Fig. 7.

Difference between excitatory and inhibitory intracollicular synaptic projections constructs a Mexican hat-type center–surround interaction within the SC. Wider inhibitory connections width (${\mathit{\sigma }}_{\mathrm{inh}}=1.2$ mm > ${\mathit{\sigma }}_{\mathrm{exc}}=0.4$ mm) with larger excitatory connection weight (${\overline{w}}_{\mathrm{exc}}=160$ pS $>{\overline{w}}_{\mathrm{inh}}=50$ pS results in local excitation and global inhibition. ${\overline{w}}_{\mathrm{exc}}$ and ${\overline{w}}_{\mathrm{inh}}$ values are optimized by a genetic algorithm to minimize burst profile dissimilarities (Eqs. 12, 11). It thus accounts for the synchronization of burst profiles within the population