Search results for "Evolution of the brain"

2017

Functional near infrared spectroscopy (fNIRS) is a promising neuroimaging method for investigating networks of cortical regions over time. We propose a directed effective connectivity method (TPDC) allowing the capture of both time and frequency evolution of the brain’s networks using fNIRS data acquired from healthy subjects performing a continuous finger-tapping task. Using this method we show the directed connectivity patterns among cortical motor regions involved in the task and their significant variations in the strength of information flow exchanges. Intra and inter-hemispheric connections during the motor task with their temporal evolution are also provided. Characterisation of the …

Postpleistocene evolution of the brain?

1976

The number of extraneurons (Nc) has been calculated with the formulae of Jerison ('63) for prehistoric population samples to check the hypothesis that Nc may not only increase by increasing of cranial capacity but also by decreasing of body-weight (gracilisation). Body weight of skeletal populations has been estimated by the formula of Debetz ('67). Samples from the Western part of Europe and Egypt support the hypothesis, but Eastern europoid samples display opposite relations: Nc increases with robusticity. It seems (as Jerison already suggested) that Nc is no measurement of the level of behavior in the populations of H. sapiens; but it may point towards allometric differences between West…