2.2. Primary cortical neuron isolation and culture

Cerebral cortices were extracted from embryonic day 18 Sprague–Dawley rats (Charles River) and dissociated to isolate cortical neurons, as described (Struzyna et al., 2015b). Following dissociation, neurons were resuspended at 2–4 × 10⁵ cells/ml in defined co-culture medium (neurobasal medium +2% B-27, 1% G-5 and 0.25% L-glutamine). To assess the interaction between neurons and stretched astrocyte processes, approximately 10–20 μl neuronal solution was added to the cultures containing stretched astrocytes; however, the neurons were added some distance away from the processes in order to enable the assessment of neuronal migration onto the ‘stretch-grown’ astrocyte processes.