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Biomedical subjects

M Laska

Publications and source records attributed to M Laska.

At least 37 records · Page 2Linked to original sources
PubMed1999

Odor identification, consistency of label use, olfactory threshold and their relationships to odor memory over the human lifespan.

The purpose of this study was to investigate olfactory threshold, odor identification, consistency of label use and their relationships to odor memory in the context of semantic/episodic memory across the human lifespan. A total of 137 subjects aged 4-90 years were tested with several olfactory test procedures. We found that olfactory sensitivity was well developed in children despite the finding that their odor naming and odor memory were inferior to that of adults. In the elderly population, olfactory functions gradually declined, with odor memory and odor identification demonstrating the most significant decline. Semantic encoding was differentially related to odor memory over the human age span. Whereas consistency of label use was the main predictor for odor memory in children and young adults, olfactory identification ability was the main predictor in the elderly study group. We also calculated response bias for the separate age groups and found no differences between children, young adults and elderly. However, with age false alarm rates increased. We conclude that children possess equal olfactory sensitivity compared with adults; however, due to limitations in linguistic capabilities and familiarity to odorants, odor memory and odor identification performance was limited. Additionally, our data indicate major alterations of olfactory processing in advanced age with substantial losses in odor memory and odor identification performance.

Adolescent↗
PubMed1999

Olfactory discrimination ability and odor structure-activity relationships in honeybees.

Using the training procedure introduced by von Frisch in 1919, we tested the ability of free-flying honeybees to discriminate a conditioning odor from an array of 44 simultaneously presented substances. The stimuli included homologous series of aliphatic alcohols, aldehydes and ketones, isomeric forms of some of these substances, as well as several terpenes and odor mixtures, and thus comprised stimuli of varying degrees of structural similarity to any conditioning odor. We found (i) that the honeybees significantly distinguished between 97.0% of the 1848 odor pairs tested, thus showing an excellent discrimination performance when tested in a free-flying situation with an array of structurally related substances; (ii) a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length with all aliphatic substance classes tested; (iii) that both the position and type of a functional group also affected discriminability of odorants in a substance class-specific manner; and (iv) striking similarities in odor structure-activity relationships between honeybees and human and nonhuman primates tested previously on a subset of substances employed here. Our findings demonstrate that the similarities found in the structural organization of the olfactory systems of insects and vertebrates are paralleled by striking similarities in relative discrimination abilities. This strongly suggests that similar mechanisms of odor coding and discrimination may underlie olfaction in vertebrates and insects.

Animals↗
PubMed1999

Enantioselectivity of odor perception in squirrel monkeys and humans.

With use of a conditioning paradigm, the ability of six squirrel monkeys to distinguish between 10 pairs of enantiomers, i.e., odorants that are identical except for chirality, was investigated. As a group, the animals were only able to discriminate between the optical isomers of alpha-pinene, carvone, limonene, and fenchone, whereas they failed to distinguish between the (+) and (-) forms of beta-citronellol, menthol, rose oxide, 2-butanol, alpha-terpineol, and camphor. With use of a triple forced-choice procedure, 10 human subjects were tested for their ability to discriminate between the same enantiomeric odor pairs in parallel and, with the exception of fenchone, showed a very similar pattern of performance compared with the squirrel monkeys. These findings support the assumption that human and nonhuman primates may share common principles of odor quality perception. Furthermore, the results suggest that, in both species, enantioselective molecular odor receptors may only exist for some, but not all volatile enantiomers and thus that chiral recognition of odorants is not a general phenomenon, but may be restricted to some substances.

Adult↗
PubMed1998

Assessing olfactory performance in an Old World primate, Macaca nemestrina.

The present study demonstrates that an operant conditioning paradigm, originally designed for assessing olfactory performance in a small New World primate, the squirrel monkey, can successfully be adapted for use with a large Old World primate, the pigtail macaque. Using a task designed to simulate olfactory-guided foraging behavior, based on multiple discrimination of simultaneously presented odor stimuli, we could show that Macaca nemestrina is able to learn to discriminate between objects on the basis of odor cues. Moreover, they could readily transfer to new S+ and S- stimuli and could remember the significance of previously learned odor stimuli even after a 3-week break. Furthermore, we could show that this method is suitable for obtaining reliable measures of olfactory sensitivity. The few modifications of the original method employed here did not affect essential features such as the mode of stimulus presentation (odorized paper strips attached to manipulation objects) and the choice criterion (opening or rejecting the odorized manipulation objects), thus for the first time enabling valid interspecific comparisons of olfactory capabilities between a catarrhine and a platyrrhine primate species. Our results indicate that M. nemestrina and Saimiri sciureus are similar with regard to several measures of olfactory performance, such as speed of initial task acquisition and ability to master transfer tasks as well as their sensitivity to a food-related odorant.

Animals↗
PubMed1998

Laterality in the use of the prehensile tail in the spider monkey (Ateles geoffroyi).

