Area V5—a microcosm of the visual brain

Abstract

Area V5 of the visual brain, first identified anatomically in 1969 as a separate visual area, is critical for the perception of visual motion. As one of the most intensively studied parts of the visual brain, it has yielded many insights into how the visual brain operates. Among these are: the diversity of signals that determine the functional capacities of a visual area; the relationship between single cell activity in a specialized visual area and perception of, and preference for, attributes of a visual stimulus; the multiple asynchronous inputs into, and outputs from, an area as well as the multiple operations that it undertakes asynchronously; the relationship between activity at given, specialized, areas of the visual brain and conscious awareness; and the mechanisms used to “bind” signals from one area with those from another, with a different specialization, to give us our unitary perception of the visual world. Hence V5 is, in a sense, a microcosm of the visual world and its study gives important insights into how the whole visual brain is organized—anatomically, functionally and perceptually.

Individual differences in visual motion perception and neurotransmitter concentrations in the human brain

“…An examination of the relationship between the perceived strength of each single motion phenomenon and the concentrations of neurotransmitters in the V1 should be performed in future studies. A similar argument can be applied to the fact that we did not find a correlation between the individual differences in motion perception and the neurotransmitter concentrations in the MT, where it is crucially important for motion perception [6,32]. If we examine the relationship between the neurotransmitter concentrations and the perceived strength of motion assimilation in the spatiotopic coordinate, but not motion contrast in the retinotopic coordinate, we might have some clues regarding the function of neurotransmitters on visual motion perception in the MT.…”

“…Therefore, if an individual difference is based on the perceived strength of motion contrast, which might originate in V1, the GABA concentration in the V1 could be correlated with an individual difference because of the inhibitory nature of the motion contrast, a subtype of the motion aftereffect [6,9,14]. Second, the MT is known to play a crucial role in visual motion perception [6,32], and this representation would be based on the spatiotopic coordinates [17,18]. Therefore, if an individual difference is rooted in motion assimilation, which might originate in the MT, the neurotransmitter concentration in the MT could be correlated with an individual difference.…”

Towards a unified perspective of object shape and motion processing in human dorsal cortex

“…In the example of the parent chasing a child, the motion signals available at the retinae are a combination of signals that arise from the parent turning their head, moving their eyes, moving their body through the environment, and the motion of the child. Intriguingly, many regions of dorsal cortex that are implicated the coding of 3-D shape, such as V3A, V6, V6A and regions along IPS, are also known to be involved in global motion perception (for reviews, see Galletti & Fattori, 2018; Gilaie-Dotan, 2016; Kravitz et al, 2011; Zeki, 2015). In fact, there is a tight relationship between motion and shape processing (for a review, see Mather, Pavan, Marotti, Campana, & Casco, 2013).…”

Neural plasticity and concepts ontogeny

“…In the visual cortex of marmoset monkeys Bourne and Rosa (2006) found that areas higher than V1 develop later, with the sole exception of the middle temporal area MT, which is also a phylogenetically old area, found in all primates, discovered and studied for decades by Zeki (1974Zeki ( , 2015. In humans the homologous of MT is area V5, and its old phylogenetic origin is probably related to its early development, and a strong genetic determination of its connectivity.…”