David Laing - Academia.edu (original) (raw)

Papers by David Laing

Research paper thumbnail of Chemosensory Loss during a Traumatic Brain Injury Suggests a Central Pathway for the Rehabilitation of Anosmia

Chemical Senses, 2021

Currently, no method has been developed for rehabilitating olfaction in anosmic patients followin... more Currently, no method has been developed for rehabilitating olfaction in anosmic patients following a traumatic brain injury (TBI). Here a method for rehabilitation is described which is based on a recent finding that the human posterior pyriform cortex (PPC) generates predictive odor “search images” in advance of an encounter with an olfactory stimulus. The search image enhances perceptual sensitivity and allows the odor it represents to be identified without input occurring from the olfactory receptors or bulbs. Furthermore, based on the finding here that anosmics with a TBI often have normal trigeminal and gustatory function, it is proposed that normality in these chemosensory systems may indicate that key cortical regions including the PPC are intact in anosmics and capable of processing olfactory information. In addition, the results of chemosensory tests of the olfactory, gustatory, and intranasal trigeminal systems of 18 patients with a TBI are given that identify which patien...

Research paper thumbnail of Odor Detection in Rats with Lesions of Olfactory Bulb Areas Identified Using 2-DG

Annals of the New York Academy of Sciences, 1987

A number of studies using the 2-DG metabolic method have identified areas within the olfactory bu... more A number of studies using the 2-DG metabolic method have identified areas within the olfactory bulb glomerular layer that increase in activity with exposure of animals to specific odors. Because these results provide evidence for a spatial mechanism for coding odors, an examination of their functional significance is of interest. Recently, Laing et al.' found a distinct 2-DG focus centered in the glomerular layer of the dorsomedial quadrant of the rostral olfactory bulb in rats exposed to propionic acid vapor. We have examined the effects of destroying this quadrant of the bulb in rats on their ability to detect propionic acid and other odors.

Research paper thumbnail of Hedonic responses to taste solutions: a cross-cultural study of Japanese and Australians

Chemical Senses, 1992

Abstract. A group of Japanese and a group of Australians rated their liking for solutions of seve... more Abstract. A group of Japanese and a group of Australians rated their liking for solutions of seven tastants: sucrose, NaCl, citric acid, caffeine and three umami tastes (MSG, IMP, GMP). The patterns of response were similar in both groups for all of the tastants. Differences between the ...

Research paper thumbnail of The capacity of humans to identify components in complex odor-taste mixtures. Chem. Senses 31:539–545

Despite the fact that humans experiencemixtures of odors and tastes each time they eat, little is... more Despite the fact that humans experiencemixtures of odors and tastes each time they eat, little is known of their capacity to detect the individual components of foods. To investigate this capacity, 43 subjects were trained to identify three odors and three tastes and were required to indicate which of these could be identified in stimuli consisting of one to six components. Although the odor and taste components of most binary mixtures were identified, subjects encountered substantial difficulties with more complex mixtures with only two components being identified in the four- to six-component mixtures. In general, tastes were more easily identified than smells and were the only stimuli identified in the five- to six-component mixtures. Several mechanisms are proposed to account for the poor identification of components. Key words: analytical capacity, humans, odor–taste mixtures

Research paper thumbnail of Relationship between Molecular Structure, Concentration and Odor Qualities of Oxygenated Aliphatic Molecules

Chemical Senses, 2003

Increasing the concentration of an odorant increases the number of receptor cells and glomeruli i... more Increasing the concentration of an odorant increases the number of receptor cells and glomeruli in the olfactory bulb that are stimulated, and it is commonly acknowledged that these represent increased numbers of receptor types. Currently, it is not known whether a receptor type is associated with a unique quality and a unique molecular feature of an odorant, or its activation is used by the brain in a combinatorial manner with other activated receptor types to produce a characteristic quality. The present study investigated the proposal that a molecular feature common to several aliphatic odorants and known to be the key feature required to stimulate the same mitral cells in the olfactory bulb results in a quality that is common to the odorants. Since the common structural feature may activate a specific receptor type possibly at a similar concentration, the qualities of the odorants were determined at seven concentrations where the lowest and highest concentrations were the detection threshold (DT) and 729DT of each subject. A list of 146 descriptors was used by 15 subjects to describe the qualities of each odorant at each concentration. The results indicate that each of the five odorants was characterized by different qualities and the qualities of four of the odorants changed with changes in concentration. Importantly, no quality common to each of the odorants that had the same molecular feature could be identified and it is proposed that identification of the odorants occurs via a combinatorial mechanism involving several types of receptors.

