Brain Activity

The goal of this clinical trial is to learn whether a single session of high-intensity interval exercise (HIIT) affects cognitive performance and brain activity in older adults, and whether cardiorespiratory fitness influences these effects. The main questions it aims to answer are: * Does a single HIIT session change performance on a task-switching test of cognitive flexibility? * Does a single HIIT session change prefrontal brain activity during cognitive testing, as measured by functional near-infrared spectroscopy (fNIRS)? * Do older adults with higher cardiorespiratory fitness show greater cognitive and brain changes in response to HIIT than those with lower fitness? Participants will: * Visit the laboratory on two separate days * Complete a sub-maximal graded exercise test during the first visit to measure cardiorespiratory fitness * Complete a single \~30-minute HIIT cycling session during the second visit * Complete a task-switching cognitive test before and after the HIIT session * Have their brain activity monitored with fNIRS while completing the cognitive tests

Adult epilepsy patients who are undergoing intracranial monitoring will participate in a simple behavioral task during the clinical recording period.

The goal of this pilot clinical trial is to test whether transcranial photobiomodulation (tPBM), a non-invasive brain stimulation technique using near-infrared light, can improve brain blood flow regulation (neurovascular coupling) and cognitive function in older adults. The main questions it aims to answer are: * Does tPBM enhance neurovascular coupling responses during memory and finger tapping tasks? * Are these improvements linked to better cognitive performance and lower levels of brain inflammation and oxidative stress? Researchers will compare an active tPBM treatment arm to a sham treatment arm to see if tPBM leads to measurable improvements in brain activity and cognitive function compared to no active stimulation. Participants will: * Receive either active tPBM or sham stimulation sessions for 4 weeks, every other day using a portable intervention device. * Complete questionnaires and an iPAD-based cognitive testing protocol * Complete memory and motor tasks while their brain activity is measured using non-invasive techniques: simultaneous functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG), transcranial doppler (TCD) flowmetry. * Retinal vessel reactivity will be measured during flickering light stimulus using a special camera (dynamic vessel analysis, DVA). * Provide blood samples to test for biomarkers of inflammation, oxidative stress and brain cell damage.

Linguistic irregularities in number naming systems, such as the inversion of number words, affect the processing of Arabic numerals. Recently, it has been claimed that there is even a syntactic representation of number words. participant investigate the neurofunctional correlates of the syntactic processing of number words by examining different levels of place-value processing in a study with two complementary successive phases (Group 1 and Group 2) in healthy adults. In the first phase with Group 1, participant evaluate the unit-decade compatibility effect (UDCE) in two-digit magnitude comparisons. In the second phase with Group 2, participant investigate the carry-over effect in two-digit addition problems.