Localization of cortical sites in subjects not having MRIs

Carducci, F.; Babiloni, Claudio; Babiloni, Fabio; Cincotti, Febo; Moretti, Davide Vito; Rizzuto, Marco; Rossini, Paolo Maria

doi:10.1016/s1053-8119(01)91434-x

Cited by 2 publications

(3 citation statements)

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“…3). The additional localisation error introduced by the procedure is of the same order as the grid used to reconstruct the MEG SAM source image (5 mm) and is similar to that reported by Carducci [ 2001]. As we apply MEG/MRI co‐registration methods in which millimetre accuracy in registration can be obtained, we suspect that the accuracy of the approximated group functional images approaches or even exceeds that in MEG studies using MRIs for each participant but which neglect a precise co‐registration methodology [Singh et al, 1997].…”

Section: Discussionmentioning

confidence: 99%

“…Other workers have advanced similar suggestions recently and argued for the utility of an approach using approximations of the brain volume. Carducci et al [ 2001] used a method in which scalp locations on each participant were identified on the MNI averaged brain and the underlying brain location estimated by perpendicular projection from the surface of the MNI brain. They report that the mean difference in Talairach co‐ordinates between estimates using the real scalp and the averaged MNI scalp locations is <1 cm, and typically 4–6 mm.…”

Section: Introductionmentioning

confidence: 99%

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Accuracy and applications of group MEG studies using cortical source locations estimated from participants' scalp surfaces

Holliday¹,

Barnes²,

Hillebrand³

et al. 2003

Human Brain Mapping

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We contend that powerful group studies can be conducted using magnetoencephalography (MEG), which can provide useful insights into the approximate distribution of the neural activity detected with MEG without requiring magnetic resonance imaging (MRI) for each participant. Instead, a participant's MRI is approximated with one chosen as a best match on the basis of the scalp surface from a database of available MRIs. Because large inter-individual variability in sulcal and gyral patterns is an inherent source of blurring in studies using grouped functional activity, the additional error introduced by this approximation procedure has little effect on the group results, and offers a sufficiently close approximation to that of the participants to yield a good indication of the true distribution of the grouped neural activity. T1-weighted MRIs of 28 adults were acquired in a variety of MR systems. An artificial functional image was prepared for each person in which eight 5 x 5 x 5 mm regions of brain activation were simulated. Spatial normalisation was applied to each image using transformations calculated using SPM99 with (1) the participant's actual MRI, and (2) the best matched MRI substituted from those of the other 27 participants. The distribution of distances between the locations of points using real and substituted MRIs had a modal value of 6 mm with 90% of cases falling below 12.5 mm. The effects of this approach on real grouped SAM source imaging of MEG data in a verbal fluency task are also shown. The distribution of MEG activity in the estimated average response is very similar to that produced when using the real MRIs.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Accuracy and applications of group MEG studies using cortical source locations estimated from participants' scalp surfaces

Holliday¹,

Barnes²,

Hillebrand³

et al. 2003

Human Brain Mapping

View full text Add to dashboard Cite

show abstract

“…The role of the precuneus in decision-making under uncertainty had also been suggested by Paulus et al (2001), who asserted that both “STG and precuneus have been associated with sub processes that are consistent with the maintenance of strategies in the presence of uncertainty” (p. 97).…”

Section: Discussionmentioning

confidence: 69%

Retrieval, Monitoring, and Control Processes: A 7 Tesla fMRI Approach to Memory Accuracy

Risius¹,

Staniloiu²,

Piefke³

et al. 2013

Front. Behav. Neurosci.

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Memory research has been guided by two powerful metaphors: the storehouse (computer) and the correspondence metaphor. The latter emphasizes the dependability of retrieved mnemonic information and draws upon ideas about the state dependency and reconstructive character of episodic memory. We used a new movie to unveil the neural correlates connected with retrieval, monitoring, and control processes, and memory accuracy (MAC), according to the paradigm of Koriat and Goldsmith (1996a,b). During functional magnetic resonance imaging, subjects performed a memory task which required (after an initial learning phase) rating true and false statements [retrieval phase (RP)], making confidence judgments in the respective statement [monitoring phase (MP)], and deciding for either venturing (volunteering) the respective answer or withholding the response [control phase (CP)]. Imaging data pointed to common and unique neural correlates. Activations in brain regions related to RP and MAC were observed in the precuneus, middle temporal gyrus, and left hippocampus. MP was associated with activation in the left anterior and posterior cingulate cortex along with bilateral medial temporal regions. If an answer was volunteered (as opposed to being withheld) during the CP, temporal, and frontal as well as middle and posterior cingulate areas and the precuneus revealed activations. Increased bilateral hippocampal activity was found during withholding compared to volunteering answers. The left caudate activation detected during withholding compared to venturing an answer supports the involvement of the left caudate in inhibiting unwanted responses. Contrary to expectations, we did not evidence prefrontal activations during withholding (as opposed to volunteering) answers. This may reflect our design specifications, but alternative interpretations are put forth.

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Localization of cortical sites in subjects not having MRIs

Cited by 2 publications

References 0 publications

Accuracy and applications of group MEG studies using cortical source locations estimated from participants' scalp surfaces

Accuracy and applications of group MEG studies using cortical source locations estimated from participants' scalp surfaces

Retrieval, Monitoring, and Control Processes: A 7 Tesla fMRI Approach to Memory Accuracy

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