Research paper thumbnail of Olfactory function in children assessed with psychophysical and electrophysiological techniques

Behavioural Brain Research, 2007

The olfactory information processing abilities of children undergo changes during early life. The... more The olfactory information processing abilities of children undergo changes during early life. The aims of the present study were to describe these changes and to probe for their electrophysiological correlates. These aims were investigated in two experiments. In Experiment 1, responses of 146 subjects (3-12 years) were tested with psychophysical tools. Approximately 2/3 of the subjects completed the olfactory tests ("Sniffin' Sticks"). In Experiment 2, 12 additional subjects (3-10 years) were tested with electrophysiological tools. Event-related potentials (ERPs) were recorded in response to olfactory stimulation with H 2 S. Results from Experiment 1 indicated that data from the group of 3-5-year olds were very unreliable, with 44% of incomplete measures rendering the tests unsuitable for routine use with 3-5-year olds. From an age of 6 years on the results suggested that the development of olfactory function was well advanced with a significant increase found only for odor identification, but not for odor thresholds, or odor discrimination. Results from Experiment 2 indicated an increase of the P2 latency with age, although the small sample size has to be considered in the interpretation of these data. While more research is needed, these results may be interpreted such that children attach more meaning to odorous stimuli with age.

Research paper thumbnail of The Human Sense of Smell

Research paper thumbnail of The influence of chemical complexity on the perception of multicomponent odor mixtures

Perception & Psychophysics

The present study investigates the hypothesis that complex object odors (odors that emanate from ... more The present study investigates the hypothesis that complex object odors (odors that emanate from flowers, foods, sewage, etc.) that consist of dozens of odorants are processed and encoded as discrete entities, as if each was a single chemical odor. To test this hypothesis, the capacity of trained subjects to discriminate and identify the components of stimuli consisting of one to eight object odors was determined. The results indicated that subjects could only identify up to four object odors in a mixture, which is similar to earlier findings with mixtures that contained only single chemical odors. The limited capacity was also reflected in the number of odors selected, regardless of whether the choices were correct or incorrect, in confidence ratings, and in decision times. The identification of a limited number of object odors in every mixture that was presented suggests that both associative (synthetic) and dissociative (analytic) processes are involved in the perceptual analysis...

Research paper thumbnail of Reduced taste function and taste papillae density in children with chronic kidney disease

Pediatric Nephrology, 2015

Taste loss may contribute to the loss of appetite in children with chronic kidney disease (CKD) a... more Taste loss may contribute to the loss of appetite in children with chronic kidney disease (CKD) and other serious medical conditions that result in malnutrition. Traditional methods for measurement of taste loss commonly use aqueous tastant solutions that can induce nausea, vomiting, or even pain in the mouth. An alternative is to measure fungiform papillae density on the anterior tongue since this correlates with taste sensitivity. Here we aimed to develop a non-invasive method for assessing papillae density on the anterior tongue and to use the method to determine if CKD patients [estimated glomerular filtrate (eGFR < 60 ml/min/1.73 m(2))] have a lower density than clinical controls (CC)(eGFR > 89 ml/min/1.73 m(2)). Thirty-five healthy adults participated in the development of a method, which was assessed by 24 children, 12 of whom were CKD patients and 12 were clinical controls. Similar papillae densities were found using invasive and non-invasive methods (F(1,34) = 0.647, p = 0.427). The CKD group had a significantly lower papillae density (X(2) = 7.17, p = 0.007) and poorer taste sensitivity than the CC group (p = 0.0272), and the density correlated significantly with eGFR (r = 0.56, p < 0.01). Loss of taste in children with CKD is due to the reduced number of papillae and their taste-sensing receptor cells.

Research paper thumbnail of Perceptual characteristics of binary, trinary, and quaternary odor mixtures consisting of unpleasant constituents

Physiology & behavior, 1994

Among the most obnoxious stimuli that the population at large is exposed to during everyday life ... more Among the most obnoxious stimuli that the population at large is exposed to during everyday life are odorous emissions from sewage treatment plants. Such emissions are complex and contain many different types of odorants that vary in quantity depending upon the contents and efficiency of treatment processes. Because little is known about how individual odorants in complex mixtures affect the perception of each other, it is difficult to develop mathematical models that can predict the pleasantness, strength, and quality characteristics of an emission at different distances from a source. In the present study, the interactions of the four major types of odorants emitted by treatment plants worldwide, namely, hydrogen sulphide, isovaleric acid, butanethiol, and skatole, were investigated by measuring the perceived intensity of individual odorants alone and in mixtures, and the overall perceived intensity, unpleasantness, and qualities of mixtures. In addition, models for predicting odo...

