Biomedical subjects

M Laska

Publications and source records attributed to M Laska.

At least 19 recordsLinked to original sources

PubMed2006

Olfactory discrimination ability of CD-1 mice for a large array of enantiomers.

With use of a conditioning paradigm, the ability of eight CD-1 mice to distinguish between 15 enantiomeric odor pairs was investigated. The results demonstrate a) that CD-1 mice are capable of discriminating between all odor pairs tested, b) that the enantiomeric odor pairs clearly differed in their degree of discriminability and thus in their perceptual similarity, and c) that pre-training with the rewarded stimuli led to improved initial but not terminal or overall performance. A comparison between the proportion of discriminated enantiomeric odor pairs of the CD-1 mice and those of other species tested in earlier studies on the same discrimination tasks (or on subsets thereof) shows a significant positive correlation between discrimination performance and the number of functional olfactory receptor genes. These findings provide the first evidence of a highly developed ability of CD-1 mice to discriminate between an array of non-pheromonal chiral odorants. Further, they suggest that a species' olfactory discrimination capabilities for these odorants may be correlated with its number of functional olfactory receptor genes. The data presented here may provide useful information for the interpretation of findings from electrophysiological or imaging studies in the mouse and the elucidation of odor structure-activity relationships.

Animals↗

PubMed2003

Olfactory sensitivity for aliphatic aldehydes in squirrel monkeys and pigtail macaques.

Using a conditioning paradigm, the olfactory sensitivity of three squirrel monkeys and three pigtail macaques for a homologous series of aliphatic aldehydes ( n-butanal to n-nonanal) was assessed. With only few exceptions, the animals of both species significantly discriminated concentrations below 1 ppm from the odorless solvent, and with n-butanal and n-hexanal individual pigtail macaques even demonstrated thresholds below 1 ppb. The results showed (1). both primate species to have a well-developed olfactory sensitivity for aliphatic aldehydes, (2). pigtail macaques to generally perform better than squirrel monkeys in detecting members of this class of odorants, and (3). no significant correlation between perceptibility in terms of olfactory detection thresholds and carbon chain length of the aliphatic aldehydes in both species tested. These findings lend further support to the growing body of evidence suggesting that between-species comparisons of the number of functional olfactory receptor genes or of neuroanatomical features are poor predictors of olfactory performance. Further, our findings suggest that olfaction may play an important and hitherto underestimated role in the regulation of behavior in the species tested.

Administration, Inhalation↗

PubMed2001

Olfactory discrimination ability for homologous series of aliphatic ketones and acetic esters.

We tested the ability of human subjects to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-decanone) and acetic esters (ethyl acetate to n-octyl acetate). In a forced-choice triangular test procedure, 20 subjects per series were repeatedly presented with all 21 binary combinations of the seven stimuli and asked to identify the bottle containing the odd stimulus. We found (a) that as a group, the subjects performed significantly above chance level in all tasks but three with the ketones, and all tasks but six with the acetic esters, and thus were clearly able to discriminate between most of the odor pairs presented; (b) marked interindividual differences in discrimination performance, ranging from subjects who were able to significantly distinguish between all 21 odor pairs of a series to subjects who failed to do so with the majority of tasks; and (c) a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length for both homologous series. In line with findings of two previous studies using homologous series of aliphatic alcohols, aldehydes, and carboxylic acids, our results suggest that carbon chain length may generally be an important determinant of the interaction between stimulus molecule and receptor, and thus may generally be a molecular property affecting odor quality of aliphatic substances.

Acetates↗

PubMed2001

Unilateral olfactory perception and magical ideation.

We assessed olfactory detection thresholds and discrimination abilities in 40 healthy right-handers (20 women and 20 men). All subjects were also required to complete the Magical Ideation (MI) scale, a well-validated 30-item schizotypy inventory. Over both nostrils, we found elevated thresholds for subjects with high MI scores (at or above the median score of 9.0) compared with those with low scores. In men but not women, specifically left-nostril acuity was inversely correlated to MI raw scores. MI was unrelated to olfactory discrimination performance. These results suggest an association, at least in healthy men, between even moderate signs of schizotypy and deficits in odor detection. The selective impairment of left-nostril performance adds to the growing evidence for left temporal lobe functional abnormalities in people high on MI. This laterality effect is known from previous studies in patients with schizophrenia. However, as a rule, in psychiatric patients olfactory identification rather than simple detection performance was found to be impaired, indicating that the integration of odor information is affected at different levels of processing in schizotypy compared with schizophrenia. Work with completely normal subjects may reasonably complement clinical studies of olfactory perception. Among its advantages are the good subject compliance and the absence of medication effects.

