in the resarch article Nicotine excites VIP interneurons to disinhibit pyramidal nuerons in auditory cortex what is the difference between direct and indiect depolarisation and why is the differentiation significant to the results Nicotine excites VIP interneurons to disinhibit pyramidal nuerons in auditory cortex what is the difference between direct and indiect depolarisation and why is the differentiation significant to the results.