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Ferris CF. Applications in Awake Animal Magnetic Resonance Imaging. Front Neurosci 2022; 16:854377. [PMID: 35450017 PMCID: PMC9017993 DOI: 10.3389/fnins.2022.854377] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/09/2022] [Indexed: 12/16/2022] Open
Abstract
There are numerous publications on methods and applications for awake functional MRI across different species, e.g., voles, rabbits, cats, dogs, and rhesus macaques. Each of these species, most obviously rhesus monkey, have general or unique attributes that provide a better understanding of the human condition. However, much of the work today is done on rodents. The growing number of small bore (≤30 cm) high field systems 7T- 11.7T favor the use of small animals. To that point, this review is primarily focused on rodents and their many applications in awake function MRI. Applications include, pharmacological MRI, drugs of abuse, sensory evoked stimuli, brain disorders, pain, social behavior, and fear.
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Iriah SC, Trivedi M, Kenkel W, Grant SE, Moore K, Yee JR, Madularu D, Kulkarni P, Ferris CF. Oxycodone Exposure: A Magnetic Resonance Imaging Study in Response to Acute and Chronic Oxycodone Treatment in Rats. Neuroscience 2018; 398:88-101. [PMID: 30550747 DOI: 10.1016/j.neuroscience.2018.11.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 11/16/2022]
Abstract
The present study was designed to use blood-oxygen-level dependent (BOLD) imaging to "fingerprint" the change in activity in response to oxycodone (OXY) in drug naïve rats before and after repeated exposure to OXY. It was hypothesized that repeated exposure to OXY would initiate adaptive changes in brain organization that would be reflected in an altered response to opioid exposure. Male rats exposed to OXY repeatedly showed conditioned place preference, evidence of drug-seeking behavior and putative neuroadaptation. As these studies were done on awake rats we discovered it was not possible to image rats continuously exposed to OXY due to motion artifact judged to be withdrawal while in the scanner. To circumvent this problem manganese-enhanced MRI (MEMRI) was used to map the distributed integrated activity pattern resulting from continuous OXY exposure. Rats were administered OXY (2.5 mg/kg, i.p.) during image acquisition and changes in BOLD signal intensity were recorded and the activation and deactivation of integrated neural circuits involved in olfaction and motivation were identified. Interestingly, the circuitry of the mesencephalic dopaminergic system showed little activity to the first exposure of OXY. In the MEMRI study, rats received OXY treatments (2.5 mg/kg, twice daily) for four consecutive days following intraventricular MnCl2. Under isoflurane anesthesia, T1-weighted images were acquired and subsequently analyzed showing activity in the forebrain limbic system, ventral striatum, accumbens, amygdala and hippocampus. These results show brain activity is markedly different when OXY is presented to drug naïve rats versus rats with prior, repeated exposure to drug.
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Affiliation(s)
- Sade C Iriah
- Northeastern Univ., Center for Translational NeuroImaging, Boston, MA, USA
| | - Malav Trivedi
- NOVA Southeastern University, Ft. Lauderdale, FL, USA
| | - William Kenkel
- The Kinsey Institute, Indiana University, Bloomington, IN, USA
| | - Simone E Grant
- Northeastern Univ., Center for Translational NeuroImaging, Boston, MA, USA
| | - Kelsey Moore
- Northeastern Univ., Center for Translational NeuroImaging, Boston, MA, USA
| | - Jason R Yee
- Northeastern Univ., Center for Translational NeuroImaging, Boston, MA, USA
| | - Dan Madularu
- Northeastern Univ., Center for Translational NeuroImaging, Boston, MA, USA; Douglas Hospital, McGill University, Montreal, QC, Canada; Carleton University, Ottawa, ON, Canada
| | - Praveen Kulkarni
- Northeastern Univ., Center for Translational NeuroImaging, Boston, MA, USA
| | - Craig F Ferris
- Northeastern Univ., Center for Translational NeuroImaging, Boston, MA, USA.
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Tuite P. Brain Magnetic Resonance Imaging (MRI) as a Potential Biomarker for Parkinson's Disease (PD). Brain Sci 2017; 7:E68. [PMID: 28621758 PMCID: PMC5483641 DOI: 10.3390/brainsci7060068] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/09/2017] [Accepted: 06/13/2017] [Indexed: 12/14/2022] Open
Abstract
Magnetic resonance imaging (MRI) has the potential to serve as a biomarker for Parkinson's disease (PD). However, the type or types of biomarker it could provide remain to be determined. At this time there is not sufficient sensitivity or specificity for MRI to serve as an early diagnostic biomarker, i.e., it is unproven in its ability to determine if a single individual is normal, has mild PD, or has some other forms of degenerative parkinsonism. However there is accumulating evidence that MRI may be useful in staging and monitoring disease progression (staging biomarker), and also possibly as a means to monitor pathophysiological aspects of disease and associated response to treatments, i.e., theranostic marker. As there are increasing numbers of manuscripts that are dedicated to diffusion- and neuromelanin-based imaging methods, this review will focus on these topics cursorily and will delve into pharmacodynamic imaging as a means to get at theranostic aspects of PD.
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Affiliation(s)
- Paul Tuite
- Neurology Department, University of Minnesota, MMC 295, 420 Delaware St SE, Minneapolis, MN 55455, USA.
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Ferris CF, Kulkarni P, Yee JR, Nedelman M, de Jong IEM. The Serotonin Receptor 6 Antagonist Idalopirdine and Acetylcholinesterase Inhibitor Donepezil Have Synergistic Effects on Brain Activity-A Functional MRI Study in the Awake Rat. Front Pharmacol 2017; 8:279. [PMID: 28659792 PMCID: PMC5467007 DOI: 10.3389/fphar.2017.00279] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 05/03/2017] [Indexed: 12/05/2022] Open
Abstract
The 5-HT6 receptor is a promising target for cognitive disorders, in particular for Alzheimer's disease (AD) and other CNS disorders. The high-affinity and selective 5-HT6 receptor antagonist idalopirdine (Lu AE58054) is currently in development for mild-moderate AD as adjunct therapy to acetylcholinesterase inhibitors (AChEIs). We studied the effects of idalopirdine alone and in combination with the AChEI donepezil on brain activity using BOLD (Blood Oxygen Level Dependent) functional magnetic resonance imaging (fMRI) in the awake rat. Idalopirdine (2 mg/kg, i.v.) alone had a modest effect on brain activity, resulting in activation of eight brain regions at the peak response. Of these, the cholinergic diagonal band of Broca, the infralimbic cortex, the ventral pallidum, the nucleus accumbens shell, and the magnocellular preoptic area were shared with the effects of donepezil (0.3 mg/kg, i.v.). Donepezil alone activated 19 brain regions at the peak response, including several cortical regions, areas of the septo-hippocampal system and the serotonergic raphe nucleus. When idalopirdine and donepezil were combined, there was a robust stimulation pattern with activation of 36 brain regions spread across the extended-amygdala-, striato-pallidal, and septo-hippocampal networks as well as the cholinergic system. These findings indicate that, whilst idalopirdine and donepezil recruit a number of overlapping regions including one of the forebrain cholinergic nuclei, the synergistic effect of both compounds extends beyond the cholinergic system and the effects of donepezil alone toward recruitment of multiple neural circuits and neurotransmitter systems. These data provide new insight into the mechanisms via which idalopirdine might improve cognition in donepezil-treated AD patients.
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Affiliation(s)
- Craig F Ferris
- Department of Psychology, Center for Translational NeuroImaging, Northeastern UniversityBoston, MA, United States
| | - Praveen Kulkarni
- Department of Psychology, Center for Translational NeuroImaging, Northeastern UniversityBoston, MA, United States
| | - Jason R Yee
- Department of Psychology, Center for Translational NeuroImaging, Northeastern UniversityBoston, MA, United States
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Jauhar S, Veronese M, Rogdaki M, Bloomfield M, Natesan S, Turkheimer F, Kapur S, Howes OD. Regulation of dopaminergic function: an [ 18F]-DOPA PET apomorphine challenge study in humans. Transl Psychiatry 2017; 7:e1027. [PMID: 28170002 PMCID: PMC5438020 DOI: 10.1038/tp.2016.270] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 07/25/2016] [Accepted: 08/02/2016] [Indexed: 02/08/2023] Open
Abstract
Dopaminergic function has a key role in normal brain function, dopaminergic dysfunction being implicated in numerous neuropsychiatric disorders. Animal studies show that dopaminergic stimulation regulates dopaminergic function, but it is not known whether this exists in humans. In the first study (study 1), we measured dopamine synthesis capacity (indexed as Kicer) to identify the relationship between baseline and change in Kicer under resting conditions for comparison with effects of dopaminergic stimulation. In the second study (study 2), we used a within-subjects design to test effects of dopaminergic stimulation on dopamine synthesis capacity. In study 1, eight volunteers received two 18F-DOPA scans on separate days, both at rest. In study 2, 12 healthy male volunteers received two 18F-DOPA positron emission tomographic (PET) scans after treatment with either the dopamine partial agonist apomorphine (0.03 or 0.005 mg kg-1) or placebo. In study 1, no significant correlation was found between baseline and change in dopamine synthesis capacity between scans (r=-0.57, n=8, P=0.17, two-tailed). In study 2, a significant negative correlation was found between baseline dopamine synthesis capacity and percentage change in dopamine synthesis capacity after apomorphine challenge (r=-0.71, n=12, P=0.01, two-tailed). This correlation was significantly different (P<0.01) from the correlation between baseline and change in dopamine synthesis capacity under unstimulated conditions. One-way repeated-measures analysis of variance showed a significant group (study 1/study 2) × time interaction (F(1,18)=11.5, P=0.003). Our findings suggest that regulation of dopamine synthesis capacity by apomorphine depends on baseline dopamine function, consistent with dopamine stimulation stabilizing dopaminergic function. Loss of this autoregulation may contribute to dopaminergic dysfunction in brain disorders such as schizophrenia, substance dependence, and Parkinson's disease.
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Affiliation(s)
- S Jauhar
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - M Veronese
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - M Rogdaki
- MRC London Institute of Medical Sciences, London, UK
| | - M Bloomfield
- MRC London Institute of Medical Sciences, London, UK
| | - S Natesan
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - F Turkheimer
- Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - S Kapur
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
| | - O D Howes
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College, London, UK
- MRC London Institute of Medical Sciences, London, UK
- Institute of Clinical Sciences, Department of Medicine, Imperial College London, London, UK
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Moore K, Madularu D, Iriah S, Yee JR, Kulkarni P, Darcq E, Kieffer BL, Ferris CF. BOLD Imaging in Awake Wild-Type and Mu-Opioid Receptor Knock-Out Mice Reveals On-Target Activation Maps in Response to Oxycodone. Front Neurosci 2016; 10:471. [PMID: 27857679 PMCID: PMC5094148 DOI: 10.3389/fnins.2016.00471] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/03/2016] [Indexed: 02/06/2023] Open
Abstract
Blood oxygen level dependent (BOLD) imaging in awake mice was used to identify differences in brain activity between wild-type, and Mu (μ) opioid receptor knock-outs (MuKO) in response to oxycodone (OXY). Using a segmented, annotated MRI mouse atlas and computational analysis, patterns of integrated positive and negative BOLD activity were identified across 122 brain areas. The pattern of positive BOLD showed enhanced activation across the brain in WT mice within 15 min of intraperitoneal administration of 2.5 mg of OXY. BOLD activation was detected in 72 regions out of 122, and was most prominent in areas of high μ opioid receptor density (thalamus, ventral tegmental area, substantia nigra, caudate putamen, basal amygdala, and hypothalamus), and focus on pain circuits indicated strong activation in major pain processing centers (central amygdala, solitary tract, parabrachial area, insular cortex, gigantocellularis area, ventral thalamus primary sensory cortex, and prelimbic cortex). Importantly, the OXY-induced positive BOLD was eliminated in MuKO mice in most regions, with few exceptions (some cerebellar nuclei, CA3 of the hippocampus, medial amygdala, and preoptic areas). This result indicates that most effects of OXY on positive BOLD are mediated by the μ opioid receptor (on-target effects). OXY also caused an increase in negative BOLD in WT mice in few regions (16 out of 122) and, unlike the positive BOLD response the negative BOLD was only partially eliminated in the MuKO mice (cerebellum), and in some case intensified (hippocampus). Negative BOLD analysis therefore shows activation and deactivation events in the absence of the μ receptor for some areas where receptor expression is normally extremely low or absent (off-target effects). Together, our approach permits establishing opioid-induced BOLD activation maps in awake mice. In addition, comparison of WT and MuKO mutant mice reveals both on-target and off-target activation events, and set an OXY brain signature that should, in the future, be compared to other μ opioid agonists.