Research paper thumbnail of The sources of odors from stressed rats

Physiology & behavior, 1981

... Copyright 1981 Brain Research Publications Inc.--0031-9384/81/090511-03502.00/0 512 MACKAY-SI... more ... Copyright 1981 Brain Research Publications Inc.--0031-9384/81/090511-03502.00/0 512 MACKAY-SIM AND LAING The wooden walls of the runway were painted matt black and the floor was of stainless steel bars (1 cm dia., centers 2 cm apart) covered with paper towelling. ...

Research paper thumbnail of Rats' responses to blood and body odors of stressed and non-stressed conspecifics

Physiology & behavior, 1981

ABSTRACT

Research paper thumbnail of Selective attention and the perceptual analysis of odor mixtures

Physiology & behavior, 1992

Two psychophysical methods were used to investigate the capacity of humans to identify the consti... more Two psychophysical methods were used to investigate the capacity of humans to identify the constituents of odor mixtures consisting of up to six components. With one method subjects were required to identify all the components present in each stimulus; with the other, a selective attention procedure was used where subjects had to identify only one component at each trial. Little difference was found between the levels of identification obtained with both methods, reinforcing the finding that humans have great difficulty in identifying more than three components in an odor mixture and indicating that it is unlikely that olfactory adaptation influenced the identification process.

Research paper thumbnail of Discrimination of odors from stressed rats by non-stressed rats

Physiology & Behavior, 1980

... 5. Cattarelli, M., E. Vernet-Maury, J. Chanel, P. MacLeod and AM Brandon. Olfactory bulb and ... more ... 5. Cattarelli, M., E. Vernet-Maury, J. Chanel, P. MacLeod and AM Brandon. Olfactory bulb and integration of some odorous signals in the rat: Behavioral and electrophysiological study. ... Keim, KL and EB Sigg. Physiological and biochemical concomitants of restraint stress in rats. ...

Research paper thumbnail of Pulsed amperometric detection of thaumatin using antibody-containing poly(pyrrole) electrodes

The Analyst, 1994

ABSTRACT An electrochemical sensor produced by direct incorporation of anti-thaumatin into a poly... more ABSTRACT An electrochemical sensor produced by direct incorporation of anti-thaumatin into a polypyrrole film was developed. The use of flow injection analysis and pulsed amperometric detection permitted the development of a sensitive, reversible and rapid electrochemical immunoassay for thaumatin.

Research paper thumbnail of The influence of odor type on the discrimination and identification of odorants in multicomponent odor mixtures

Physiology & Behavior, 1998

Using a limited set of odorants, previous studies have indicated that the ability of humans to di... more Using a limited set of odorants, previous studies have indicated that the ability of humans to discriminate and identify the components of olfactory mixtures is limited to approximately four. However, the ability to generalize these results may have been limited by specific neural or cognitive interactions among the particular odorants used. In the present experiment, 41 subjects examined the influence of odor type (different individual odorants), from two very different odor sets, on the perception of the components of complex mixtures. One set contained odors that were selected by an expert panel to blend well in mixtures (good blenders), whereas the other contained odors that blended poorly in mixtures (poor blenders). The stimuli were common, dissimilar odorants of equivalent, moderate intensity, each of which was a single chemical. A computer-controlled air dilution olfactometer delivered a single odorant or a mixture containing up to eight odorants. Although the poor blenders were more easily discriminated, this superiority was displayed within a narrow range, and the ability of subjects to identify mixture components with either odor set was limited to approximately four. The results indicate that, whereas odor type can alter which odorants will be perceived in a mixture, the limited capacity to discriminate mixture components is independent of the type of odorants. These findings are discussed in terms of their implications for olfactory coding.

