differences between techniques or species?

The holy grail of comparative neuroanatomy is to show how humans are unique. Yet most recent evidence seems to suggest a remarkable degree of similarity. One well known claim for a uniquely human anatomical structure concerned the extreme capsule fibre complex (ECFC), a prominent white bundle connecting brain regions involved in language and social cognition. The strong extensions of this bundle to occipital cortex evident in the human seemed to be lacking in the monkey. But analyses of this tract in humans were based on diffusion-MRI tractography – a technique used to map white matter systems – while the monkey studies used invasive tracer techniques – aimed to reveal the connections of individual neurons. In a paper published in Brain Structure and Function Rogier Mars shows how apparent differences between species disappear when both species are analysed using the same technique, diffusion-MRI tractography.