Neuronal activity-induced changes of local cerebral microvascular blood oxygenation in the rat: effect of systemic hyperoxia or hypoxia

Lindauer, Ute; Gethmann, Jörn; Kühl, Marc; Kohl‐Bareis, Matthias; Dirnagl, Ulrich

doi:10.1016/s0006-8993(03)02602-7

Cited by 36 publications

(29 citation statements)

References 28 publications

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“…The putative relationship between the initial dip and oxygen metabolism has led some to suggest that the dip may offer improved spatial specificity (Malonek et al, 1997), and a subsequent fMRI study demonstrated this capability . Other groups, however, either fail to detect the dip (Mandeville et al, 1998;Marota et al, 1999;Silva et al, 2000), or are unable to generate reproducible maps (this study and Logothetis, 2000), possibly because of its sensitivity to anesthetic level and biologic fluctuations (Buxton, 2001;Cohen et al, 2002;Lindauer et al, 2003). Recent work has also shown that the flow (Duong et al, 2001) and volume (Sheth et al, 2004a) components of the hemodynamic response can provide spatial specificity sufficient to resolve submillimeter functional architecture.…”

Section: Implications For Functional Brain Imagingmentioning

confidence: 79%

Spatiotemporal Evolution of Functional Hemodynamic Changes and Their Relationship to Neuronal Activity

Sheth

Nemoto

Guiou

et al. 2005

J Cereb Blood Flow Metab

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Brain imaging techniques such as functional magnetic resonance imaging (fMRI) have provided a wealth of information about brain organization, but their ability to investigate fine-scale functional architecture is limited by the spatial specificity of the hemodynamic responses upon which they are based. We investigated the spatiotemporal evolution of hemodynamic responses in rat somatosensory cortex to electrical hindpaw stimulation. We combined the advantages of optical intrinsic signal imaging and spectroscopy to produce high-resolution two-dimensional maps of functional changes in tissue oxygenation and blood volume. Cerebral blood flow changes were measured with laser-Doppler flowmetry, and simultaneously recorded field potentials allowed comparison between hemodynamic changes and underlying neuronal activity. For the first 2 to 3 secs of activation, hemodynamic responses overlapped in a central parenchymal focus. Over the next several seconds, cerebral blood volume changes propagated retrograde into feeding arterioles, and oxygenation changes anterograde into draining veins. By 5 to 6 secs, responses localized primarily in vascular structures distant from the central focus. The peak spatial extent of the hemodynamic response increased linearly with synaptic activity. This spatial spread might be because of lateral subthreshold activation or passive vascular overspill. These results imply early microvascular changes in volume and oxygenation localize to activated neural columns, and that spatial specificity will be optimal within a 2-to 3-sec window after neuronal activation.

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Section: Implications For Functional Brain Imagingmentioning

confidence: 79%

Spatiotemporal Evolution of Functional Hemodynamic Changes and Their Relationship to Neuronal Activity

Sheth

Nemoto

Guiou

et al. 2005

J Cereb Blood Flow Metab

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“…similar changes of oxy-and deoxy-Hb during the post-stimulus period. These studies investigated whisker deflection in the rat (Lindauer et al, 2001(Lindauer et al, , 2003 or visual and motor stimulation in humans (Jasdzewski et al, 2003;Schroeter et al, 2004a).…”

Section: Discussionmentioning

confidence: 99%

Investigating the post-stimulus undershoot of the BOLD signal—a simultaneous fMRI and fNIRS study

et al. 2006

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Measuring the hemodynamic response with functional magnetic resonance imaging (fMRI) together with functional near-infrared spectroscopy (fNIRS) may overcome limitations of single-method approaches. Accordingly, we measured the event-related hemodynamic response with both imaging methods simultaneously in young subjects during visual stimulation. An intertrial interval of 60 s was chosen to include the prolonged post-stimulus undershoot of the blood oxygenation level dependent (BOLD) signal. During visual stimulation, the BOLD signal, oxy-, and total hemoglobin (Hb) increased, whereas deoxy-Hb decreased. The post-stimulus period was characterized by an undershoot of the BOLD signal, oxy-Hb, and an overshoot of deoxy-Hb. Total Hb as measured by fNIRS returned to baseline immediately after the end of stimulation. Results suggest that the post-stimulus events as measured by fNIRS are dominated by a prolonged high-level oxygen consumption in the microvasculature. The contribution of a delayed return of blood volume to the BOLD post-stimulus undershoot in post-capillary veins as suggested by the Balloon and Windkessel models remains ambiguous. Temporal changes in the BOLD signal were highly correlated with deoxy-Hb, with lower correlation values for oxy-and total Hb. Furthermore, data show that fNIRS covers the outer 1 cm of the brain cortex. These results were confirmed by simultaneous fMRI/fNIRS measurements during rest. In conclusion, multimodal imaging approaches may contribute to the understanding of neurovascular coupling. D

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“…They found similar localization or signal intensity time courses, supporting the use of 570 nm signals as an indicator of CBV. However, there seem to be differences in the time courses between total hemoglobin concentration measured by diffuse optical tomography and cerebral plasma volume measured by MRI using an exogenous contrast agent (Siegel et al, 2003 (Lindauer et al, 2001(Lindauer et al, , 2003. Although deoxyhemoglobin is the most dominant absorbing species in this wavelength range, oxyhemoglobin also absorbs 610 nm light with approximately one-third the absorption coefficient in a braintissue-simulating phantom (Sato et al, 2002).…”

Section: And 610 Nm Signal Etiologymentioning

confidence: 99%

“…For example, different anesthetic, surgical, and stimulation protocols could lead to different excitatory and inhibitory neuronal processes in thalamocortical and intracortical circuits (Simons and Carvell, 1989;CastroAlamancos and Oldford, 2002) and different hemodynamic responses. Moreover, the balance of 610 nm signal determinants (see Materials and Methods) can easily vary depending on the latency and magnitude of hemodynamic responses, which are significantly affected by manipulation of P CO 2 and P O 2 (Lindauer et al, 2003). This inconsistency and apparent dependency on various physiological parameters raises concern as to whether the spatial profiles and magnitudes of early oxygenation signals reflect neuronal population activity per se.…”

Section: Early Oxygenation Signals and Neuronal Activitymentioning

confidence: 99%

Functional Signal- and Paradigm-Dependent Linear Relationships between Synaptic Activity and Hemodynamic Responses in Rat Somatosensory Cortex

Nemoto¹,

Sheth²,

Guiou³

et al. 2004

J. Neurosci.

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Linear relationships between synaptic activity and hemodynamic responses are critically dependent on functional signal etiology and paradigm. To investigate these relationships, we simultaneously measured local field potentials (FPs) and optical intrinsic signals in rat somatosensory cortex while delivering a small number of electrical pulses to the hindpaw with varied stimulus intensity, number, and interstimulus interval. We used 570 and 610 nm optical signals to estimate cerebral blood volume (CBV) and oxygenation, respectively.The

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Neuronal activity-induced changes of local cerebral microvascular blood oxygenation in the rat: effect of systemic hyperoxia or hypoxia

Cited by 36 publications

References 28 publications

Spatiotemporal Evolution of Functional Hemodynamic Changes and Their Relationship to Neuronal Activity

Spatiotemporal Evolution of Functional Hemodynamic Changes and Their Relationship to Neuronal Activity

Investigating the post-stimulus undershoot of the BOLD signal—a simultaneous fMRI and fNIRS study

Functional Signal- and Paradigm-Dependent Linear Relationships between Synaptic Activity and Hemodynamic Responses in Rat Somatosensory Cortex

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