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Affiliation(s)
- Kelsey Moore
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University Boston, MA, USA
| | - Dan Madularu
- Brain Imaging Center, Douglas Hospital Research Institute, McGill University Montreal, QC, Canada
| | - Sade Iriah
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University Boston, MA, USA
| | - Jason R Yee
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University Boston, MA, USA
| | - Praveen Kulkarni
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University Boston, MA, USA
| | - Emmanuel Darcq
- Brain Imaging Center, Douglas Hospital Research Institute, McGill University Montreal, QC, Canada
| | - Brigitte L Kieffer
- Brain Imaging Center, Douglas Hospital Research Institute, McGill University Montreal, QC, Canada
| | - Craig F Ferris
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University Boston, MA, USA
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Ek F, Malo M, Åberg Andersson M, Wedding C, Kronborg J, Svensson P, Waters S, Petersson P, Olsson R. Behavioral Analysis of Dopaminergic Activation in Zebrafish and Rats Reveals Similar Phenotypes. ACS Chem Neurosci 2016; 7:633-46. [PMID: 26947759 DOI: 10.1021/acschemneuro.6b00014] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Zebrafish is emerging as a complement to mammals in behavioral studies; however, there is a lack of comparative studies with rodents and humans to establish the zebrafish as a predictive translational model. Here we present a detailed phenotype evaluation of zebrafish larvae, measuring 300-3000 variables and analyzing them using multivariate analysis to identify the most important ones for further evaluations. The dopamine agonist apomorphine has previously been shown to have a complex U-shaped dose-response relationship in the variable distance traveled. In this study, we focused on breaking down distance traveled into more detailed behavioral phenotypes for both zebrafish and rats and identified in the multivariate analysis low and high dose phenotypes with characteristic behavioral features. Further analysis of single parameters also identified an increased activity at the lowest concentration indicative of a U-shaped dose-response. Apomorphine increased the distance of each swim movement (bout) at both high and low doses, but the underlying behavior of this increase is different; at high dose, both bout duration and frequency increased whereas bout max speed was higher at low dose. Larvae also displayed differences in place preference. The low dose phenotype spent more time in the center, indicative of an anxiolytic effect, while the high-dose phenotype had a wall preference. These dose-dependent effects corroborated findings in a parallel rat study and previous observations in humans. The translational value of pharmacological zebrafish studies was further evaluated by comparing the amino acid sequence of the dopamine receptors (D1-D4), between zebrafish, rats and humans. Humans and zebrafish share 100% of the amino acids in the binding site for D1 and D3 whereas D2 and D4 receptors share 85-95%. Molecular modeling of dopamine D2 and D4 receptors indicated that nonconserved amino acids have limited influence on important ligand-receptor interactions.
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Affiliation(s)
| | | | | | | | | | - Peder Svensson
- Integrative Research Laboratories Sweden AB, 413 46 Gothenburg, Sweden
| | - Susanna Waters
- Integrative Research Laboratories Sweden AB, 413 46 Gothenburg, Sweden
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Functional magnetic resonance imaging in awake transgenic fragile X rats: evidence of dysregulation in reward processing in the mesolimbic/habenular neural circuit. Transl Psychiatry 2016; 6:e763. [PMID: 27003189 PMCID: PMC4872441 DOI: 10.1038/tp.2016.15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/06/2015] [Accepted: 01/19/2016] [Indexed: 01/19/2023] Open
Abstract
Anxiety and social deficits, often involving communication impairment, are fundamental clinical features of fragile X syndrome. There is growing evidence that dysregulation in reward processing is a contributing factor to the social deficits observed in many psychiatric disorders. Hence, we hypothesized that transgenic fragile X mental retardation 1 gene (fmr1) KO (FX) rats would display alterations in reward processing. To this end, awake control and FX rats were imaged for changes in blood oxygen level dependent (BOLD) signal intensity in response to the odor of almond, a stimulus to elicit the innate reward response. Subjects were 'odor naive' to this evolutionarily conserved stimulus. The resulting changes in brain activity were registered to a three-dimensional segmented, annotated rat atlas delineating 171 brain regions. Both wild-type (WT) and FX rats showed robust brain activation to a rewarding almond odor, though FX rats showed an altered temporal pattern and tended to have a higher number of voxels with negative BOLD signal change from baseline. This pattern of greater negative BOLD was especially apparent in the Papez circuit, critical to emotional processing and the mesolimbic/habenular reward circuit. WT rats showed greater positive BOLD response in the supramammillary area, whereas FX rats showed greater positive BOLD response in the dorsal lateral striatum, and greater negative BOLD response in the retrosplenial cortices, the core of the accumbens and the lateral preoptic area. When tested in a freely behaving odor-investigation paradigm, FX rats failed to show the preference for almond odor which typifies WT rats. However, FX rats showed investigation profiles similar to WT when presented with social odors. These data speak to an altered processing of this highly salient novel odor in the FX phenotype and lend further support to the notion that altered reward systems in the brain may contribute to fragile X syndrome symptomology.
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Miller B, Lim AN, Heidbreder AF, Black KJ. An Automated Motion Detection and Reward System for Animal Training. Cureus 2015; 7:e397. [PMID: 26798573 PMCID: PMC4699987 DOI: 10.7759/cureus.397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
A variety of approaches has been used to minimize head movement during functional brain imaging studies in awake laboratory animals. Many laboratories expend substantial effort and time training animals to remain essentially motionless during such studies. We could not locate an “off-the-shelf” automated training system that suited our needs. We developed a time- and labor-saving automated system to train animals to hold still for extended periods of time. The system uses a personal computer and modest external hardware to provide stimulus cues, monitor movement using commercial video surveillance components, and dispense rewards. A custom computer program automatically increases the motionless duration required for rewards based on performance during the training session but allows changes during sessions. This system was used to train cynomolgus monkeys (Macaca fascicularis) for awake neuroimaging studies using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). The automated system saved the trainer substantial time, presented stimuli and rewards in a highly consistent manner, and automatically documented training sessions. We have limited data to prove the training system's success, drawn from the automated records during training sessions, but we believe others may find it useful. The system can be adapted to a range of behavioral training/recording activities for research or commercial applications, and the software is freely available for non-commercial use.
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Affiliation(s)
- Brad Miller
- Psychiatry, Washington University School of Medicine
| | - Audrey N Lim
- Psychiatry, Washington University School of Medicine
| | | | - Kevin J Black
- Departments of Psychiatry, Neurology, Radiology, and Anatomy & Neurobiology, Washington University School of Medicine
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Martino G, Capasso M, Nasuti M, Bonanni L, Onofrj M, Thomas A. Dopamine transporter single-photon emission computerized tomography supports diagnosis of akinetic crisis of parkinsonism and of neuroleptic malignant syndrome. Medicine (Baltimore) 2015; 94:e649. [PMID: 25837755 PMCID: PMC4554017 DOI: 10.1097/md.0000000000000649] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Akinetic crisis (AC) is akin to neuroleptic malignant syndrome (NMS) and is the most severe and possibly lethal complication of parkinsonism. Diagnosis is today based only on clinical assessments yet is often marred by concomitant precipitating factors. Our purpose is to evidence that AC and NMS can be reliably evidenced by FP/CIT single-photon emission computerized tomography (SPECT) performed during the crisis. Prospective cohort evaluation in 6 patients. In 5 patients, affected by Parkinson disease or Lewy body dementia, the crisis was categorized as AC. One was diagnosed as having NMS because of exposure to risperidone. In all FP/CIT, SPECT was performed in the acute phase. SPECT was repeated 3 to 6 months after the acute event in 5 patients. Visual assessments and semiquantitative evaluations of binding potentials (BPs) were used. To exclude the interference of emergency treatments, FP/CIT BP was also evaluated in 4 patients currently treated with apomorphine. During AC or NMS, BP values in caudate and putamen were reduced by 95% to 80%, to noise level with a nearly complete loss of striatum dopamine transporter-binding, corresponding to the "burst striatum" pattern. The follow-up re-evaluation in surviving patients showed a recovery of values to the range expected for Parkinsonisms of same disease duration. No binding effects of apomorphine were observed. By showing the outstanding binding reduction, presynaptic dopamine transporter ligand can provide instrumental evidence of AC in Parkinsonism and NMS.
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Affiliation(s)
- G Martino
- From the Department of Radiology and Radiotherapy, Nuclear Medicine University G. d'Annunzio of Chieti-Pescara (GM, MN); Neurology Clinic, State Hospital (MC, LB, MO, AT); and Department of Neuroscience and Imaging and Aging Research Center, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy (LB, MO, AT)
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Yee JR, Kenkel W, Caccaviello JC, Gamber K, Simmons P, Nedelman M, Kulkarni P, Ferris CF. Identifying the integrated neural networks involved in capsaicin-induced pain using fMRI in awake TRPV1 knockout and wild-type rats. Front Syst Neurosci 2015; 9:15. [PMID: 25745388 PMCID: PMC4333803 DOI: 10.3389/fnsys.2015.00015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/31/2015] [Indexed: 12/18/2022] Open
Abstract
In the present study, we used functional MRI in awake rats to investigate the pain response that accompanies intradermal injection of capsaicin into the hindpaw. To this end, we used BOLD imaging together with a 3D segmented, annotated rat atlas and computational analysis to identify the integrated neural circuits involved in capsaicin-induced pain. The specificity of the pain response to capsaicin was tested in a transgenic model that contains a biallelic deletion of the gene encoding for the transient receptor potential cation channel subfamily V member 1 (TRPV1). Capsaicin is an exogenous ligand for the TRPV1 receptor, and in wild-type rats, activated the putative pain neural circuit. In addition, capsaicin-treated wild-type rats exhibited activation in brain regions comprising the Papez circuit and habenular system, systems that play important roles in the integration of emotional information, and learning and memory of aversive information, respectively. As expected, capsaicin administration to TRPV1-KO rats failed to elicit the robust BOLD activation pattern observed in wild-type controls. However, the intradermal injection of formalin elicited a significant activation of the putative pain pathway as represented by such areas as the anterior cingulate, somatosensory cortex, parabrachial nucleus, and periaqueductal gray. Notably, comparison of neural responses to capsaicin in wild-type vs. knock-out rats uncovered evidence that capsaicin may function in an antinociceptive capacity independent of TRPV1 signaling. Our data suggest that neuroimaging of pain in awake, conscious animals has the potential to inform the neurobiological basis of full and integrated perceptions of pain.
