Brief hearing loss disrupts binaural integration during two early critical periods of auditory cortex development.

Early binaural experience can recalibrate central auditory circuits that support spatial hearing. However, it is not known how binaural integration matures shortly after hearing onset or whether various developmental stages are differentially impacted by disruptions of normal binaural experience. Here we induce a brief, reversible unilateral conductive hearing loss (CHL) at several experimentally determined milestones in mouse primary auditory cortex (A1) development and characterize its effects ~1 week after normal hearing is restored.

Functional brain imaging of a complex navigation task following one night of total sleep deprivation: a preliminary study.

Several neuroimaging studies have demonstrated compensatory cerebral responses consequent to sleep deprivation (SD), but all have focused on simple tasks with limited behavioral response options. We assessed the cerebral effects associated with SD during the performance of a complex, open-ended, dual-joystick, 3D navigation task (simulated orbital docking) in a cross-over protocol, with counterbalanced orders of normal sleep (NS) and a single night of total SD (approximately 27 h). Behavioral performance on multiple measures was comparable in the two sleep conditions.

Hemodynamic evoked response of the sensorimotor cortex measured noninvasively with near-infrared optical imaging.

We have performed a noninvasive bilateral optical imaging study of the hemodynamic evoked response to unilateral finger opposition task, finger tactile, and electrical median nerve stimulation in the human sensorimotor cortex. This optical study shows the hemoglobin-evoked response to voluntary and nonvoluntary stimuli. We performed measurements on 10 healthy volunteers using block paradigms for motor, sensory, and electrical stimulations of the right and left hands separately.

A quantitative comparison of simultaneous BOLD fMRI and NIRS recordings during functional brain activation.

Near-infrared spectroscopy (NIRS) has been used to noninvasively monitor adult human brain function in a wide variety of tasks. While rough spatial correspondences with maps generated from functional magnetic resonance imaging (fMRI) have been found in such experiments, the amplitude correspondences between the two recording modalities have not been fully characterized. To do so, we simultaneously acquired NIRS and blood-oxygenation level-dependent (BOLD) fMRI data and compared Delta(1/BOLD) (approximately R(2)(*)) to changes in oxyhemoglobin, deoxyhemoglobin, and total hemoglobin concentrations derived from the NIRS data from subjects performing a simple motor task.