Research paper thumbnail of A Comparison of the Ability of 8–9-Year-Old Children and Adults to Detect Taste Stimuli

Physiology & Behavior, 1997

A comparison of the ability of 8-9-year-old children and adults to detect taste stimuli. PHYSIOL ... more A comparison of the ability of 8-9-year-old children and adults to detect taste stimuli. PHYSIOL BEHAV 62(1) [193][194][195][196][197] 1997.-Conflicting data exist in the literature regarding the maturity of the human sense of taste during childhood and if gender influences gustatory development. To investigate these 2 questions, taste detection thresholds for the 4 common tastants sucrose, sodium chloride, citric acid, and caffeine were established for 61 young adults and 68 children aged 8-9 years old, using a paired-comparison forced-choice procedure. No significant differences were found between the mean thresholds of women and men, or between those of female children and adults. In contrast, male children had significantly higher thresholds for all 4 tastants than adult females, for all tastants except caffeine than adult men, and for sucrose and sodium chloride than female children. It is concluded that the taste sensitivity of 8-9-year-old males, although well developed, has not fully matured, and that taste sensitivity is not affected by gender in young adults. ᭧ 1997 Elsevier Science Inc.

Research paper thumbnail of Chemosensory function and food preferences of children with cystic fibrosis

Pediatric Pulmonology, 2010

A major problem for patients with cystic fibrosis (CF) is the maintenance of adequate nutrition t... more A major problem for patients with cystic fibrosis (CF) is the maintenance of adequate nutrition to maintain normal growth. The hypotheses that poor nutrition could be due to smell and/or taste dysfunction has been pursued in several studies with contradictory results. None, however, investigated whether inadequate nutrition is due to CF patients having different liking for foods compared to healthy children and whether liking can be linked to specific changes in smell or taste function. Here, the relationships between food liking, BMI, and smell and taste function in 42 CF and 42 healthy 5- to 18-year olds is pursued. A three-choice 16-item odor identification test and a gustatory identification test involving five concentrations of sweet, sour, bitter, and salty tastes, were used to assess chemosensory function. Food liking was assessed using a 94-item questionnaire. Patients identified significantly fewer odors than controls (89.8% vs. 95.7% correct; P < 0.001). However, only a few patients were affected and their loss of olfactory function was not substantial and unlikely to affect their liking for foods. Taste identification was similar for the two groups (patients 92.6% vs. controls 94.2% correct). There was no correlation between age and odor identification ability, but taste performance improved with age (r = 0.39, P < 0.05), suggesting cognition was the cause. Patients liked several types of foods and high-fat foods more than the controls. Both groups had a similar liking for low-fat foods and both liked high-fat foods more than low-fat foods. No significant relationships existed between FEV(1) and smell or taste function or liking for foods, the BMI of the groups were similar and there was no relationship between BMI and smell or taste function. The results indicate that the abnormal eating behavior reported for many CF patients is not due to changes in chemosensory function which remains normal in most CF patients at least to 18 years of age.

Research paper thumbnail of Erratum: Chemosensory function and food preferences of children with cystic fibrosis

Pediatric Pulmonology, 2010

Research paper thumbnail of Smell and taste function in children with chronic kidney disease

Pediatric Nephrology, 2010

Loss of appetite and poor growth are common in children with chronic kidney disease (CKD), and ch... more Loss of appetite and poor growth are common in children with chronic kidney disease (CKD), and changes in smell and/or taste function may be responsible, but the hypothesis has not been proven. This aims of this prospective age- and gender-controlled study were to determine whether: (1) changes in smell and taste function occur in children with CKD; (2) smell or taste dysfunction are associated with estimated glomerular filtration rate (eGFR); (3) there is an association between smell or taste loss and body mass index (BMI). The study cohort consisted of 72 children of whom 20 were CKD stage 3-5 patients, 12 were CKD stage 2 patients, 20 were clinical controls (CC) and 20 were healthy children (HC). The CKD patients and clinical controls were recruited from Sydney Children's Hospital and The Children's Hospital, Westmead, and healthy controls were recruited from a local school. Scores for each group from taste and smell chemosensory function tests were compared, and their relationship with renal function and BMI investigated. The CKD stage 3-5 group had a significantly lower taste identification score (85.6%, P < 0.001) than the CC (94.8%) and HC (94.8%) groups, with almost one third of the children in the CKD stage 3-5 group exhibiting taste loss. Decreased taste function was associated with decreased eGFR (r = 0.43, P < 0.01), but no association between BMI and taste function was found (r = 0.001, P > 0.9). Odour identification scores were not different; however, there was a positive relationship with BMI (r = 0.427, P = 0.006). We conclude that a loss of taste can occur in children with CKD and that when it occurs, it worsens as eGFR declines and is found early in kidney disease.