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Affiliation(s)
- Jason R Yee
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | - William Kenkel
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | - John C Caccaviello
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | | | | | | | - Praveen Kulkarni
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
| | - Craig F Ferris
- Center for Translational NeuroImaging, Department of Psychology, Northeastern University Boston, MA, USA
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12
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Kashiwagi Y, Rokugawa T, Yamada T, Obata A, Watabe H, Yoshioka Y, Abe K. Pharmacological MRI response to a selective dopamine transporter inhibitor, GBR12909, in awake and anesthetized rats. Synapse 2015; 69:203-12. [PMID: 25612063 DOI: 10.1002/syn.21803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/06/2015] [Indexed: 12/20/2022]
Abstract
Pharmacological magnetic resonance imaging (phMRI) is a powerful tool for imaging the effects of drugs on brain activity. In preclinical phMRI studies, general anesthesia used for minimizing head movements is thought to influence the phMRI responses to drugs. In this study we investigated the phMRI responses to a selective dopamine transporter (DAT) inhibitor, GBR12909, and a dopamine (DA) releaser, d-amphetamine (AMPH), in the isoflurane anesthetized and awake rats using a relative cerebral blood volume (rCBV) method. AMPH (1 mg/kg i.p.) caused an increase in rCBV in the dopaminergic circuitry in the both anesthetized and awake rats. The striatal rCBV change was correlated with the change of the striatal DA concentration induced by AMPH in the both anesthetized and awake rats. GBR12909 (10 mg/kg i.p.) caused a positive rCBV response and showed a similar regional pattern of rCBV response to AMPH in the awake rats, and the correlation between the change of the striatal rCBV and the striatal DA concentration was observed. However, in the anesthetized rats, GBR12909 induced a widespread negative rCBV response, whereas an increase in striatal DA concentration was observed. These findings indicate that phMRI responses to activation of DA neurotransmission by GBR12909 or AMPH are overall identical in the awake state, while the phMRI response to a DAT inhibitor, GBR12909 but not to AMPH was changed by isoflurane anesthesia. For the evaluation of neuroactive drugs using phMRI, isoflurane anesthesia might be complicated the interpretation of pharmacodynamic effects of drugs in preclinical studies.
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Affiliation(s)
- Yuto Kashiwagi
- Department of Drug Metabolism and Pharmacokinetics, Research Laboratory for Development, Shionogi and Co., Ltd., Osaka, Japan; Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
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13
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Seah S, Asad ABA, Baumgartner R, Feng D, Williams DS, Manigbas E, Beaver JD, Reese T, Henry B, Evelhoch JL, Chin CL. Investigation of cross-species translatability of pharmacological MRI in awake nonhuman primate - a buprenorphine challenge study. PLoS One 2014; 9:e110432. [PMID: 25337714 PMCID: PMC4206294 DOI: 10.1371/journal.pone.0110432] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 09/22/2014] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Pharmacological MRI (phMRI) is a neuroimaging technique where drug-induced hemodynamic responses can represent a pharmacodynamic biomarker to delineate underlying biological consequences of drug actions. In most preclinical studies, animals are anesthetized during image acquisition to minimize movement. However, it has been demonstrated anesthesia could attenuate basal neuronal activity, which can confound interpretation of drug-induced brain activation patterns. Significant efforts have been made to establish awake imaging in rodents and nonhuman primates (NHP). Whilst various platforms have been developed for imaging awake NHP, comparison and validation of phMRI data as translational biomarkers across species remain to be explored. METHODOLOGY We have established an awake NHP imaging model that encompasses comprehensive acclimation procedures with a dedicated animal restrainer. Using a cerebral blood volume (CBV)-based phMRI approach, we have determined differential responses of brain activation elicited by the systemic administration of buprenorphine (0.03 mg/kg i.v.), a partial µ-opioid receptor agonist, in the same animal under awake and anesthetized conditions. Additionally, region-of-interest analyses were performed to determine regional drug-induced CBV time-course data and corresponding area-under-curve (AUC) values from brain areas with high density of µ-opioid receptors. PRINCIPAL FINDINGS In awake NHPs, group-level analyses revealed buprenorphine significantly activated brain regions including, thalamus, striatum, frontal and cingulate cortices (paired t-test, versus saline vehicle, p<0.05, n = 4). This observation is strikingly consistent with µ-opioid receptor distribution depicted by [6-O-[(11)C]methyl]buprenorphine ([(11)C]BPN) positron emission tomography imaging study in baboons. Furthermore, our findings are consistent with previous buprenorphine phMRI studies in humans and conscious rats which collectively demonstrate the cross-species translatability of awake imaging. Conversely, no significant change in activated brain regions was found in the same animals imaged under the anesthetized condition. CONCLUSIONS Our data highlight the utility and importance of awake NHP imaging as a translational imaging biomarker for drug research.
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Affiliation(s)
- Stephanie Seah
- Imaging, Merck & Co. Inc., West Point, Pennsylvania, United States of America
- Translational Medicine Research Centre, MSD, Singapore, Singapore
| | - Abu Bakar Ali Asad
- Imaging, Merck & Co. Inc., West Point, Pennsylvania, United States of America
- Translational Medicine Research Centre, MSD, Singapore, Singapore
| | - Richard Baumgartner
- Biostatistics and Research Decision Sciences, Merck & Co. Inc., Rahway, New Jersey, United States of America
| | - Dai Feng
- Biostatistics and Research Decision Sciences, Merck & Co. Inc., Rahway, New Jersey, United States of America
| | - Donald S. Williams
- Imaging, Merck & Co. Inc., West Point, Pennsylvania, United States of America
| | | | | | - Torsten Reese
- Translational Medicine Research Centre, MSD, Singapore, Singapore
| | - Brian Henry
- Translational Medicine Research Centre, MSD, Singapore, Singapore
| | - Jeffrey L. Evelhoch
- Imaging, Merck & Co. Inc., West Point, Pennsylvania, United States of America
| | - Chih-Liang Chin
- Imaging, Merck & Co. Inc., West Point, Pennsylvania, United States of America
- Translational Medicine Research Centre, MSD, Singapore, Singapore
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Pharmacologic MRI (phMRI) as a tool to differentiate Parkinson's disease-related from age-related changes in basal ganglia function. Neurobiol Aging 2014; 36:1174-82. [PMID: 25443764 DOI: 10.1016/j.neurobiolaging.2014.10.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/27/2014] [Accepted: 10/12/2014] [Indexed: 12/24/2022]
Abstract
The prevalence of both parkinsonian signs and Parkinson's disease (PD) per se increases with age. Although the pathophysiology of PD has been studied extensively, less is known about the functional changes taking place in the basal ganglia circuitry with age. To specifically address this issue, 3 groups of rhesus macaques were studied: normal middle-aged animals (used as controls), middle-aged animals with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism, and aged animals (>20 years old) with declines in motor function. All animals underwent the same behavioral and pharmacologic magnetic resonance imaging (phMRI) procedures to measure changes in basal ganglia function in response to dopaminergic drug challenges consisting of apomorphine administration followed by either a D1 (SCH23390) or a D2 (raclopride) receptor antagonist. Significant functional changes were predominantly seen in the external segment of the globus pallidus (GPe) in aged animals and in the striatum (caudate nucleus and putamen) in MPTP-lesioned animals. Despite significant differences seen in the putamen and GPe between MPTP-lesioned versus aged animals, a similar response profile to dopaminergic stimulations was found between these 2 groups in the internal segment of the GP. In contrast, the pharmacologic responses seen in the control animals were much milder compared with the other 2 groups in all the examined areas. Our phMRI findings in MPTP-lesioned parkinsonian and aged animals suggest that changes in basal ganglia function in the elderly may differ from those seen in parkinsonian patients and that phMRI could be used to distinguish PD from other age-associated functional alterations in the brain.
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15
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Ferris CF, Kulkarni P, Toddes S, Yee J, Kenkel W, Nedelman M. Studies on the Q175 Knock-in Model of Huntington's Disease Using Functional Imaging in Awake Mice: Evidence of Olfactory Dysfunction. Front Neurol 2014; 5:94. [PMID: 25071696 PMCID: PMC4074991 DOI: 10.3389/fneur.2014.00094] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/25/2014] [Indexed: 12/04/2022] Open
Abstract
Blood oxygen level dependent (BOLD) imaging in awake mice was used to identify differences in brain activity between wild-type, HETzQ175, and HOMzQ175 genotypes in response to the odor of almond. The study was designed to see how alterations in the huntingtin gene in a mouse model of Huntington’s disease would affect the perception and processing of almond odor, an evolutionarily conserved stimulus with high emotional and motivational valence. Moreover, the mice in this study were “odor naïve,” i.e., never having smelled almond or any nuts. Using a segmented, annotated MRI atlas of the mouse and computational analysis, 17 out of 116 brain regions were identified as responding differently to almond odor across genotypes. These regions included the glomerulus of the olfactory bulb, forebrain cortex, anterior cingulate, subiculum, and dentate gyrus of the hippocampus, and several areas of the hypothalamus. In many cases, these regions showed a gene-dose effect with HETzQ175 mice showing a reduction in brain activity from wild-type that is further reduced in HOMzQ175 mice. Conspicuously absent were any differences in brain activity in the caudate/putamen, thalamus, CA3, and CA1 of the hippocampus and much of the cortex. The glomerulus of the olfactory bulb in HOMzQ175 mice showed a reduced change in BOLD signal intensity in response to almond odor as compared to the other phenotypes suggesting a deficit in olfactory sensitivity.
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Affiliation(s)
- Craig F Ferris
- Center for Translational NeuroImaging, Northeastern University , Boston, MA , USA
| | - Praveen Kulkarni
- Center for Translational NeuroImaging, Northeastern University , Boston, MA , USA
| | | | - Jason Yee
- Center for Translational NeuroImaging, Northeastern University , Boston, MA , USA
| | - William Kenkel
- Center for Translational NeuroImaging, Northeastern University , Boston, MA , USA
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16
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Papoti D, Yen CCC, Mackel JB, Merkle H, Silva AC. An embedded four-channel receive-only RF coil array for fMRI experiments of the somatosensory pathway in conscious awake marmosets. NMR IN BIOMEDICINE 2013; 26:1395-1402. [PMID: 23696219 PMCID: PMC4200535 DOI: 10.1002/nbm.2965] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/22/2013] [Accepted: 03/25/2013] [Indexed: 06/01/2023]
Abstract
fMRI has established itself as the main research tool in neuroscience and brain cognitive research. The common marmoset (Callithrix jacchus) is a non-human primate model of increasing interest in biomedical research. However, commercial MRI coils for marmosets are not generally available. The present work describes the design and construction of a four-channel receive-only surface RF coil array with excellent signal-to-noise ratio (SNR) specifically optimized for fMRI experiments in awake marmosets in response to somatosensory stimulation. The array was designed as part of a helmet-based head restraint system used to prevent motion during the scans. High SNR was obtained by building the coil array using a thin and flexible substrate glued to the inner surface of the restraint helmet, so as to minimize the distance between the array elements and the somatosensory cortex. Decoupling between coil elements was achieved by partial geometrical overlapping and by connecting them to home-built low-input-impedance preamplifiers. In vivo images show excellent coverage of the brain cortical surface with high sensitivity near the somatosensory cortex. Embedding the coil elements within the restraint helmet allowed fMRI data in response to somatosensory stimulation to be collected with high sensitivity and reproducibility in conscious, awake marmosets.
