Physiological arousal affects attention and memory, sometimes enhancing and other times impairing what we attend to and remember. In the present study, we investigated how changes in physiological arousal - induced through short bursts of isometric handgrip exercise - affected subsequent working memory performance. A sample of 57 younger (ages 18-29) and 56 older (ages 65-85) participants performed blocks of isometric handgrip exercise in which they periodically squeezed a therapy ball, alternating with blocks of an auditory working memory task. We found that, compared with those in a control group, participants who performed isometric handgrip had faster reaction times on the working memory task. Handgrip-speeded responses were observed for both younger and older participants, across working memory loads. Analysis of multimodal physiological responses indicated that physiological arousal increased during handgrip. Our findings suggest that performing short bouts of isometric handgrip exercise can improve processing speed, and they offer testable possibilities for the mechanism underlying handgrip’s effects on performance. The potential for acute isometric exercise to temporarily improve processing speed may be of particular relevance for older adults who show declines in processing speed and working memory.
Abstract Outcome-guided behavior requires knowledge about the identity of future rewards. Previous work across species has shown that the dopaminergic midbrain responds to violations in expected reward identity and that the lateral orbitofrontal cortex (OFC) represents reward identity expectations. Here we used network-targeted transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) during a trans-reinforcer reversal learning task to test the hypothesis that outcome expectations in the lateral OFC contribute to the computation of identity prediction errors (iPE) in the midbrain. Network-targeted TMS aiming at lateral OFC reduced the global connectedness of the lateral OFC and impaired reward identity learning in the first block of trials. Critically, TMS disrupted neural representations of expected reward identity in the OFC and modulated iPE responses in the midbrain. These results support the idea that iPE signals in the dopaminergic midbrain are computed based on outcome expectations represented in the lateral OFC.
Physiological arousal affects attention and memory, sometimes enhancing and other timesimpairing what we attend to and remember.In the present study, we investigated how changes in physiological arousal -induced through short bursts of isometric handgrip exercise -affected subsequent working memory performance.A sample of 57 younger (ages 18-29) and 56 older (ages 65-85) participants performed blocks of isometric handgrip exercise in which they periodically squeezed a therapy ball, alternating with blocks of an auditory working memory task.We found that, compared with those in a control group, participants who performed isometric handgrip had faster reaction times on the working memory task.Handgrip-speeded responses were observed for both younger and older participants, across working memory loads.Analysis of multimodal physiological responses indicated that physiological arousal increased during handgrip.Our findings suggest that performing short bouts of isometric handgrip exercise can improve processing speed, and they offer testable possibilities for the mechanism underlying handgrip's effects on performance.The potential for acute isometric exercise to temporarily improve processing speed may be of particular relevance for older adults who show declines in processing speed and working memory.
1S. Attanti is a second-year medical student, Mayo Clinic School of Medicine–Scottsdale Campus, Scottdale, Arizona; email: [email protected]. Acknowledgments: The author would like to thank Michael Molloy, MD, for his patience, kindness, and excellence in teaching.
