Document Detail


Influence of fMRI data sampling on the temporal characterization of the hemodynamic response.
MedLine Citation:
PMID:  12948736     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Experimental and modeling studies were used to estimate the effect of different sampling rates (repetition times, TR) and different sampling positions on the estimates of the temporal properties of the hemodynamic response function (HRF) derived from fMRI studies. Data were acquired at a TR of 250 ms and then subjected to various degrees of undersampling. Using a gaussian fitting function it is demonstrated that the accuracy of HRF peak time determination decreases with lower sampling rate (higher TR). The decrease in accuracy amounts to about 50 ms per second of TR increase. In addition, temporal shifts of the HRF peak time are found when reducing the influence of the more variable descending part of HRF curve by using a temporal cut-off after HRF peak time. The shift scales with TR, amounts up to 100 ms for a TR of 1500 ms and a cut-off of 3-4 s and depends on the sampling position. The use of the full HRF function does not lead to a shift but increases the influence of potential confounding factors as large veins and poststimulus undershoot. Since both accuracy and potential shifts of HRF peak determination scale with TR, it is important that temporal fMRI studies are carried out with high sampling rates.
Authors:
Bixente Dilharreguy; Richard A Jones; Chrit T W Moonen
Related Documents :
2485396 - Splenomegaly in papua new guineans and in japanese living in papua new guinea: report o...
7484176 - Cardiovascular response to exercise in humans following acclimatization to extreme alti...
17805096 - Military applications of hypoxic training for high-altitude operations.
3064236 - Altitude, training and human performance.
10450026 - Behavioral management for oropharyngeal dysphagia.
9460826 - Lack of willpower or lack of wherewithal? "internal" and "external" barriers to changin...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  NeuroImage     Volume:  19     ISSN:  1053-8119     ISO Abbreviation:  Neuroimage     Publication Date:  2003 Aug 
Date Detail:
Created Date:  2003-09-01     Completed Date:  2003-10-23     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9215515     Medline TA:  Neuroimage     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1820-8     Citation Subset:  IM    
Affiliation:
Imagerie Moléculaire et Fonctionnelle: de la Physiologie à la Thérapie, ERT CNRS/Université Bordeaux 2, 146 Rue Léo Saignat (case 117), 33076 Bordeaux, France.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Arousal / physiology*
Attention / physiology*
Brain Mapping / methods
Cerebral Cortex / blood supply*,  physiology
Hemodynamics / physiology*
Humans
Image Processing, Computer-Assisted / methods,  statistics & numerical data*
Magnetic Resonance Imaging / methods,  statistics & numerical data*
Mathematical Computing*
Nerve Net / blood supply,  physiology
Normal Distribution
Oxygen / blood
Pattern Recognition, Visual / physiology*
Sensitivity and Specificity
Visual Cortex / blood supply,  physiology
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Positron emission tomography during transcranial magnetic stimulation does not require micro-metal s...
Next Document:  Multitracer: a Java-based tool for anatomic delineation of grayscale volumetric images.