Adult↗

PubMed2001

A two-choice discrimination method to assess olfactory performance in pigtailed macaques, Macaca nemestrina.

Four pigtailed macaques were trained in a new two-choice olfactory discrimination method. They learned the initial task within 3 months, requiring a maximum of 900 trials. After the method was established, we investigated the olfactory threshold of three monkeys for the odors peanut, iso-amyl acetate, and n-pentanoic acid. The animals detected peanut odor in dilutions as low as 1:10000. They were able to perceive iso-amyl acetate up to a 30000-fold dilution (animals F1 and M2), respectively in a 30 Mio-fold dilution (animal M1). The sensitivity for n-pentanoic acid ranged between a dilution of 1:30000 (F1), 1:100000 (M2), and 1:300000 (M1). A comparison with the thresholds of other species demonstrates that the olfactory sensitivity of pigtailed macaques is not necessarily inferior to that of species that are believed to have a very keen sense of smell, such as dogs and rats. The sensitivity for certain odors seems to reflect their biological relevance for the tested species. The fact that the threshold for peanut odor obtained in this study is lower than the one found in a previous study with pigtailed macaques using a multiple olfactory discrimination method indicates that the new two-choice discrimination method is a better candidate for the assessment of olfactory abilities in pigtailed macaques.

Animals↗

PubMed2001

A comparison of food preferences and nutrient composition in captive squirrel monkeys, Saimiri sciureus, and pigtail macaques, Macaca nemestrina.

I assessed the occurrence of food preferences in captive squirrel monkeys and pigtail macaques and analyzed whether their preferences correlate with nutrient composition. Using a two-alternative choice test, I repeatedly presented six Saimiri sciureus and six Macaca nemestrina with all possible binary combinations of 12 types of food that are part of their diet in captivity. The two species exhibited significantly different rank orders of preference. Correlational analyses revealed that the preference ranking of the squirrel monkeys was significantly positively correlated with total energy content, irrespective of the source of energy as neither total carbohydrate content nor protein or lipid content was significantly correlated with food preference. In contrast, the preference ranking of the pigtail macaques showed a significant positive correlation with total carbohydrate content and with fructose content but not with total energy content of the food items. These results suggest that squirrel monkeys are opportunistic feeders with regard to maximizing net gain of energy, whereas pigtail macaques are not but rather seek to meet their requirements of metabolic energy by preferring foods that are high in carbohydrates.

Animals↗

PubMed2001

Gustatory responsiveness to polycose in four species of nonhuman primates.

The taste responsiveness of six squirrel monkeys, five pigtail macaques, four olive baboons, and four spider monkeys to polycose, a starch-derived polysaccharide, was assessed in two-bottle preference tests of brief duration (2 min). In experiment 1, the monkeys were given the choice between tap water and defined concentrations of polycose dissolved in tap water. In experiment 2, the animals were given the choice between polycose and sucrose, fructose, glucose, lactose, and maltose presented in equimolar concentrations of 100 and 200 mM, respectively. The animals were found to prefer concentrations of polycose as low as 10 mM (pigtail macaques), 30 mM (olive baboons and spider monkeys), and 60 mM (squirrel monkeys) over tap water. Relative taste preferences were stable across the concentrations tested and indicate an order of relative effectiveness (sucrose > polycose > or = maltose) in squirrel monkeys, spider monkeys, and olive baboons that is similar to the order of relative sweetness in humans. Pigtail macaques, however, displayed an order of relative effectiveness (maltose > polycose > or = sucrose) that differs markedly from that found in the other primate species tested and is similar to relative taste preferences found in rodents such as rats. Both the high sensitivity of the pigtail macaques to polycose and their vivid predilection for this polysaccharide and its disaccharide constituent maltose suggest that Macaca nemestrina, unlike other primates, but like rodents, may have specialized taste receptors for starch.

Adaptation, Physiological↗

PubMed2001

Enantioselectivity of odor perception in honeybees (Apis mellifera carnica).

