PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “gustatory cortex”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1987

Architecture and frontal cortical connections of the premotor cortex (area 6) in the rhesus monkey.

The premotor cortex (area 6) has several architectonic sectors that can be delineated on the basis of cytoarchitectonic and myeloarchitectonic features. Area 6 may be broadly subdivided into a dorsal and a ventral sector at the spur of the arcuate sulcus. Dorsal 6 lacks a granular layer IV, but ventral 6 has an emergent layer IV that separates laminae III and V. Dorsal 6 has a higher myelin content than ventral 6. Dorsal area 6 is further subdivided into a caudal and a rostral sector on the basis of the presence of large pyramidal cells in the caudal but not in the rostral sector. The rostral sector of area 6 can be subdivided into a medial region distinguished from a more laterally situated area by the presence of more compact and darkly stained cells in layers III and V. Ventral area 6 can be subdivided into an upper and lower division. The upper part has more prominent pyramidal cells in layers III and V, and a better developed outer Baillarger band and vertical plexus than the lower division. The efferent and afferent connections of area 6 were studied with anterograde and retrograde tracers. The frontal connections of dorsal area 6 are restricted to neighboring dorsal frontal regions. Only the caudal sector of dorsal area 6 is connected with the motor cortex. In contrast, ventral area 6 is not only connected with the prefrontal cortex, but also directly with the motor cortex, the parainsular gustatory area, and with somatosensory areas in the frontal operculum. The widespread connections of ventral area 6 may be related to the specialization of the head, neck, and face structures that are represented ventrally within the premotor cortex.

Afferent Pathways↗
PubMed1991

Cytochrome oxidase staining facilitates unequivocal visualization of the primary gustatory area in the fronto-operculo-insular cortex of macaque monkeys.

Fronto-opercular and insular cortices of Japanese macaques were histochemically stained for cytochrome oxidase activity. The laminated pattern of enzyme activity differed in the different cytoarchitectonic areas. Area G, the presumed primary gustatory area, as well as area 3 were prominent because the third stripe, corresponding to the termination layers of the specific thalamocortical projection in these areas was very dark and thick in comparison with that from the neighboring areas. This approach provides a convenient histological aid for identification of area G.

Animals↗
PubMed1990

Gustatory responses of single neurons in the caudolateral orbitofrontal cortex of the macaque monkey.

1. In recordings made from 3,120 single neurons, a secondary cortical taste area was found in the caudolateral part of the orbitofrontal cortex of the cynomolgus macaque monkey, Macaca fascicularis. The area is part of the dysgranular field of the orbitofrontal cortex and is situated anterior to the primary cortical taste areas in the frontal opercular and adjoining insular cortices. 2. The responses of 49 single neurons with gustatory responses in the caudolateral orbitofrontal taste cortex were analyzed using the taste stimuli glucose, NaCl, HCl, quinine HCl, water, and blackcurrant juice. 3. A breadth-of-tuning coefficient was calculated for each neuron. This is a metric that can range from 0.0 for a neuron that responds specifically to only one of the four basic taste stimuli to 1.0 for one that responds equally to all four stimuli. The mean coefficient for 49 cells in the caudolateral orbitofrontal cortex was 0.39. This tuning is much sharper than that of neurons in the nucleus of the solitary tract of the monkey, and sharper than that of neurons in the primary frontal opercular and insular taste cortices. 4. A cluster analysis showed that at least seven different groups of neurons were present. For each of the taste stimuli glucose, blackcurrant juice, NaCl, and water, there was one group of neurons that responded much more to that tastant than to the other tastants. The other groups of neurons responded to two or more of these tastants, such as glucose and blackcurrant juice. In this particular region neurons were not found with large responses to HCl or quinine HCl, although such neurons could be present in other parts of the orbitofrontal cortex. 5. On the basis of this and other evidence it is concluded that in the caudolateral orbitofrontal cortex there is a secondary cortical taste area in which the tuning of neurons has become finer than in early areas of taste processing, in which foods, water, and NaCl are strongly represented and where motivation dependence first becomes manifest in the taste system.

