxygenated blood in the brain are commonly used as a correlate of heightened neural activity. For two important imaging modalities, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) (1) and intrinsic optical signal imaging (IOS) (2), the signals are generated by a complex interplay of the rate of oxidative metabolism, the flux of blood in the underlying angioarchitecture, and changes in vascular volume (3). The locus for the increase in vascular volume that follows sensory stimulation (i.e., arterioles or venules) is an enduring controversy that bears directly on interpreting and quantifying fMRI signals (4-6). To resolve this question, we used in vivo two-photon laserscanning microscopy to image spontaneous and sensory evoked vascular dynamics in the vibrissa area of parietal cortex of awake, head-fixed mice. All data were collected through a reinforced thin-skull window (7) (Fig. 1A); this method obviates potential complications from inflammation or changes in cranial pressure that may occur with a craniotomy (8). ResultsImages of the pial surface and measurements of the diameter of the lumen of surface arterioles and venules were performed while the mouse sat passively (Fig. 1B). Dilations greater than 5% of the baseline diameter occurred with frequencies of 0.07 ± 0.05 Hz (mean ± SD, n = 118 arteries in six mice). The diameters of short segments of arterioles (red in Fig. 1B) exhibited relatively large spontaneous increases in the spectral range between 0.1 Hz and 1 Hz ( Fig. 1 C and D). The peak amplitude of these fluctuations was 23% ± 10% of the initial vessel diameter across all arterioles, with instances of a 50% increases in diameter. Further, these lowfrequency oscillations were strongly coherent and synchronous over a distance of several hundred micrometers across cortex (198 pairs of vessels, in six mice, that were separated by 20-315 μm; slope of coherence = 0.001 μm −1 [nonsignificant (NS)] and slope of phase shift = 0.0009 rad/μm

show abstract

“…It is possible that the PSU is due to vascular recovery and is not neural in origin. There is increasing evidence to suggest that the PSU can be attributed to temporal mismatches between cerebral blood flow and cerebral blood volume or cerebral oxygenation consumption (Frahm et al, 1996;Silva, Koretsky & Duyn, 2007), with a review paper concluding that the PSU is due to increased sustained oxygen metabolism when cerebral blood volume and blood flow has returned to baseline (van Ziji, Hua & Lu, 2012). However, the individual differences in PSU magnitude could be related to inhibitory mechanisms.…”

Section: Discussionmentioning

confidence: 99%

Cortical excitability and the shape of the haemodynamic response

2015

View full text Add to dashboard Cite

Individual differences in the temporal dynamics of the haemodynamic response can reflect cortical excitation and can reveal underlying cortical physiology. Here, we show differences in the shape of the haemodynamic response that are dependent on stimulus parameters. Two sets of visual stimuli were used varying in parameters that are known to manipulate the haemodynamic response in the visual cortex. We measured the oxyhaemoglobin response using near infrared spectroscopy. The first set of stimuli comprised chromatic square-wave gratings that varied with respect to the separation in the CIE UCS chromaticities of the alternating bars. The gratings with large separations in chromaticity evoked an oxyhaemoglobin response with greater amplitude, consistent with greater activation of the visual cortex. The second set of stimuli comprised horizontal achromatic gratings that (1) were static, (2) drifted at a constant velocity towards fixation, or (3) reversed direction every half spatial cycle to create a vertical vibrating motion. Although the three types of grating had a similar effect on the amplitude of the oxyhaemoglobin response, the moving gratings (2 and 3) evoked a steeper decrease in oxyhaemoglobin concentration after stimulus-offset. The steeper slope appears to reflect the poststimulus undershoot and the slope may provide a correlate of cortical excitability when the amplitude of the haemodynamic response has saturated.

show abstract

Functional MRI impulse response for BOLD and CBV contrast in rat somatosensory cortex

Cited by 125 publications

References 39 publications

Cortical Depth-Dependent Temporal Dynamics of the BOLD Response in the Human Brain

Cortical Depth-Dependent Temporal Dynamics of the BOLD Response in the Human Brain

Fluctuating and sensory-induced vasodynamics in rodent cortex extend arteriole capacity

Cortical excitability and the shape of the haemodynamic response

Contact Info

Product

Resources

About