The authors tested the ability of 60 free-flying honeybees (Apis mellifera carnica) to discriminate a conditioning odor from an array of 26 simultaneously presented substances. The stimuli included 10 pairs of enantiomers and 6 essential oils. The bees (a) significantly distinguished between 98% of the 540 odor pairs tested, thus showing an excellent overall discrimination performance, and (b) were able to discriminate between the optical isomers of limonene, alpha-pinene, beta-citronellol, menthol, and carvone but failed to distinguish between the (+)- and (-)-forms of alpha-terpineol, camphor, rose oxide, fenchone, and 2-butanol. The findings support the assumptions that enantioselective molecular odor receptors may exist only for some volatile enantiomers and that insects and mammals may share common principles of odor quality perception, irrespective of their completely differing repertoires of olfactory receptors.

Animals↗

PubMed2001

Perception of trigeminal chemosensory qualities in the elderly.

One hundred healthy elderly subjects (65-88 years) were tested for their ability to: (i) assign verbal labels from a list of trigeminal type descriptors to six odorants known to have a strong trigeminal component; (ii) discriminate between intensity-matched pairs of these odorants in an odd-ball paradigm. Their performance was compared with that of 100 young controls (23--36 years). Young controls judged menthol and cineole as distinctly cool and fresh, acetic cid as pungent and sour and acetone as pungent, but showed no clear descriptive profile for ethanol and propanol. The descriptive profiles given by the elderly subjects correlated significantly with those given by the young controls for all six odorants and thus indicate a high degree of conformity in trigeminal perception of chemosensory qualities between the two age groups. In the odd-ball test the young controls correctly discriminated an average of 8.0 of 9 stimulus pairs presented, with most mistakes occurring in response to pairs with a similar trigeminal profile. With an average of 6.4 of 9 items correct, the discrimination performance of the elderly subjects was significantly poorer than that of the young controls but nevertheless significantly above chance at the group level with all 9 stimulus pairs. These results suggest that the nasal trigeminal system may experience some degree of age-related impairment but still contributes considerably to the perception and discrimination of chemosensory qualities in the elderly.

1-Propanol↗

PubMed2000

Gustatory responsiveness to food-associated sugars and acids in pigtail macaques, Macaca nemestrina.

Taste-preference thresholds for five food-associated sugars and acids, respectively, as well as relative sweet-taste preferences were assessed in six pigtail macaques using two-bottle choice tests of brief duration (1 min). In experiment 1, the animals were found to significantly prefer concentrations as low as 10 mM maltose and sucrose, 20 mM fructose and glucose, and 30 mM lactose over tap water. In experiment 2, the monkeys were given a choice between all binary combinations of the same five saccharides presented in equimolar concentrations of 50, 100, 200, and 400 mM. Preferences for individual sugars were stable across the concentrations tested and indicate the following order of relative effectiveness: maltose>sucrose>glucose> or =fructose> or =lactose. In experiment 3, Macaca nemestrina was found to significantly discriminate concentrations as low as 5 mM malic acid, 10 mM ascorbic acid, 20 mM citric acid and acetic acid, and 0.5 mM tannic acid from the alternative stimulus. With the latter substance, the monkeys rejected all suprathreshold concentrations tested, whereas with the former four substances, the animals showed an inverted U-shaped function of preference. The results showed pigtail macaques to be the first primate species tested so far whose taste-preference threshold for maltose is as low as that for sucrose, and which - similar to rodents - prefers maltose over equimolar concentrations of sucrose and other saccharides. Further, unlike most other primates, pigtail macaques do not generally reject acidic tastants but show a substance- and concentration-dependent change in their behavioral response that may range from rejection to preference. The results support the assumption that the gustatory responsiveness of M. nemestrina to food-associated sugars and acidic tastants might reflect an evolutionary adaptation to its dietary habits.

Acetic Acid↗

PubMed2000

Laterality of tail resting posture in three species of New World primates.