Animals↗
PubMed2001

Parasympathetic and sympathetic control of the pancreas: a role for the suprachiasmatic nucleus and other hypothalamic centers that are involved in the regulation of food intake.

To reveal brain regions and transmitter systems involved in control of pancreatic hormone secretion, specific vagal and sympathetic denervation were combined with injection of a retrograde transsynaptic tracer, pseudorabies virus (PRV), into the pancreas. After sympathetic or vagal transsection first-order neurons were revealed in the dorsal motor nucleus of the vagus (DMV) or in preganglionic spinal cord neurons (SPN), respectively. Careful timing of the survival of the animals allowed the detection of cell groups in immediate control of these DMV or SPN neurons. A far larger number of cell groups is involved in the control of DMV than of SPN neurons. Examples are given of a high level of interaction between the sympathetic and parasympathetic nervous system. Several cell groups project to both branches of the autonomic nervous system, sometimes even the same neurotransmitter is used, e.g., oxytocin neurons in the paraventricular nucleus and melanin-concentrating hormone and orexin neurons in the lateral hypothalamus project to both the DMV and SPN neurons. Moreover, the appearance of third-order neurons located in the sympathetic SPN after complete sympathectomy and in the DMV after complete vagotomy illustrates the possibility that motor neurons of the sympathetic and parasympathetic system may exchange information by means of interneurons. The presence of second-order neurons in prefrontal, gustatory, and piriform cortex may provide an anatomic basis for the involvement of these cortices in the cephalic insulin response. The observation that second-order neurons in both vagal and sympathetic control of the pancreas contain neuropeptides that are known to play a role in food intake indicates a direct association between behavioral and autonomic functions. Finally, the observation of third-order neurons in the suprachiasmatic nucleus and ventromedial hypothalamus shows the modulatory action of the time of the day and metabolic state, respectively.

Animals↗
PubMed2005

The appreciation of wine by sommeliers: a functional magnetic resonance study of sensory integration.

We set out to investigate how the expertise of a sommelier is embodied in neural circuitry by comparing brain activity elicited by wine tasting with that found in naive drinkers of wine. We used fMRI to study 7 sommeliers and 7 age- and sex-matched control subjects to test the hypothesis that any difference in brain activity would reflect a learned ability to integrate information from gustatory and olfactory senses with past experience. A group analysis showed activation of a cerebral network involving the left insula and adjoining orbito-frontal cortex in sommeliers. Both these areas have been implicated in gustatory/olfactory integration in primates. In addition, activation was found bilaterally in the dorsolateral prefrontal cortex, which is implicated in high-level cognitive processes such as working memory and selection of behavioral strategies. Naive individuals activated the primary gustatory cortex and brain areas, including the amygdala, implicated in emotional processing.

Adult↗
PubMed1987

Reciprocal functional connections of the olfactory bulbs and other olfactory related areas with the prefrontal cortex.

