It seems to be involved in the evaluative function," Kable says. In other words, it was more active for positive events than for negative events, but it was not influenced at all by vividness. "One network, which we'll call the dorsal default mode network, was influenced by valence. The work confirmed two sub-networks at play. Each time, the Penn researchers watched brain activity from the fMRI. Participants went through the process four times. How positive or negative is the event? Is this something you want to have happen or not?" "Vividness is the degree to which the image that comes to mind has a lot of details and how much those details subjectively pop as opposed to being vague," Kable says. Participants had seven seconds to read one of 32 cues such as, "Imagine you're sitting on a warm beach on a tropical island," or "Imagine you win the lottery next year." They then had 12 seconds to think about the scenario, followed by 14 seconds to rate vividness and valence. To do so, he and his team created a study in which 13 females and 11 males received prompts while in a functional magnetic resonance imaging (fMRI) machine. Kable wanted to test that idea further, to better pinpoint the implicated regions and what's happening in each. Previous research had revealed which areas make up the DMN and that constructing and evaluating imagined events activates different components. "When you put people into a brain scanner and ask them to not do anything, to just sit there, these are the brain regions that seem to be active," he says. ![]() The DMN itself includes the ventromedial prefrontal cortex, posterior cingulate cortex, and regions in the medial temporal and parietal lobes, such as the hippocampus. But a critical function is the evaluative function it's not just about coming up with a possibility but also evaluating it as good or bad." "When psychologists talk about why humans have the ability to imagine the future, usually it's so we can decide what to do, plan, make decisions. The other assesses whether that newly constructed event is positive or negative, what they call the "evaluative" function. One helps create and predict the imagined event, what the researchers call the "constructive" function. In a paper published in the Journal of Neuroscience, the research team discovered that, when it comes to imagining the future, the default mode network actually splits into two complementary parts. Now, research from Kable and two former graduate students in his lab, Trishala Parthasarathi, associate director of scientific services at OrtleyBio, and Sangil Lee, a postdoc at University of California, Berkeley, sheds light on the matter. ![]() ![]() Though the field has long suspected that this neural network plays a role in imagining the future, precisely how it works hadn't been fully understood. "These regions seem to be active when people aren't asked to do anything in particular, as opposed to being asked to do something cognitively," says Penn neuroscientist Joseph Kable. In quiet moments, the brain likes to wander-to the events of tomorrow, an unpaid bill, an upcoming vacation.ĭespite little external stimulation in these instances, a part of the brain called the default mode network (DMN) is hard at work.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |