Regional Neural Response Differences in the Determination of Faces or Houses Positioned in a Wide Visual Field

Bin Wang,Susumu Kanazawa,Jinglong Wu,Tianyi Yan,Seiichiro Ohno,Kewei Chen,Satoshi Imajyo

doi:10.1371/journal.pone.0072728

Abstract

In human visual cortex, the primary visual cortex (V1) is considered to be essential for visual information processing; the fusiform face area (FFA) and parahippocampal place area (PPA) are considered as face-selective region and places-selective region, respectively. Recently, a functional magnetic resonance imaging (fMRI) study showed that the neural activity ratios between V1 and FFA were constant as eccentricities increasing in central visual field. However, in wide visual field, the neural activity relationships between V1 and FFA or V1 and PPA are still unclear. In this work, using fMRI and wide-view present system, we tried to address this issue by measuring neural activities in V1, FFA and PPA for the images of faces and houses aligning in 4 eccentricities and 4 meridians. Then, we further calculated ratio relative to V1 (RRV1) as comparing the neural responses amplitudes in FFA or PPA with those in V1. We found V1, FFA, and PPA showed significant different neural activities to faces and houses in 3 dimensions of eccentricity, meridian, and region. Most importantly, the RRV1s in FFA and PPA also exhibited significant differences in 3 dimensions. In the dimension of eccentricity, both FFA and PPA showed smaller RRV1s at central position than those at peripheral positions. In meridian dimension, both FFA and PPA showed larger RRV1s at upper vertical positions than those at lower vertical positions. In the dimension of region, FFA had larger RRV1s than PPA. We proposed that these differential RRV1s indicated FFA and PPA might have different processing strategies for encoding the wide field visual information from V1. These different processing strategies might depend on the retinal position at which faces or houses are typically observed in daily life. We posited a role of experience in shaping the information processing strategies in the ventral visual cortex.

Highlights

The human visual cortex is organized hierarchically
The neural response amplitudes and the values of ratio relative to central position (RRCP) demonstrated the significant differences for each position in V1, fusiform face area (FFA), and parahippocampal place area (PPA)
Measuring the ratio relative to V1 (RRV1), we found that the FFA and PPA process the visual information from V1 using different neural processing strategies

Summary

Introduction

The human visual cortex is organized hierarchically. The visual information from retinal ganglion cells is eventually processed in the visual cortex. A number of strategies are used for efficient information processing within this hierarchy, including linear and nonlinear filtering [1,2] These strategies are used with the aim of creating different compact visual and functional representations in the organization of the visual cortex [3,4,5,6]. The visual system seems to represent central stimuli with a fair degree of fidelity, but it more crudely encodes stimuli in peripheral field. Even with such imprecise encoding, the visual stimuli from our peripheral vision are important in determining eye movements [8,9] and in object-motion perception [10], for example. Peripheral vision has mostly been characterized in terms of the reductions in resolution or contrast sensitivity as the eccentricity increasing [11,12]

Methods

Results

Discussion

Conclusion