Reciprocal putative connections of the prefrontal cortex (PFC) (agranular insular, ventral and lateral orbital region) with the ipsi and contralateral main olfactory bulb (IOB; COB), the mediodorsal thalamic nucleus (MD), the basolateral amygdaloid nucleus (BLA) and the piriform cortex (PC) were investigated with electrophysiological techniques. Evoked field responses and orthodromic unit driving, generated in PFC following electrical stimulation of the above mentioned structures, were abolished following topical application of KCl, except for COB evoked mass potentials. Thus, locally generated activity was elicited in agranular insular cortex following IOB activation, the same region where recently, the taste cortex in the rat was localized. Since gustatory-visceral afferent information reaches insular cortex via 2-3 synaptic relays, autonomic, olfactory and gustatory inputs may interact at this level, and, as suggested previously for the mouse, play a key integrative role in flavor perception. Antidromically invaded neurons, 47% of which were identified by the collision-extinction technique, were also found in PFC areas which overlapped to a considerable extent with those from which orthodromic unit responses were obtained. In particular, closely spaced neurons in ventrolateral orbital (VLO) and lateral orbital (LO) regions were antidromically invaded following IOB and PC shocks; some neurons antidromically discharged by IOB were also transsynaptically activated following PC stimulation. These findings are in agreement with recent neuroanatomical studies which demonstrate axonal projections from PFC neurons to the IOB and COB in the rat and South American armadillo. In addition, stimulation of PFC regions dorsal to the rhinal fissure mostly inhibited spontaneous unit discharges recorded at the mitral cell layer of the IOB, suggesting that this effect may be partially mediated by excitatory inputs of prefrontal axons onto granule cells. The conduction properties, antidromic thresholds and activity-dependent variations in conduction velocity (CV) of bulbopetal neurons in prefrontal cortex were found to be similar to those exhibited by cells projecting to the IOB from olfactory peduncle regions, but not to those present in bulbopetal neurons of the horizontal limb of diagonal band, indicating that the OB may be subjected to centrifugal control by at least two cell groups differing in both histochemical and electrophysiological properties.

Afferent Pathways↗
PubMed2000

The effect of lesions of the insular cortex on instrumental conditioning: evidence for a role in incentive memory.

In three experiments, we assessed the effect of lesions aimed at the gustatory region of the insular cortex on instrumental conditioning in rats. In experiment 1, the lesion had no effect on the acquisition of either lever pressing or chain pulling in food-deprived rats whether these actions earned food pellets or a maltodextrin solution. The lesion did, however, attenuate the impact of outcome devaluation, induced by sensory-specific satiety, on instrumental performance but only when assessed in an extinction test. This effect was not secondary to an impairment in instrumental learning; in experiment 2, no evidence was found to suggest that the lesioned rats differed from shams in their ability to encode the specific action-outcome contingencies to which they were exposed during training. In experiment 3, however, lesioned rats were found to be insensitive to the impact of an incentive learning treatment conducted when they were undeprived; although, again, this deficit was confined to a test conducted in extinction. These results are consistent with the view that, in instrumental conditioning, the gustatory region of the insular cortex is involved in encoding the taste of food outcomes in memory and, hence, in encoding the incentive value assigned to these outcomes on the basis of prevailing motivational conditions.

Analysis of Variance↗
PubMed2004

To-and-fro optical voltage signal propagation between the insular gustatory and parietal oral somatosensory areas in rat cortex slices.

Taste perception depends not only on special taste information processed in the insular cortex, but also on oral somesthetic processing in the parietal cortex. Many insular cortex neurons show multimodal responsiveness. Such multimodality may be enabled by signal exchange between these two cortices. By using the protocol that we have developed, a synchronized population oscillation of synaptic potentials was induced in the parietal cortex by stimulation to the insular cortex in rat neocortex slices. The spatiotemporal pattern of propagation of this oscillation was studied by recording voltage-sensitive optical signals and field potentials. The first wavelet of the oscillation was propagated from the insular stimulation site to the parietal cortex. However, the second and later wavelets propagated back from the parietal cortex to the insular cortex. The oscillation was detected in the insular cortex as well, but was actually generated in the parietal cortex. Thus, the initial peak of optical signal, sent from the insular to parietal cortex, served to generate oscillatory responses in the parietal cortex, which propagated back to the insular cortex wave-by-wave. We propose that this to-and-fro propagation may be an artificially exaggerated demonstration of an intrinsic mechanism relevant to signal exchange between the parietal and insular cortices.

Animals↗
PubMed1975

Cortical responses to electrical and gustatory stimuli in the rabbit.