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Affiliation(s)
| | | | | | | | - Afonso C. Silva
- Address for correspondence: Afonso C. Silva, Ph.D., Chief, Cerebral Microcirculation Unit, Laboratory of Functional and Molecular Imaging, National Institute of neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive MSC 1065, Building 10, Room B1D106, Bethesda, MD, 20892-1065, USA, Phone: +1-301-402-9703, Fax: +1-301-480-2558,
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17
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Miller B, Marks LA, Koller JM, Newman BJ, Bretthorst GL, Black KJ. Prolactin and fMRI response to SKF38393 in the baboon. PeerJ 2013; 1:e195. [PMID: 24255811 PMCID: PMC3817584 DOI: 10.7717/peerj.195] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 10/10/2013] [Indexed: 11/20/2022] Open
Abstract
Background. This study's goal was to provide dose-response data for a dopamine agonist in the baboon using standard methods (replicate measurements at each dose, across a range of doses), as a standard against which to subsequently validate a novel pharmacological MRI (phMRI) method. Dependent variables were functional MRI (fMRI) data from brain regions selected a priori, and systemic prolactin release. Necessary first steps included estimating the magnitude and time course of prolactin response to anesthesia alone and to various doses of agonist. These first steps ("time course studies") were performed with three agonists, and the results were used to select promising agonists and to guide design details for the single-dose studies needed to generate dose-response curves. Methods. We studied 6 male baboons (Papio anubis) under low-dose isoflurane anesthesia after i.m. ketamine. Time course studies charted the changes in plasma prolactin levels over time after anesthesia alone or after an intravenous (i.v.) dose of the dopamine D 1-like agonists SKF82958 and SKF38393 or the D 2-like agonist pramipexole. In the single-dose dopamine agonist studies, one dose of SKF38393 (ranging from 0.0928-9.28 mg/kg, N = 5 animals) or pramipexole (0.00928-0.2 mg/kg, N = 1) was given i.v. during a 40-min blood oxygen level dependent (BOLD) fMRI session, to determine BOLD and plasma prolactin responses to different drug concentrations. BOLD response was quantified as the area under the time-signal curve for the first 15 min after the start of the drug infusion, compared to the linearly predicted signal from the baseline data before drug. The ED50 (estimated dose that produces 50% of the maximal possible response to drug) for SKF38393 was calculated for the serum prolactin response and for phMRI responses in hypothalamus, pituitary, striatum and midbrain. Results. Prolactin rose 2.4- to 12-fold with anesthesia alone, peaking around 50-90 min after ketamine administration and gradually tapering off but still remaining higher than baseline on isoflurane 3-5 h after ketamine. Baseline prolactin level increased with age. SKF82958 0.1 mg/kg i.v. produced no noticeable change in plasma prolactin concentration. SKF38393 produced a substantial increase in prolactin release that peaked at around 20-30 min and declined to pre-drug levels in about an hour. Pramipexole quickly reduced prolactin levels below baseline, reaching a nadir 2-3 h after infusion. SKF38393 produced clear, dose-responsive BOLD signal changes, and across the four regions, ED50 was estimated at 2.6-8.1 mg/kg. Conclusions. In the baboon, the dopamine D 1 receptor agonist SKF38393 produces clear plasma prolactin and phMRI dose-response curves. Variability in age and a modest sample size limit the precision of the conclusions.
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Affiliation(s)
- Brad Miller
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - Lauren A. Marks
- Washington University School of Medicine, St. Louis, MO, USA
| | - Jonathan M. Koller
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - Blake J. Newman
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - G. Larry Bretthorst
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kevin J. Black
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
- Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, MO, USA
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18
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Kaufman MJ, Janes AC, Frederick BD, Brimson-Théberge M, Tong Y, McWilliams SB, Bear A, Gillis TE, Schrode KM, Renshaw PF, Negus SS. A method for conducting functional MRI studies in alert nonhuman primates: initial results with opioid agonists in male cynomolgus monkeys. Exp Clin Psychopharmacol 2013; 21:323-31. [PMID: 23773004 PMCID: PMC3916219 DOI: 10.1037/a0033062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Functional MRI (fMRI) has emerged as a powerful technique for assessing neural effects of psychoactive drugs and other stimuli. Several experimental approaches have been developed to use fMRI in anesthetized and awake animal subjects, each of which has its advantages and complexities. We sought to assess whether one particular method to scan alert postanesthetized animals can be used to assess fMRI effects of opioid agonists. To date, the use of fMRI as a method to compare pharmacological effects of opioid drugs has been limited. Such studies are important because mu and kappa opioid receptor agonists produce distinct profiles of behavioral effects related both to clinically desirable endpoints (e.g., analgesia) and to undesirable effects (e.g., abuse potential). This study sought to determine whether we could use our fMRI approach to compare acute effects of behaviorally equipotent (3.2 μg/kg) intravenous doses of fentanyl and U69,593 (doses that do not affect cardiorespiratory parameters). Scans were acquired in alert male cynomolgus macaques acclimated to undergo fMRI scans under restraint, absent excessive stress hormone increases. These opioid agonists activated bilateral striatal and nucleus accumbens regions of interest. At the dose tested, U69,593 induced greater left nucleus accumbens BOLD activation than fentanyl, while fentanyl activated left dorsal caudate nucleus more than U69,593. Our results suggest that our fMRI approach could be informative for comparing effects of opioid agonists.
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MESH Headings
- Adrenocorticotropic Hormone/blood
- Analgesics, Opioid/administration & dosage
- Analgesics, Opioid/pharmacology
- Animals
- Benzeneacetamides/administration & dosage
- Benzeneacetamides/pharmacology
- Caudate Nucleus/drug effects
- Caudate Nucleus/metabolism
- Conditioning, Psychological
- Fentanyl/administration & dosage
- Fentanyl/pharmacology
- Hydrocortisone/blood
- Injections, Intravenous
- Macaca fascicularis/physiology
- Magnetic Resonance Imaging/adverse effects
- Magnetic Resonance Imaging/veterinary
- Male
- Nerve Tissue Proteins/agonists
- Nerve Tissue Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Nucleus Accumbens/drug effects
- Nucleus Accumbens/metabolism
- Pyrrolidines/administration & dosage
- Pyrrolidines/pharmacology
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/metabolism
- Restraint, Physical/adverse effects
- Restraint, Physical/veterinary
- Stress, Physiological
- Stress, Psychological/blood
- Stress, Psychological/etiology
- Wakefulness
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Affiliation(s)
- Marc J Kaufman
- McLean Imaging Center, McLean Hospital, Belmont, MA 02478, USA.
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19
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Black KJ, Koller JM, Miller BD. Rapid quantitative pharmacodynamic imaging by a novel method: theory, simulation testing and proof of principle. PeerJ 2013; 1:e117. [PMID: 23940831 PMCID: PMC3740141 DOI: 10.7717/peerj.117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/08/2013] [Indexed: 11/20/2022] Open
Abstract
Pharmacological challenge imaging has mapped, but rarely quantified, the sensitivity of a biological system to a given drug. We describe a novel method called rapid quantitative pharmacodynamic imaging. This method combines pharmacokinetic-pharmacodynamic modeling, repeated small doses of a challenge drug over a short time scale, and functional imaging to rapidly provide quantitative estimates of drug sensitivity including EC 50 (the concentration of drug that produces half the maximum possible effect). We first test the method with simulated data, assuming a typical sigmoidal dose-response curve and assuming imperfect imaging that includes artifactual baseline signal drift and random error. With these few assumptions, rapid quantitative pharmacodynamic imaging reliably estimates EC 50 from the simulated data, except when noise overwhelms the drug effect or when the effect occurs only at high doses. In preliminary fMRI studies of primate brain using a dopamine agonist, the observed noise level is modest compared with observed drug effects, and a quantitative EC 50 can be obtained from some regional time-signal curves. Taken together, these results suggest that research and clinical applications for rapid quantitative pharmacodynamic imaging are realistic.
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Affiliation(s)
- Kevin J Black
- Departments of Psychiatry, Neurology, Radiology, and Anatomy & Neurobiology, Washington University School of Medicine , St. Louis, MO , USA
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20
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Pharmacological imaging as a tool to visualise dopaminergic neurotoxicity. Neuropharmacology 2013; 84:159-69. [PMID: 23851258 DOI: 10.1016/j.neuropharm.2013.06.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 06/06/2013] [Accepted: 06/27/2013] [Indexed: 11/20/2022]
Abstract
Dopamine abnormalities underlie a wide variety of psychopathologies, including ADHD and schizophrenia. A new imaging technique, pharmacological magnetic resonance imaging (phMRI), is a promising non-invasive technique to visualize the dopaminergic system in the brain. In this review we explore the clinical potential of phMRI in detecting dopamine dysfunction or neurotoxicity, assess its strengths and weaknesses and identify directions for future research. Preclinically, phMRI is able to detect severe dopaminergic abnormalities quite similar to conventional techniques such as PET and SPECT. phMRI benefits from its high spatial resolution and the possibility to visualize both local and downstream effects of dopaminergic neurotransmission. In addition, it allows for repeated measurements and assessments in vulnerable populations. The major challenge is the complex interpretation of phMRI results. Future studies in patients with dopaminergic abnormalities need to confirm the currently reviewed preclinical findings to validate the technique in a clinical setting. Eventually, based on the current review we expect that phMRI can be of use in a clinical setting involving vulnerable populations (such as children and adolescents) for diagnosis and monitoring treatment efficacy. This article is part of the Special Issue Section entitled 'Neuroimaging in Neuropharmacology'.
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21
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Passamonti L, Salsone M, Toschi N, Cerasa A, Giannelli M, Chiriaco C, Cascini GL, Fera F, Quattrone A. Dopamine-transporter levels drive striatal responses to apomorphine in Parkinson's disease. Brain Behav 2013; 3:249-62. [PMID: 23785657 PMCID: PMC3683285 DOI: 10.1002/brb3.115] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 11/15/2012] [Accepted: 11/30/2012] [Indexed: 11/21/2022] Open
Abstract
Dopaminergic therapy in Parkinson's disease (PD) can improve some cognitive functions while worsening others. These opposite effects might reflect different levels of residual dopamine in distinct parts of the striatum, although the underlying mechanisms remain poorly understood. We used functional magnetic resonance imaging (fMRI) to address how apomorphine, a potent dopamine agonist, influences brain activity associated with working memory in PD patients with variable levels of nigrostriatal degeneration, as assessed via dopamine-transporter (DAT) scan. Twelve PD patients underwent two fMRI sessions (Off-, On-apomorphine) and one DAT-scan session. Twelve sex-, age-, and education-matched healthy controls underwent one fMRI session. The core fMRI analyses explored: (1) the main effect of group; (2) the main effect of treatment; and (3) linear and nonlinear interactions between treatment and DAT levels. Relative to controls, PD-Off patients showed greater activations within posterior attentional regions (e.g., precuneus). PD-On versus PD-Off patients displayed reduced left superior frontal gyrus activation and enhanced striatal activation during working-memory task. The relation between DAT levels and striatal responses to apomorphine followed an inverted-U-shaped model (i.e., the apomorphine effect on striatal activity in PD patients with intermediate DAT levels was opposite to that observed in PD patients with higher and lower DAT levels). Previous research in PD demonstrated that the nigrostriatal degeneration (tracked via DAT scan) is associated with inverted-U-shaped rearrangements of postsynaptic D2-receptors sensitivity. Hence, it can be hypothesized that individual differences in DAT levels drove striatal responses to apomorphine via D2-receptor-mediated mechanisms.