Research paper thumbnail of Chemosensory Loss during a Traumatic Brain Injury Suggests a Central Pathway for the Rehabilitation of Anosmia

Chemical Senses, 2021

Currently, no method has been developed for rehabilitating olfaction in anosmic patients followin... more Currently, no method has been developed for rehabilitating olfaction in anosmic patients following a traumatic brain injury (TBI). Here a method for rehabilitation is described which is based on a recent finding that the human posterior pyriform cortex (PPC) generates predictive odor “search images” in advance of an encounter with an olfactory stimulus. The search image enhances perceptual sensitivity and allows the odor it represents to be identified without input occurring from the olfactory receptors or bulbs. Furthermore, based on the finding here that anosmics with a TBI often have normal trigeminal and gustatory function, it is proposed that normality in these chemosensory systems may indicate that key cortical regions including the PPC are intact in anosmics and capable of processing olfactory information. In addition, the results of chemosensory tests of the olfactory, gustatory, and intranasal trigeminal systems of 18 patients with a TBI are given that identify which patien...

Research paper thumbnail of Odor Detection in Rats with Lesions of Olfactory Bulb Areas Identified Using 2-DG

Annals of the New York Academy of Sciences, 1987

A number of studies using the 2-DG metabolic method have identified areas within the olfactory bu... more A number of studies using the 2-DG metabolic method have identified areas within the olfactory bulb glomerular layer that increase in activity with exposure of animals to specific odors. Because these results provide evidence for a spatial mechanism for coding odors, an examination of their functional significance is of interest. Recently, Laing et al.' found a distinct 2-DG focus centered in the glomerular layer of the dorsomedial quadrant of the rostral olfactory bulb in rats exposed to propionic acid vapor. We have examined the effects of destroying this quadrant of the bulb in rats on their ability to detect propionic acid and other odors.

Research paper thumbnail of Hedonic responses to taste solutions: a cross-cultural study of Japanese and Australians

Chemical Senses, 1992

Abstract. A group of Japanese and a group of Australians rated their liking for solutions of seve... more Abstract. A group of Japanese and a group of Australians rated their liking for solutions of seven tastants: sucrose, NaCl, citric acid, caffeine and three umami tastes (MSG, IMP, GMP). The patterns of response were similar in both groups for all of the tastants. Differences between the ...

Research paper thumbnail of The capacity of humans to identify components in complex odor-taste mixtures. Chem. Senses 31:539–545

Despite the fact that humans experiencemixtures of odors and tastes each time they eat, little is... more Despite the fact that humans experiencemixtures of odors and tastes each time they eat, little is known of their capacity to detect the individual components of foods. To investigate this capacity, 43 subjects were trained to identify three odors and three tastes and were required to indicate which of these could be identified in stimuli consisting of one to six components. Although the odor and taste components of most binary mixtures were identified, subjects encountered substantial difficulties with more complex mixtures with only two components being identified in the four- to six-component mixtures. In general, tastes were more easily identified than smells and were the only stimuli identified in the five- to six-component mixtures. Several mechanisms are proposed to account for the poor identification of components. Key words: analytical capacity, humans, odor–taste mixtures

Research paper thumbnail of Relationship between Molecular Structure, Concentration and Odor Qualities of Oxygenated Aliphatic Molecules

Chemical Senses, 2003

Increasing the concentration of an odorant increases the number of receptor cells and glomeruli i... more Increasing the concentration of an odorant increases the number of receptor cells and glomeruli in the olfactory bulb that are stimulated, and it is commonly acknowledged that these represent increased numbers of receptor types. Currently, it is not known whether a receptor type is associated with a unique quality and a unique molecular feature of an odorant, or its activation is used by the brain in a combinatorial manner with other activated receptor types to produce a characteristic quality. The present study investigated the proposal that a molecular feature common to several aliphatic odorants and known to be the key feature required to stimulate the same mitral cells in the olfactory bulb results in a quality that is common to the odorants. Since the common structural feature may activate a specific receptor type possibly at a similar concentration, the qualities of the odorants were determined at seven concentrations where the lowest and highest concentrations were the detection threshold (DT) and 729DT of each subject. A list of 146 descriptors was used by 15 subjects to describe the qualities of each odorant at each concentration. The results indicate that each of the five odorants was characterized by different qualities and the qualities of four of the odorants changed with changes in concentration. Importantly, no quality common to each of the odorants that had the same molecular feature could be identified and it is proposed that identification of the odorants occurs via a combinatorial mechanism involving several types of receptors.

