Brain can indeed be modelled by NNs, however the neurons in brain are more complex and requires use of more complex neural models like Hodgkin–Huxley model or c

Brain can indeed be modelled by NNs, however the neurons in brain are more complex and requires use of more complex neural models like Hodgkin–Huxley model or can be approximated by more simplified models like Integrate and Fire models. ( ref: https://www.humanbrainproject.eu/en/ https://www.humanbrainproject.eu/en/ )