The distribution of surface positive cortical potentials evoked by electrical stimulation of the chorda tympani, glossopharyngeal and lingual nerves which innervate the tongue was mapped in rabbits. All projections were bilateral. Judging from the extent of the cortical response area and the amplitude and latency of the responses, the major projection of the chorda tympani was ipsilateral, whereas that of the lingual and the glossopharyngeal nerves was contralateral. Both the chorda tympani and the glossopharyngeal nerve project to a confined area in the insular cortex and the lingual nerve projects to the appropriate part of the somatotopic pattern of somatic sensory area I. Further, a single unit study was undertaken to characterize the response of units in the cerebral cortex which was induced by gustatory stimulation of the anterior tongue, Twenty-four gustatory units were found in the insular cortex and the claustrum. The gustatory units were divided into an early response type (21 units) and a late response type (3 units) based on latency measurements. Gustatory units were also classified according to discharge patterns into excitation type (21 units) and inhibition type (4 units). Eleven units responded to 1 or 2 kinds of conventional taste stimuli, and 13 units responded to more than 3 different taste stimuli. Sensitivities of cortical units to the 4 conventional taste stimuli were found to be mutually independent and randomly distributed among cortical units. The frequency of discharges increased in the excitation type units and decreased in the inhibition type units monotonically with the excitation type units and decreased in the inhibition type units monotonically with an increse of NaCl concentration exfept at the highest concentrations.

Animals↗
PubMed1992

Cytoarchitecture and neural afferents of orbitofrontal cortex in the brain of the monkey.

The orbitofrontal cortex of the monkey can be subdivided into a caudal agranular sector, a transitional dysgranular sector, and an anterior granular sector. The neural input into these sectors was investigated with the help of large horseradish peroxidase injections that covered the different sectors of orbitofrontal cortex. The distribution of retrograde labeling showed that the majority of the cortical projections to orbitofrontal cortex arises from a restricted set of telencephalic sources, which include prefrontal cortex, lateral, and inferomedial temporal cortex, the temporal pole, cingulate gyrus, insula, entorhinal cortex, hippocampus, amygdala, and claustrum. The posterior portion of the orbitofrontal cortex receives additional input from the piriform cortex and the anterolateral portion from gustatory, somatosensory, and premotor areas. Thalamic projections to the orbitofrontal cortex arise from midline and intralaminar nuclei, from the anteromedial nucleus, the medial dorsal nucleus, and the pulvinar nucleus. Orbitofrontal cortex also receives projections from the hypothalamus, nucleus basalis, ventral tegmental area, the raphe nuclei, the nucleus locus coeruleus, and scattered neurons of the pontomesencephalic tegmentum. The non-isocortical (agranular-dysgranular) sectors of orbitofrontal cortex receive more intense projections from the non-isocortical sectors of paralimbic areas, the hippocampus, amygdala, and midline thalamic nuclei, whereas the isocortical (granular) sector receives more intense projections from the dorsolateral prefrontal area, the granular insula, granular temporopolar cortex, posterolateral temporal cortex, and from the medial dorsal and pulvinar thalamic nuclei. Retrograde labeling within cingulate, entorhinal, and hippocampal cortices was most pronounced when the injection site extended medially into the dysgranular paraolfactory cortex of the gyrus rectus, an area that can be conceptualized as an orbitofrontal extension of the cingulate complex. These observations demonstrate that the orbitofrontal cortex has cytoarchitectonically organized projections and that it provides a convergence zone for afferents from heteromodal association and limbic areas. The diverse connections of orbitofrontal cortex are in keeping with the participation of this region in visceral, gustatory, and olfactory functions and with its importance in memory, motivation, and epileptogenesis.

Afferent Pathways↗
PubMed2002

Neurons associated with behavioral context errors in the primary and higher-order gustatory cortices in the monkey.

Cue responses of neurons in the taste-related cortex of Japanese macaque monkeys were studied during a NaCl-water discrimination GO-NOGO task, to compare the correct and incorrect responses. Most neurons produced a steady pattern of discharges in response to a given cue at both correct and incorrect responses, presumably responding to the physicochemical nature of the cue. Some neurons showed the discharge pattern for a certain cue changing to that for another cue at task error, presumably representing the subsequent behavioral reaction or behavioral context. These neurons were mainly located in the precentral operculum and orbitofrontal cortex, and rarely in the primary gustatory area, area G.