Research paper thumbnail of Olfactory function in children assessed with psychophysical and electrophysiological techniques

Behavioural Brain Research, 2007

The olfactory information processing abilities of children undergo changes during early life. The... more The olfactory information processing abilities of children undergo changes during early life. The aims of the present study were to describe these changes and to probe for their electrophysiological correlates. These aims were investigated in two experiments. In Experiment 1, responses of 146 subjects (3-12 years) were tested with psychophysical tools. Approximately 2/3 of the subjects completed the olfactory tests ("Sniffin' Sticks"). In Experiment 2, 12 additional subjects (3-10 years) were tested with electrophysiological tools. Event-related potentials (ERPs) were recorded in response to olfactory stimulation with H 2 S. Results from Experiment 1 indicated that data from the group of 3-5-year olds were very unreliable, with 44% of incomplete measures rendering the tests unsuitable for routine use with 3-5-year olds. From an age of 6 years on the results suggested that the development of olfactory function was well advanced with a significant increase found only for odor identification, but not for odor thresholds, or odor discrimination. Results from Experiment 2 indicated an increase of the P2 latency with age, although the small sample size has to be considered in the interpretation of these data. While more research is needed, these results may be interpreted such that children attach more meaning to odorous stimuli with age.

Research paper thumbnail of The Human Sense of Smell

Research paper thumbnail of The influence of chemical complexity on the perception of multicomponent odor mixtures

Perception & Psychophysics

The present study investigates the hypothesis that complex object odors (odors that emanate from ... more The present study investigates the hypothesis that complex object odors (odors that emanate from flowers, foods, sewage, etc.) that consist of dozens of odorants are processed and encoded as discrete entities, as if each was a single chemical odor. To test this hypothesis, the capacity of trained subjects to discriminate and identify the components of stimuli consisting of one to eight object odors was determined. The results indicated that subjects could only identify up to four object odors in a mixture, which is similar to earlier findings with mixtures that contained only single chemical odors. The limited capacity was also reflected in the number of odors selected, regardless of whether the choices were correct or incorrect, in confidence ratings, and in decision times. The identification of a limited number of object odors in every mixture that was presented suggests that both associative (synthetic) and dissociative (analytic) processes are involved in the perceptual analysis...

Research paper thumbnail of Reduced taste function and taste papillae density in children with chronic kidney disease

Pediatric Nephrology, 2015

Taste loss may contribute to the loss of appetite in children with chronic kidney disease (CKD) a... more Taste loss may contribute to the loss of appetite in children with chronic kidney disease (CKD) and other serious medical conditions that result in malnutrition. Traditional methods for measurement of taste loss commonly use aqueous tastant solutions that can induce nausea, vomiting, or even pain in the mouth. An alternative is to measure fungiform papillae density on the anterior tongue since this correlates with taste sensitivity. Here we aimed to develop a non-invasive method for assessing papillae density on the anterior tongue and to use the method to determine if CKD patients [estimated glomerular filtrate (eGFR < 60 ml/min/1.73 m(2))] have a lower density than clinical controls (CC)(eGFR > 89 ml/min/1.73 m(2)). Thirty-five healthy adults participated in the development of a method, which was assessed by 24 children, 12 of whom were CKD patients and 12 were clinical controls. Similar papillae densities were found using invasive and non-invasive methods (F(1,34) = 0.647, p = 0.427). The CKD group had a significantly lower papillae density (X(2) = 7.17, p = 0.007) and poorer taste sensitivity than the CC group (p = 0.0272), and the density correlated significantly with eGFR (r = 0.56, p < 0.01). Loss of taste in children with CKD is due to the reduced number of papillae and their taste-sensing receptor cells.

Research paper thumbnail of Perceptual characteristics of binary, trinary, and quaternary odor mixtures consisting of unpleasant constituents

Physiology & behavior, 1994

Among the most obnoxious stimuli that the population at large is exposed to during everyday life ... more Among the most obnoxious stimuli that the population at large is exposed to during everyday life are odorous emissions from sewage treatment plants. Such emissions are complex and contain many different types of odorants that vary in quantity depending upon the contents and efficiency of treatment processes. Because little is known about how individual odorants in complex mixtures affect the perception of each other, it is difficult to develop mathematical models that can predict the pleasantness, strength, and quality characteristics of an emission at different distances from a source. In the present study, the interactions of the four major types of odorants emitted by treatment plants worldwide, namely, hydrogen sulphide, isovaleric acid, butanethiol, and skatole, were investigated by measuring the perceived intensity of individual odorants alone and in mixtures, and the overall perceived intensity, unpleasantness, and qualities of mixtures. In addition, models for predicting odo...

