Area Prostriata in the Human Brain

Abstract

Area prostriata is a cortical area at the fundus of the calcarine sulcus, described anatomically in humans [1-5] and other primates [6-9]. It is lightly myelinated and lacks the clearly defined six-layer structure evident throughout the cerebral cortex, with a thinner layer 4 and thicker layer 2 [10], characteristic of limbic cortex [11]. In the marmoset and rhesus monkey, area prostriata has cortical connections with MT+ [12], the cingulate motor cortex [8], the auditory cortex [13], the orbitofrontal cortex, and the frontal polar cortices [14]. Here we use functional magnetic resonance together with a wide-field projection system to study its functional properties in humans. With population receptive field mapping [15], we show that area prostriata has a complete representation of the visual field, clearly distinct from the adjacent area V1. As in the marmoset, the caudal-dorsal border of human prostriata-abutting V1-represents the far peripheral visual field, with eccentricities decreasing toward its rostral boundary. Area prostriata responds strongly to very fast motion, greater than 500°/s. The functional properties of area prostriata suggest that it may serve to alert the brain quickly to fast visual events, particularly in the peripheral visual field.

Neural bases of self‐ and object‐motion in a naturalistic vision

“…Finally, we observed evidence of motion-related responses also in the ventral part of the calcarine scissure, where Mikellidou et al (2017) have recently identified the human prostriate area, a retinotopic region located medially in between RSC and PPA regions responsive to extremely fast motion over a wide visual field (see Supporting Information for details on the mapping procedures and Figure S2A for the anatomical position, MNI coordinates, and size of the region). The prostriate, although not activated on average by motion conditions relative to the Static condition as the PPA, revealed a preference for the Disjoint condition relative to Onboard (see Figure S2B).…”

Visual Cortex: The Eccentric Area Prostriata in the Human Brain

“…Nonetheless, the small size and relative anonymity of this area has left it untouched by human neuroscientists peering inside the brain with tools such as fMRI. A new study by Mikellidou and colleagues in Current Biology [5] is thus bound to garner a lot of attention by providing the first functional description of area Prostriata in the human brain. The authors used a novel method to carry out fMRI mapping of responses to stimuli presented over an unusually wide range of positions, including the far periphery of the visual field.…”

“…This can be particularly important when faced with sudden changes in environmental conditions, as in the case of looming stimuli, and is pivotal to self-motion stabilization, head and body orientation [6]. In keeping with this notion, the study by Mikellidou et al [5] provides the first example of functional preference for very fast motion in any human visual area. The physiological, connectional and anatomical properties of Prostriata together suggest an anatomical network for the analysis of motion in the far periphery that is largely segregated from that in well-studied cortical areas primarily devoted to central vision.…”

“…In summary, the study by Mikellidou et al [5] described for the first time the functional properties of area Prostriata in the human brain. This has been possible by introducing several important novelties in the neuroimaging approach to vision: the use of a wide-field projection system able to map the visual periphery, the choice of stimuli moving at varying speeds, and analysis methods that favor comparisons with previous neurophysiological studies in monkeys.…”

The visual white matter connecting human area prostriata and the thalamus is retinotopically organized

“…described for the first time the functional properties of area prostriata in humans using a novel wide-field visual stimulation system (Greco et al 2016). In humans, area prostriata is located at the junction between the calcarine and parietooccipital (POS) sulci, adjacent to the far peripheral representation of V1 and ventral V2 (Mikellidou et al 2017b). Area prostriata preferentially responds to very fast motion, greater than 500 deg/sec, and has a complete representation of the visual field, clearly distinct from the adjacent area V1.…”