Retinotopic mapping of the peripheral visual field to human visual cortex by functional magnetic resonance imaging

Abstract

Retinotopic mapping is a key property of organization in the human occipital cortex. The retinotopic organization of the central visual field of visual areas V1, V2, and V3 has been well established. We used fMRI to measure the retinotopic map of the peripheral visual field (eccentricity up to 60°). We estimated the sizes of the visual areas between 0° and 60° and obtained results consistent with anatomical studies. We also estimated the cortical distances and magnification factors for reconstruction of the retinotopic map using the peripheral wedge dipole model. By comparing the retinotopic map with the flattened surface, we analyzed the datasets used to reconstruct the map. We found that: (1) the percentage of the striate cortex devoted to peripheral vision in humans is significantly larger than that in the macaque, (2) the estimate of the scaling factor in linear magnification is larger than that found in previous studies focusing on central vision, and (3) the estimate of the peripheral factor in the dipolar model is too large to make the curve direction of the dipolar map in the periphery equivalent to that in the center. On the basis of our results, we revised the dipolar map to fit our conditions. The revised map in humans has a similar elliptical shape to that of macaques, and the central parts of the two species are the same. The different parts of the map are the peripheral regions, for which the peripheral wedge dipole model in humans is reversed compared to that of macaques.

Retinotopic mapping of visual event-related potentials

“…Stimuli consisted of a dartboard centered on a gray background, as employed in mfVEPs studies (Baseler et al, 1994;Horton and Hoyt, 1991b;Wu et al, 2012). The diameter of the dartboard was 40 cm.…”

“…It was divided into 60 sectors of different polar angle and eccentricity. Each sector comprised a white and black checkerboard of 4 by 4 checks, scaled accordingly to compensate for cortical magnification (Baseler et al, 1994;Horton and Hoyt, 1991b;Wu et al, 2012). Thus, the sectors were placed in six concentric rings of radius 1.2°, 2.6°, 5.8°, 9.8°, 14.9° and 22.2° (see Figure 1).…”

Representation of central and peripheral vision in the primate cerebral cortex: Insights from studies of the marmoset brain

“…The representation of the peripheral visual field in the human cortex is poorly understood, largely due to technical difficulties related to the delivery of visual stimuli in MRI scanners. However, wide-field stimulus delivery systems are becoming more common in fMRI studies (Cheng et al, 1995;Pitzalis et al, 2006;Wu et al, 2012Wu et al, , 2013. Prostriata activation has likely been observed in fMRI experiments (for example, Huang and Sereno, 2013), but because it has not yet been formally established by fMRI as a visual area in the human brain, this may have been erroneously attributed to V1, or generically classified as activation of the retrosplenial cortex.…”

Novel magnetomechanical MR compatible vibrational device for producing kinesthetic illusion during fMRI

“…This method is typically used in retinotopic studies to map activations in the visual cortex due to a changing stimulus. 22,23 The stimulus was approximated to a box car function of 6 s of flexion illusion (12.5 → 83 Hz) and 6 s of extension illusion (83 → 12.5 Hz). The resulting waveform was convolved with the hemodynamic response function (HRF) to produce a model of the expected response.…”