Research paper thumbnail of The sources of odors from stressed rats

Physiology & behavior, 1981

... Copyright 1981 Brain Research Publications Inc.--0031-9384/81/090511-03502.00/0 512 MACKAY-SI... more ... Copyright 1981 Brain Research Publications Inc.--0031-9384/81/090511-03502.00/0 512 MACKAY-SIM AND LAING The wooden walls of the runway were painted matt black and the floor was of stainless steel bars (1 cm dia., centers 2 cm apart) covered with paper towelling. ...

Research paper thumbnail of Rats' responses to blood and body odors of stressed and non-stressed conspecifics

Physiology & behavior, 1981

ABSTRACT

Research paper thumbnail of Selective attention and the perceptual analysis of odor mixtures

Physiology & behavior, 1992

Two psychophysical methods were used to investigate the capacity of humans to identify the consti... more Two psychophysical methods were used to investigate the capacity of humans to identify the constituents of odor mixtures consisting of up to six components. With one method subjects were required to identify all the components present in each stimulus; with the other, a selective attention procedure was used where subjects had to identify only one component at each trial. Little difference was found between the levels of identification obtained with both methods, reinforcing the finding that humans have great difficulty in identifying more than three components in an odor mixture and indicating that it is unlikely that olfactory adaptation influenced the identification process.

Research paper thumbnail of Discrimination of odors from stressed rats by non-stressed rats

Physiology & Behavior, 1980

... 5. Cattarelli, M., E. Vernet-Maury, J. Chanel, P. MacLeod and AM Brandon. Olfactory bulb and ... more ... 5. Cattarelli, M., E. Vernet-Maury, J. Chanel, P. MacLeod and AM Brandon. Olfactory bulb and integration of some odorous signals in the rat: Behavioral and electrophysiological study. ... Keim, KL and EB Sigg. Physiological and biochemical concomitants of restraint stress in rats. ...

Research paper thumbnail of Pulsed amperometric detection of thaumatin using antibody-containing poly(pyrrole) electrodes

The Analyst, 1994

ABSTRACT An electrochemical sensor produced by direct incorporation of anti-thaumatin into a poly... more ABSTRACT An electrochemical sensor produced by direct incorporation of anti-thaumatin into a polypyrrole film was developed. The use of flow injection analysis and pulsed amperometric detection permitted the development of a sensitive, reversible and rapid electrochemical immunoassay for thaumatin.

Research paper thumbnail of The influence of odor type on the discrimination and identification of odorants in multicomponent odor mixtures

Physiology & Behavior, 1998

Using a limited set of odorants, previous studies have indicated that the ability of humans to di... more Using a limited set of odorants, previous studies have indicated that the ability of humans to discriminate and identify the components of olfactory mixtures is limited to approximately four. However, the ability to generalize these results may have been limited by specific neural or cognitive interactions among the particular odorants used. In the present experiment, 41 subjects examined the influence of odor type (different individual odorants), from two very different odor sets, on the perception of the components of complex mixtures. One set contained odors that were selected by an expert panel to blend well in mixtures (good blenders), whereas the other contained odors that blended poorly in mixtures (poor blenders). The stimuli were common, dissimilar odorants of equivalent, moderate intensity, each of which was a single chemical. A computer-controlled air dilution olfactometer delivered a single odorant or a mixture containing up to eight odorants. Although the poor blenders were more easily discriminated, this superiority was displayed within a narrow range, and the ability of subjects to identify mixture components with either odor set was limited to approximately four. The results indicate that, whereas odor type can alter which odorants will be perceived in a mixture, the limited capacity to discriminate mixture components is independent of the type of odorants. These findings are discussed in terms of their implications for olfactory coding.

