BOLD responses to trigeminal nerve stimulation

Just, Nathalie; Petersen, Carl C. H.; Gruetter, Rolf

doi:10.1016/j.mri.2010.02.002

Cited by 25 publications

(37 citation statements)

References 51 publications

(73 reference statements)

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“…induced robust and intense BOLD activation in the barrel cortex for a well-defined range of stimulus current intensities and stimulus frequencies using a short stimulation paradigm (Just et al, 2010). Prolonged TGN stimulation demonstrated that BOLD activation takes place similarly in the primary somatosensory barrel field cortex although the number of active pixels was only slightly decreased compared to short stimulation.…”

Section: Tablementioning

confidence: 94%

“…The cathode was inserted in the hiatus infraorbitalis as described in Nielsen and Lauritzen (2001) and the anode was inserted in the masticatory muscles. Electrical stimulation of one trigeminal nerve was performed by delivering square pulses using an external stimulator (WPI, Stevenage, UK) (Just et al, 2010). Previous investigations using TGN electrical stimulations demonstrated that the BOLD response was optimized for stimulation currents in the range 1-3 mA and for a stimulation frequency of 1 Hz (Just et al, 2010).…”

Section: Trigeminal Nerve Stimulationmentioning

confidence: 99%

“…Electrical stimulation of one trigeminal nerve was performed by delivering square pulses using an external stimulator (WPI, Stevenage, UK) (Just et al, 2010). Previous investigations using TGN electrical stimulations demonstrated that the BOLD response was optimized for stimulation currents in the range 1-3 mA and for a stimulation frequency of 1 Hz (Just et al, 2010). Experiments were performed with a current intensity of 2 mA and a stimulation frequency of 1 Hz.…”

Section: Trigeminal Nerve Stimulationmentioning

confidence: 99%

“…Neurons of the whisker barrel system in the rodent primary somatosensory cortex are known to encode external events in time and space and thus offer an excellent model to study BOLD activation processes (de Celis Alonso et al, 2012;Lu et al, 2003;Yang et al, 1996Yang et al, , 1997. The rat barrel cortex can also be reliably and reproducibly activated through trigeminal nerve (TGN) stimulation (Nielsen and Lauritzen, 2001;Just et al, 2010;Fanselow and Nicolelis, 1999). BOLD responses to short TGN stimulations (30 s) were characterized as a function of stimulus frequency and current intensity (Just et al, 2010) showing robust and reproducible BOLD activation of the primary somatosensory barrel field cortex (S1BF).…”

Section: Introductionmentioning

confidence: 99%

“…The rat barrel cortex can also be reliably and reproducibly activated through trigeminal nerve (TGN) stimulation (Nielsen and Lauritzen, 2001;Just et al, 2010;Fanselow and Nicolelis, 1999). BOLD responses to short TGN stimulations (30 s) were characterized as a function of stimulus frequency and current intensity (Just et al, 2010) showing robust and reproducible BOLD activation of the primary somatosensory barrel field cortex (S1BF). If sustained stimulation is straightforward in humans (Chen et al, 1993;Prichard et al, 1991;Mangia et al, 2007a,b;Bandettini et al, 1997), it is not as straightforward in rodents due to the difficult control of physiology under anesthesia and adaptation.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of sustained BOLD activation in the rat barrel cortex and neurochemical consequences

Just¹,

Xin²,

Frenkel³

et al. 2013

NeuroImage

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To date, only a couple of functional MR spectroscopy (fMRS) studies were conducted in rats. Due to the low temporal resolution of 1 H MRS techniques, prolonged stimulation paradigms are necessary for investigating the metabolic outcome in the rat brain during functional challenge. However, sustained activation of cortical areas is usually difficult to obtain due to neural adaptation. Anesthesia, habituation, high variability of the basal state metabolite concentrations as well as low concentrations of the metabolites of interest such as lactate (Lac), glucose (Glc) or γ-aminobutyric acid (GABA) and small expected changes of metabolite concentrations need to be addressed. In the present study, the rat barrel cortex was reliably and reproducibly activated through sustained trigeminal nerve (TGN) stimulation. In addition, TGN stimulation induced significant positive changes in lactate (+1.01 μmol/g, p b 0.008) and glutamate (+0.92 μmol/g, p b 0.02) and significant negative aspartate changes (−0.63 μmol/g, p b 0.004) using functional 1 H MRS at 9.4 T in agreement with previous changes observed in human fMRS studies. Finally, for the first time, the dynamics of lactate, glucose, aspartate and glutamate concentrations during sustained somatosensory activation in rats using fMRS were assessed. These results allow demonstrating the feasibility of fMRS measurements during prolonged barrel cortex activation in rats.

