Time-dependent effects of hyperoxia on the BOLD fMRI signal in primate visual cortex and LGN

Wibral, Michael; Muckli, Lars; Melnikovic, Katharina; Scheller, Bertram; Alink, Arjen; Singer, Wolf; Munk, Matthias H. J.

doi:10.1016/j.neuroimage.2006.12.039

Cited by 18 publications

(12 citation statements)

References 62 publications

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“…However those hemodynamic delays are far larger than the neural delays directly measured in electrophysiology, which are in the [10;100 ms] range (Saul and Feidler, 2002). Thus, the hemodynamic delays we measured here could as well be due to effective delays in the neural response than to different vascular, or neurovascular coupling dynamics (Li and Freeman, 2007, Wibral et al, 2007). Nonetheless, this could be combined with continuously moving bars stimuli that has been shown to produce retinotopic measurements in a much shorter time than by stimulating selectively and successively sectors of the visual field (Kalatsky and Stryker, 2003; Vanni et al, 2010a, Vanni et al, 2010b).…”

Section: Discussionmentioning

confidence: 93%

3D functional ultrasound imaging of the cerebral visual system in rodents

et al. 2017

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3D functional imaging of the whole brain activity during visual task is a challenging task in rodents due to the complex tri-dimensional shape of involved brain regions and the fine spatial and temporal resolutions required to reveal the visual tract. By coupling functional ultrasound (fUS) imaging with a translational motorized stage and an episodic visual stimulation device, we managed to accurately map and to recover the activity of the visual cortices, the Superior Colliculus (SC) and the Lateral Geniculate Nuclei (LGN) in 3D. Cerebral Blood Volume (CBV) responses during visual stimuli were found to be highly correlated with the visual stimulus time profile in visual cortices (r=0.6), SC (r=0.7) and LGN (r=0.7). These responses were found dependent on flickering frequency and contrast, and optimal stimulus parameters for largest CBV increases were obtained. In particular, increasing the flickering frequency higher than 7 Hz revealed a decrease of visual cortices response while the SC response was preserved. Finally, cross-correlation between CBV signals exhibited significant delays (d=0.35 s +/−0.1 s) between blood volume response in SC and visual cortices in response to our visual stimulus. These results emphasize the interest of fUS imaging as a whole brain neuroimaging modality for brain vision studies in rodent models.

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Section: Discussionmentioning

confidence: 93%

3D functional ultrasound imaging of the cerebral visual system in rodents

et al. 2017

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“…Physiological parameters that influence the BOLD (blood oxygen level independent) signal include breathing patterns [295], heart rate [296,297] and the concentration of carbon dioxide [298] and oxygen [299]. Future MRI techniques have to control for these factors in order to improve the reliability of fMRI markers.…”

Section: Discussionmentioning

confidence: 99%

Abnormal Functional and Structural Asymmetry as Biomarker for Schizophrenia

Oertel-Knöchel¹,

Knöchel²,

Stäblein³

et al. 2012

Current Topics in Medicinal Chemistry

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The hemispheres of the human brain are anatomically and functionally asymmetric. Many cognitive and motor functions such as language and handedness are lateralized. In this review, we discuss the principles of laterality and brain asymmetry in relation to schizophrenia. Schizophrenia is one of the most disabling forms of mental illness. One important challenge is to develop and set up biological markers, which can accurately identify at-risk individuals in preclinical stages and thus improve the effects of early intervention strategies. The concept of hemispheric laterality plays a central role in current neuropsychological and pathophysiological models of schizophrenia. Recent research reflects an increasing interest in the molecular and population genetics of laterality and its potential use as biological marker for the illness. The review is an overview of literature from the 1990's on cerebral asymmetry in schizophrenia. We critically discuss the use of cerebral asymmetry for biomarker research, regarding diagnosis improvements, the improvement of psychopharmacology and the prediction of conversion in at-risk individuals. We propose that abnormal cerebral asymmetry is an attractive biomarker candidate for schizophrenia that could index changes in a range of pathophysiological pathways.

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“…Functional images were acquired at the Brain Imaging Center of Frankfurt University, Frankfurt, Germany, on a 3-T MR system with eight-channel head coil (Siemens Trio, Erlangen, Germany) as T2*-weighted echo-planar image (EPI) volumes using a sequence optimized by Wibral et al (2007). Twenty transverse slices were obtained with a repetition time of 2 s (echo time, 30 ms; flip angle, 70°; 2 ϫ 2 ϫ 2-mm voxels; 0.5-mm gap).…”

Section: Participants and Data Acquisitionmentioning

confidence: 99%

Graded Size Sensitivity of Object-Exemplar–Evoked Activity Patterns Within Human LOC Subregions

Eger

Kell²,

Kleinschmidt³

2008

Journal of Neurophysiology

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Eger E, Kell CA, Kleinschmidt A. Graded size sensitivity of objectexemplar-evoked activity patterns within human LOC subregions. J Neurophysiol 100: 2038 -2047, 2008. First published July 16, 2008 doi:10.1152/jn.90305.2008. A central issue for understanding visual object recognition is how the cortical hierarchy represents incoming sensory information and transforms it across successive processing stages. The format of object representation in the human brain has thus far mostly been studied using adaptation paradigms because the neuronal layout of object selectivities was thought to be beyond the resolution of conventional functional MRI (fMRI). Recently, however, multivariate pattern recognition succeeded in discriminating fMRI responses of object-selective cortex to different object exemplars within a given category. Here, we use increased spatial fMRI resolution to explore size sensitivity and tolerance to size change of response patterns evoked by object exemplars across a range of three sizes. Results from Support Vector Classification on responses of the human lateral occipital complex (LOC) show that discrimination of size (for a given object) and discrimination of objects across changes in size depended on the amount of size difference. Even across the largest amount of size change, accuracy for generalization was still significant in LOC, whereas the same comparison was at chance performance in early visual (calcarine) cortex. Analyzing subregions, we further found an anterior-posterior gradient in the degree of size sensitivity and size generalization within the posterior-dorsal and anterior-ventral parts of LOC. These results speak against fully size-invariant representation of object information in human LOC and are hence congruent with findings in monkeys showing object identity and size information in population activity of inferotemporal cortex. Moreover, these results provide evidence for a fine-grained functional heterogeneity within human LOC beyond the commonly used LO/ fusiform subdivision.

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Time-dependent effects of hyperoxia on the BOLD fMRI signal in primate visual cortex and LGN

Cited by 18 publications

References 62 publications

3D functional ultrasound imaging of the cerebral visual system in rodents

3D functional ultrasound imaging of the cerebral visual system in rodents

Abnormal Functional and Structural Asymmetry as Biomarker for Schizophrenia

Graded Size Sensitivity of Object-Exemplar–Evoked Activity Patterns Within Human LOC Subregions

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