Age-related Reduction in Functional MRI Response to Photic Stimulation

Ross, Marjorie H.; Yurgelun‐Todd, Deborah; Renshaw, Perry F.; Maas, Luis C.; Mendelson, Joseph; Mello, Nancy K.; B, Cohen; Levin, Jonathan M.

doi:10.1212/wnl.48.1.173

Cited by 159 publications

(129 citation statements)

References 9 publications

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“…There were no significant age differences between our three groups, so that age-related effects (9) are not a consideration. Two additional findings were seen only in the PPR patients: simultaneous with the signal increase in visual cortex, there was signal decrement in perirolandic regions, even in the absence of a PPR; and immediately after the end of stimulation, a marked signal "undershoot" was present in widespread, scattered cortical areas, including both occipital and posterior cingulate regions.…”

Section: Discussionmentioning

confidence: 76%

Photosensitive Epilepsy Studied by Functional Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy

Chiappa¹,

Hill²,

Huang-Hellinger

et al. 1999

Epilepsia

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Summary:Purpose: To study metabolic and hemodynamic correlates of photic stimulation-triggered discharges.Methods: Simultaneous EEG, functional MRI (fMRI) and magnetic resonance spectroscopy (MRS) were performed in nine patients with photosensitive epilepsy and in 12 normal subjects.Results: Prominent visual cortex activation was seen in all normal subjects and patients, and no fMRI-registered hemodynamic abnormalities were correlated with the brief photoparoxysmal spike-wave activity evoked in the photosensitive patients. However, irrespective of the presence of a spike-wave response to the photic stimulation, the photosensitive patients showed four findings not seen in the normal subjects: (a) slightly, but significantly, elevated lactate levels in the occipital cortex in the resting state; (b) an increased area of visual cortical activation with photic stimulation; (c) simultaneous with the occipital cortex stimulus-induced increased M R I signal, there were noncontiguous areas of signal attenuation most prominent in perirolandic regions; and (d) a marked decrement (undershoot) of fMRI signal intensity immediately after the photic stimulation in the occipital cortex and in the region of the posterior cingulate gyrus.Conclusions: These findings suggest abnormal interictal metabolism and increased vascular reactivity in the photosensitive patients. Key Words: Functional MRI-MR spectroscopyGeneralized epilepsy-Photosensitive-EEG.Functional magnetic resonance imaging (fMRI) during focal seizures has revealed localized changes in CBF (1,2). Warach et al. (3) used fMRI to study blood-flow changes related to epileptic discharges in two patients, one with generalized spike-wave discharges, both of whom showed focal increases in signal intensity indicative of focal increased blood flow. 'H Magnetic resonance spectroscopy (MRS) showed an increase in lactate during physiologic photic stimulation in normal subjects (4), but Cendes et al. (5) found no lactate changes in five patients during or soon after absence seizures associated with generalized epilepsy. We performed fMRI and 'H MRS in patients with a photoparoxysmal response (PPR) by using EEG recordings during MR data acquisition to verify the presence of a PPR. METHODSNine patients, eight women, with a mean age of 28 years (range, 18-46 years), with primary generalized epiDr. Hill is currently at

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Section: Discussionmentioning

confidence: 76%

Photosensitive Epilepsy Studied by Functional Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy

Chiappa¹,

Hill²,

Huang-Hellinger

et al. 1999

Epilepsia

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“…These age-related changes most likely exert minimal effect on neural function per se, but may underlie the compromised performance of the neurovascular system [22]. Age-related changes in human cerebrovasculature are likely to exert effects on the coupling between neural activity and hemodynamic response [23][24][25][26]. Agerelated changes in noise and signal-noise characteristics of fMRI have also been observed [23].…”

Section: Vascular Density and Vascular Compliance Varies Between Braimentioning

confidence: 99%

Hemodynamic scaling of fMRI-BOLD signal: validation of low-frequency spectral amplitude as a scalability factor

Biswal

Kannurpatti²,

Rypma

2007

Magnetic Resonance Imaging

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AbstractfMRI-BOLD signal representing neural activity may be optimized by discriminating MR signal components related to neural activity and those related to intrinsic properties of the cortical vasculature. The objective of this study was to diminish the hemodynamic change independent of neural activity to obtain a scaled fMRI-BOLD response using two factors namely the low frequency spectral amplitude (LFSA) and breath hold amplitude (BHA). Ten subjects (22-38 years of age) were scanned during various task conditions; (a) rest while breathing room air; (b) bilateral finger-tapping breathing room air; (c) rest during a partial inspirational breath hold; and (d) rest during moderate hypercapnia (breathing 5% CO 2 , 20% O 2 , and 75% N 2 ). In all subjects who breathed 5% CO 2 , regions with significant BOLD response during breath hold correlated significantly with the percent signal increase during 5% CO 2 inhalation. Finger tapping-induced responses in the motor cortex were diminished to a similar extent after scaling using either the LFSA or the BHA. Inter and intra-subject variation in the amplitude of the BOLD signal response reduced after hemodynamic scaling using LFSA or BHA. The results validate the hemodynamic amplitude scaling using the LFSA with earlier established BHA. LFSA free from motor task contamination can be used to calibrate the fMRI-BOLD response in lieu of BHA or hypercapnia to minimize intra and inter subject variation arising from vascular anatomy and vasodilative capacity.

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“…Principally, these studies have used functional magnetic resonance imaging (fMRI) techniques to clarify the impact of aging on regional brain activation patterns (D'Esposito et al, 1999;Hesselmann et al, 2001;Huettel et al, 2001;Mattay et al, 2002;Mehagnoul-Schipper et al, 2002;Ross et al, 1997;Taoka et al, 1998). In this context, the utility of fMRI is directly related to the degree to which the relation between MR signal changes and underlying neuronal activation can be established.…”

Section: *Department Of Neurology and †Section Of Mr Of The Cns Depamentioning

confidence: 99%

Relation between Regional Functional MRI Activation and Vascular Reactivity to Carbon Dioxide during Normal Aging

Riecker

Grodd

Klose

et al. 2003

J Cereb Blood Flow Metab

103

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Summary:Recent blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging studies have shown a reduction of cerebral activation during aging, which may be associated with age-related changes of the cerebral vascular system. The authors used a global hypercapnic breathholding challenge to define nonneuronal contributions to a significantly reduced activation in the primary sensorimotor cortex during finger tapping in a group of old (n ‫ס‬ 6; mean age 65 years) compared with a group of young (n ‫ס‬ 6; mean age 27 years) subjects. Within significantly activated voxels in both groups during finger tapping, the mean BOLD signal amplitudes were significantly smaller in the group of older subjects for both tasks. In those voxels showing significant activation only in young subjects during finger tapping, the response to hypercapnia was also greatly diminished in older subjects. The attenuated hypercapnic BOLD signal response in older subjects within this region suggests that age-dependent changes of the cerebral vasculature may alter the neuronal-vascular coupling. In older subjects, cerebral vessels may not react as effectively in response to a vasodilating stimulus, which will lead to differences in the number of voxels that pass a criterion threshold despite similar neuronal activation.

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Age-related Reduction in Functional MRI Response to Photic Stimulation

Cited by 159 publications

References 9 publications

Photosensitive Epilepsy Studied by Functional Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy

Photosensitive Epilepsy Studied by Functional Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy

Hemodynamic scaling of fMRI-BOLD signal: validation of low-frequency spectral amplitude as a scalability factor

Relation between Regional Functional MRI Activation and Vascular Reactivity to Carbon Dioxide during Normal Aging

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