Detection of pharmacologically mediated changes in cerebral activity by functional magnetic resonance imaging: the effects of sulpiride in the brain of the anaesthetised rat

Neuroadaptive responses to citalopram in rats using pharmacological magnetic resonance imaging

“…It is a requirement in the majority of small animal imaging studies to anesthetize the subjects despite its potential confounding effects on brain metabolic activity, which may interfere with the BOLD response under study (Leslie and James 2000). An increasing number of fMRI studies report on anesthetics not affecting BOLD signals, but these results must be interpreted with caution since they have been shown to filter specific signals produced by different neurotransmitter systems [halothane (Chan and Durieux 1997), alpha-chloralose (Preece et al 2001), urethane (Lowe et al 2002;Shoaib et al 2004), isoflurane (Littlewood et al 2006), etc]. Despite such potential limitations, our experimental protocol appeared to be successful in detecting the central actions of citalopram in the mammalian brain without monitoring physiological changes, since our method of analysis, which corrects for global changes, has been used previously to tease out changes in neuronal activity from those occurring in the vasculature (Lowe et al 2002;Shoaib et al 2004).…”

Neuroanatomical targets of reboxetine and bupropion as revealed by pharmacological magnetic resonance imaging

“…In the majority of the small animal imaging studies, it has been necessary to anaesthetise the subjects despite the potential confounding effects on brain metabolic activity and the potential interference with the BOLD response under study (Disbrow et al 1999;Leslie and James 2000). Though the profound implications of the anaesthetics on the haemodynamic parameters and neurovascular coupling are still a subject of debate, an increasing number of fMRI studies illustrate that anaesthetics do not abolish the BOLD response but that the results are to be interpreted with caution, since they may filter specific signals produced by different neurotransmitter systems (halothane- (Chan and Durieux 1997), alpha-chloralose- (Preece et al 2001), urethane- (Lowe et al 2002) and (Shoaib et al 2004), isoflurane- (Steward et al 2004), etc. ).…”

Real-time electrochemical monitoring of brain tissue oxygen: A surrogate for functional magnetic resonance imaging in rodents

“…BOLD fMRI is a key tool in neuroscience because it provides a powerful non-invasive way of mapping the regional activity of the brain during the performance of sensory, motor or cognitive tasks. Image resolution to a few hundred micron also means that detailed structural and functional imaging data can be acquired in small laboratory animals (Houston et al, 2001;Jones et al, 2005;Preece, et al, 2001). However, motion constraints necessitate the use of anaesthetics in the majority of studies, thus limiting the functional processes that can be engaged whilst the animal is being scanned and potentially altering circuitry engagement.…”