The 5th Edition has updated artwork that contains numerous, critical errors. Two examples:
In the chapter on synaptic plasticity, there is a figure on the property of associativity with a text box that says synapse not strengthened, when it should say strengthened. The 4th edition does not have this error.
In the chapter on upper motor neuron control, the first figure shows that the upper motor neurons from the cortex synapse mainly on the medial horn grey matter, when it should say the lateral grey horn matter. Again, the 4th edition does not have this error.
There are other, smaller errors in figures (transporters showing Na moving in the wrong direction) that are correct in the 4th Edition.
Bottom Line- It's a good text, but every figure you look at you'll be wondering if it's correct or an error. It wastes your time. Get the 4th Edition.