scholarly journals Physiological Basis and Image Processing in Functional Magnetic Resonance Imaging: Neuronal and Motor Activity in Brain

10.5772/39036 ◽  
2012 ◽  
Author(s):  
Rakesh Sharma ◽  
Avdhesh Sharm
Keyword(s):  
Magnetic Resonance Imaging ◽  
Image Processing ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Motor Activity ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Physiological Basis

scholarly journals Cerebral Functional Magnetic Resonance Imaging Activation Modulated by a Single Dose of the Monoamine Neurotransmission Enhancers Fluoxetine and Fenozolone during Hand Sensorimotor Tasks

1999 ◽  
Vol 19 (12) ◽  
pp. 1365-1375 ◽  
Author(s):  
Isabelle Loubinoux ◽  
Keder Boulanouar ◽  
Jean-Philippe Ranjeva ◽  
Christophe Carel ◽  
Isabelle Berry ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Single Dose ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Motor Activity ◽  
Healthy Subjects ◽  
Drug Effects ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging

Fluoxetine inhibits the reuptake of serotonin, and dextroamphetamine enhances presynaptic release of monoamines. Although the excitatory effect of both noradrenaline and dopamine on motor behavior generally is accepted, the role of serotonin on motor output is under debate. In the current investigation, the authors evidenced a putative role of monoamines and, more specifically, of serotonin in the regulation of cerebral motor activity in healthy subjects. The effects on cerebral motor activity of a single dose of fluoxetine (20 mg), an inhibitor of serotonin reuptake, and fenozolone (20 mg/50 kg), an amphetamine-like drug, were assessed by functional magnetic resonance imaging. Subjects performed sensorimotor tasks with the right hand. Functional magnetic resonance imaging studies were performed in two sessions on two different days. The first session, with two scan experiments separated by 5 hours without any drug administration, served as time-effect control. A second, similar session but with drug administration after the first scan assessed drug effects. A large increase in evoked signal intensity occurred in the ipsilateral cerebellum, and a parallel, large reduction occurred in primary and secondary motor cortices (P < 10–3). These results are consistent with the known effects of habituation. Both drugs elicited comparable effects, that is, a more focused activation in the contralateral sensorimotor area, a greater involvement of posterior supplementary motor area, and a widespread decrease of bilateral cerebellar activation (P < 10–3). The authors demonstrated for the first time that cerebral motor activity can be modulated by a single dose of fluoxetine or fenozolone in healthy subjects. Drug effects demonstrated a direct or indirect involvement of monoamines and serotonin in the facilitation of cerebral motor activity.

Spatial and temporal resolution of functional magnetic resonance imaging

1998 ◽  
Vol 76 (2-3) ◽  
pp. 560-571 ◽  
Author(s):  
Ravi S Menon ◽  
Joseph S Gati ◽  
Bradley G Goodyear ◽  
David C Luknowsky ◽  
Christopher G Thomas
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Temporal Resolution ◽  
Blood Oxygenation ◽  
Mapping Technique ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Physiological Basis ◽  
Invaluable Tool

Functional magnetic resonance imaging has become an invaluable tool for cognitive neuroscience, despite the fact that many of the physiological mechanisms giving rise to the effect are not well understood. We review the known biochemical and physiological basis of the technique and discuss how, within the noted limits, one might fully exploit the spatial and temporal resolution that is intrinsic to the very high magnetic fields that we use for human studies. This noninvasive brain mapping technique relies on the changes in blood oxygenation, blood volume, and blood flow, and we discuss some of the issues influencing the effects of these hemodynamic parameters on image intensity.Key words: fMRI, magnetic resonance imaging, BOLD, neuroimaging, functional imaging.

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