Quantifying the Effect of Repetitive Transcranial Magnetic Stimulation in the Rat Brain by μSPECT CBF Scans

Performance Characterization of an Actively Cooled Repetitive Transcranial Magnetic Stimulation Coil for the Rat

“…As a final note, the field calculations described in this study used a simplified spherical head. More accurate simulations including realistic Magnetic Resonance Imaging (MRI) and CT based rat brain models could provide a more accurate view of the actual field distribution in the rat brain. It has previously been demonstrated in a more realistic head model that, due to charge build up at tissue interfaces, the focality of the total electric field distribution is actually improved compared to the focality of the primary electric that is calculated in simple spherical head models that do not take the brain shape and tissue layers into account .…”

“…For reproducible positioning of the coil and to reduce stress during the experimental procedure, ten naïve rats were handled daily and trained for a period of 9 days prior to the start of the experiment to lie still for 30 min in a custom‐made semi‐flexible restrainer (silicone‐mold, Belosil, Equator, Belgium) , equipped with a tooth‐bar. At the end of this habituation period, the MT of each rat was determined according to the protocol described above (see Motor Threshold Determinations section).…”

SPECT-imaging of activity-dependent changes in regional cerebral blood flow induced by electrical and optogenetic self-stimulation in mice

“…99m Tc-HMPAO SPECT as a novel tool for screening of regional brain activation patterns in awake behaving rodents Wyckhuys and colleagues in a recent study in rats suggested the use of rCBF SPECT as a fast screening tool for evaluating stimulation paradigms and coil design in transcranial magnetic stimulation (Wyckhuys et al, 2013). With no need for cyclotron-produced short half-life radionuclides the logistics of SPECT-imaging are simpler than those of PET-imaging favoring more widespread uses of small-animal SPECT.…”

“…Both tracers can be injected in the awake state and the stable brain tracer-distributions after stimulation can be mapped in the anesthetized state. Thus far, however, 99m Tc-HMPAO-SPECT has only been used in restrained rats (Wyckhuys et al, 2010(Wyckhuys et al, , 2013 or anesthetized mice (Apostolova et al, 2012).…”

“…During the past decade, however, based on pinhole collimation (Beekman and van der Have, 2007) small-animal SPECTscanners have been developed that outperform micro-PET scanners in terms of spatial resolution. Using the blood flow tracer 99 mtechnetium hexamethylpropyleneamine-oxime ( 99m Tc-HMPAO) spatial patterns of neuronal activity can be mapped in the rodent brain (Wyckhuys et al, 2010(Wyckhuys et al, , 2013.…”