Working memory allows the temporary storage of information, such as memorizing a phone number for a short period of time.
Studies in animals have shown that working memory processes depend on the excitability of neurons in the prefrontal cortex, according to the researchers. There is also evidence that motor neuronal excitability might be related to the neuronal excitability of other cortical regions.
When researchers at the University of Basel studied if the excitability of the motor cortex correlates with working memory performance, results were positive.
“The motor cortical excitability can be easily studied with transcranial magnetic stimulation,” said Nathalie Schicktanz, a doctoral student and first author of the study.
During this procedure, electromagnetic impulses with increasing intensity are applied over the motor cortex.
For subjects with high motor excitability, weak impulses are sufficient to trigger certain muscles — such as those of the hand — to show a visible twitch, she explained.
In the present study, which included 188 healthy young subjects, the scientists were able to show that subjects with a high motor excitability had increased working memory performance as compared to subjects with a low excitability.
“By measuring the excitability of the motor cortex, conclusions can be drawn as to the excitability of other cortical areas,” she said.
“The findings help us to understand the importance of neuronal excitability for cognitive processes in humans,” added Kyrill Schwegler, M.D., co-author of the study.
The results might also have important clinical implications, as working memory deficits are a component of many neuropsychiatric disorders, such as schizophrenia or attention-deficit hyperactivity disorder, the researchers noted.
In a next step, the scientists plan to study the relation between neuronal excitability and memory on a molecular level, they said.
The study is part of a project led by professors Dominique de Quervain, M.D., and Andreas Papassotiropoulos, M.D. The project uses transcranial magnetic stimulation to study cognitive functions in humans. The goal is to identify the neurobiological and molecular mechanisms of human memory, the researchers reported.
Source: University of Basel