Functional brain mapping at 9.4T using a new MRI‐compatible electrode chronically implanted in rats

Abstract

There is a need for acute and chronic stimulation of the brain within the MRI for studies of epilepsy, as well as deep brain stimulation for movement and behavioral disorders. This work describes the production and characteristics of carbon fiberbased electrodes for acute and chronic stimulation in the brain. Increasing MRI field strengths are making it increasingly difficult to introduce foreign objects without a susceptibility artifact. We describe the production of, and the characteristics of carbon fiber-based electrodes. These are biocompatible and can be implanted for chronic studies. We show the use of these electrodes at 9.4T for studying functional activation. Data are presented showing regional connectivity. Activation not only occurs near the electrode, but at sites distant and often contralateral to the electrode. In addition, there were sites showing strong negative activation to stimulation both with direct stimulation and during a kindling-associated seizure. Magn Reson Med 61:222-228, 2009.

Brainstem Stimulation Increases Functional Connectivity of Basal Forebrain-Paralimbic Network in Isoflurane-Anesthetized Rats

“…We used a homemade, high-impedance, MR and biocompatible carbon fiber electrode to stimulate the PnO (Dunn et al, 2009;Jupp et al, 2006;Kitzmiller et al, 2006;Tallgren et al, 2005). As anticipated, electrical stimulation of the PnO induced an attenuation of d and h band power, an indication of cortical desynchronization ( Jones, 2004;Pillay et al, 2011).…”

“…While neuroimaging during DBS in animal models has been primarily confined to epilepsy (Canals et al, 2008;Dunn et al, 2009;Jupp et al, 2006) and Parkinson's disease Lai et al, 2014), their focus was on induced activation rather than FC changes. Further, there are no reports in the neuroimaging literature regarding how FC may be modulated by subcortical centers of the AAS during altered states of cortical arousal and consciousness.…”

“…Neuroimaging studies with DBS in animals have focused on neurological conditions, such as epilepsy (Canals et al, 2008;Dunn et al, 2009;Jupp et al, 2006) and Parkinson's disease Lai et al, 2014). Neuroimaging studies of the AAS have been scarce (Edlow et al, 2012;Langsjo et al, 2012) and have not explored the effect of DBS to-date.…”

Functional MRI response and correlated electrophysiological changes during posterior hypothalamic nucleus deep brain stimulation

“…Rats in the fMRI and intracortical microstimulation groups had PH stimulating electrodes implanted chronically whilst rats in the electrophysiological recording group had acute implantations. Rats in the fMRI group received unipolar carbon fibre (0.45 mm) electrodes (Dunn et al, 2009) anchored with plastic screws (Plastics One, Roanoke VA) to minimize imaging artifact whereas rats in the electrophysiological recordings and intracortical microstimulation groups had bipolar Teflon-coated stainless steel wire 178 μm in diameter (A-M Systems, Everett, WA) with insulation removed from the terminal ends of the electrodes which were connected to gold-plated male amphenol pins and stainless steel anchor screws.…”

“…A 9.4 T fMRI and analysis system measured MR signal intensity increases with PH stimulation delivered through a recently developed carbon fibre electrode that does not produce image distortion (Dunn et al, 2009). The fMRI data demonstrated strong activation in sensory, motor and association neocortex, prompting further electrophysiological examination of the neocortex.…”