ABSTRACT
On the one hand, there appears to be a purely anatomical distinction between ‘lower’ and ‘higher’ parts of the brain, where ‘the top’ of this axis is to be understood, somewhat loosely, as the anterior frontal regions such as the prefrontal cortex, and the bottom are the more posterior and ‘deeper’ structures terminating at the brain stem. In these terms, the model also carries evolutionary connotations, as the axis distinguishes the ‘lower’ reptile brain from the higher, more advanced mammalian – and ultimately human – brain.