Action Potentials↗
PubMed1990

A search for the cortical gustatory area in the hamster.

The gustatory area was searched in the cerebral cortex of the hamster by means of a combined approach using electrophysiological, behavioral, and histological experiments. The chorda tympani (CT), which innervates taste buds on the anterior part of the tongue, projected to a confined area anterior to the middle cerebral artery and just dorsal to the rhinal fissure. The trigeminal component of the lingual nerve (LN) area was located anterodorsal to the CT area, and the glossopharyngeal nerve (GN), which innervates taste buds on the posterior part of the tongue, was posterior to the CT area. The center of the CT and GN areas belonged to the dorsal part of the dysgranular insular cortex, and the LN area was within the primary somatosensory granular cortex. Bilateral symmetrical ablations of the CT and GN areas abolished the conditioned taste aversion (to sodium saccharin) that had been acquired before ablations, indicating a role of these areas in some cognitive processes of taste perception. Injections of horseradish peroxidase conjugated with wheat germ agglutinin (WGA-HRP) in the CT and GN areas, centered in the dysgranular insular cortex, revealed that this cortical region had major fiber connections with the contralateral homotypical cortical area, ipsilateral amygdala (central, lateral and basolateral nuclei), ipsilateral parvicellular part of the posteromedial ventral nucleus of the thalamus, bilateral parabrachial nucleus, contralateral nucleus of the solitary tract, raphe nuclei, and the locus ceruleus. Conversely, injections of WGA-HRP in these target areas showed anterograde and/or retrograde transport in the similar dysgranular insular cortex and additionally in the ventral part of the granular insular cortex. The present results suggest that the cortical gustatory area of the hamster is about 1.5 X 1.5 mm in size with the topographic organization between anterior and posterior parts of the tongue, and is located mainly in the dysgranular insular cortex around the middle cerebral artery.

Afferent Pathways↗
PubMedDate not supplied

Brain mechanisms of taste aversion learning in the rat.

This study aims to reveal brain mechanisms underlying the conditioned taste aversion (CTA) learning. To establish CTA in Wistar male adult rats, 0.01 M Na-saccharin and IP injection of 0.15 M LiCl were used for conditioned stimulus and unconditioned stimulus, respectively. Rats with ibotenic acid lesions of the pontine taste area, thalamic taste area, or basolateral nucleus of the amygdala, failed to establish CTA learning, but lesions of the amygdaloid nuclei other than the basolateral nucleus, cortical gustatory area, hippocampus, entorhinal cortex, bed nucleus of the stria terminalis, or substantia innominata, showed slight or little effects. Rats that received amino-phosphovaleric acid chronically in the amygdala failed to establish CTA. These results, together with our preliminary results, suggest that long-term potentiation of gustatory responses involving N-methyl-D-aspartate receptors in the basolateral nucleus of the amygdala is a basic mechanism for CTA learning.

2-Amino-5-phosphonovalerate↗
PubMed1999

Re-examination of the human taste region: a positron emission tomography study.

There is considerable uncertainty regarding the cortical areas in the human brain that are involved in gustatory processing. Evidence from nonhuman primates indicates that parts of the peri-central opercular region (secondary somatosensory cortex) and insular cortex may be important for gustatory processing. The aim of the study was to examine changes in cerebral blood flow during gustatory stimulation (with sucrose or water) in the insulo-opercular region of the human brain with positron emission tomography using only movement of the tongue and mouth as control conditions. This is important because subtractions of responses to one gustatory stimulus from those to another may mask gustatory activity that is common to both stimuli, even when the control stimulus is an apparently tasteless one (e.g. water). Bilateral increases in activity were observed in the insulo-opercular region and, consistent with animal work, they indicate that there are a number of separate foci within this general area where primary gustatory inputs may be processed.

Adult↗
PubMed1998

Electrophysiological responses to bitter stimuli in primate cortex.

