1.   Indeed, it is extremely difficult to distinguish between the primary visual cortex and surrounding areas in this species.

2.   Matters are further complicated by the fact that information from the two eyes is brought together in the primary visual cortex.

3.   Part of the problem is that they are often on tasks that are also severely impaired after destruction of primary visual cortex.

4.   The strongest evidence for such a contribution comes from studying the effects of removal of the primary visual cortex.

5.   Yet back in the primary visual cortex, the fourth layer is the most impressive of all.

6.   For reasons that are not yet well understood, cells in their primary auditory cortex cannot detect rapid transition phonemes, she said.

7.   From there they enter the primary auditory cortex, which contains cells that specialize in particular frequencies.

8.   The path starts with the primary visual cortex.

9.   The primary visual cortex is the area in the back of the head where information from the eyes first reaches the cortex.