What Does Local Functional Hyperemia Tell about Local Neuronal Activation?

Jukovskaya, Natalya; Tiret, Pascale; Lecoq, Jérôme; Charpak, Serge

doi:10.1523/jneurosci.3146-10.2011

Cited by 20 publications

(24 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our understanding of this phenomenon, commonly termed functional hyperemia or neurovascular coupling, remains an active area of research (Attwell et al, 2010). However, recent studies have highlighted important conditions under which neural activity and blood flow become decoupled (Devor et al, 2008;Jukovskaya et al, 2011;Sirotin and Das, 2008), and thus raise basic questions about neurovascular coupling . One set of questions concerns the patterns of neuronal signals that lead to vasoactivity.…”

Section: Introductionmentioning

confidence: 99%

Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain

Shih

Driscoll

Drew

et al. 2012

J Cereb Blood Flow Metab

410

377

View full text Add to dashboard Cite

The cerebral vascular system services the constant demand for energy during neuronal activity in the brain. Attempts to delineate the logic of neurovascular coupling have been greatly aided by the advent of two-photon laser scanning microscopy to image both blood flow and the activity of individual cells below the surface of the brain. Here we provide a technical guide to imaging cerebral blood flow in rodents. We describe in detail the surgical procedures required to generate cranial windows for optical access to the cortex of both rats and mice and the use of two-photon microscopy to accurately measure blood flow in individual cortical vessels concurrent with local cellular activity. We further provide examples on how these techniques can be applied to the study of local blood flow regulation and vascular pathologies such as small-scale stroke.

show abstract

Section: Introductionmentioning

confidence: 99%

Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain

Shih

Driscoll

Drew

et al. 2012

J Cereb Blood Flow Metab

410

377

View full text Add to dashboard Cite

show abstract

“…To measure OSN and astrocyte Ca 2+ responses alone, a movie of the ROI covering the entire glomerulus was recorded. To measure RBC velocity simultaneously, a broken line scan along a glomerular capillary and through the neighboring glomerular neuropil was used 50 .…”

Section: Methodsmentioning

confidence: 99%

Calcium dynamics in astrocyte processes during neurovascular coupling

Otsu¹,

Couchman²,

Lyons³

et al. 2014

Nat Neurosci

253

235

View full text Add to dashboard Cite

Enhanced neuronal activity in the brain triggers a local increase in blood flow, termed functional hyperemia, via several mechanisms, including calcium (Ca2+) signaling in astrocytes. However, recent in vivo studies have questioned the role of astrocytes in functional hyperemia because of the slow and sparse dynamics of their somatic Ca2+ signals and the absence of glutamate metabotropic receptor 5 in adults. Here, we reexamined their role in neurovascular coupling by selectively expressing a genetically encoded Ca2+ sensor in astrocytes of the olfactory bulb. We show that in anesthetized mice, the physiological activation of olfactory sensory neuron (OSN) terminals reliably triggers Ca2+ increases in astrocyte processes but not in somata. These Ca2+ increases systematically precede the onset of functional hyperemia by 1–2 s, reestablishing astrocytes as potential regulators of neurovascular coupling.

show abstract

“…Although the existence of this paramagnetic reporter of oxygen metabolism is fortuitous, the data it provides is only an indirect readout of neural activity (Logothetis, 2008; Sirotin and Das, 2009; Jukovskaya et al, 2011), which is limited in its spatial and temporal resolution to the dynamics of blood flow in the brain's capillary network (1–2 s). The spatial point-spread function of the hemodynamic BOLD response is in the 1 mm range, although sub-millimeter measurements, revealing cortical laminar and columnar features, have been obtained by filtering out the signals from larger blood vessels (Bandettini, 2009).…”

Section: Evaluation Of Modalitiesmentioning

confidence: 99%

Physical principles for scalable neural recording

Marblestone

Zamft

Maguire

et al. 2013

Front. Comput. Neurosci.

225

223

View full text Add to dashboard Cite

Simultaneously measuring the activities of all neurons in a mammalian brain at millisecond resolution is a challenge beyond the limits of existing techniques in neuroscience. Entirely new approaches may be required, motivating an analysis of the fundamental physical constraints on the problem. We outline the physical principles governing brain activity mapping using optical, electrical, magnetic resonance, and molecular modalities of neural recording. Focusing on the mouse brain, we analyze the scalability of each method, concentrating on the limitations imposed by spatiotemporal resolution, energy dissipation, and volume displacement. Based on this analysis, all existing approaches require orders of magnitude improvement in key parameters. Electrical recording is limited by the low multiplexing capacity of electrodes and their lack of intrinsic spatial resolution, optical methods are constrained by the scattering of visible light in brain tissue, magnetic resonance is hindered by the diffusion and relaxation timescales of water protons, and the implementation of molecular recording is complicated by the stochastic kinetics of enzymes. Understanding the physical limits of brain activity mapping may provide insight into opportunities for novel solutions. For example, unconventional methods for delivering electrodes may enable unprecedented numbers of recording sites, embedded optical devices could allow optical detectors to be placed within a few scattering lengths of the measured neurons, and new classes of molecularly engineered sensors might obviate cumbersome hardware architectures. We also study the physics of powering and communicating with microscale devices embedded in brain tissue and find that, while radio-frequency electromagnetic data transmission suffers from a severe power–bandwidth tradeoff, communication via infrared light or ultrasound may allow high data rates due to the possibility of spatial multiplexing. The use of embedded local recording and wireless data transmission would only be viable, however, given major improvements to the power efficiency of microelectronic devices.

show abstract

What Does Local Functional Hyperemia Tell about Local Neuronal Activation?

Cited by 20 publications

References 23 publications

Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain

Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain

Calcium dynamics in astrocyte processes during neurovascular coupling

Physical principles for scalable neural recording

Contact Info

Product

Resources

About