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Affiliation(s)
- Luca Passamonti
- Istituto di Scienze Neurologiche (ISN), Consiglio Nazionale delle Ricerche 88100, Catanzaro, Italia ; Dipartimento di Scienze Mediche e Chirurgiche, Università degli Studi "Magna Graecia" 88100, Catanzaro, Italia
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22
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Pharmacologic magnetic resonance imaging (phMRI): imaging drug action in the brain. Neuroimage 2012; 62:1072-85. [PMID: 22495143 DOI: 10.1016/j.neuroimage.2012.03.075] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 03/23/2012] [Indexed: 02/01/2023] Open
Abstract
The technique of functional magnetic resonance (fMRI), using various cognitive, motor and sensory stimuli has led to a revolution in the ability to map brain function. Drugs can also be used as stimuli to elicit an hemodynamic change. Stimulation with a pharmaceutical has a number of very different consequences compared to user controllable stimuli, most importantly in the time course of stimulus and response that is not, in general, controllable by the experimenter. Therefore, this type of experiment has been termed pharmacologic MRI (phMRI). The use of a drug stimulus leads to a number of interesting possibilities compared to conventional fMRI. Using receptor specific ligands one can characterize brain circuitry specific to neurotransmitter systems. The possibility exists to measure parameters reflecting neurotransmitter release and binding associated with the pharmacokinetics and/or the pharmacodynamics of drugs. There is also the ability to measure up- and down-regulation of receptors in specific disease states. phMRI can be characterized as a molecular imaging technique using the natural hemodynamic transduction related to neuro-receptor stimulus. This provides a coupling mechanism with very high sensitivity that can rival positron emission tomography (PET) in some circumstances. The large numbers of molecules available, that do not require a radio-label, means that phMRI becomes a very useful tool for performing drug discovery. Data and arguments will be presented to show that phMRI can provide information on neuro-receptor signaling and function that complements the static picture generated by PET studies of receptor numbers and occupancies.
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23
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Silva AC, Liu JV, Hirano Y, Leoni RF, Merkle H, Mackel JB, Zhang XF, Nascimento GC, Stefanovic B. Longitudinal functional magnetic resonance imaging in animal models. Methods Mol Biol 2011; 711:281-302. [PMID: 21279608 PMCID: PMC4748954 DOI: 10.1007/978-1-61737-992-5_14] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Functional magnetic resonance imaging (fMRI) has had an essential role in furthering our understanding of brain physiology and function. fMRI techniques are nowadays widely applied in neuroscience research, as well as in translational and clinical studies. The use of animal models in fMRI studies has been fundamental in helping elucidate the mechanisms of cerebral blood-flow regulation, and in the exploration of basic neuroscience questions, such as the mechanisms of perception, behavior, and cognition. Because animals are inherently non-compliant, most fMRI performed to date have required the use of anesthesia, which interferes with brain function and compromises interpretability and applicability of results to our understanding of human brain function. An alternative approach that eliminates the need for anesthesia involves training the animal to tolerate physical restraint during the data acquisition. In the present chapter, we review these two different approaches to obtaining fMRI data from animal models, with a specific focus on the acquisition of longitudinal data from the same subjects.
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Affiliation(s)
- Afonso C Silva
- Cerebral Microcirculation Unit, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
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24
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Zhao F, Fan X, Grondin R, Edwards R, Forman E, Moorehead J, Gerhardt G, Wang X, Zhang Z. Improved methods for electroacupuncture and electromyographic recordings in normal and parkinsonian rhesus monkeys. J Neurosci Methods 2010; 192:199-206. [PMID: 20654649 DOI: 10.1016/j.jneumeth.2010.07.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/13/2010] [Accepted: 07/14/2010] [Indexed: 12/22/2022]
Abstract
Although acupuncture has been widely and routinely used in healthcare in the USA, its use has been based more on empirical observation than on scientific knowledge. Therefore, there is a great need for better understanding the underlying mechanism(s) of action. A great body of evidence supports that nonhuman primates are a candidate for studying human diseases. However, the use of nonhuman primates in neurophysiological, neuroimaging and neurochemical studies is extremely challenging, especially under fully conscious, alert conditions. In the present study, we developed a protocol for safely performing acupuncture, electroacupuncture (EA) and electromyography (EMG) in both normal nonhuman primates and animals with parkinsonian-like symptoms. Four normal and four hemiparkinsonian middle-aged rhesus monkeys were extensively trained, behaviorally monitored, and received both EA and EMG for several months. The results demonstrated that (1) all rhesus monkeys used in the study could be trained for procedures including EA and EMG; (2) all animals tolerated the procedures involving needle/electrode insertion; (3) EA procedures used in the study did not adversely alter the animal's locomotor activities; rather, MPTP-treated animals showed a significant improvement in movement speed; and (4) EMG detected significant differences in muscle activity between the arms with and without MPTP-induced rigidity. Our results support that rhesus monkeys can be used as an experimental animal model to study EA and that EMG has the potential to be used to objectively assess the effects of antiparkinsonian therapies. The results also indicate that animals, especially those with parkinsonian-like symptoms, could benefit from long-term EA stimulations.
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Affiliation(s)
- Feng Zhao
- Department of Physiology, Key Laboratory for Neurodegenerative Disorders of the Ministry Education, Capital Medical University, Beijing 100069, PR China
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25
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Figley CR, Leitch JK, Stroman PW. In contrast to BOLD: signal enhancement by extravascular water protons as an alternative mechanism of endogenous fMRI signal change. Magn Reson Imaging 2010; 28:1234-43. [PMID: 20299173 DOI: 10.1016/j.mri.2010.01.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 12/23/2009] [Accepted: 01/08/2010] [Indexed: 12/14/2022]
Abstract
Despite the popularity and widespread application of functional magnetic resonance imaging (fMRI) in recent years, the physiological bases of signal change are not yet fully understood. Blood oxygen level-dependant (BOLD) contrast - attributed to local changes in blood flow and oxygenation, and therefore magnetic susceptibility - has become the most prevalent means of functional neuroimaging. However, at short echo times, spin-echo sequences show considerable deviations from the BOLD model, implying a second, non-BOLD component of signal change. This has been dubbed "signal enhancement by extravascular water protons" (SEEP) and is proposed to result from proton-density changes associated with cellular swelling. Given that such changes are independent of magnetic susceptibility, SEEP may offer new and improved opportunities for carrying out fMRI in regions with close proximity to air-tissue and/or bone-tissue interfaces (e.g., the prefrontal cortex and spinal cord), as well as regions close to large blood vessels, which may not be ideally suited for BOLD imaging. However, because of the interdisciplinary nature of the literature, there has yet to be a thorough synthesis, tying together the various and sometimes disparate aspects of SEEP theory. As such, we aim to provide a concise yet comprehensive overview of SEEP, including recent and compelling evidence for its validity, its current applications and its future relevance to the rapidly expanding field of functional neuroimaging. Before presenting the evidence for a non-BOLD component of endogenous functional contrast, and to enable a more critical review for the nonexpert reader, we begin by reviewing the fundamental principles underlying BOLD theory.
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Affiliation(s)
- Chase R Figley
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
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Functional magnetic resonance imaging of awake behaving macaques. Methods 2010; 50:178-88. [DOI: 10.1016/j.ymeth.2009.08.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Accepted: 08/09/2009] [Indexed: 11/19/2022] Open
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den Dekker AJ, Poot DHJ, Bos R, Sijbers J. Likelihood-based hypothesis tests for brain activation detection from MRI data disturbed by colored noise: a simulation study. IEEE TRANSACTIONS ON MEDICAL IMAGING 2009; 28:287-296. [PMID: 19188115 DOI: 10.1109/tmi.2008.2004427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Functional magnetic resonance imaging (fMRI) data that are corrupted by temporally colored noise are generally preprocessed (i.e., prewhitened or precolored) prior to functional activation detection. In this paper, we propose likelihood-based hypothesis tests that account for colored noise directly within the framework of functional activation detection. Three likelihood-based tests are proposed: the generalized likelihood ratio (GLR) test, the Wald test, and the Rao test. The fMRI time series is modeled as a linear regression model, where one regressor describes the task-related hemodynamic response, one regressor accounts for a constant baseline and one regressor describes potential drift. The temporal correlation structure of the noise is modeled as an autoregressive (AR) model. The order of the AR model is determined from practical null data sets using Akaike's information criterion (with penalty factor 3) as order selection criterion. The tests proposed are based on exact expressions for the likelihood function of the data. Using Monte Carlo simulation experiments, the performance of the proposed tests is evaluated in terms of detection rate and false alarm rate properties and compared to the current general linear model (GLM) test, which estimates the coloring of the noise in a separate step. Results show that theoretical asymptotic distributions of the GLM, GLR, and Wald test statistics cannot be reliably used for computing thresholds for activation detection from finite length time series. Furthermore, it is shown that, for a fixed false alarm rate, the detection rate of the proposed GLR test statistic is slightly, but (statistically) significantly improved compared to that of the common GLM-based tests. Finally, simulations results reveal that all tests considered show seriously inferior performance if the order of the AR model is not chosen sufficiently high to give an adequate description of the correlation structure of the noise, whereas the effects of (slightly) overmodeling are observed to be less harmful.
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Affiliation(s)
- A J den Dekker
- Delft University of Technology, Delft Center for Systems and Control, 2828 CD Delft, The Netherlands.
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Ferris CF, Stolberg T, Kulkarni P, Murugavel M, Blanchard R, Blanchard DC, Febo M, Brevard M, Simon NG. Imaging the neural circuitry and chemical control of aggressive motivation. BMC Neurosci 2008; 9:111. [PMID: 19014547 PMCID: PMC2601047 DOI: 10.1186/1471-2202-9-111] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 11/13/2008] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND With the advent of functional magnetic resonance imaging (fMRI) in awake animals it is possible to resolve patterns of neuronal activity across the entire brain with high spatial and temporal resolution. Synchronized changes in neuronal activity across multiple brain areas can be viewed as functional neuroanatomical circuits coordinating the thoughts, memories and emotions for particular behaviors. To this end, fMRI in conscious rats combined with 3D computational analysis was used to identifying the putative distributed neural circuit involved in aggressive motivation and how this circuit is affected by drugs that block aggressive behavior. RESULTS To trigger aggressive motivation, male rats were presented with their female cage mate plus a novel male intruder in the bore of the magnet during image acquisition. As expected, brain areas previously identified as critical in the organization and expression of aggressive behavior were activated, e.g., lateral hypothalamus, medial basal amygdala. Unexpected was the intense activation of the forebrain cortex and anterior thalamic nuclei. Oral administration of a selective vasopressin V1a receptor antagonist SRX251 or the selective serotonin reuptake inhibitor fluoxetine, drugs that block aggressive behavior, both caused a general suppression of the distributed neural circuit involved in aggressive motivation. However, the effect of SRX251, but not fluoxetine, was specific to aggression as brain activation in response to a novel sexually receptive female was unaffected. CONCLUSION The putative neural circuit of aggressive motivation identified with fMRI includes neural substrates contributing to emotional expression (i.e. cortical and medial amygdala, BNST, lateral hypothalamus), emotional experience (i.e. hippocampus, forebrain cortex, anterior cingulate, retrosplenial cortex) and the anterior thalamic nuclei that bridge the motor and cognitive components of aggressive responding. Drugs that block vasopressin neurotransmission or enhance serotonin activity suppress activity in this putative neural circuit of aggressive motivation, particularly the anterior thalamic nuclei.
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Affiliation(s)
- Craig F Ferris
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
- Department of Psychology, Northeastern University, Boston, Massachusetts 02115-5000, USA
| | - Tara Stolberg
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
| | - Praveen Kulkarni
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
| | - Murali Murugavel
- Dept Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Robert Blanchard
- Department of Psychology, University of Hawaii, Honolulu, Hawaii, USA
| | | | - Marcelo Febo
- Center for Translational NeuroImaging, Northeastern University, Boston, Massachusetts, USA
| | - Mathew Brevard
- Insight Neuroimaging Systems, Worcester, Massachusetts, USA
| | - Neal G Simon
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, USA
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Luan L, Ding F, Ai Y, Andersen A, Hardy P, Forman E, Gerhardt GA, Gash DM, Grondin R, Zhang Z. Pharmacological MRI (phMRI) Monitoring of Treatment in Hemiparkinsonian Rhesus Monkeys. Cell Transplant 2008. [DOI: 10.3727/096368908784423319] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
There is a great need for the development of noninvasive, highly sensitive, and widely available imaging methods that can potentially be used to longitudinally monitor treatment of Parkinson's disease (PD). Here we report the monitoring of GDNF-induced functional changes of the basal ganglia in hemiparkinsonian monkeys via pharmacological MRI measuring the blood oxygenation level-dependent (BOLD) response to a direct dopamine agonist (apomorphine, APO). After testing BOLD responsiveness to APO in their normal state, two additional scans were taken with the same dose of APO stimulation after induced parkinsonism. Then all animals were chronically treated with GDNF for 18 weeks by a programmable pump and catheter system. The catheter was surgically implanted into the right putamen and connected to the pump via flexible polyurethane tubing. phMRI scans were taken at both 6 and 18 weeks while they received 22.5 μg of GDNF per day. In addition, behavioral changes were monitored throughout the entire study. The primary finding of this study was that APO-evoked activations in the DA denervated putamen were attenuated by the chronic intraputamenal infusion of GDNF accompanied by improvements of parkinsonian features, movement speed, and APO-induced rotation compared to data collected before the chronic GDNF treatment. The results suggest that phMRI methods in combination with administration of a selective DA agonist may be useful for monitoring neurorestorative therapies in PD patients in the future.