Research paper thumbnail of A Comparison of the Ability of 8–9-Year-Old Children and Adults to Detect Taste Stimuli

Physiology & Behavior, 1997

A comparison of the ability of 8-9-year-old children and adults to detect taste stimuli. PHYSIOL ... more A comparison of the ability of 8-9-year-old children and adults to detect taste stimuli. PHYSIOL BEHAV 62(1) [193][194][195][196][197] 1997.-Conflicting data exist in the literature regarding the maturity of the human sense of taste during childhood and if gender influences gustatory development. To investigate these 2 questions, taste detection thresholds for the 4 common tastants sucrose, sodium chloride, citric acid, and caffeine were established for 61 young adults and 68 children aged 8-9 years old, using a paired-comparison forced-choice procedure. No significant differences were found between the mean thresholds of women and men, or between those of female children and adults. In contrast, male children had significantly higher thresholds for all 4 tastants than adult females, for all tastants except caffeine than adult men, and for sucrose and sodium chloride than female children. It is concluded that the taste sensitivity of 8-9-year-old males, although well developed, has not fully matured, and that taste sensitivity is not affected by gender in young adults. ᭧ 1997 Elsevier Science Inc.

Research paper thumbnail of Chemosensory function and food preferences of children with cystic fibrosis

Pediatric Pulmonology, 2010

A major problem for patients with cystic fibrosis (CF) is the maintenance of adequate nutrition t... more A major problem for patients with cystic fibrosis (CF) is the maintenance of adequate nutrition to maintain normal growth. The hypotheses that poor nutrition could be due to smell and/or taste dysfunction has been pursued in several studies with contradictory results. None, however, investigated whether inadequate nutrition is due to CF patients having different liking for foods compared to healthy children and whether liking can be linked to specific changes in smell or taste function. Here, the relationships between food liking, BMI, and smell and taste function in 42 CF and 42 healthy 5- to 18-year olds is pursued. A three-choice 16-item odor identification test and a gustatory identification test involving five concentrations of sweet, sour, bitter, and salty tastes, were used to assess chemosensory function. Food liking was assessed using a 94-item questionnaire. Patients identified significantly fewer odors than controls (89.8% vs. 95.7% correct; P < 0.001). However, only a few patients were affected and their loss of olfactory function was not substantial and unlikely to affect their liking for foods. Taste identification was similar for the two groups (patients 92.6% vs. controls 94.2% correct). There was no correlation between age and odor identification ability, but taste performance improved with age (r = 0.39, P < 0.05), suggesting cognition was the cause. Patients liked several types of foods and high-fat foods more than the controls. Both groups had a similar liking for low-fat foods and both liked high-fat foods more than low-fat foods. No significant relationships existed between FEV(1) and smell or taste function or liking for foods, the BMI of the groups were similar and there was no relationship between BMI and smell or taste function. The results indicate that the abnormal eating behavior reported for many CF patients is not due to changes in chemosensory function which remains normal in most CF patients at least to 18 years of age.

Research paper thumbnail of Erratum: Chemosensory function and food preferences of children with cystic fibrosis

Pediatric Pulmonology, 2010

Research paper thumbnail of Smell and taste function in children with chronic kidney disease

Pediatric Nephrology, 2010

Loss of appetite and poor growth are common in children with chronic kidney disease (CKD), and ch... more Loss of appetite and poor growth are common in children with chronic kidney disease (CKD), and changes in smell and/or taste function may be responsible, but the hypothesis has not been proven. This aims of this prospective age- and gender-controlled study were to determine whether: (1) changes in smell and taste function occur in children with CKD; (2) smell or taste dysfunction are associated with estimated glomerular filtration rate (eGFR); (3) there is an association between smell or taste loss and body mass index (BMI). The study cohort consisted of 72 children of whom 20 were CKD stage 3-5 patients, 12 were CKD stage 2 patients, 20 were clinical controls (CC) and 20 were healthy children (HC). The CKD patients and clinical controls were recruited from Sydney Children's Hospital and The Children's Hospital, Westmead, and healthy controls were recruited from a local school. Scores for each group from taste and smell chemosensory function tests were compared, and their relationship with renal function and BMI investigated. The CKD stage 3-5 group had a significantly lower taste identification score (85.6%, P < 0.001) than the CC (94.8%) and HC (94.8%) groups, with almost one third of the children in the CKD stage 3-5 group exhibiting taste loss. Decreased taste function was associated with decreased eGFR (r = 0.43, P < 0.01), but no association between BMI and taste function was found (r = 0.001, P > 0.9). Odour identification scores were not different; however, there was a positive relationship with BMI (r = 0.427, P = 0.006). We conclude that a loss of taste can occur in children with CKD and that when it occurs, it worsens as eGFR declines and is found early in kidney disease.