Showing papers by "Ralph Norgren published in 1986"
TL;DR: The efferent projections of the parvicellular division of the ventroposteromedial nucleus of the thalamus (VMPpc; thalamic taste area) were traced to cortex in Macaca fascicularis by using tritiated amino acid autoradiography.
Abstract: The efferent projections of the parvicellular division of the ventroposteromedial nucleus of the thalamus (VMPpc; thalamic taste area) were traced to cortex in Macaca fascicularis by using tritiated amino acid autoradiography. Labeled fascicles could be traced from VPMpc to two discrete regions of cortex. The primary efferent projection was located on ipsilateral insular-opercular cortex adjacent to the superior limiting sulcus and extended as far rostrally as the posterior lateral orbitofrontal cortex. An additional projection was located within primary somatosensory (SI) cortex subjacent to the anterior subcentral sulcus. Following autoradiographic injections in VPM, the trigeminal somatosensory relay, a dense terminal plexus was labeled on SI cortex of both pre- and postcentral gyri, but not within insular-opercular cortex. The autoradiographic data were verified by injecting each cortical projection area with horseradish peroxidase (HRP) and observing the pattern of retrogradely labeled somata within the thalamus. Injections in the precentral gyrus near the anterior subcentral sulcus retrogradely labeled neurons within VPMpc, whereas injections further caudally near the floor of the central sulcus labeled neurons within VPM. Injections of HRP within opercular, insular, or posterior lateral orbitofrontal cortex retrogradely labeled neurons within VPMpc.
276 citations
TL;DR: Tongue temperature was found to be represented in the cortical area previously termed gustatory, i.e., in ventral granular cortex where layer IV attenuates, in contrast to its traditional assignation to granular insular cortex.
248 citations
TL;DR: Electromyographic responses to intraoral sapid stimulation were recorded from a subset of orofacial and pharyngeal muscles in a freely moving chronic preparation suggesting that tactile (fluid) stimulation initiates the ingestive sequence and that gustatory stimuli modulate this ongoing activity.
Abstract: Previous behavior studies (Grill & Norgren, 1978) demonstrated that gustatory stimuli produce stereotyped orofacial movements that constitute the observable concomitants of ingestion and rejection. For further clarification of the relation between these orofacial movements (the buccal phase of ingestion) and the act of swallowing (the pharyngeal phase), electromyographic responses to intraoral sapid stimulation were recorded from a subset of orofacial and pharyngeal muscles in a freely moving chronic preparation. Activity in a jaw opening muscle {anterior digastric), a facial muscle (zygomatic), tongue protruder (genioglossus), tongue retractor (styloglossus), and a pharyngeal constrictor used in swallowing (thyropharyngeus) differentiated between ingestive sequences to water (W), sucrose (S), and NaCl (N) and a rejection response elicited by quinine monohydrochloride (Q). Ingestion responses to W, S, and N consisted of rhythmic alternations between genioglossus and styloglossus activity (intraoral licks) accompanied by episodic bursts of pharyngeal constrictor activity (swallowing). Both bout duration and the number of swallows increased at higher concentrations of S and N. In contrast, Q stimulation elicited a rejection response, characterized by several licks and followed by long duration contractions of the zygomatic and anterior digastric muscles (gapes). During gapes, styloglossus activity rather than genioglossus activity was simultaneous with that of the anterior digastric. At higher concentrations of Q, the latency to gape decreased and the latency to swallow increased. The earliest components of the response to S, N, or Q were virtually indistinguishable from one another, results suggesting that tactile (fluid) stimulation initiates the ingestive sequence and that gustatory stimuli modulate this ongoing activity.
180 citations
TL;DR: If both the anterior tongue and nasoincisor ducts are included, stimulation of taste receptors in the anterior oral cavity of the rat produces good responses to stimuli representing 3 of the 4 classical taste qualities: sweet, salty, and sour.
160 citations
TL;DR: The thalamic relay for lingual tactile, thermal, and gustatory sensibility was defined electrophysiologically in the rat and injections of tritiated leucine were centered in these functionally defined locations in separate series of rats.
140 citations
01 Jan 1986