Complex sentence: Adapting direction selective neurons hyperpolarize due to long duration intracellular sodium and calcium accumulation; and trigger an increase in brain tissue excitability; which spreads via ionic diffusion in the extracellular space and glial assisted mechanisms.
Split into simpler sentences: Adapting direction selective neurons hyperpolarize due to long duration intracellular sodium and calcium ion accumulation. This causes extracellular imbalances and an increase in brain tissue excitability; which spreads via ionic diffusion in extracellular space and glial assisted mechanisms.