Studies investigating fine details of gustatory coding in the domain of each basic taste quality have been completed for sweet, salt, and sour stimuli. In the present experiment, we used chemicals that humans describe as predominantly bitter. We recorded the activity of 50 taste neurons in insular cortex of two cynomolgus macaques. Stimuli were water, fruit juice, glucose, NaCl, HCl, and 16 bitter solutions. In a multidimensional taste space the 16 bitter stimuli formed a coherent cluster composed of three main subgroups: (1) QHCl, phenylalanine, theophylline, caffeine, propyl-thiouracil (PROP), and phenylthiocarbamide (PTC), all of which humans describe as rather purely bitter, (2) MgCl2, CaCl2, NH4Cl, and arginine, which humans describe as salty-bitter, and (3) urea, cysteine, and vitamin B1, which are described as sour-bitter. Vitamin B2, histidine and nicotine were in the center of the bitter cluster. Human descriptions of taste qualities conformed well to the presumed quality of each stimulus as inferred from its position in the multidimensional space (MDS), reinforcing the use of the macaque as a neural model for human gustation.

Animals↗
PubMed1998

Cortical, thalamic, and amygdaloid connections of the anterior and posterior insular cortices.

Cortical, thalamic, and amygdaloid projections of the rat anterior and posterior insular cortices were examined using the anterograde transport of biocytin. Granular and dysgranular posterior insular areas between bregma and 2 mm anterior to bregma projected to the gustatory thalamic nucleus. Granular cortex projected to the subjacent dysgranular cortex which in turn projected to the agranular (all layers) and granular cortices (layers I and VI). Both granular and dysgranular posterior areas projected heavily to the dysgranular anterior insular cortex. Agranular posterior insular cortex projected to medial mediodorsal nucleus, agranular anterior insular and infralimbic cortices as well as granular and dysgranular posterior insula. No projections to the amygdala were observed from posterior granular cortex, although dysgranular cortex projected to the lateral central nucleus, dorsolateral lateral nucleus, and posterior basolateral nucleus. Agranular projections were similar, although they included medial and lateral central nucleus and the ventral lateral nucleus. Dysgranular anterior insular cortex projected to lateral agranular frontal cortex and granular and dysgranular posterior insular regions. Agranular anterior insular cortex projected to the dysgranular anterior and prelimbic cortices. Anterior insuloamygdaloid projections targeted the rostral lateral and anterior basolateral nuclei with sparse projections to the rostral central nucleus. The data suggest that the anterior insula is an interface between the posterior insular cortex and motor cortex and is connected with motor-related amygdala regions. Amygdaloid projections from the posterior insular cortex appear to be organized in a feedforward parallel fashion targeting all levels of the intraamygdaloid connections linking the lateral, basolateral, and central nuclei.

Amygdala↗
PubMed1984

Taste agnosia following gustatory neocortex ablation: dissociation from odor and generality across taste qualities.

In Experiment 1, rats trained to avoid drinking in the presence of a compound odor (benzyl acetate) and taste (sucrose) conditional stimulus (CS) lost the taste habit but retained the odor habit following gustatory neocortex (GN) ablation. Conversely, olfactory bulb ablation resulted in loss of the odor habit but retention of the taste habit. In Experiment 2, rats lacking GN did not retain preoperatively instated learned aversions to a suprathreshold quinine hydrochloride (bitter) taste solution which had been employed as a CS. However, rats with GN lesions that were virtually identical to those of the bitter-trained group retained a preoperatively learned aversion to a hydrochloric acid (sour) CS. Experiment 3 demonstrated that reliable agnosia for an acid CS could be produced by lesions that extended more deeply into perirhinal areas near the claustrum at the level of the GN. It is concluded that the agnosia following GN ablation is relatively specific to gustation and that agnosia for preoperatively acquired taste aversion habits occurs for all four basic gustatory stimuli following anterolateral cortex ablations centered on the GN.

Agnosia↗