While the rectum is innervated by visceral afferents, the anal canal is innervated by the somatosensory pudendal nerve. The representation of these two central domains of intestinal sensations in the human brain is largely unknown. Nonpainful pneumatic stimulation of the anal canal and the distal rectum using event-related functional magnetic resonance imaging (fMRI) was performed in eight heal...

Peripheral somatosensory circuits are known to respond to diverse stimulus modalities. The energy modalities capable of eliciting somatosensory responses traditionally belong to mechanical, thermal, electromagnetic, and photonic domains. Ultrasound (US) applied to the periphery has also been reported to evoke diverse somatosensations. These observations however have been based primarily on subj...

UNLABELLED Reward-related dopaminergic influences on learning and overt behaviour are well established, but any influence on sensory decision-making is largely unknown. We used functional magnetic resonance imaging (fMRI) while participants judged electric somatosensory stimuli on one hand or other, before being rewarded for correct performance at trial end via a visual signal, at one of four a...

Pioneering mapping studies of the human cortex have established the notion of somatotopy in sensory representation, which transpired into Penfield and Rasmussen's famous sensory homunculus diagram. However, regarding the primary cortical representation of the genitals, classical and modern findings appear to be at odds with the principle of somatotopy, often assigning it to the cortex on the me...

1. This investigation was designed to identify the source of cholinergic basal forebrain projections to somatosensory cortex in the cat. 2. Injections of horseradish peroxidase (HRP) into cortical areas 3a, 3b, and 1 after a 36 to 48-h survival period, labeled neurons in the basal forebrain. The distribution of retrogradely labeled neurons was compared with the distribution of cells labeled by ...

We review research on somatosensory (tactile) processing of the tongue based on data obtained using non-invasive neurophysiological and neuroimaging methods. Technical difficulties in stimulating the tongue, due to the noise elicited by the stimulator, the fixation of the stimulator, and the vomiting reflex, have necessitated the development of specialized devices. In this article, we show the ...

Mice homozygous for the barrelless (brl) mutation, mapped here to chromosome 11, lack barrel-shaped arrays of cell clusters termed "barrels" in the primary somatosensory cortex. Deoxyglucose uptake demonstrated that the topology of the cortical whisker representation is nevertheless preserved. Anterograde tracers revealed a lack of spatial segregation of thalamic afferents into individual barre...

To study the patterns of supraspinal pain processing in neonates, we hypothesized that acute pain causes haemodynamic changes associated with activation of the primary somatosensory cortex. Forty preterm neonates at 28-36 weeks of gestation (mean=32.0) and at 25-42 h (mean=30.7) of age were studied following standardized tactile (skin disinfection) and painful (venipuncture) stimuli. Changes in...

Transcranial magnetic stimulation (TMS) has been used to document some apparent interhemispheric influences behaviorally, with TMS over the right parietal cortex reported to enhance processing of touch for the ipsilateral right hand (Seyal et al., 1995). However, the neural bases of such apparent interhemispheric influences from TMS remain unknown. Here, we studied this directly by combining TM...

Change in transmitting time of impulses along axons is traditionally attributed to two parameters: the myelin formation and the diameter of neurite, both rising during the postnatal development. In the previous study, we showed that conduction velocity of the fibers projecting from the thalamus to the layer IV of the somatosensory (barrel) cortex increases as a function of age. However, the con...