Evolutionary MRI

Proc Natl Acad Sci U S A. 2013 Mar 12; 110(11): 4380-5 Kozberg MG, Chen BR, DeLeo SE, Bouchard MB, Hillman EM The adult brain exhibits a local increase in cortical blood flow in response to external stimulus. However, broadly varying hemodynamic responses in the brains of newborn and young infants have been reported. Particular controversy exists over whether the "true" neonatal response to stimulation consists of a decrease or an increase in local deoxyhemoglobin, corresponding to a positive (adult-like) or negative blood oxygen level-dependent (BOLD) signal in functional magnetic resonance imaging (fMRI), respectively. A major difficulty with previous studies has been the variability in human subjects and measurement paradigms. Here, we present a systematic study in neonatal rats that charts the evolution of the cortical blood flow response during postnatal development using exposed-cortex multispectral optical imaging. We demonstrate that postnatal-day-12-13 rats (equivalent to...

Acta Radiol. 2013 Apr 1; 54(3): 313-23 Chen X, Yin J, Wu X, Li R, Fang J, Chen R, Zhang B, Zhang W Increasing evidence suggests that endothelial progenitor cells (EPCs), a subgroup of bone marrow hematopoietic stromal cells, play a critical role in neovascularization and tissue repair.To explore the effect of exogenous EPCs on the cerebral blood perfusion and microvessels in the injured region in rat model with traumatic brain injury (TBI).EPCs were collected from the spleens of healthy Sprague-Dawley rats. Fifty-four Sprague-Dawley rats were randomly divided into six groups. The controlled cortical impact TBI was performed. Spleen-derived exogenous EPCs labeled with super-paramagnetic iron oxide (SPIO) (SPIO-EPCs) were transplanted into the blood by tail vein of rats at 6 and 12 h after TBI, respectively. Magnetic resonance imaging (MRI) and computed tomography perfusion imaging were performed at various time points. Microvascular density was determined by immunohistochemistry.In...

J Pharmacol Exp Ther. 2013 Apr; 345(1): 41-51 Becerra L, Upadhyay J, Chang PC, Bishop J, Anderson J, Baumgartner R, Schwarz AJ, Coimbra A, Wallin D, Nutile L, George E, Maier G, Sunkaraneni S, Iyengar S, Evelhoch JL, Bleakman D, Hargreaves R, Borsook D Pharmacological magnetic resonance imaging (phMRI) is one method by which a drug's pharmacodynamic effects in the brain can be assessed. Although phMRI has been frequently used in preclinical and clinical settings, the extent to which a phMRI signature for a compound translates between rodents and humans has not been systematically examined. In the current investigation, we aimed to build on recent clinical work in which the functional response to 0.1 and 0.2 mg/70 kg i.v. buprenorphine (partial µ-opioid receptor agonist) was measured in healthy humans. Here, we measured the phMRI response to 0.04 and 0.1 mg/kg i.v. buprenorphine in conscious, naive rats to establish the parallelism of the phMRI signature of buprenorphine across...

J Acoust Soc Am. 2013 May; 133(5): 3262 Arvanitis C, McDannold N Harnessing ultrasound/microbubble interactions in the brain may make possible a number of therapeutic ultrasound applications, such as targeted drug delivery, sonothrombolysis, and cavitation-enhanced ablation. However, methods to guide these emerging therapies are presently lacking. Here, we integrated a linear US imaging transducer with a clinical transcranial MRI-guided focused ultrasound (MRgFUS) system and evaluated passive cavitation imaging to monitor microbubble-enhanced sonications. A nonhuman primate skull filled with brain-mimicking phantom was used for the experiments. First, we sonicated the phantom over a range of powers (20-60 W) to induce cavitation-enhanced heating. Using transcranial passive cavitation mapping and MR thermometry, we assessed the ability of the integrated system to simultaneously visualize temperature changes and microbubble activity. In another experiment, we traversed the phantom with...

J Neurosci. 2013 Mar 13; 33(11): 4854-66 Adler A, Finkes I, Katabi S, Prut Y, Bergman H Information is encoded in the nervous system through the discharge and synchronization of single neurons. The striatum, the input stage of the basal ganglia, is divided into three territories: the putamen, the caudate, and the ventral striatum, all of which converge onto the same motor pathway. This parallel organization suggests that there are multiple and competing systems in the basal ganglia network controlling behavior. To explore which mechanism(s) enables the different striatal domains to encode behavioral events and to control behavior, we compared the neural activity of phasically active neurons [medium spiny neurons (MSNs), presumed projection neurons] and tonically active neurons (presumed cholinergic interneurons) across striatal territories from monkeys during the performance of a well practiced task. Although neurons in all striatal territories displayed similar spontaneous discharge...

Neuron. 2013 Mar 20; 77(6): 1174-86 Arsenault JT, Nelissen K, Jarraya B, Vanduffel W Stimulus-reward coupling without attention can induce highly specific perceptual learning effects, suggesting that reward triggers selective plasticity within visual cortex. Additionally, dopamine-releasing events-temporally surrounding stimulus-reward associations-selectively enhance memory. These forms of plasticity may be evoked by selective modulation of stimulus representations during dopamine-inducing events. However, it remains to be shown whether dopaminergic signals can selectively modulate visual cortical activity. We measured fMRI activity in monkey visual cortex during reward-only trials apart from intermixed cue-reward trials. Reward without visual stimulation selectively decreased fMRI activity within the cue representations that had been paired with reward during other trials. Behavioral tests indicated that these same uncued reward trials strengthened cue-reward associations....

Related Articles Combustion resistance of the 129Xe hyperpolarized nuclear spin state. Phys Chem Chem Phys. 2013 Jan 7;15(1):94-7 Authors: Stupic KF, Six JS, Olsen MD, Pavlovskaya GE, Meersmann T Abstract Using a methane-xenon mixture for spin exchange optical pumping, MRI of combustion was enabled. The (129)Xe hyperpolarized nuclear spin state was found to sufficiently survive the complete passage through the harsh environment of the reaction zone. A velocity profile (V(z)(z)) of a flame was recorded to demonstrate the feasibility of MRI velocimetry of transport processes in combustors. PMID: 23165418 [PubMed - indexed for MEDLINE]

Proc Natl Acad Sci U S A. 2013 Mar 5; 110(10): 4093-8 Liu HS, Chefer S, Lu H, Guillem K, Rea W, Kurup P, Yang Y, Peoples L, Stein EA Chronic drug administration induces neuroplastic changes within brain circuits regulating cognitive control and/or emotions. Following repeated pairings between drug intake and environmental cues, increased sensitivity to or salience of these contextual cues provoke conscious or unconscious craving and enhance susceptibility to relapse. To explore brain circuits participating in such experience-induced plasticity, we combined functional MRI with a preclinical drug vs. food self-administration (SA) withdrawal model. Specifically, two groups of rats were trained to associate odor cues with the availability of i.v. cocaine or oral sucrose, respectively. After 20 d of cocaine or sucrose SA followed by prolonged (30 d) forced abstinence, animals were presented with odor cues previously associated with or without (S+/S-) reinforcer (cocaine/sucrose)...