scholarly journals Stimulus selectivity of broadband field potentials, but not gamma oscillations, matches population responses as measured by BOLD fMRI in human visual cortex

2014 ◽  
Vol 14 (10) ◽  
pp. 1432-1432
Author(s):  
D. Hermes ◽  
K. Kay ◽  
J. Winawer
Keyword(s):  
Visual Cortex ◽  
Gamma Oscillations ◽  
Field Potentials ◽  
Bold Fmri ◽  
Human Visual Cortex ◽  
Population Responses

scholarly journals Voxel-Wise Linearity Analysis of Increments and Decrements in BOLD Responses in Human Visual Cortex Using a Contrast Adaptation Paradigm

2021 ◽  
Vol 15 ◽  
Author(s):  
Yun Lin ◽  
Xi Zhou ◽  
Yuji Naya ◽  
Justin L. Gardner ◽  
Pei Sun
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Bold Signal ◽  
Transient Responses ◽  
Bold Fmri ◽  
Human Visual Cortex ◽  
Contrast Adaptation ◽  
Bold Responses

The linearity of BOLD responses is a fundamental presumption in most analysis procedures for BOLD fMRI studies. Previous studies have examined the linearity of BOLD signal increments, but less is known about the linearity of BOLD signal decrements. The present study assessed the linearity of both BOLD signal increments and decrements in the human primary visual cortex using a contrast adaptation paradigm. Results showed that both BOLD signal increments and decrements kept linearity to long stimuli (e.g., 3 s, 6 s), yet, deviated from linearity to transient stimuli (e.g., 1 s). Furthermore, a voxel-wise analysis showed that the deviation patterns were different for BOLD signal increments and decrements: while the BOLD signal increments demonstrated a consistent overestimation pattern, the patterns for BOLD signal decrements varied from overestimation to underestimation. Our results suggested that corrections to deviations from linearity of transient responses should consider the different effects of BOLD signal increments and decrements.

scholarly journals Orientation and color tuning of the human visual gamma rhythm

2021 ◽  
Author(s):  
Ye Li ◽  
William Bosking ◽  
Michael S Beauchamp ◽  
Sameer A Sheth ◽  
Daniel Yoshor ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Large Scale ◽  
Brain Activity ◽  
Population Level ◽  
Gamma Oscillations ◽  
Cell Orientation ◽  
Population Activity ◽  
Color Tuning ◽  
Human Visual Cortex ◽  
Gamma Rhythm

Narrowband gamma oscillations (NBG: ~20-60Hz) in visual cortex reflect rhythmic fluctuations in population activity generated by underlying circuits tuned for stimulus location, orientation, and color. Consequently, the amplitude and frequency of induced NBG activity is highly sensitive to these stimulus features. For example, in the non-human primate, NBG displays biases in orientation and color tuning at the population level. Such biases may relate to recent reports describing the large-scale organization of single-cell orientation and color tuning in visual cortex, thus providing a potential bridge between measurements made at different scales. Similar biases in NBG population tuning have been predicted to exist in the human visual cortex, but this has yet to be fully examined. Using intracranial recordings from human visual cortex, we investigated the tuning of NBG to orientation and color, both independently and in conjunction. NBG was shown to display a cardinal orientation bias (horizontal) and also an end- and mid-spectral color bias (red/blue and green). When jointly probed, the cardinal bias for orientation was attenuated and an end-spectral preference for red and blue predominated. These data both elaborate on the close, yet complex, link between the population dynamics driving NBG oscillations and known feature selectivity biases in visual cortex, adding to a growing set of stimulus dependencies associated with the genesis of NBG. Together, these two factors may provide a fruitful testing ground for examining multi-scale models of brain activity, and impose new constraints on the functional significance of the visual gamma rhythm.

scholarly journals Timing, Timing, Timing: Fast Decoding of Object Information from Intracranial Field Potentials in Human Visual Cortex

Neuron ◽  
2009 ◽  
Vol 62 (2) ◽  
pp. 281-290 ◽  
Author(s):  
Hesheng Liu ◽  
Yigal Agam ◽  
Joseph R. Madsen ◽  
Gabriel Kreiman
Keyword(s):  
Visual Cortex ◽  
Field Potentials ◽  
Human Visual Cortex ◽  
Fast Decoding

The properties of induced gamma oscillations in human visual cortex show individual variability in their dependence on stimulus size

NeuroImage ◽  
2013 ◽  
Vol 68 ◽  
pp. 83-92 ◽  
Author(s):  
Gavin Perry ◽  
Khalid Hamandi ◽  
Lisa M. Brindley ◽  
Suresh D. Muthukumaraswamy ◽  
Krish D. Singh
Keyword(s):  
Visual Cortex ◽  
Gamma Oscillations ◽  
Individual Variability ◽  
Stimulus Size ◽  
Human Visual Cortex

scholarly journals Stimulus Dependence of Gamma Oscillations in Human Visual Cortex

2014 ◽  
Vol 25 (9) ◽  
pp. 2951-2959 ◽  
Author(s):  
D. Hermes ◽  
K.J. Miller ◽  
B.A. Wandell ◽  
J. Winawer
Keyword(s):  
Visual Cortex ◽  
Gamma Oscillations ◽  
Human Visual Cortex

scholarly journals Simultaneous task-based BOLD-fMRI and [18-F] FDG functional PET for measurement of neuronal metabolism in the human visual cortex

NeuroImage ◽  
2019 ◽  
Vol 189 ◽  
pp. 258-266 ◽  
Author(s):  
Sharna D. Jamadar ◽  
Phillip GD. Ward ◽  
Shenpeng Li ◽  
Francesco Sforazzini ◽  
Jakub Baran ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Bold Fmri ◽  
Human Visual Cortex ◽  
Neuronal Metabolism
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