PET scanners allow doctors to actually see and study human brain activity. Though this method is exponentially more reliable than examining the brain of a rodent, animal experiments continue to provide inaccurate data for human neuroscience.
If research funding was channelled into breakthrough technology like this, it's hard to imagine how far we might have already come for patients with Parkinson's, Alzheimer's, and Multiple Sclerosis.
What about the argument that animal experimentation is indispensable as our only model of intact metabolic systems?
This assertion suggests that in vitro research methodologies, though valuable, cannot predict what will happen in a whole living system, which is true. But history has proven that results in lab animals are even more inadequate - predicting results solely for the animal tested, not humans.
Given that metabolic processes differ greatly between species, information garnered in animal experiments has no predictive value and is wholly unscientific when applied to humans. Very often substances that have proven effective in animals demonstrate no curative value for humans, sometimes even causing harm.
By using in vitro research and new technology we can simulate the living intact human far better than a lab animal can. All drugs must eventually be tested on humans, and those humans are every bit the lab creatures that animals are. These "clinical phases" of drug testing, as they are called, submit human volunteers to what are at first very incremental dosages, monitor their reactions, and slowly increase dosage.
Clinical testing and subsequent non-animal methods, such as epidemiology and post-marketing drug surveillance, provide what lab animals cannot - 100% accurate measures of the human metabolic processes.