A variety of mammalian species including prosimian and simian primates wrap their tails around their bodies as a means of thermoregulation and for reasons of comfort during resting or sleep. Adopting such a resting posture requires an animal to move its tail either to the right or to the left of the midline of its body, and thus to perform a lateralized behavior. The purpose of this study was to assess the occurrence of lateral biases in tail resting posture in three species of New World primates. Twenty squirrel monkeys, spider monkeys, and howler monkeys, respectively, were observed and data on tail resting posture were collected and analyzed. The results demonstrate (1) that individual squirrel monkeys and spider monkeys exhibit highly significant lateral biases in tail resting posture; (2) a lack of a lateral bias at the group level; (3) that howler monkeys fail to show side preferences in tail wrapping; (4) a lack of sex differences in this behavior in all three species; and (5) a lack of significant correlations between preferred side of tail resting posture and preferred side of hand use in simple reaching tasks which had been assessed with a subset of animals in previous studies. Thus, the present study provides evidence for a behavioral asymmetry which is well-known to occur in rats but has not been described so far in nonhuman primates, and which might offer an additional approach to the investigation of the mechanisms underlying functional cerebral asymmetries.

Alouatta↗

PubMed2000

'Microsmatic' primates revisited: olfactory sensitivity in the squirrel monkey.

Using a conditioning paradigm, the olfactory sensitivity of three squirrel monkeys to nine odorants representing different chemical classes as well as members of a homologous series of substances was investigated. The animals significantly discriminated dilutions as low as 1:10,000 n-propionic acid, 1:30,000 n-butanoic acid and n-pentanoic acid, 1:100,000 n-hexanoic acid, 1:1Mio n-heptanoic acid, 1:30, 000 1-pentanol, 1:300,000 1,8-cineole, 1:1Mio n-heptanal and 1:30Mio amyl acetate from the near-odorless solvent, with single individuals scoring even slightly better. The results showed (i) the squirrel monkey to have an unexpectedly high olfactory sensitivity, which for some substances matches or even is better than that of species such as the rat or the dog, and (ii) a significant negative correlation between perceptibility in terms of olfactory detection thresholds and carbon chain length of carboxylic acids. These findings support the assumptions that olfaction may play a significant and hitherto underestimated role in the regulation of primate behavior, and that the concept of primates as primarily visual and 'microsmatic' animals needs to be revised.

Aldehydes↗

PubMed2000

Olfactory discrimination ability for aliphatic odorants as a function of oxygen moiety.

We tested the ability of human subjects to distinguish between aliphatic odorants sharing the same number of carbon atoms but differing in their functional groups. 1-Alcohols, n-aldehydes, 2-ketones and n-carboxylic acids of four, six and eight carbon atoms, respectively, were employed. In a forced-choice triangular test procedure 20 subjects were repeatedly presented with 18 odor pairs and asked to identify the bottle containing the odd stimulus. We found (i) that as a group, the subjects performed significantly above chance level in all tasks and thus were clearly able to discriminate between all odor pairs presented; (ii) marked interindividual differences in discrimination performance, ranging from subjects who were able to significantly distinguish between all 18 odor pairs to subjects who failed to do so with 1/3 of the tasks; (iii) a lack of significant differences in performance between male and female, and between Japanese and German subjects; (iv) that odor pairs that involved 2-ketones and/or n-carboxylic acids were significantly easier to discriminate compared to odor pairs that involved 1-alcohols and/or n-aldehydes, and thus a clear dependence of discriminability on type of functional group; and (v) that aliphatic odorants with eight carbon atoms (irrespective of their oxygen moiety) were significantly more difficult to discriminate from each other compared to substances with four or six carbon atoms. The results suggest that functional groups may be an important determinant of the interaction between stimulus molecule and olfactory receptor in aliphatic substances, and thus may be a molecular property affecting odor quality in a substance class-specific manner.

Adult↗

PubMed1999

Different forms of human odor memory: a developmental study.

Recognizing odors is an important biological function, both in the animal kingdom as well as for humans. It has been debated whether there exist different forms of human odor memory. For verbal memory, the concept of recollection and familiarity for conscious and unconscious recognition is widely accepted. Here we introduce a similar model for human odor memory. We use a combination of an odor naming and odor recognition memory task to estimate the relationship between depth of processing and retention of olfactory information. A developmental approach with children, young adults, middle aged adults and elderly subjects was chosen in order to study the influence of age. Our results indicate the existence of two separable forms of odor memory depending on whether the odors were correctly or incorrectly named during the naming task. These two forms of odor memory were differently represented across the human age range. Intact familiarity-based memory was found in all age groups, whereas memory based on recollection was impaired in the elderly and not yet fully developed in children. Our data show, for the first time, two different forms of human odor memory across the human life span.

