Browsing by Author "Hautasaari, Pekka"
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Item Bilateral activations in operculo-insular area show temporal dissociation after peripheral electrical stimulation in healthy adults(2020-12) Hautasaari, Pekka; Saloranta, Harri; Savić, Andrej M.; Korniloff, Katariina; Kujala, Urho M.; Tarkka, Ina M.; Tecnalia Research & InnovationInterhemispheric transfer is necessary for sensory integration and coordination of body sides. We studied how somatosensory input from one body side may reach both body sides. First, we investigated with 17 healthy adults in which uni- and bilateral brain areas were involved in consecutive stages of automatic sensory processing of non-nociceptive peripheral stimulation. Somatosensory evoked fields (SEFs) to electrical stimulation were recorded with 306-channel magnetoencephalography in two conditions. First, SEFs were registered following sensory radial nerve (RN) stimulation to dorsal surface of the right hand and second, following median nerve (MN) stimulation at the right wrist. Cortical activations were located in contralateral postcentral gyrus after MN and RN stimulations and in bilateral operculo-insular area after RN stimulation. First component occurred earlier after MN than RN stimulation. Middle latency components had similar latencies with stronger activation in contralateral postcentral gyrus after MN than RN stimulation. Interestingly, long latency components located in bilateral operculo-insular area after RN stimulation showed latency difference between hemispheres, i.e. activation peaked earlier in contralateral than in ipsilateral side. Additional experiments comparing novel intracutaneous nociceptive, RN and MN electrical stimuli confirmed bilateral long latency activation elicited by each stimulus type and highlighted latency differences between hemispheres. Variations in activation of bilateral operculo-insular areas may corroborate their role in pain network and in multisensory integration. Our findings imply that these areas present a relay station in multisensory stimulus detection.Item Long-term physical activity may modify brain structure and function: Studies in young healthy twins(2019) Tarkka, Ina M.; Hautasaari, Pekka; Pesonen, Heidi; Niskanen, Eini; Rottensteiner, Mirva; Kaprio, Jaakko; Savić, Andrej M.; Kujala, Urho M.; Tecnalia Research & InnovationBackground: Physical activity (PA) is said to be beneficial to many bodily functions. However, the effects of PA in the brain are still inadequately known. The authors aimed to uncover possible brain modulation linked with PA. Here, they combine 4 of their studies with monozygotic twins, who were within-pair discordant in PA for a minimum of 1 year. Methods: The authors performed brain imaging, brain electrophysiology, and cardiovascular and body composition assessments, and collected questionnaire-based data. The present synopsis elucidates the differences associated with differing PA history in conditions without genetic variability. They present new structural and electrophysiological results. Participants, healthy, 45 male monozygotic twins (mean age 34.5 [1.5] y) differed in aerobic capacity and fat percentage (P < .001). Results: More active co-twins showed larger gray matter volumes in striatal, prefrontal, and hippocampal regions, and smaller gray matter volumes in the anterior cingulate area than less active co-twins. Functionally, visual and somatosensory automatic change detection processes differed between more and less active co-twins. Conclusions: In monozygotic twins, who differed in their PA history, differences were observed in identifiable anatomic brain locations involved with motor control and memory functions, as well as in electrophysiological measures detecting brain’s automatic processes. Better aerobic capacity may modify brain morphology and sensory function.Item Somatosensory Brain Function and Gray Matter Regional Volumes Differ According to Exercise History: Evidence from Monozygotic Twins: Evidence from Monozygotic Twins(2017-01-01) Hautasaari, Pekka; Savić, Andrej M.; Loberg, Otto; Niskanen, Eini; Kaprio, Jaakko; Kujala, Urho M.; Tarkka, Ina M.; Tecnalia Research & InnovationAssociations between long-term physical activity and cortical function and brain structure are poorly known. Our aim was to assess whether brain functional and/or structural modulation associated with long-term physical activity is detectable using a discordant monozygotic male twin pair design. Nine monozygotic male twin pairs were carefully selected for an intrapair difference in their leisure-time physical activity of at least three years duration (mean age 34 ± 1 years). We registered somatosensory mismatch response (SMMR) in EEG to electrical stimulation of fingers and whole brain MR images. We obtained exercise history and measured physical fitness and body composition. Equivalent electrical dipole sources of SMMR as well as gray matter (GM) voxel counts in regions of interest indicated by source analysis were evaluated. SMMR dipolar source strengths differed between active and inactive twins within twin pairs in postcentral gyrus, medial frontal gyrus and superior temporal gyrus and in anterior cingulate (AC) GM voxel counts differed similarly. Compared to active twins, their inactive twin brothers showed greater dipole strengths in short periods of the deviant-elicited SMMR and larger AC GM voxel counts. Stronger activation in early unattended cortical processing of the deviant sensory signals in inactive co-twins may imply less effective gating of somatosensory information in inactive twins compared to their active brothers. Present findings indicate that already in 30′s long-term physical activity pattern is linked with specific brain indices, both in functional and structural domains.