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Affiliation(s)
- Liming Luan
- Department of Anatomy & Neurobiology, College of Medicine, University of Kentucky, Lexington, KY, USA
- Department of Neurosurgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, PR China
| | - Feng Ding
- Department of Anatomy & Neurobiology, College of Medicine, University of Kentucky, Lexington, KY, USA
- Department of Neurosurgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, PR China
| | - Yi Ai
- Department of Anatomy & Neurobiology, College of Medicine, University of Kentucky, Lexington, KY, USA
- Morris K. Udall Parkinson's Disease Research Center of Excellence, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Anders Andersen
- Morris K. Udall Parkinson's Disease Research Center of Excellence, College of Medicine, University of Kentucky, Lexington, KY, USA
- Magnetic Resonance Imaging and Spectroscopy Center, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Peter Hardy
- Magnetic Resonance Imaging and Spectroscopy Center, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Eric Forman
- Department of Anatomy & Neurobiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Greg A. Gerhardt
- Department of Anatomy & Neurobiology, College of Medicine, University of Kentucky, Lexington, KY, USA
- Morris K. Udall Parkinson's Disease Research Center of Excellence, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Don M. Gash
- Department of Anatomy & Neurobiology, College of Medicine, University of Kentucky, Lexington, KY, USA
- Morris K. Udall Parkinson's Disease Research Center of Excellence, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Richard Grondin
- Department of Neurosurgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, PR China
- Morris K. Udall Parkinson's Disease Research Center of Excellence, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Zhiming Zhang
- Department of Anatomy & Neurobiology, College of Medicine, University of Kentucky, Lexington, KY, USA
- Morris K. Udall Parkinson's Disease Research Center of Excellence, College of Medicine, University of Kentucky, Lexington, KY, USA
- Magnetic Resonance Imaging and Spectroscopy Center, College of Medicine, University of Kentucky, Lexington, KY, USA
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Chin CL, Pauly JR, Surber BW, Skoubis PD, McGaraughty S, Hradil VP, Luo Y, Cox BF, Fox GB. Pharmacological MRI in awake rats predicts selective binding of α4β2 nicotinic receptors. Synapse 2008; 62:159-68. [DOI: 10.1002/syn.20474] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Chin CL, Tovcimak AE, Hradil VP, Seifert TR, Hollingsworth PR, Chandran P, Zhu CZ, Gauvin D, Pai M, Wetter J, Hsieh GC, Honore P, Frost JM, Dart MJ, Meyer MD, Yao BB, Cox BF, Fox GB. Differential effects of cannabinoid receptor agonists on regional brain activity using pharmacological MRI. Br J Pharmacol 2007; 153:367-79. [PMID: 17965748 DOI: 10.1038/sj.bjp.0707506] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Activation of cannabinoid CB1 and/or CB2 receptors mediates analgesic effects across a broad spectrum of preclinical pain models. Selective activation of CB2 receptors may produce analgesia without the undesirable psychotropic side effects associated with modulation of CB1 receptors. To address selectivity in vivo, we describe non-invasive, non-ionizing, functional data that distinguish CB1 from CB2 receptor neural activity using pharmacological MRI (phMRI) in awake rats. EXPERIMENTAL APPROACH Using a high field (7 T) MRI scanner, we examined and quantified the effects of non-selective CB1/CB2 (A-834735) and selective CB2 (AM1241) agonists on neural activity in awake rats. Pharmacological specificity was determined using selective CB1 (rimonabant) or CB2 (AM630) antagonists. Behavioural studies, plasma and brain exposures were used as benchmarks for activity in vivo. KEY RESULTS The non-selective CB1/CB2 agonist produced a dose-related, region-specific activation of brain structures that agrees well with published autoradiographic CB1 receptor density binding maps. Pretreatment with a CB1 antagonist but not with a CB2 antagonist, abolished these activation patterns, suggesting an effect mediated by CB1 receptors alone. In contrast, no significant changes in brain activity were found with relevant doses of the CB2 selective agonist. CONCLUSION AND IMPLICATIONS These results provide the first clear evidence for quantifying in vivo functional selectivity between CB1 and CB2 receptors using phMRI. Further, as the presence of CB2 receptors in the brain remains controversial, our data suggest that if CB2 receptors are expressed, they are not functional under normal physiological conditions.
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Affiliation(s)
- C-L Chin
- Advanced Technology, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064, USA
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Luo F, Li Z, Treistman SN, Kim YR, King JA, Fox GB, Ferris CF. Confounding effects of volatile anesthesia on CBV assessment in rodent forebrain following ethanol challenge. J Magn Reson Imaging 2007; 26:557-63. [PMID: 17729349 DOI: 10.1002/jmri.21083] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To compare and contrast the pattern and characteristics of the cerebral blood volume (CBV) response to ethanol (EtOH) in rats under awake and anesthetized conditions. MATERIALS AND METHODS Acute EtOH (0.75 g/kg) challenge-induced CBV changes were measured using a contrast-enhanced functional MRI CBV method in 15 male Sprague Dawley rats under three experimental conditions: 1.0% to 1.2% isoflurane (N = 5); 0.8% halothane (N = 5); and awake with no anesthetic (N = 5). Physiological parameters were collected from bench settings in nine rats from the above different conditions. Four parameters: 1) area under the curve (AUC%); 2) the maximum signal change (Max%); 3) EtOH absorption rate (alpha(2)); and 4) EtOH elimination rate (alpha(1)) were employed to compare EtOH-induced MRI signals between the awake and anesthetized groups. RESULTS Both awake and anesthetized animals responded with an increase in CBV to EtOH challenge. However, the presence of anesthesia promoted a significant preferential flow to subcortical areas not seen in the awake condition. CONCLUSION Unclear mechanisms of anesthesia add a layer of uncertainty to the already complex interpretation of EtOH's influence on neuronal activity, cellular metabolism, and hemodynamic coupling.
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Affiliation(s)
- Feng Luo
- Experimental Imaging Abbott Laboratories, Abbott Park, Illinois 60064, USA.
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Chin CL, Fox GB, Hradil VP, Osinski MA, McGaraughty SP, Skoubis PD, Cox BF, Luo Y. Pharmacological MRI in awake rats reveals neural activity in area postrema and nucleus tractus solitarius: relevance as a potential biomarker for detecting drug-induced emesis. Neuroimage 2006; 33:1152-60. [PMID: 17023182 DOI: 10.1016/j.neuroimage.2006.06.059] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2006] [Revised: 06/15/2006] [Accepted: 06/30/2006] [Indexed: 11/15/2022] Open
Abstract
Drug-induced vomiting (emesis) is a major concern in patient care and a significant hurdle in the development of novel therapeutics. With respect to the latter, rodents, such as the rat and mouse, are typically used in efficacy and safety studies; however, drug-induced emesis cannot be readily observed in these species due to the lack of an emetic reflex. It is known that emesis can be triggered by neural activity in brain regions including area postrema (AP) and nucleus tractus solitarius (NTS). In this study, using pharmacological magnetic resonance imaging (phMRI) and a blood-pool contrast agent, we imaged the hemodynamic consequences of brain activity in awake rats initiated by the administration of compounds (apomorphine 0.1, 0.3 micromol/kg i.v. and ABT-594 0.03, 0.1, 0.3 micromol/kg i.v.) that elicit emesis in other species. Regional drug-induced relative cerebral blood volume (rCBV) changes and percent activated area within the AP and NTS were calculated, in which a dose-dependent relationship was evident for both apomorphine and ABT-594. Additionally, to correlate with behavioral readouts, it was found that the activation of AP and NTS was observed at plasma concentrations consistent with those that induced emesis in ferrets for both drugs. Our data thus suggest that phMRI in awake rats may be a useful tool for predicting emetic liability of CNS-acting drugs and may provide insights into depicting the underlying emetic neural pathways in vivo.
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Affiliation(s)
- Chih-Liang Chin
- Global Pharmaceutical Research and Development, Abbott Laboratories, R46R Bldg. AP9-1, 100 Abbott Park Road, Abbott Park, IL 60064-6119, USA
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Zhang Z, Andersen AH, Ai Y, Loveland A, Hardy PA, Gerhardt GA, Gash DM. Assessing nigrostriatal dysfunctions by pharmacological MRI in parkinsonian rhesus macaques. Neuroimage 2006; 33:636-43. [PMID: 16949305 DOI: 10.1016/j.neuroimage.2006.07.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 06/07/2006] [Accepted: 07/07/2006] [Indexed: 11/23/2022] Open
Abstract
New imaging techniques are needed to longitudinally monitor the development, progression and treatment of Parkinson's disease. The present study was designed to test whether the blood oxygenation level-dependent (BOLD) response to dopaminergic stimulation as measured by pharmacological MRI (phMRI) correlated to specific histological and behavioral features of the parkinsonian state. Nine adult rhesus monkeys were rendered hemiparkinsonian by intracarotid administration of MPTP. Three months after MPTP treatment, the trained, MRI-adapted awake animals were scanned with a phMRI technique while being administered a presynaptic (D-amphetamine) or postsynaptic (apomorphine) dopamine stimulating agents. The primary findings were (1) the putamen and substantia nigra (SN) but not the caudate nucleus displayed significant BOLD responses to these dopaminergic drugs; (2) a significant relationship was found between amphetamine-evoked activation and the number of surviving dopamine neurons in the SN, which was also correlated with bradykinesia; and (3) inverse relationships were seen in response to apomorphine and amphetamine stimulation between the MPTP-lesioned and unlesioned putamen and SN. The results suggest that phMRI may prove useful for longitudinally monitoring the progression and treatment of PD.
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Affiliation(s)
- Zhiming Zhang
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY 40536, USA.
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35
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Schwarz AJ, Danckaert A, Reese T, Gozzi A, Paxinos G, Watson C, Merlo-Pich EV, Bifone A. A stereotaxic MRI template set for the rat brain with tissue class distribution maps and co-registered anatomical atlas: Application to pharmacological MRI. Neuroimage 2006; 32:538-50. [PMID: 16784876 DOI: 10.1016/j.neuroimage.2006.04.214] [Citation(s) in RCA: 257] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 02/22/2006] [Accepted: 04/05/2006] [Indexed: 11/17/2022] Open
Abstract
We describe a stereotaxic rat brain MRI template set with a co-registered digital anatomical atlas and illustrate its application to the analysis of a pharmacological MRI (phMRI) study of apomorphine. The template set includes anatomical images and tissue class probability maps for brain parenchyma and cerebrospinal fluid (CSF). These facilitate the use of standard fMRI software for spatial normalisation and tissue segmentation of rat brain data. A volumetric reconstruction of the Paxinos and Watson rat brain atlas is also co-localised with the template, enabling the atlas structure and stereotaxic coordinates corresponding to a feature within a statistical map to be interactively reported, facilitating the localisation of functional effects. Moreover, voxels falling within selected brain structures can be combined to define anatomically based 3D volumes of interest (VOIs), free of operator bias. As many atlas structures are small relative to the typical resolution of phMRI studies, a mechanism for defining composite structures as agglomerations of individual atlas structures is also described. This provides a simple and robust means of interrogating structures that are otherwise difficult to delineate and an objective framework for comparing and classifying compounds based on an anatomical profile of their activity. These developments allow a closer alignment of pre-clinical and clinical analysis techniques.
