That's not a brain, it's the soft tissues of the neck after a melanoma resection. What I'm showing in the video is the occipital artery which is pulsating if you look closely enough. Right next to this artery is the greater occipital nerve. You can see them clearly since the oncologic surgeon had to make a big hole, but you also notice that these two structures lie right next to one another. Therefore, without this big hole and if the space between these two structures is narrowed by scar or an enlarged vessel, that artery would be constantly banging against that nerve and can cause a lot of pain - i.e. occipital neuralgia.