Localization of an experimental hypothalamic and midbrain syndrome simulating sleep

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49959/1/901000309_ftp.pd

Dynamic Peer-to-Peer Competition

The dynamic behavior of a multiagent system in which the agent size $s_{i}$ is variable it is studied along a Lotka-Volterra approach. The agent size has hereby for meaning the fraction of a given market that an agent is able to capture (market share). A Lotka-Volterra system of equations for prey-predator problems is considered, the competition factor being related to the difference in size between the agents in a one-on-one competition. This mechanism introduces a natural self-organized dynamic competition among agents. In the competition factor, a parameter $\sigma$ is introduced for scaling the intensity of agent size similarity, which varies in each iteration cycle. The fixed points of this system are analytically found and their stability analyzed for small systems (with $n=5$ agents). We have found that different scenarios are possible, from chaotic to non-chaotic motion with cluster formation as function of the $\sigma$ parameter and depending on the initial conditions imposed to the system. The present contribution aim is to show how a realistic though minimalist nonlinear dynamics model can be used to describe market competition (companies, brokers, decision makers) among other opinion maker communities.Comment: 17 pages, 50 references, 6 figures, 1 tabl

Triadic (ecological, neural, cognitive) niche construction: a scenario of human brain evolution extrapolating tool use and language from the control of reaching actions

Hominin evolution has involved a continuous process of addition of new kinds of cognitive capacity, including those relating to manufacture and use of tools and to the establishment of linguistic faculties. The dramatic expansion of the brain that accompanied additions of new functional areas would have supported such continuous evolution. Extended brain functions would have driven rapid and drastic changes in the hominin ecological niche, which in turn demanded further brain resources to adapt to it. In this way, humans have constructed a novel niche in each of the ecological, cognitive and neural domains, whose interactions accelerated their individual evolution through a process of triadic niche construction. Human higher cognitive activity can therefore be viewed holistically as one component in a terrestrial ecosystem. The brain's functional characteristics seem to play a key role in this triadic interaction. We advance a speculative argument about the origins of its neurobiological mechanisms, as an extension (with wider scope) of the evolutionary principles of adaptive function in the animal nervous system. The brain mechanisms that subserve tool use may bridge the gap between gesture and language—the site of such integration seems to be the parietal and extending opercular cortices

The nuclear configuration and cortical connections of the human thalamus

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49943/1/900830102_ftp.pd

Sleep Disorders and Genes

Versão preprintThe sleep-wake cycle is a neurobiological phenomenon that shows intervals of activity alternating with restfulness that appears with a periodicity approximating the 24h day-night cycle. The sleep-wake cycle is under the control of diverse neuroanatomical and neurochemical systems, including monoaminergic, cholinergic, adenosinergic among many other systems. In addition, neuroanatomical centers linked to sleep promotion, such as hypothalamus, project to the cerebral cortex, subcortical relays and brainstem. In addition, the sleep-wake cycle has been associated to aberrant features known as sleep disorders. Here, we will discuss the role of specific gene expression on sleep disturbances. Given the expansion of the knowledge in the sleep-wake cycle area, it is indeed ambitious to describe all the genetics involved in the sleep modulation. However, in this chapter we reviewed the current understanding of the sleep disorders and gene expression.info:eu-repo/semantics/publishedVersio

Certain phylogenetic anatomical relations of localizing significance for the mammalian central nervous system

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49919/1/900710202_ftp.pd

Corticostriatal connectivity fingerprints:Probability maps based on resting-state functional connectivity

Over the last decade, structure-function relationships have begun to encompass networks of brain areas rather than individual structures. For example, corticostriatal circuits have been associated with sensorimotor, limbic, and cognitive information processing, and damage to these circuits has been shown to produce unique behavioral outcomes in Autism, Parkinson's Disease, Schizophrenia and healthy ageing. However, it remains an open question how abnormal or absent connectivity can be detected at the individual level. Here, we provide a method for clustering gross morphological structures into subregions with unique functional connectivity fingerprints, and generate network probability maps usable as a baseline to compare individual cases against. We used connectivity metrics derived from resting-state fMRI (N = 100), in conjunction with hierarchical clustering methods, to parcellate the striatum into functionally distinct clusters. We identified three highly reproducible striatal subregions, across both hemispheres and in an independent replication dataset (N = 100) (dice-similarity values 0.40-1.00). Each striatal seed region resulted in a highly reproducible distinct connectivity fingerprint: the putamen showed predominant connectivity with cortical and cerebellar sensorimotor and language processing areas; the ventromedial striatum cluster had a distinct limbic connectivity pattern; the caudate showed predominant connectivity with the thalamus, frontal and occipital areas, and the cerebellum. Our corticostriatal probability maps agree with existing connectivity data in humans and non-human primates, and showed a high degree of replication. We believe that these maps offer an efficient tool to further advance hypothesis driven research and provide important guidance when investigating deviant connectivity in neurological patient populations suffering from e.g., stroke or cerebral palsy. Hum Brain Mapp 38:1478-1491, 2017. © 2016 Wiley Periodicals, Inc.status: publishe