Carlos Paladini, UTSA associate professor of biology, was awarded a $1.3 million, five-year grant from the National Institutes of Health to study which inputs in the brain drive dopamine cells to fire faster.
Dopamine cells release a chemical or neurotransmitter in the brain called dopamine, which drives motivated and reward-related behaviors. The loss of dopamine cells in the brain is associated with Parkinson’s disease cases, and the effects of drugs of abuse on dopamine cells can lead to addiction. Paladini hopes the research results will eventually assist in helping to find therapies to cure drug addiction and treat patients with Parkinson’s disease.
The researcher and his graduate students are focusing on the spikes of electrical activity associated with dopamine cells in the brain and the effects they have in driving motivated behavior. They hope to learn how dopamine cells get access to information in the brain that drives reward-related behavior.
"We want to find out what are the inputs to the dopamine cells that actually drive the cells to either increase their activity in terms of a reward or reward signal, and what are the inputs that drive the cell to decrease their activity if the reward that was expected was not received," said Paladini. "We don’t know which inputs or which parts of the brain connect to dopamine cells to inform the cell and give it all the information it needs to calculate whether it should fire faster or slower."
To conduct the research, the scientists are using optical fibers to stimulate dopamine cell inputs that produce a protein that is sensitive to blue light. A virus with a gene is injected into the inputs and that gene makes the cells produce a protein that is sensitive to blue light. When the protein is shone with blue light, it activates the cell, which is similar to what occurs when a reward takes place.
"If we go to the region where the dopamine cells are and shine a blue light, only those inputs that are producing that protein will be activated," Paladini said. "We will know for certain that when we shine blue light and activate only one input, whatever effect we see in a dopamine cell is going to be due to the effect on those inputs that have that specific protein and not any other inputs that are there."