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Section: Tablementioning

confidence: 94%

Section: Trigeminal Nerve Stimulationmentioning

confidence: 99%

Section: Trigeminal Nerve Stimulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization of sustained BOLD activation in the rat barrel cortex and neurochemical consequences

Just¹,

Xin²,

Frenkel³

et al. 2013

NeuroImage

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Cerebral Vascular Control and Metabolism in Heat Stress

Bain

Nybo

Ainslie

2015

Comprehensive Physiology

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This review provides an in-depth update on the impact of heat stress on cerebrovascular functioning. The regulation of cerebral temperature, blood flow, and metabolism are discussed. We further provide an overview of vascular permeability, the neurocognitive changes, and the key clinical implications and pathologies known to confound cerebral functioning during hyperthermia. A reduction in cerebral blood flow (CBF), derived primarily from a respiratory-induced alkalosis, underscores the cerebrovascular changes to hyperthermia. Arterial pressures may also become compromised because of reduced peripheral resistance secondary to skin vasodilatation. Therefore, when hyperthermia is combined with conditions that increase cardiovascular strain, for example, orthostasis or dehydration, the inability to preserve cerebral perfusion pressure further reduces CBF. A reduced cerebral perfusion pressure is in turn the primary mechanism for impaired tolerance to orthostatic challenges. Any reduction in CBF attenuates the brain's convective heat loss, while the hyperthermic-induced increase in metabolic rate increases the cerebral heat gain. This paradoxical uncoupling of CBF to metabolism increases brain temperature, and potentiates a condition whereby cerebral oxygenation may be compromised. With levels of experimentally viable passive hyperthermia (up to 39.5-40.0 °C core temperature), the associated reduction in CBF (∼ 30%) and increase in cerebral metabolic demand (∼ 10%) is likely compensated by increases in cerebral oxygen extraction. However, severe increases in whole-body and brain temperature may increase blood-brain barrier permeability, potentially leading to cerebral vasogenic edema. The cerebrovascular challenges associated with hyperthermia are of paramount importance for populations with compromised thermoregulatory control--for example, spinal cord injury, elderly, and those with preexisting cardiovascular diseases.

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Imaging of prolonged BOLD response in the somatosensory cortex of the rat

et al. 2015

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Blood oxygenation level-dependent (BOLD) functional MRI is a widely employed methodology in experimental and clinical neuroscience, although its nature is not fully understood. To gain insights into BOLD mechanisms and take advantage of the new functional methods, it is of interest to investigate prolonged paradigms of activation suitable for long experimental protocols and to observe any long-term modifications induced by these functional challenges. While different types of sustained stimulation paradigm have been explored in human studies, the BOLD response is typically limited to a few minutes in animal models, due to fatigue, anesthesia effects and physiological instability. In the present study, the rat forepaw was electrically stimulated for 2 h, which resulted in a prolonged and localized cortical BOLD response over that period. The stimulation paradigm, including an inter-stimulus interval (ISI) of 10 s, that is 25% of the total time, was applied at constant or variable frequency over 2 h. The steady-state level of the BOLD response was reached after 15-20 min of stimulation and was maintained until the end of the stimulation. On average, no substantial loss in activated volume was observed at the end of the stimulation, but less variability in the fraction of remaining activated volume and higher steady-state BOLD amplitude were observed when stimulation frequency was varied between 2 and 3 Hz every 5 min. We conclude that the combination of ISI and variable stimulus frequency reproducibly results in robust, prolonged and localized BOLD activation.

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BOLD responses to trigeminal nerve stimulation

Cited by 25 publications

References 51 publications

Characterization of sustained BOLD activation in the rat barrel cortex and neurochemical consequences

Characterization of sustained BOLD activation in the rat barrel cortex and neurochemical consequences

Cerebral Vascular Control and Metabolism in Heat Stress

Imaging of prolonged BOLD response in the somatosensory cortex of the rat

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