Minor formatting fix to stevens_jn13 notebook
Minor formatting fix to stevens_jn13 notebook

ioam/topographica,mjabri/topographica,Tasignotas/topographica_mirror,Tasignotas/topographica_mirror,Tasignotas/topographica_mirror,ioam/topographica,ioam/topographica,ioam/topographica,mjabri/topographica,Tasignotas/topographica_mirror,ioam/topographica,Tasignotas/topographica_mirror,mjabri/topographica,mjabri/topographica,mjabri/topographica