Spiral wave in a two-layer neuronal network Yu Feng, Abdul Jalil M. Khalaf, Fawaz E. Alsaadi, Tasawar Hayat and Viet-Thanh Pham Eur. Phys. J. Special Topics, 228 11 (2019) 2371-2379 Published online: 28 October 2019 DOI: 10.1140/epjst/e2019-900082-6