Electroencephalographic (EEG) coherence was assessed during a 4-s aiming period prior to trigger pull in expert marksmen (n = 10) and skilled shooters (n = 9) over the course of a regulation round of small-bore rifle shooting. Although both groups were highly experienced, the skilled group had lower ability. Given that specialization of cortical function occurs as domain-specific expertise increases, experts were predicted to exhibit less cortico-cortical communication, especially between cognitive and motor areas, compared to the skilled group. Coherence was assessed for three frequency bands (low alpha, 8–10 Hz; high alpha, 10–13 Hz; and low beta, 13–22 Hz) using sites F3, Fz, F4, C3, Cz, C4, T3, T4, P3, Pz, P4, O1, and O2. Compared to the skilled group, experts exhibited lower coherence between left temporal (T3) and mid-line frontal (Fz) regions for low-alpha and low-beta frequencies, lower coherence for high-alpha between all left hemisphere sites and (Fz), and lower coherence between T3 and all midline sites for the low-beta band. The results reveal that, compared to lesser skilled shooters, experts engage in less cortico-cortical communication, particularly between left temporal association and motor control regions, which implies decreased involvement of cognition with motor processes.

Background Human studies on exercise, cognition, and apolipoprotein E (APOE) genotype show that ε4 carriers may benefit from regular physical activity. Methods We examined voluntary wheel-running, memory, and hippocampal plasticity in APOE ε3 and APOE ε4 transgenic mice at 10–12 months of age. Results Sedentary ε4 mice exhibited deficits in cognition on the radial-arm water maze (RAWM), a task dependent on the hippocampus. Six weeks of wheel-running in ε4 mice resulted in improvements on the RAWM to the level of ε3 mice. Hippocampal brain-derived neurotrophic factor (BDNF) levels were similar in ε3 and ε4 mice, and after exercise BDNF was similarly increased in both ε3 and ε4 mice. In sedentary ε4 mice, tyrosine kinase B (Trk B) receptors were reduced by 50%. Exercise restored Trk B in ε4 mice to the level of ε3 mice, and in ε4 mice, exercise dramatically increased synaptophysin, a marker of synaptic function. Conclusions Our results support the hypothesis that exercise can improve cognitive function, particularly in ε4 carriers.

The authors assessed electroencephalographic coherence to determine the relation between cortico-cortical communication and visuomotor skill in 15 expert and 21 novice rifle shooters. They then calculated coherence and phase angles among the prefrontal (F3, F4) and ipsilateral cortical regions (central, temporal, parietal, occipital) during the aiming period for the theta (4-7 Hz), low-alpha (8-10 Hz), high-alpha (11-13 Hz), low-beta (14-22 Hz), high-beta (23-35 Hz), and gamma (36-44 Hz) bands. The authors subjected them separately to a series of analyses of variance (Group X Hemisphere X Region X Epoch). Experts generally exhibited lower coherence compared with novices, with the effect most prominent in the right hemisphere. The groups also exhibited differences in phase angle in a number of frequency bands. Coherence was positively related to aiming movement variability in experts. The results support refinement of cortical networks in experts and differences in strategic planning related to memory processes and executive influence over visual-spatial cues.

Performance on the Sternberg working memory task, and MEG cortical response on a variation of the Sternberg task were examined in middle-aged carriers and non-carriers of the APOE epsilon4 allele. Physical activity was also assessed to examine whether exercise level modifies the relationship between APOE genotype and neurocognitive function. Regression revealed that high physical activity was associated with faster RT in the six- and eight-letter conditions of the Sternberg in epsilon4 carriers, but not in the non-carriers after controlling for age, gender, and education (N=54). Furthermore, the MEG analysis revealed that sedentary epsilon4 carriers exhibited lower right temporal lobe activation on matching probe trials relative to high-active epsilon4 carriers, while physical activity did not distinguish non-carriers (N=23). The M170 peak was identified as a potential marker for pre-clinical decline as epsilon4 carriers exhibited longer M170 latency, and highly physically active participants exhibited greater M170 amplitude to matching probe trials.