Lateral frontal cortex oxygenation changes during translation and language switching revealed by non-invasive near-infrared multi-point measurements.

The organisation of language in the brain of multilingual people remains controversial. Using a high temporal resolution 12-channel near-infrared continuous wave spectroscopy system, we have demonstrated that it is possible to monitor non-invasively, comfortably and, without the interferences due to intrinsic limitations of positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), cortical oxygenation changes in the Broca's area in response to translation of short sentences and language switching. Eight Dutch students proficient in English translated aloud from their native language into English or vice versa or alternating (switching) short visually presented sentences.

Simultaneous measurements of cerebral oxygenation changes during brain activation by near-infrared spectroscopy and functional magnetic resonance imaging in healthy young and elderly subjects.

Near infrared spectroscopy (NIRS) and functional magnetic resonance imaging (fMRI) both allow non-invasive monitoring of cerebral cortical oxygenation responses to various stimuli. To compare these methods in elderly subjects and to determine the effect of age on cortical oxygenation responses, we determined motor-task-related changes in deoxyhemoglobin concentration ([HHb]) over the left motor cortex in six healthy young subjects (age 35 +/- 9 years, mean +/- SD) and five healthy elderly subjects (age 73 +/- 3 years) by NIRS and blood-oxygen-level-dependent (BOLD) fMRI simultaneously. The motor-task consisted of seven cycles of 20-sec periods of contralateral finger-tapping at a rate as fast as possible alternated with 40-sec periods of rest.

Effects of acetazolamide and furosemide on ventilation and cerebral blood volume in normocapnic and hypercapnic patients with COPD.

Study Objectives: Effects of chronic metabolic alkalosis and acidosis and their relation to central chemoregulation may differ between normocapnic and chronic hypercapnic patients with COPD. The relationship between responses of inspired ventilation (VI), mouth occlusion pressure (P(0.1)), and cerebral blood volume (CBV), to short-term changes in arterial PCO(2) was measured.