Sharp transients, in electrical recordings, represent a measure of neural activity corresponding to an action potential at a single neuron. Such spike activity reflects the output of a given brain area, yet many regions receive input in the form of excitatory or inhibitory synaptic potentials without generating spikes. This input activity is an important form of computational integration, detected in extracellular recordings as perturbations of the local field potential (LFP). Quantitative analysis of the LFP is performed in the frequency domain, providing a measure of synchronous activity across neurons. Logothetis et al. (2001) showed that BOLD may reflect an area's input in the form of synaptic potentials, rather than its output in the form of spikes. Synaptic inputs can be excitatory or inhibitory, and both forms involve metabolic demands that may alter BOLD and complicate models interpreting BOLD as a proxy for cognitive engagement. The time- courses of oscillations in various frequency bands, and excitatory and inhibitory synaptic potentials, and the relationship between these forms of activity and cognition as reflected by BOLD, is poorly understood. Thus, it is essential to examine the correspondence between certain forms of neural activity, BOLD, and the engagement of cognitive processes. Negative BOLD signals in some cases, for example, demand a nuanced interpretation. The subtractive nature of fMRI initially suggests that negative BOLD simply reflects increased activation during the baseline. However, a number of findings have suggested that negative BOLD represents a distinct phenomenon. This proposal is focused on examining the evidence that negative BOLD reflects decreases in neural activity, associated with cognition. Calibrated MR measures of BOLD and CBF will be performed using tasks previously shown to produce reliable deactivations. These MR measures of flow and oxygenation will be used to determine relative CMRO2 and the oxygen extraction to fully assess the physiologic underpinnings of BOLD. Simultaneous EEC will be recorded and EEC power in multiple frequency bands compared with the MR measures. Much work has been performed characterizing EEC changes in the tasks to be used, but little work has attempted to relate EEC to MR signals. This work will provide insight into the relationship between MR signal changes in cognitive tasks, and EEC changes as measured with surface, and in a limited number of patients, subdural electrodes. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS051622-02
Application #
7262554
Study Section
Medical Imaging Study Section (MEDI)
Program Officer
Babcock, Debra J
Project Start
2006-07-20
Project End
2011-04-30
Budget Start
2007-05-01
Budget End
2008-04-30
Support Year
2
Fiscal Year
2007
Total Cost
$360,483
Indirect Cost
Name
Yale University
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Roth, Jennifer K; Johnson, Marcia K; Tokoglu, Fuyuze et al. (2014) Modulating intrinsic connectivity: adjacent subregions within supplementary motor cortex, dorsolateral prefrontal cortex, and parietal cortex connect to separate functional networks during task and also connect during rest. PLoS One 9:e90672
Ciris, Pelin Aksit; Qiu, Maolin; Constable, R Todd (2014) Noninvasive MRI measurement of the absolute cerebral blood volume-cerebral blood flow relationship during visual stimulation in healthy humans. Magn Reson Med 72:864-75
Ciris, Pelin Aksit; Qiu, Maolin; Constable, Robert Todd (2014) Non-invasive quantification of absolute cerebral blood volume during functional activation applicable to the whole human brain. Magn Reson Med 71:580-90
Scheinost, Dustin; Hampson, Michelle; Qiu, Maolin et al. (2013) A graphics processing unit accelerated motion correction algorithm and modular system for real-time fMRI. Neuroinformatics 11:291-300
Cope, Natalie; Eicher, John D; Meng, Haiying et al. (2012) Variants in the DYX2 locus are associated with altered brain activation in reading-related brain regions in subjects with reading disability. Neuroimage 63:148-56
Hampson, Michelle; Stoica, Teodora; Saksa, John et al. (2012) Real-time fMRI biofeedback targeting the orbitofrontal cortex for contamination anxiety. J Vis Exp :
Scheinost, D; Benjamin, J; Lacadie, C M et al. (2012) The intrinsic connectivity distribution: a novel contrast measure reflecting voxel level functional connectivity. Neuroimage 62:1510-9
Hampson, Michelle; Scheinost, Dustin; Qiu, Maolin et al. (2011) Biofeedback of real-time functional magnetic resonance imaging data from the supplementary motor area reduces functional connectivity to subcortical regions. Brain Connect 1:91-8
Laufer, Ilan; Negishi, Michiro; Lacadie, Cheryl M et al. (2011) Dissociation between the activity of the right middle frontal gyrus and the middle temporal gyrus in processing semantic priming. PLoS One 6:e22368
Martuzzi, Roberto; Ramani, Ramachandran; Qiu, Maolin et al. (2011) A whole-brain voxel based measure of intrinsic connectivity contrast reveals local changes in tissue connectivity with anesthetic without a priori assumptions on thresholds or regions of interest. Neuroimage 58:1044-50

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