The evolution of primate short-term memory

Short-term memory is implicated in a range of cognitive abilities and is critical for understanding primate cognitive evolution. To investigate the effects of phylogeny, ecology and sociality on short-term memory, we tested the largest and most diverse primate sample to date (421 non-human primates across 41 species) in an experimental delayed-response task. Our results confirm previous findings that longer delays decrease memory performance across species and taxa. Our analyses demonstrate a considerable contribution of phylogeny over ecological and social factors on the distribution of short-term memory performance in primates; closely related species had more similar short-term memory abilities. Overall, individuals in the branch of Hominoidea performed better compared to Cercopithecoidea, who in turn performed above Platyrrhini and Strepsirrhini. Interdependencies between phylogeny and socioecology of a given species presented an obstacle to disentangling the effects of each of these factors on the evolution of shortterm memory capacity. However, this study offers an important step forward in understanding the interspecies and individual variation in short-term memory ability by providing the first phylogenetic reconstruction of this trait’s evolutionary history. The dataset constitutes a unique resource for studying the evolution of primate cognition and the role of short-term memory in other cognitive abilities

Connectivity of the Cingulate Sulcus Visual Area (CSv) in Macaque Monkeys

International audienceIn humans, the posterior cingulate cortex contains an area sensitive to visual cues to self-motion. This cingulate sulcus visual area (CSv) is structurally and functionally connected with several (multi)sensory and (pre)motor areas recruited during locomotion. In nonhuman primates, electrophysiology has shown that the cingulate cortex is also related to spatial navigation. Recently, functional MRI in macaque monkeys identified a cingulate area with similar visual properties to human CSv. In order to bridge the gap between human and nonhuman primate research, we examined the structural and functional connectivity of putative CSv in three macaque monkeys adopting the same approach as in humans based on diffusion MRI and resting-state functional MRI. The results showed that putative monkey CSv connects with several visuo-vestibular areas (e.g., VIP/FEFsem/VPS/MSTd) as well as somatosensory cortex (e.g., dorsal aspects of areas 3/1/2), all known to process sensory signals that can be triggered by self-motion. Additionally, strong connections are observed with (pre)motor areas located in the dorsal prefrontal cortex (e.g., F3/F2/F1) and within the anterior cingulate cortex (e.g., area 24). This connectivity pattern is strikingly reminiscent of that described for human CSv, suggesting that the sensorimotor control of locomotion relies on similar organizational principles in human and nonhuman primates

The evolution of primate short-term memory

Short-term memory is implicated in a range of cognitive abilities and is critical for understanding primate cognitive evolution. To investigate the effects of phylogeny, ecology and sociality on short-term memory, we tested the largest and most diverse primate sample to date (421 non-human primates across 41 species) in an experimental delayed-response task. Our results confirm previous findings that longer delays decrease memory performance across species and taxa. Our analyses demonstrate a considerable contribution of phylogeny over ecological and social factors on the distribution of short-term memory performance in primates; closely related species had more similar short-term memory abilities. Overall, individuals in the branch of Hominoidea performed better compared to Cercopithecoidea, who in turn performed above Platyrrhini and Strepsirrhini. Interdependencies between phylogeny and socioecology of a given species presented an obstacle to disentangling the effects of each of these factors on the evolution of shortterm memory capacity. However, this study offers an important step forward in understanding the interspecies and individual variation in short-term memory ability by providing the first phylogenetic reconstruction of this trait’s evolutionary history. The dataset constitutes a unique resource for studying the evolution of primate cognition and the role of short-term memory in other cognitive abilities