Showing papers by "Francisco Aboitiz published in 2021"

The Enigmatic Reissner's Fiber and the Origin of Chordates.

Abstract: Reissner's fiber (RF) is a secreted filament that floats in the neural canal of chordates. Since its discovery in 1860, there has been no agreement on its primary function, and its strong conservation across chordate species has remained a mystery for comparative neuroanatomists. Several findings, including the chemical composition and the phylogenetic history of RF, clinical observations associating RF with the development of the neural canal, and more recent studies suggesting that RF is needed to develop a straight vertebral column, may shed light on the functions of this structure across chordates. In this article, we will briefly review the evidence mentioned above to suggest a role of RF in the origin of fundamental innovations of the chordate body plan, especially the elongation of the neural tube and maintenance of the body axis. We will also mention the relevance of RF for medical conditions like hydrocephalus, scoliosis of the vertebral spine and possibly regeneration of the spinal cord.

Agency Improves Working Memory and Accelerates Visual and Attentional Processing

Abstract: Agency, understood as the ability of an organism to control stimuli onset, modulates perceptual and attentional functions. Since stimulus encoding is an essential component of working memory (WM), we conjectured that the perceptual process9s agency would positively modulate WM. To corroborate this proposition, we tested twenty-five healthy subjects in a modified-Sternberg WM task under three stimuli presentation conditions: an unpredictable presentation of encoding stimulus, self-initiated presentation of the stimulus, and self-initiation presentation with random-delay stimulus onset. Concurrently, we recorded the subjects9 electroencephalographic signals during WM encoding. We found that the self-initiation condition was associated with better WM accuracy, and earlier latencies of N100 and P200 evoked potential components representing visual and attentional processes, respectively. Our work demonstrates that agency enhances WM performance and accelerates early visual and attentional processes deployed during WM encoding. We also found that self-initiation presentation correlates with an increased attentional state compared to the other two conditions, suggesting a role for temporal stimuli predictability. Our study remarks on the relevance of agency in sensory and attentional processing for WM.

Are there differences in the development of the executive functions of children with a typical and atypical development stimulated by a game on a tablet

Abstract: "Introduction: Executive functions (EF) are developed early, building a fundamental basis of higher cognitive processes in adulthood (Garon et al., 2008). There are studies with children of typical development (Passolunghi et al., 2006; Welsh et al., 2010) that have demonstrated the key role of EF, such as working memory, inhibitory control, planning and attentional flexibility, in initial literacy and precalculus. What is still unclear is whether these EF can be stimulated early and if it has any effect on their development. At the same time, it is known that children with atypical development, such as ADHD, have deficiencies in the development of EF (Barkley, 1997). Early stimulation of EF in this type of population will have the same effects as in a typical development population? The objective of the study is to evaluate the effect of a stimulation program of the EF (working memory, inhibitory control, planning and attentional flexibility), by means of a tablet digital game, in the development of the EF of preschool children with and without symptoms of ADHD, of socioeconomically disadvantaged sectors. Method: Two groups, control (CG) and intervention (IG) were selected at random, both were evaluated twice (before and after). In total there were 408 participants, 212 with typical development and 196 with atypical development. The IG was exposed to a digital game of EF through a tablet during 12 sessions (in the classroom). Results: The main results show differences in favor of IG in the different EF evaluated, both for children with and without ADHD symptoms, with the exception of attentional variable for which no differences were observed. There are differences in the effect of EF among children evaluated. Discussion: These differences and their possible implications in the educational and social environment are discussed."