A new patterned air-flow device to reveal the network for tactile motion coding using fMRI.

BACKGROUND: Studying brain processes underlying tactile perception induced by natural-like stimulation is challenging yet crucial to closely match real-world situations. NEW METHOD: We developed a computer-controlled pneumatic device that allows the delivery of complex airflow patterns on subject's body, through a MR-compatible system fixed on an independent clippable mounting device. The intensity of stimulation as well as the timing of each of the four air channels are completely programmable and independent, allowing the precise control and modularity of the airflow delivery. RESULTS: An analysis of signal-to-noise ratio (SNR) measurements did not show any impact of the PAF device on anatomical or functional scan acquisitions. A psychophysical experiment was also performed on 24 volunteers to evaluate the perception of different airflow patterns delivered over the lower part of their face. It revealed that all participants were able to finely discriminate the direction of these leftward to rightward flow motions. The fMRI experiment, which consisted in presenting to 20 participants four different airflow patterns, shed light on the brain network associated with tactile motion perception. A multivariate analysis further showed a specific coding of the different patterns inside this tactile brain network including the primary and secondary somatosensory cortex COMPARISON WITH EXISTING METHOD(S): The Patterned Air-Flow (PAF) is an easy-to-set-up, portable, adaptable device, which can be spatially and temporally modulated to provide complex tactile stimuli. CONCLUSIONS: This device will be useful to further explore complex dynamic touch exerted over various body parts and can also be combined with visual or auditory stimulation to study multisensory mechanisms.

Early head movements elicited by visual stimuli or collicular electrical stimulation in the cat.

During the course of previous recordings of visually-triggered gaze shifts in the head-unrestrained cat, we occasionally observed small head movements which preceded the initiation of the saccadic eye/head gaze shift toward a visual target. These early head movements (EHMs) were directed toward the target and occurred with a probability varying between animals from 0.4% to 16.4% (mean=5.2%, n=11 animals). The amplitude of EHM ranged from 0.4 degrees to 8.3 degrees (mean=1.9 degrees ), their latency from 66 to 270 ms (median=133 ms) and the delay from EHM onset to gaze shift onset averaged 183+/-108 ms (n=240). Their occurrence did not depend on visual target eccentricity in the studied range (7-35 degrees ), but influenced the metrics and dynamics of the ensuing gaze shifts (gain and velocity reduced). We also found in the two tested cats that low intensity microstimulation of the superior colliculus deeper layers elicited a head movement preceding the gaze shift. Altogether, these results suggest that the presentation of a visual target can elicit a head movement without triggering a saccadic eye/head gaze shift. The visuomotor pathways triggering these early head movements can involve the deep superior colliculus.

Lingual ischemia following tongue entrapment in a glass bottle.

A 10-year-old, previously healthy female presented to the emergency department via emergency medical service transport, with her tongue tightly entrapped inside a glass bottle (9 oz, Yoohoo brand of chocolate drink). The tongue was massively edematous and ecchymotic due to impaired venous return from constriction by the neck of the bottle. After repeated attempts at mechanically reducing the tongue out of the bottle, a professional glazier was contacted, who was able to remove the bottle in the operating room with a steel glass cutter. Needle evacuation of a small hematoma was then performed to decrease the pressure ischemia to the tongue, which began to improve quickly.