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Affiliation(s)
- Adam J Schwarz
- Department of Neuroimaging, Psychiatry Centre of Excellence in Drug Discovery, GlaxoSmithKline Medicines Research Centre, Via Fleming 4, 37135 Verona, Italy.
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Joseph JE, Powell DK, Andersen AH, Bhatt RS, Dunlap MK, Foldes ST, Forman E, Hardy PA, Steinmetz NA, Zhang Z. fMRI in alert, behaving monkeys: an adaptation of the human infant familiarization novelty preference procedure. J Neurosci Methods 2006; 157:10-24. [PMID: 16675025 DOI: 10.1016/j.jneumeth.2006.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 03/21/2006] [Accepted: 03/24/2006] [Indexed: 11/30/2022]
Abstract
Functional magnetic resonance imaging (fMRI) is increasingly used in non-human primate research. In the present study, we adapt the familiarization-novelty preference (FNP) procedure used in human infant research to examine visual behavior in alert, unanaesthetized rhesus monkeys that were acclimated to the fMRI environment, but did not undergo behavioral training. In keeping with the typical FNP paradigm, we recorded eye movements (looking time and number of fixations) while monkeys viewed a series of four identical pictures (familiarization phase) followed by two different pictures (novelty phase). Number of fixations and looking time both increased during the novelty phase, thereby demonstrating visual discrimination of the new from the old picture. Importantly, discrimination did not occur on catch trials in which six identical pictures were presented. Moreover, brain activation in the amygdala was more strongly associated with the novelty phase than with the familiarization phase. In addition, magnitude of brain activation in the amygdala was correlated with the behavioral effect of visual discrimination. These findings demonstrate the feasibility of using eye movements as an index of visual discrimination in untrained monkeys during fMRI scanning. This methodological approach helps to extend the repertoire of research tools for fMRI in non-human primates.
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Affiliation(s)
- Jane E Joseph
- Department of Anatomy and Neurobiology, University of Kentucky, Lexington, KY, USA.
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Ferris CF, Febo M, Luo F, Schmidt K, Brevard M, Harder JA, Kulkarni P, Messenger T, King JA. Functional magnetic resonance imaging in conscious animals: a new tool in behavioural neuroscience research. J Neuroendocrinol 2006; 18:307-18. [PMID: 16629829 PMCID: PMC1448699 DOI: 10.1111/j.1365-2826.2006.01424.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- C F Ferris
- Center for Comparative Neuroimaging, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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Baslow MH, Dyakin VV, Nowak KL, Hungund BL, Guilfoyle DN. 2-PMPA, a NAAG peptidase inhibitor, attenuates magnetic resonance BOLD signals in brain of anesthetized mice: evidence of a link between neuron NAAG release and hyperemia. J Mol Neurosci 2005; 26:1-15. [PMID: 15968081 DOI: 10.1385/jmn:26:1:001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2004] [Accepted: 11/15/2004] [Indexed: 11/11/2022]
Abstract
N-acetylaspartylglutamate (NAAG), a dipeptide derivative of N-acetylaspartate (NAA) and glutamate (Glu), is present in neurons. Upon neurostimulation, NAAG is exported to astrocytes where it activates a specific metabotropic Glu surface receptor (mGluR3), and is then hydrolyzed by an astrocyte-specific enzyme, NAAG peptidase, liberating Glu, which can then be taken up by the astrocyte. NAAG is a selective mGluR3 agonist, one of several mGluRs that, when activated, triggers Ca2+ waves that spread to astrocytic endfeet in contact with the vascular system, where a secondary release of vasoactive agents induces a focal hyperemic response providing increased oxygen and nutrient availability to the stimulated neurons. Changes in blood oxygen levels can be assessed in vivo using a blood oxygenation level-dependent (BOLD) magnetic resonance imaging technique that reflects a paramagnetic effect of deoxyhemoglobin. In this study we used the competitive NAAG peptidase inhibitor 2-(phosphonomethyl) pentanedioic acid (2-PMPA) as a probe to interrupt the NAAG-mGluR3- Glu-astrocyte Ca2+ activation sequence. Using this probe, we investigated the relationship between release of the endogenous neuropeptide NAAG and brain blood oxygenation levels, as measured by changes in BOLD signals. In an anesthetized mouse, using an overtly nontoxic dose of 2-PMPA of 250 mg/kg i.p., there was an initial global BOLD signal increase of about 3% above control, lasting about 4 min, followed by a decrease from control of about 4%, sustained over a 32.5-min period of the drug test procedure. Similar changes, but of reduced magnitude and duration, were observed at a dose of 167 mg/kg. The 2-PMPA-induced decreases in BOLD signals appear to indicate that blood deoxyhemoglobin is elevated when endogenous NAAG cannot be hydrolyzed, thus linking the efflux of NAAG from neurons and its hydrolysis by astrocytes to hyperemic oxygenation responses in brain.
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Affiliation(s)
- Morris H Baslow
- Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
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King JA, Garelick TS, Brevard ME, Chen W, Messenger TL, Duong TQ, Ferris CF. Procedure for minimizing stress for fMRI studies in conscious rats. J Neurosci Methods 2005; 148:154-60. [PMID: 15964078 PMCID: PMC2962951 DOI: 10.1016/j.jneumeth.2005.04.011] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2004] [Revised: 04/22/2005] [Accepted: 04/25/2005] [Indexed: 11/22/2022]
Abstract
Functional magnetic resonance imaging (fMRI) in conscious animals is evolving as a critical tool for neuroscientists. The present study explored the effectiveness of an acclimation procedure in minimizing the stress experienced by the animal as assessed by alterations in physiological parameters including heart rate, respiratory rate, and serum corticosterone levels. Results confirm that as the stress of the protocol is minimized, there is a significant decrease in head movements and enhancement in data quality. The feasibility of improving the quality of fMRI data acquired in alert rats by utilizing a relatively simple technique is presented.
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Affiliation(s)
- Jean A King
- Center for Comparative Neuroimaging, Department of Psychiatry, University of Massachusetts Medical Center, Worcester, MA 01655, USA.
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Gozzi A, Schwarz AJ, Reese T, Crestan V, Bertani S, Turrini G, Corsi M, Bifone A. Functional magnetic resonance mapping of intracerebroventricular infusion of a neuroactive peptide in the anaesthetised rat. J Neurosci Methods 2005; 142:115-24. [PMID: 15652624 DOI: 10.1016/j.jneumeth.2004.08.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Revised: 07/31/2004] [Accepted: 08/11/2004] [Indexed: 10/26/2022]
Abstract
Pharmacological magnetic resonance imaging (phMRI) methods map the cerebral haemodynamic response to challenge with psychotropic agents as a surrogate for drug-induced changes in brain activity. However, many neuroactive compounds present low blood-brain barrier penetration and thus systemic administration may result in insufficient brain concentration. Intracerebroventricular (ICV) administration has been long used as an effective way of bypassing the blood-brain barrier in studies with non-brain-penetrant compounds, such as neuropeptides. In order to extend the range of pharmacological substances accessible to phMRI, we have developed methods to map relative cerebral blood volume (rCBV) changes induced by in situ ICV administration of neuroactive agents in the anaesthetised rat. We have applied this method to study for the first time the phMRI response to central administration of a neuropeptide, the metabolically stable and potent NK1 receptor agonist GR-73632. ICV administration of 4.2 pmol of GR-73632 produced a rapid onset and sustained rCBV increase in several brain structures, such as the amygdala, the caudate putamen and the cortex. These results demonstrate the feasibility of phMRI as a tool to study the functional correlates of brain activity induced by central administration of neuroactive agents.
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Affiliation(s)
- Alessandro Gozzi
- Department of Neuroimaging, Psychiatry Centre of Excellence in Drug Discovery, GlaxoSmithKline Medicines Research Centre, Via Fleming 4, 37135 Verona, Italy.
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41
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Abstract
Recently, there has been growing interest in using functional magnetic resonance imaging (fMRI) for the evaluation of psychopharmacological drugs. fMRI studies in healthy human volunteers and psychiatric patients focus on cerebral activity following acute drug administration (single challenge) and on adaptive effects on neural networks due to long-term medication. In our own fMRI studies, the effects of olanzapine or amisulpride in never treated or medication-free schizophrenic patients using robust motor, visual, and acoustic tasks was longitudinally examined. In agreement with previous reports in the literature it could be shown that, in contrast to traditional neuroleptics, atypical drugs do not decrease the activation of the sensorimotor cortex but rather normalize the reduced frontoparietal activation as well as the neuropsychological test results. This encourages the assumption that atypical antipsychotics seem to support the recovery or normalization of frontoparietal brain dysfunction in schizophrenia. However, with these new opportunities additional methodological considerations and limitations emerge.
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Affiliation(s)
- D F Braus
- NeuroImage Nord, Psychiatrie sowie Zentrum für Psychosoziale Medizin, Universitätsklinikum Hamburg-Eppendorf.
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42
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Ireland MD, Lowe AS, Reavill C, James MF, Leslie RA, Williams SCR. Mapping the effects of the selective dopamine D2/D3 receptor agonist quinelorane using pharmacological magnetic resonance imaging. Neuroscience 2005; 133:315-26. [PMID: 15893653 DOI: 10.1016/j.neuroscience.2005.02.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Revised: 01/18/2005] [Accepted: 02/03/2005] [Indexed: 11/18/2022]
Abstract
Dopamine agonists with a high affinity for D2 and D3 receptors have a biphasic effect on rodent locomotion, inducing hypolocomotion at low doses and hyperlocomotion at higher doses. Controversy surrounds the role of the D3 receptor in mediating the hypolocomotor response to low agonist doses. This study examines patterns of neuronal activation induced by varying doses of the D2/D3 receptor agonist quinelorane using blood oxygen level dependent (BOLD) pharmacological magnetic resonance imaging (phMRI), and compares them with corresponding behavioural responses. Quinelorane (3 microg/kg) induced hypolocomotion in rats naive to the testing environment, and in phMRI experiments increased neuronal activity within the anterior olfactory nuclei, nucleus accumbens and islets of Calleja, regions containing a high density of D3 receptors. A 30 microg/kg dose of quinelorane resulted in biphasic locomotor effects, with initial hypolocomotion followed by sustained hyperlocomotion. phMRI indicated that this higher dose increased cerebral activity within limbic and olfactory regions, as did the lower drug dose, but induced additional activation in the caudate-putamen and globus pallidus, areas dense in D2 receptors but containing few D3 receptors. The more restricted pattern of activation at low agonist doses and close temporal relationship between behavioural and BOLD signal responses to quinelorane suggest that those nuclei most dense in D3 receptors play a key role in mediating the hypolocomotor effects of quinelorane. However, the presence of D3 receptors in activated brain regions may be coincidental, and further studies are required to show definitively which class of receptors mediates agonist-induced hypolocomotion. In contrast, the activation of D2 receptors within the striatum appears necessary for quinelorane-induced hyperlocomotion.
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Affiliation(s)
- M D Ireland
- Neuroimaging Research Group, Institute of Psychiatry, Denmark Hill, London SE5 8AF, UK.