Adolescent↗

PubMed1999

Taste difference thresholds for sucrose in two species of nonhuman primates.

The purpose of this study was to determine taste difference thresholds for sucrose in frugivorous spider monkeys and omnivorous baboons. Using a two-bottle preference test of brief duration, we presented four Ateles geoffroyi and four Papio hamdryas anubis with six different reference concentrations (RCs) of 25, 50, 100, 200, 300, and 400 mM sucrose and tested their ability to discriminate these from lower concentrations of this carbohydrate. The just noticeable differences (JNDs), expressed as Weber ratios (delta/I), were found to range from 0.075-0.25 in the spider monkeys, with a tendency for lower values with higher RCs. In contrast, the baboons showed the reverse trend, with the lowest Weber ratio of 0.10 at the two lowest RCs and higher values of up to 0.25 with the highest RC tested. Thus, the JNDs were found to be generally similar in both species and at least as low as in humans. The results support the assumption that both spider monkeys and baboons may use sweetness as a criterion for food selection. The different patterns of differential sensitivity for sucrose across the range of concentrations tested suggest a correlation between the ability to discriminate between different concentrations of sucrose and the dietary habits of the two species.

Animals↗

PubMed1999

Odor structure-activity relationships compared in human and nonhuman primates.

The ability of 4 squirrel monkeys to distinguish between members of 3 homologous series of substances (aliphatic alcohols, aldehydes, and ketones) was investigated, and their performance was compared with that of a group of 10 human participants. With all 3 substance classes, and in both species, a significant negative correlation was found between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length. These findings suggest carbon chain length of aliphatic odorants to be one of presumably several determinants of the interaction between stimulus molecule and olfactory receptor and support the assumption that human and nonhuman primates may share common mechanisms of odor quality perception.

Adult↗

PubMed1999

Olfactory discrimination ability of human subjects for ten pairs of enantiomers.

We tested the ability of human subjects to distinguish between enantiomers, i.e. odorants which are identical except for chirality. In a forced-choice triangular test procedure 20 subjects were repeatedly presented with 10 enantiomeric odor pairs and asked to identify the bottle containing the odd stimulus. We found (i) that as a group, the subjects were only able to significantly discriminate the optical isomers of alpha-pinene, carvone and limonene, whereas they failed to distinguish between the (+)- and (-)-forms of menthol, fenchone, rose oxide, camphor, alpha-terpineol, beta-citronellol and 2-butanol; (ii) marked individual differences in discrimination performance, ranging from subjects who were able to significantly discriminate between 6 of the 10 odor pairs to subjects who failed to do so with 9 of the 10 tasks; (iii) that with none of the 10 odor pairs were the antipodes reported to differ significantly in subjective intensity when presented at equal concentrations; and (iv) that error rates were quite stable and did not differ significantly between sessions, and thus, we observed a lack of learning or training effects. Additional tests of the degree of trigeminality and threshold measurements of the optical isomers of alpha-pinene, carvone and limonene suggest that the discriminability of these three enantiomeric odor pairs is indeed due to differences in odor quality. These findings support the assumption that enantioselective molecular odor receptors may only exist for some but not all volatile enantiomers and thus that chiral recognition of odorants may not be a general phenomenon but is restricted to some substances.

Adult↗

PubMed1999

Olfactory discrimination ability for homologous series of aliphatic alcohols and aldehydes.

We tested the ability of human subjects to distinguish between members of homologous series of aliphatic alcohols (ethanol to n-octanol) and aldehydes (n-butanal to n-decanal). In a forced-choice triangular test procedure 20 subjects per series were repeatedly presented with all 21 binary combinations of the seven stimuli and asked to identify the bottle containing the odd stimulus. We found (i) that as a group, the subjects performed significantly above chance level in all tasks but two with the alcohols and all tasks but four with the aldehydes, and thus were clearly able to discriminate between most of the odor pairs presented; (ii) marked interindividual differences in discrimination performance, ranging from subjects who were able to significantly distinguish between all 21 odor pairs of a series to subjects who failed to do so with the majority of tasks; and (iii) a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length for both homologous series. This suggests that carbon chain length may be one of presumably several determinants of the interaction between stimulus molecule and receptor, and thus may be a molecular property affecting odor quality of aliphatic alcohols and aldehydes.

Adult↗