Journal Article

In vivo functional localization of the temporal monocular crescent representation in human primary visual cortex

LaPierre, Cristen, Stockmann, Jason P., Polimeni, Jonathan R., Nasr, Shahin, Witzel, Thomas, Vaughn, Christopher E.

2020

Overview

The temporal monocular crescent (TMC) is the most peripheral portion of the visual field whose perception relies solely on input from the ipsilateral eye. According to a handful of post-mortem histological studies in humans and non-human primates, the TMC is represented visuotopically within the most anterior portion of the primary visual cortical area (V1). However, functional evidence of the TMC visuotopic representation in human visual cortex is rare, mostly due to the small size of the TMC representation (~6% of V1) and due to the technical challenges of stimulating the most peripheral portion of the visual field inside the MRI scanner. In this study, by taking advantage of custom-built MRI-compatible visual stimulation goggles with curved displays, we successfully stimulated the TMC region of the visual field in eight human subjects, half of them right-eye dominant, inside a 3 ​T MRI scanner. This enabled us to localize the representation of TMC, along with the blind spot representation (another visuotopic landmark in V1), in all volunteers, which match the expected spatial pattern based on prior anatomical studies. In all hemispheres, the TMC visuotopic representation was localized along the peripheral border of V1, within the most anterior portion of the calcarine sulcus, without any apparent extension into the second visual area (V2). We further demonstrate the reliability of this localization within/across experimental sessions, and consistency in the spatial location of TMC across individuals after accounting for inter-subject structural differences. •We used custom-built goggles to stimulate the temporal monocular crescent (TMC).•Accelerated imaging was used to achieve 1.2-mm isotropic voxels in a 3T scanner.•We have provided in vivo functional evidence for the TMC cortical representation.•We found a consistency in the TMC and blind spot representations across subjects.

• Publisher: Elsevier Inc,Elsevier Limited,Elsevier
• Subject: Adult / Blind spot / Brain Mapping - instrumentation / Brain Mapping - methods / Cortex (temporal) / Eye Protective Devices / Female / Functional MRI / Humans / Light emitting diodes / Localization / Magnetic resonance imaging / Magnetic Resonance Imaging - methods / Male / Medical imaging / MRI-Compatible goggles / Optic Disk - anatomy & histology / Optic Disk - diagnostic imaging / Optic Disk - physiology / Photic Stimulation / Scanners / TMC / Transistors / Visual cortex / Visual Cortex - anatomy & histology / Visual Cortex - diagnostic imaging / Visual Cortex - physiology / Visual field / Visual Fields - physiology / Visual perception / Visual stimuli / Visuotopy / Young Adult