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43
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Tenney JR, Marshall PC, King JA, Ferris CF. fMRI of generalized absence status epilepticus in conscious marmoset monkeys reveals corticothalamic activation. Epilepsia 2004; 45:1240-7. [PMID: 15461678 DOI: 10.1111/j.0013-9580.2004.21504.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE A nonhuman primate model of generalized absence status epilepticus was developed for use in functional magnetic resonance imaging (fMRI) experiments to elucidate the brain mechanisms underlying this disorder. METHODS Adult male marmoset monkeys (Callithrix jacchus) were treated with gamma-butyrolactone (GBL) to induce prolonged absence seizures, and the resulting spike-wave discharges (SWDs) were analyzed to determine the similarity to the 3-Hz SWDs that characterize the disorder. In addition, blood-oxygenation-level-dependent (BOLD) fMRI was measured at 4.7 Tesla after absence seizure induction with GBL. RESULTS Electroencephalographic recordings during imaging showed 3-Hz SWDs typical of human absence seizures. This synchronized EEG pattern started within 15 to 20 min of drug administration and persisted for >60 min. In addition, pretreatment with the antiepileptic drug, ethosuximide (ESM), blocked the behavioral and EEG changes caused by GBL. Changes in BOLD signal intensity in the thalamus and sensorimotor cortex correlated with the onset of 3-Hz SWDs. The change in BOLD signal intensity was bilateral but heterogeneous, affecting some brain areas more than others. No significant negative BOLD changes were seen. CONCLUSIONS The BOLD fMRI data obtained in this marmoset monkey model of absence status epilepticus shows activation within the thalamus and cortex.
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Affiliation(s)
- Jeffrey R Tenney
- Center for Comparative Neuroimaging, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
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44
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Rilling JK, Sanfey AG, Aronson JA, Nystrom LE, Cohen JD. Opposing BOLD responses to reciprocated and unreciprocated altruism in putative reward pathways. Neuroreport 2004; 15:2539-43. [PMID: 15538191 DOI: 10.1097/00001756-200411150-00022] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Mesencephalic dopamine neurons are believed to facilitate reward-dependent learning by computing errors in reward predictions. We used fMRI to test whether this system was activated as expected in response to errors in predictions about whether a social partner would reciprocate an act of altruism. Nineteen subjects received fMRI scans as they played a series of single-shot Prisoner's Dilemma games with partners who were outside the scanner. In both ventromedial prefrontal cortex and ventral striatum, reciprocated and unreciprocated cooperation were associated with positive and negative BOLD responses, respectively. Our results are consistent with the hypothesis that mesencephalic dopamine projection sites carry information about errors in reward prediction that allow us to learn who can and cannot be trusted to reciprocate favors.
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Affiliation(s)
- James K Rilling
- Center for the Study of Brain, Mind and Behavior, Princeton University, Princeton, NJ 08544, USA.
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45
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Gonul AS, Kula M, Bilgin AG, Tutus A, Oguz A. The regional cerebral blood flow changes in major depressive disorder with and without psychotic features. Prog Neuropsychopharmacol Biol Psychiatry 2004; 28:1015-21. [PMID: 15380862 DOI: 10.1016/j.pnpbp.2004.05.036] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/10/2004] [Indexed: 11/16/2022]
Abstract
Depressive patients with psychotic features demonstrate distinct biological abnormalities in the hypothalamic-pituitary-adrenal axis (HPA), dopaminergic activity, electroencephalogram sleep profiles and measures of serotonergic function when compared to nonpsychotic depressive patients. However, very few functional neuroimaging studies were specifically designed for studying the effects of psychotic features on neuroimaging findings in depressed patients. The objective of the present study was to compare brain Single Photon Emission Tomography (SPECT) images in a group of unmedicated depressive patients with and without psychotic features. Twenty-eight patients who fully met DSM-IV criteria for major depressive disorder (MDD, 12 had psychotic features) were included in the study. They were compared with 16 control subjects matched for age, gender and education. Both psychotic and nonpsychotic depressed patients showed significantly lower regional cerebral blood flow (rCBF) values in the left and right superior frontal cortex, and left anterior cingulate cortex compared to those of controls. In comparison with depressive patients without psychotic features (DwoPF), depressive patients with psychotic features (DwPF) showed significantly lower rCBF perfusion ratios in left parietal cortex, left cerebellum but had higher rCBF perfusion ratio in the left inferior frontal cortex and caudate nucleus. The present study showed that DwPF have a different rCBF pattern compared to patients without psychotic features. Abnormalities involving inferior frontal cortex, striatum and cerebellum may play an important role in the generation of psychotic symptoms in depression.
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Affiliation(s)
- Ali Saffet Gonul
- Department of Psychiatry, Ege University, School of Medicine, 35100-Izmir, Turkey.
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46
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Andersen AH, Rayens WS. Structure-seeking multilinear methods for the analysis of fMRI data. Neuroimage 2004; 22:728-39. [PMID: 15193601 DOI: 10.1016/j.neuroimage.2004.02.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2003] [Revised: 02/13/2004] [Accepted: 02/19/2004] [Indexed: 10/26/2022] Open
Abstract
In comprehensive fMRI studies of brain function, the data structures often contain higher-order ways such as trial, task condition, subject, and group in addition to the intrinsic dimensions of time and space. While multivariate bilinear methods such as principal component analysis (PCA) have been used successfully for extracting information about spatial and temporal features in data from a single fMRI run, the need to unfold higher-order data sets into bilinear arrays has led to decompositions that are nonunique and to the loss of multiway linkages and interactions present in the data. These additional dimensions or ways can be retained in multilinear models to produce structures that are unique and which admit interpretations that are neurophysiologically meaningful. Multiway analysis of fMRI data from multiple runs of a bilateral finger-tapping paradigm was performed using the parallel factor (PARAFAC) model. A trilinear model was fitted to a data cube of dimensions voxels by time by run. Similarly, a quadrilinear model was fitted to a higher-way structure of dimensions voxels by time by trial by run. The spatial and temporal response components were extracted and validated by comparison to results from traditional SVD/PCA analyses based on scenarios of unfolding into lower-order bilinear structures.
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Affiliation(s)
- Anders H Andersen
- Department of Anatomy and Neurobiology, Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, KY 40536-0098, USA.
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47
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Abstract
PURPOSE EEG-triggered functional magnetic resonance imaging (fMRI) was used to identify areas of brain activation during spontaneous spike-and-wave discharges (SWDs) in an epileptic rat strain under awake conditions. METHODS Spontaneous absence seizures from 10 WAG/Rij rats were imaged by using T2*-weighted echo planar imaging at 4.7 Tesla. fMRI of the blood-oxygenation-level-dependent (BOLD) signal was triggered based on EEG recordings during imaging. Images obtained during spontaneous SWDs were compared with baseline images. RESULTS Significant positive BOLD signal changes were apparent in several areas of the cortex and several important nuclei of the thalamus. In addition, no negative BOLD signal was found in any brain area. CONCLUSIONS We have shown that EEG-triggered BOLD fMRI can be used to detect cortical and thalamic activation related to the spontaneous SWDs that characterize absence seizures in awake WAG/Rij rats. These results draw an anatomic correlation between areas in which increased BOLD signal is found and those in which SWDs have been recorded. In addition, no negative BOLD signal was found to be associated with these spontaneous SWDs. We also demonstrated the technical feasibility of using EEG-triggered fMRI in a genetic rat model of absence seizure.
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Affiliation(s)
- Jeffrey R Tenney
- Center for Comparative Neuroimaging, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
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48
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Dubowitz DJ. Direct Comparison of Visual Cortex Activation in Human and Nonhuman Primates Using Functional Magnetic Resonance Imaging. Methods Enzymol 2004; 385:102-34. [PMID: 15130736 DOI: 10.1016/s0076-6879(04)85007-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- David J Dubowitz
- Department of Radiology, Center for Functional Magnetic Resonance Imaging, University of California-San Diego, La Jolla, CA 92093-0677, USA
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49
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Tenney JR, Duong TQ, King JA, Ludwig R, Ferris CF. Corticothalamic modulation during absence seizures in rats: a functional MRI assessment. Epilepsia 2003; 44:1133-40. [PMID: 12919383 PMCID: PMC2962948 DOI: 10.1046/j.1528-1157.2003.61002.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Functional magnetic resonance imaging (fMRI) was used to identify areas of brain activation during absence seizures in an awake animal model. METHODS Blood-oxygenation-level-dependent (BOLD) fMRI in the brain was measured by using T2*-weighted echo planar imaging at 4.7 Tesla. BOLD imaging was performed before, during, and after absence seizure induction by using gamma-butyrolactone (GBL; 200 mg/kg, intraperitoneal). RESULTS The corticothalamic circuitry, critical for spike-wave discharge (SWD) formation in absence seizure, showed robust BOLD signal changes after GBL administration, consistent with EEG recordings in the same animals. Predominantly positive BOLD changes occurred in the thalamus. Sensory and parietal cortices showed mixed positive and negative BOLD changes, whereas temporal and motor cortices showed only negative BOLD changes. CONCLUSIONS With the BOLD fMRI technique, we demonstrated signal changes in brain areas that have been shown, with electrophysiology experiments, to be important for generating and maintaining the SWDs that characterize absence seizures. These results corroborate previous findings from lesion and electrophysiological experiments and show the technical feasibility of noninvasively imaging absence seizures in fully conscious rodents.
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Affiliation(s)
- Jeffrey R Tenney
- Center for Comparative Neuroimaging, Department of Psychiatry, University of Massachusetts Medical School Worcester, Massachusetts 01655, USA.
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50
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Sicard K, Shen Q, Brevard ME, Sullivan R, Ferris CF, King JA, Duong TQ. Regional cerebral blood flow and BOLD responses in conscious and anesthetized rats under basal and hypercapnic conditions: implications for functional MRI studies. J Cereb Blood Flow Metab 2003; 23:472-81. [PMID: 12679724 PMCID: PMC2989608 DOI: 10.1097/01.wcb.0000054755.93668.20] [Citation(s) in RCA: 174] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Anesthetics, widely used in magnetic resonance imaging (MRI) studies to avoid movement artifacts, could have profound effects on cerebral blood flow (CBF) and cerebrovascular coupling relative to the awake condition. Quantitative CBF and tissue oxygenation (blood oxygen level-dependent [BOLD]) were measured, using the continuous arterial-spin-labeling technique with echo-planar-imaging acquisition, in awake and anesthetized (2% isoflurane) rats under basal and hypercapnic conditions. All basal blood gases were within physiologic ranges. Blood pressure, respiration, and heart rates were within physiologic ranges in the awake condition but were depressed under anesthesia (P < 0.05). Regional CBF was heterogeneous with whole-brain CBF values of 0.86 +/- 0.25 and 1.27 +/- 0.29 mL. g-1. min-1 under awake and anesthetized conditions, respectively. Surprisingly, CBF was markedly higher (20% to 70% across different brain conditions) under isoflurane-anesthetized condition compared with the awake state (P < 0.01). Hypercapnia decreased pH, and increased Pco(2) and Po(2). During 5% CO(2) challenge, under awake and anesthetized conditions, respectively, CBF increased 51 +/- 11% and 25 +/- 4%, and BOLD increased 7.3 +/- 0.7% and 5.4 +/- 0.4%. During 10% CO(2) challenge, CBF increased 158 +/- 28% and 47 +/- 11%, and BOLD increased 12.5 +/- 0.9% and 7.2 +/- 0.5%. Since CBF and BOLD responses were substantially higher under awake condition whereas blood gases were not statistically different, it was concluded that cerebrovascular reactivity was suppressed by anesthetics. This study also shows that perfusion and perfusion-based functional MRI can be performed in awake animals.
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Affiliation(s)
- Kenneth Sicard
- Center for Comparative NeuroImaging, Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts, U.S.A
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