Complex sentence: The limbic cortex was separated from the remainder of the cortex by Broca for two reasons: first that it is not convoluted, and second that the gyri are directed parasagitally (contrary to the transverse gyrification).
Split into simpler sentences: The limbic cortex was separated from the remaining of the cortex by Broca on two arguments. The second is that the gyri are directed parasagitally (contrary to the transverse gyrification).