It was the object of this study to measure the time course of the action potential in individual human sensory nerve fibres in relation to conduction properties of the axons. For this purpose, the technique of percutaneous microneurography was combined with intradermal electrical stimulation of distal portions of the axons. Recordings were made at the wrist level from 57 type-identified mechano...

We used psychometric techniques and neurophysiological recordings to study the role of the putamen in somesthetic perception. Four monkeys were trained to categorize the speed of moving tactile stimuli. Animals performed a task in which one of two target switches had to be pressed with the right hand to indicate whether the speed of probe movement across the glabrous skin of the left, restraine...

Our aim was to investigate the influence of microgravity on the sensitivity of the skin to mechanical stimulation, epidermal thickness, peripheral nerve density in the upper dermis, and serum levels of a stress marker in a rat hindlimb suspension (HS) model. Thirty 8-week-old male Wistar rats were randomly divided into 3 groups: HS, n=10; sham HS, n=10; control, n=10. The suspension system was ...

OBJECTIVE Tactile spatial acuity is routinely tested in neurology to assess the state of the dorsal column system. In contrast, spatial acuity for pain is not assessed, having never been systematically characterized. More than a century after the initial description of tactile acuity across the body, we provide the first systematic whole-body mapping of spatial acuity for pain. METHODS We eva...

The effects of a mild freeze injury to the skin on responses of nociceptive dorsal horn neurons to cold and heat stimuli were examined in anesthetized rats. Electrophysiological recordings were obtained from 72 nociceptive spinal neurons located in the superficial and deep dorsal horn. All neurons had receptive fields (RFs) on the glabrous skin of the hindpaw, and neurons were functionally divi...

The capacity of single neurons of the dorsal column nuclei (DCN) for coding vibrotactile information from the hairy skin has been investigated in anesthetized cats to permit quantitative comparison first with the capacities of DCN neurons responding to glabrous skin vibrotactile inputs and second with those of spinocervical tract neurons responding to vibrotactile inputs from hairy skin. Dynami...

A new pneumatic tactile stimulator, called the TAC-Cell, was developed in our laboratory to non-invasively deliver patterned cutaneous stimulation to the face and hand in order to study the neuromagnetic response adaptation patterns within the primary somatosensory cortex (S1) in young adult humans. Individual TAC-Cells were positioned on the glabrous surface of the right hand, and midline of t...

The coexistence of distinct phenotypes within populations has long been investigated in evolutionary ecology. Recent studies have identified the genetic basis of distinct phenotypes, but it is poorly understood how the variation in candidate loci is maintained in natural environments. In this study, we examined fitness consequences and genetic basis of variation in trichome production in a natu...

Quantitative variation for leaf trichome number is observed within and among Gossypium species, varying from glabrous to densely pubescent phenotypes. Moreover, economically important cotton lint fibers are modified trichomes. Earlier studies have mapped quantitative trait loci (QTLs) affecting leaf pubescence in Gossypium using allotetraploids. In this study, we mapped genes responsible for le...