Researchers at Harvard Medical School have been able to pinpoint the neurons that are capable of deciphering the value that people attach to different items. The activity of these neurons predicts the nature of decision making, when a person needs to choose from an array of items available.
To quote the words of Camillo Padoa-Schioppa, PhD, HMS research fellow in neurobiology and lead author of the paper 'We have long known that different neurons in various parts of the brain respond to separate attributes, such as quantity, color, and taste. But when we make a choice, for example: between different foods, we combine all these attributes--we assign a value to each available item. The neurons we have identified encode the value individuals assign to the available items when they make choices based on subjective preferences, a behavior called 'economic choice.'
We are making choices everyday, and some of them range between a choice of working and earning more or enjoying more leisure time, or choosing to invest in bonds or in stocks. There is an apparent neural bases of an economic choice, which actually involves assigning value to the available options in front of us. Now, researchers are trying to comprehend the brain mechanisms that are actually working to make this possible.
In the study, Padoa-Schioppa and John Assad, PhD, HMS associate professor of neurobiology, found a sizeable number of neurons located in the orbitofrontal cortex (OFC) that assigns values to different goods on a common value scale. Assigning values on a common scale allows comparing goods, like apples and oranges, that otherwise lack a natural basis for comparison.
Padoa-Schioppa says 'The activity of these neurons reflects the value subjects assign to the available goods when they make choices. A concrete possibility is that various choice deficits may result from an impaired or dysfunctional activity of this population, though this hypothesis remains to be tested.'
In the experiment conducted by Padoa-Schioppa, macaque monkeys were observed making a choice between two types of juice offered in different amounts. Dung the course of some trials, the monkeys chose between one drop of grape juice and one drop of apple juice. In other trials, the monkey chose between one drop of grape juice and two drops of apple juice, etc Padoa-Schioppa observed a compromise between the type of juice and the quantity of juice, portraying that the value attached by the monkey to one drop of grape juice is approximately equal to the value the monkey assigns to three drops of apple juice.
These choices made by the monkeys were linked to the neuron activity. The activity of one particular neuron could be low when the monkey chose one drop of grape juice or when it chose three drops of apple juice. The activity of the same neuron might have been moderately high when the monkey chose two drops of grape juice or when it chose six drops of apple juice. And the activity of the same neuron would have been high when the monkey chose three drops of grape juice or when it chose 10 drops of apple juice.
This means that the activity of such OFC neurons is important that actually assigns the value chosen by the monkey, which is exclusive of any of the traits of the juice, either taste or quantity. The choice pattern exhibited by the monkeys, could be based on the activity of these neurons.
Source: Eureka Alert