Strengthening and weakening the connections between neurons, known as synapses, is vital to the brain's development and everyday function. One way that neurons weaken their synapses is by swallowing up receptors on their surfaces that normally respond to glutamate, one of the brain's excitatory chemicals
Human activities that can increase the rate would be air from a car exhaust, large factories, and gas lawn mowers. All of these make rain more acidic which causes more chemical weathering.
