scholarly journals Insights from Neuroenergetics into the Interpretation of Functional Neuroimaging: An Alternative Empirical Model for Studying the Brain's Support of Behavior

2014 ◽  
Vol 34 (11) ◽  
pp. 1721-1735 ◽  
Author(s):  
Robert G Shulman ◽  
Fahmeed Hyder ◽  
Douglas L Rothman
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Neuronal Activity ◽  
Mental Causation ◽  
Functional Neuroimaging ◽  
Resonance Spectroscopy ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Baseline Activity

Functional neuroimaging measures quantitative changes in neurophysiological parameters coupled to neuronal activity during observable behavior. These results have usually been interpreted by assuming that mental causation of behavior arises from the simultaneous actions of distinct psychological mechanisms or modules. However, reproducible localization of these modules in the brain using functional magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging has been elusive other than for sensory systems. In this paper, we show that neuroenergetic studies using PET, calibrated functional magnetic resonance imaging (fMRI), 13C magnetic resonance spectroscopy, and electrical recordings do not support the standard approach, which identifies the location of mental modules from changes in brain activity. Of importance in reaching this conclusion is that changes in neuronal activities underlying the fMRI signal are many times smaller than the high ubiquitous, baseline neuronal activity, or energy in resting, awake humans. Furthermore, the incremental signal depends on the baseline activity contradicting theoretical assumptions about linearity and insertion of mental modules. To avoid these problems, while making use of these valuable results, we propose that neuroimaging should be used to identify observable brain activities that are necessary for a person's observable behavior rather than being used to seek hypothesized mental processes.

scholarly journals Functional Magnetic Resonance Imaging: From Acquisition to Application

2016 ◽  
Vol 20 (1) ◽  
pp. 2
Author(s):  
Gail Yarmish ◽  
Michael L. Lipton
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Neuronal Activity ◽  
Cerebral Blood Volume ◽  
Brain Regions ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Bold Effect ◽  
Neurosurgical Planning

Functional magnetic resonance imaging (fMRI) is a technique that exploits magnetic resonance imaging (MRI) to detect regional brain activity through measurement of the hemodynamic response that is coupled to electrical neuronal activity. The most common fMRI method detects blood oxygen level dependent (BOLD) contrast. The BOLD effect represents alteration in the ratio of deoxygenated to oxygenated hemoglobin within brain tissue following neuronal activity. Alterations in this hemoglobin ratio result from changes in cerebral oxygen extraction, cerebral blood flow, and cerebral blood volume that occur in response to neuronal activity. The small, but detectable, change in magnetics resonance signal intensity is due to the sensitivity of magnetic resonance (MR) images to the paramagnetic deoxygenated state of hemoglobin that is the basis of contrast in fMRI applications. This review describes the physical and physiological bases of the MR signal, the principle of the BOLD effect, technical issues related to fMRI implementation, and fMRI experimental design. Research and clinical applications of fMRI are presented, including the use of fMRI in neurosurgical planning. Since it provides an individualized map of brain function, fMRI enables accurate localization of eloquent brain regions prior to surgery, allowing assessment of surgical risk and prognosis, as well as planning surgical approach.

Functional Magnetic Resonance Imaging

2014 ◽  
Author(s):  
Emmanuel A. Stamatakis ◽  
Eleni Orfanidou ◽  
Andrew C. Papanicolaou
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Functional Neuroimaging ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Blood Oxygen Level ◽  
The One

Functional magnetic resonance imaging (fMRI) is the most frequently used functional neuroimaging method and the one that accounts for most of the neuroimaging literature. It measures the blood oxygen level-dependent (BOLD) signal in different parts of the brain during rest and during task-induced activation of functional networks mediating basic and higher functions. A basic understanding of the various instruments and techniques of recording the hemodynamic responses of different brain regions and the manner in which we establish activation and connectivity patterns out of these responses is necessary for an appreciation of the contemporary functional neuroimaging literature. To facilitate such an understanding is the purpose of this chapter.

On the origin of sustained negative BOLD response

2012 ◽  
Vol 108 (9) ◽  
pp. 2339-2342 ◽  
Author(s):  
Marta Moraschi ◽  
Mauro DiNuzzo ◽  
Federico Giove
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Neuronal Activity ◽  
Neural Activity ◽  
Brain Regions ◽  
Bold Response ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Negative Bold

Several brain regions exhibit a sustained negative BOLD response (NBR) during specific tasks, as assessed with functional magnetic resonance imaging. The origin of the NBR and the relationships between the vascular/metabolic dynamics and the underlying neural activity are highly debated. Converging evidence indicates that NBR, in human and non-human primates, can be interpreted in terms of decrease in neuronal activity under its basal level, rather than a purely vascular phenomenon. However, the scarcity of direct experimental evidence suggests caution and encourages the ongoing utilization of multimodal approaches in the investigation of this effect.

scholarly journals Dynamic Causal Modeling Self-Connectivity Findings in the Functional Magnetic Resonance Imaging Neuropsychiatric Literature

2021 ◽  
Vol 15 ◽  
Author(s):  
Andrew D. Snyder ◽  
Liangsuo Ma ◽  
Joel L. Steinberg ◽  
Kyle Woisard ◽  
Frederick G. Moeller
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Functional Neuroimaging ◽  
Effective Connectivity ◽  
Brain Regions ◽  
Causal Modeling ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Dynamic Causal Modeling

Dynamic causal modeling (DCM) is a method for analyzing functional magnetic resonance imaging (fMRI) and other functional neuroimaging data that provides information about directionality of connectivity between brain regions. A review of the neuropsychiatric fMRI DCM literature suggests that there may be a historical trend to under-report self-connectivity (within brain regions) compared to between brain region connectivity findings. These findings are an integral part of the neurologic model represented by DCM and serve an important neurobiological function in regulating excitatory and inhibitory activity between regions. We reviewed the literature on the topic as well as the past 13 years of available neuropsychiatric DCM literature to find an increasing (but still, perhaps, and inadequate) trend in reporting these results. The focus of this review is fMRI as the majority of published DCM studies utilized fMRI and the interpretation of the self-connectivity findings may vary across imaging methodologies. About 25% of articles published between 2007 and 2019 made any mention of self-connectivity findings. We recommend increased attention toward the inclusion and interpretation of self-connectivity findings in DCM analyses in the neuropsychiatric literature, particularly in forthcoming effective connectivity studies of substance use disorders.

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