Advanced Brain Neuroimaging Topics in Health and Disease - Methods and Applications

Papageorgiou, T. Dorina; Christopoulos, George I.; Smirnakis, Stelios M.

doi:10.5772/58256

Cited by 7 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Measurements to date have shown that these clusters have consistent locations relative to one another, but that the maps within each cluster may be oriented somewhat differently, as if, in each individual's brain, the clusters themselves each may be positioned at a slightly different rotation about the cluster's central representation. Such inter-subject variability in cloverleaf cluster positions is consistent with our understanding of the variability in molecular gradient expression underlying the development of topographical gradients in cortex [26,[59][60][61][62]. Careful analysis across individual subjects can identify common CFMs by analyzing the pattern of CFMs and cloverleaf clusters across sensory cortex.…”

Section: Cloverleaf Clusters: Macrostructural Organization Of Corticasupporting

confidence: 67%

Cloverleaf Clusters: A Common Macrostructural Organization across Human Visual and Auditory Cortex

Brewer¹,

Barton²

2018

Sensory Nervous System

View full text Add to dashboard Cite

One of the fundamental properties of mammalian brains is that sensory regions of cortex are organized into multiple, functionally specialized cortical field maps (CFMs). An individual CFM is composed of two orthogonal topographical representations, reflecting two essential aspects of a sensory feature space. Each CFM is thought to subserve a specific computation or set of computations that underlie particular perceptual behaviors by enabling the comparison and combination of the information carried by the various specialized neuronal populations within this cortical region. Multiple adjacent CFMs, in turn, have now been shown by multiple laboratories to be organized in visual and auditory cortex into a macrostructural pattern called the cloverleaf cluster. CFMs within cloverleaf clusters tend to share properties such as receptive field distribution, cortical magnification, and processing specialization. This chapter will review the evidence for CFM and cloverleaf cluster organization across human visual and auditory cortex and will discuss the utility of these measurements for determining cortical structure and function and for investigating what changes occur in sensory cortex following various types of trauma or disease.

show abstract

Section: Cloverleaf Clusters: Macrostructural Organization Of Corticasupporting

confidence: 67%

Cloverleaf Clusters: A Common Macrostructural Organization across Human Visual and Auditory Cortex

Brewer¹,

Barton²

2018

Sensory Nervous System

View full text Add to dashboard Cite

show abstract

“…Two animals (M1 and M2) participated in the MRI experiments and were implanted with an MRI-compatible plastic (PEEK) head-post, fixed to the skull with ceramic bone screws and acrylic ( Papageorgiou et al, 2014 ; Vanduffel et al, 2001 ). Anesthetics, analgesics, and monitoring procedures were similar to previous surgical procedures in our laboratory and are described in detail elsewhere ( Klink et al, 2017 ; Poort et al, 2012 ; Supèr and Roelfsema, 2005 ).…”

Section: Methodsmentioning

confidence: 99%

Population receptive fields in nonhuman primates from whole-brain fMRI and large-scale neurophysiology in visual cortex

Klink

Chen

Vanduffel

et al. 2021

eLife

View full text Add to dashboard Cite

Population receptive field (pRF) modeling is a popular fMRI method to map the retinotopic organization of the human brain. While fMRI-based pRF maps are qualitatively similar to invasively recorded single-cell receptive fields in animals, it remains unclear what neuronal signal they represent. We addressed this question in awake nonhuman primates comparing whole-brain fMRI and large-scale neurophysiological recordings in areas V1 and V4 of the visual cortex. We examined the fits of several pRF models based on the fMRI blood-oxygen-level-dependent (BOLD) signal, multi-unit spiking activity (MUA), and local field potential (LFP) power in different frequency bands. We found that pRFs derived from BOLD-fMRI were most similar to MUA-pRFs in V1 and V4, while pRFs based on LFP gamma power also gave a good approximation. fMRI-based pRFs thus reliably reflect neuronal receptive field properties in the primate brain. In addition to our results in V1 and V4, the whole-brain fMRI measurements revealed retinotopic tuning in many other cortical and subcortical areas with a consistent increase in pRF size with increasing eccentricity, as well as a retinotopically specific deactivation of default mode network nodes similar to previous observations in humans.

show abstract

“…In addition, measurements of the characteristics of these VFMs, together with an understanding of the stimulus selectivity of the neurons within them, is the foundation for understanding the specific visual computations carried out in particular cortical regions. Not only are such in vivo measurements of VFMs essential for the study of visual processing in healthy subjects, but they also are very effective for tracking changes in visual cortex in response to changes in visual inputs such as those that arise from retinal or cortical damage [8][9][10][11][12].…”

Section: Overview Of Visual Cortex Characteristicsmentioning

confidence: 99%

“…A change in the size of a specific part of a cortical representation between species or subject groups would suggest a related change in the functional properties of that region of cortex and possibly in behavior. For example, if the foveal representation of V1 is significantly reduced in extent for a particular patient group, then it is likely that there is a difference between those patients' central visual processing and that of healthy subjects with normally sized foveal representations (e.g., [8,10,12,36,37]).…”

Section: Decreases In the Cortical Magnification Of Foveal Representamentioning

confidence: 99%

“…For VFMs V1-hV4 in healthy subjects, the foveal representations are relatively magnified and also contain the smallest receptive fields [3,14,36,92]. As inputs to visual areas are degraded, as from lesions to the retina or earlier visual pathways, these receptive fields tend to change in size (e.g., [8,10,12,16,152]). Changes can either be an increase in size, as, for example, normal lateral inhibition-which tends to refine and narrow receptive fields-is lost, or be a decrease in size, as inputs to that receptive field drop out ( Figure 7B).…”

Section: Increases In the Size Of Population Receptive Fields (Prfs)mentioning

confidence: 99%

See 1 more Smart Citation

Changes in Visual Cortex in Healthy Aging and Dementia

Brewer¹,

Barton²

2016

Update on Dementia

View full text Add to dashboard Cite

This chapter reviews the differences in specific structural and functional characteristics of human visual cortex among young adults, healthy aging adults, and patients with dementia, with a primary focus on those with Alzheimer's disease (AD). Such visual cortex changes have been shown to underlie many of the behavioral deficits that develop in healthy aging and AD. Measurements of disordered visual cortex in dementia patients may be possible early in the course of neurodegeneration and thus may be useful for improving early diagnosis of these devastating diseases.

show abstract

Advanced Brain Neuroimaging Topics in Health and Disease - Methods and Applications

Cited by 7 publications

References 0 publications

Cloverleaf Clusters: A Common Macrostructural Organization across Human Visual and Auditory Cortex

Cloverleaf Clusters: A Common Macrostructural Organization across Human Visual and Auditory Cortex

Population receptive fields in nonhuman primates from whole-brain fMRI and large-scale neurophysiology in visual cortex

Changes in Visual Cortex in Healthy Aging and Dementia

Contact Info

Product

Resources

About