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In-vivo visualization of color-biased stripes in monkey secondary visual cortex (V2) using high-resolution MRI

Xiaolian Li1, John Arsenault1, 2, Thomas Janssens1, 2, Qi Zhu1 and Wim Vanduffel1, 2, 3*
  • 1 KU Leuven, Department of Neurosciences, Belgium
  • 2 Massachusetts General Hospital, United States
  • 3 Harvard Medical School, Department of Radiology, United States

Cytochrome oxidase (CO) stainings revealed three types of stripes in macaque area V2. The color-selective cells are clustered in less than 1 mm wide thin dark stripes and separated from each other by about 3 to 5 mm [1]. These color-biased stripes are hardly visible using conventional resolution fMRI due to the small size of the columns. In this study, we aimed to visualize the color stripes in vivo using high-resolution fMRI. We used the same stimuli as in our double-label deoxyglucose (2L-DG) study [1]. Moving isoluminant color and achromatic grating stimuli were presented in separate blocks while the monkey fixated at the center of the stimulus during the scan. High-resolution contrast-enhanced fMRI data (0.6 mm isotropic voxels, EPI, TR = 3 s, TE = 21 ms) was acquired using implanted phased-array receive coils developed in our lab, which increase image SNR by more than 3-fold [2]. To minimize image artifacts caused by motion of the monkey, we implemented an optimized GRAPPA reconstruction algorithm [3]. Furthermore, a B-spline grid based nonlinear registration and fieldmap-based distortion correction algorithms were implemented to achieve better frame to frame and functional to structural image alignment. Finally, a denoising technique (GLMdenoise) [4] was used to reduce physiological noise and other nuisance artifacts caused by motion of monkey in the temporal domain. We found stripe-like color activations throughout the entire extent of retinotopically-defined area V2, which are reproducible across scan sessions (on different days) in the same monkey. Moreover, color-biased activities were found in retinotopically-defined V1, V3, V4 and V4A. We also found luminance-biased activity in area MT, which is consistent with the result of the previous 2L-DG study [1]. The results of this study show that high-resolution fMRI can be reliably used to study submillimeter-scale functional organization of the brain.

References

[1] Tootell, R.B.H., et al., Search for color 'center(s)' in macaque visual cortex. Cerebral Cortex, 2004. 14(4): p. 353-363.
[2] Janssens, T., et al., An implanted 8-channel array coil for high-resolution macaque MRI at 3T. Neuroimage, 2012. 62(3): p. 1529-36.
[3] Hoge, W.S., H. Tan, and R.A. Kraft, A Method for Continuous Accelerated Echo-Planar Imaging with Self-Referenced Parallel MR Reconstruction and Artifact Correction. 2009 IEEE International Symposium on Biomedical Imaging: From Nano to Macro, Vols 1 and 2, 2009: p. 189-192.
[4] Kay, K.N., et al., GLMdenoise: a fast, automated technique for denoising task-based fMRI data. Frontiers in Neuroscience, 2013. 7.

Keywords: Visual Cortex, high-resolution MRI, Color, macaque monkey, V2

Conference: 11th National Congress of the Belgian Society for Neuroscience, Mons, Belgium, 22 May - 22 May, 2015.

Presentation Type: Poster presentation

Topic: Neuroscience

Citation: Li X, Arsenault J, Janssens T, Zhu Q and Vanduffel W (2015). In-vivo visualization of color-biased stripes in monkey secondary visual cortex (V2) using high-resolution MRI. Front. Neurosci. Conference Abstract: 11th National Congress of the Belgian Society for Neuroscience. doi: 10.3389/conf.fnins.2015.89.00071

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Received: 30 Apr 2015; Published Online: 05 May 2015.

* Correspondence: Prof. Wim Vanduffel, KU Leuven, Department of Neurosciences, Leuven, Belgium, wim.vanduffel@med.kuleuven.be