[This corrects the article on p. 709 in vol. 11, PMID: 29311789.].

• Klíčová slova
• DTI, Parkinson's disease, functional connectivity, iRBD, rotating frame MRI,
• Publikační typ
• časopisecké články MeSH
• tisková chyba MeSH

In the present study, we aimed at determining the metabolic responses of the human visual cortex during the presentation of chromatic and achromatic stimuli, known to preferentially activate two separate clusters of neuronal populations (called "blobs" and "interblobs") with distinct sensitivity to color or luminance features. Since blobs and interblobs have different cytochrome-oxidase (COX) content and micro-vascularization level (i.e., different capacities for glucose oxidation), different functional metabolic responses during chromatic vs. achromatic stimuli may be expected. The stimuli were optimized to evoke a similar load of neuronal activation as measured by the bold oxygenation level dependent (BOLD) contrast. Metabolic responses were assessed using functional 1H MRS at 7 T in 12 subjects. During both chromatic and achromatic stimuli, we observed the typical increases in glutamate and lactate concentration, and decreases in aspartate and glucose concentration, that are indicative of increased glucose oxidation. However, within the detection sensitivity limits, we did not observe any difference between metabolic responses elicited by chromatic and achromatic stimuli. We conclude that the higher energy demands of activated blobs and interblobs are supported by similar increases in oxidative metabolism despite the different capacities of these neuronal populations.

• Klíčová slova
• MR spectroscopy, energy metabolism, functional MRI, glutamate, lactate,
• MeSH
• barva * MeSH
• energetický metabolismus MeSH
• glukosa metabolismus   MeSH
• kyselina asparagová metabolismus   MeSH
• kyselina glutamová metabolismus   MeSH
• kyselina mléčná metabolismus   MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• magnetická rezonanční tomografie MeSH
• mozek - chemie fyziologie   MeSH
• neurony fyziologie   MeSH
• oxidace-redukce MeSH
• respirační komplex IV metabolismus   MeSH
• světelná stimulace * MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• zrakové evokované potenciály MeSH
• zrakové korové centrum metabolismus   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• glukosa MeSH
• kyselina asparagová MeSH
• kyselina glutamová MeSH
• kyselina mléčná MeSH
• respirační komplex IV MeSH

Idiopathic rapid eye movement sleep behavior disorder (iRBD) is a condition that often evolves into Parkinson's disease (PD). Therefore, by monitoring iRBD it is possible to track the neurodegeneration of individuals who may progress to PD. Here we aimed at piloting the characterization of brain tissue properties in mid-brain subcortical regions of 10 healthy subjects, 8 iRBD, and 9 early-diagnosed PD. We used a battery of magnetic resonance imaging (MRI) contrasts at 3 T, including adiabatic and non-adiabatic rotating frame techniques developed by our group, along with diffusion tensor imaging (DTI) and resting-state fMRI. Adiabatic T1ρ and T2ρ, and non-adiabatic RAFF4 (Relaxation Along a Fictitious Field in the rotating frame of rank 4) were found to have lower coefficient of variations and higher sensitivity to detect group differences as compared to DTI parameters such as fractional anisotropy and mean diffusivity. Significantly longer T1ρ were observed in the amygdala of PD subjects vs. controls, along with a trend of lower functional connectivity as measured by regional homogeneity, thereby supporting the notion that amygdalar dysfunction occurs in PD. Significant abnormalities in reward networks occurred in iRBD subjects, who manifested lower network strength of the accumbens. In agreement with previous studies, significantly longer T1ρ occurred in the substantia nigra compacta of PD vs. controls, indicative of neuronal degeneration, while regional homogeneity was lower in the substantia nigra reticulata. Finally, other trend-level findings were observed, i.e., lower RAFF4 and T2ρ in the midbrain of iRBD subjects vs. controls, possibly indicating changes in non-motor features as opposed to motor function in the iRBD group. We conclude that rotating frame relaxation methods along with functional connectivity measures are valuable to characterize iRBD and PD subjects, and with proper validation in larger cohorts may provide pathological signatures of iRBD and PD.

• Klíčová slova
• DTI, Parkinson's disease, functional connectivity, iRBD, rotating frame MRI,
• Publikační typ
• časopisecké články MeSH