The purpose of this study was to assess the occurrence of lateral biases in the use of the prehensile tail in Ateles geoffroyi. 24 spider monkeys were presented with three food-reaching tasks designed to differ in the precision of motor control needed for successful food retrieval and assessed for lateral preferences in tail use with a minimum of 50 caudal reaches per animal and task. Highly lateralized tail use was found in 16 animals, distributed almost equally between left- and right-preferent individuals, consistent in strength and direction across tasks, and not significantly correlated with manual preferences. Eight infant monkeys did not cooperate suggesting an age-dependency in the development of tail use skills. The results give evidence of a hitherto undescribed example of behavioral asymmetry in a nonhuman primate species which may offer an additional approach to the investigation of cortical plasticity and functional hemispheric asymmetries.

Animals↗
PubMed1998

Differences in perception of everyday odors: a Japanese-German cross-cultural study.

There is a growing appreciation that experience with odors may strongly influence their perception. To further investigate this, the responses of 40 Japanese and 44 age-matched German women to everyday odorants were compared. Subjects were presented with 18 stimuli in squeeze bottles and asked to rate them according to intensity, familiarity, pleasantness and edibility, to describe associations elicited by them and, if possible, to name them. One-third of the odorants were presumed to be familiar to the Japanese only, one-third to the Germans and one-third to both populations. Significant differences were found between the two populations on all measures. Better performance by the Japanese in providing appropriate descriptors for 'Japanese' odorants and by the Germans for 'European' odorants supported the pre-selection of stimuli as culture-typical. Particularly clear differences between the two populations were found in pleasantness ratings. In general, a positive relationship was found between pleasantness and judgement of stimuli as edible, suggesting that culture-specific experiences-particularly of foods-may significantly influence odor perception. Somewhat unexpectedly, significant differences were also found between the two populations in intensity ratings for some odorants. These differences did not seem simply to be artefacts of the test situation and raise the possibility that experience may even influence such basic aspects of odor perception as stimulus intensity.

Cultural Characteristics↗
PubMed1998

Odor structure-activity relationships of carboxylic acids correspond between squirrel monkeys and humans.

With use of a conditioning paradigm, the ability of four squirrel monkeys to distinguish n-valeric acid from n-forms and isoforms of other carboxylic acids (acetic acid to octanoic acid) was investigated. All four animals were clearly able to discriminate between all odor pairs tested and showed a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length of the carboxylic acids. Branching of the carbon chain was also found to affect odorant quality because all animals performed better in discriminating n-valeric acid from isoforms of other carboxylic acids compared with the corresponding n-forms of these substances. With use of a triple forced-choice procedure, 10 human subjects were tested on the same tasks in parallel and showed a very similar pattern of discrimination performance compared with the squirrel monkeys. Thus the results of this study provide evidence of well-developed olfactory discrimination ability in squirrel monkeys for carboxylic acids and support the assumption that human and nonhuman primates may share common principles of odor quality perception.

Adult↗
PubMed1997

Trigeminal perception of odorant quality in congenitally anosmic subjects.

Twenty congenitally anosmic subjects and 50 normosmic controls were tested for their ability (i) to assign verbal labels from a list of trigeminal-type descriptors to six odorants believed to have a strong trigeminal component; and (ii) to discriminate between intensity-matched pairs of these odorants in an odd-ball paradigm. The following was found: normosmic controls judged menthol and cineole as distinctly cool and fresh, acetic acid as pungent and sour, and acetone as pungent, but showed no clear descriptive profile for ethanol and propanol. The descriptive profiles given by the anosmic subjects correlated significantly with those given by the controls for three of the six odorants (menthol, cineol and ethanol), confirming that the sensations described may indeed be mediated by the trigeminal system. In the odd-ball test, the control subjects correctly identified an average of eight out of the nine items presented, with most mistakes occurring in response to pairs with a similar trigeminal profile. With an average of 7.2 of nine items correct, the performance of the anosmic subjects was not significantly different to that of the normosmics, except in discriminating between acetic acid and menthol. Although additional tests are necessary to decide finally whether differences in stimulus intensity may have contributed to this good discriminatory performance, the present results suggest that the nasal trigeminal system may contribute significantly to the perception of odor quality.

1-Propanol↗
PubMed1997

Olfactory discrimination ability for aliphatic esters in squirrel monkeys and humans.

Using a behavioral paradigm designed to simulate olfactory-guided foraging, the ability of five squirrel monkeys to distinguish iso-amyl acetate from n- and iso-forms of other acetic esters (ethyl acetate to decyl acetate) and from other esters carrying the iso-amyl group (iso-amyl propionate to iso-amyl capronate) was investigated. We found (i) that all five animals were clearly able to discriminate between all odor pairs tested; (ii) a significant negative correlation between discrimination performance and structural similarity of odorants in terms of differences in carbon chain length of both the aliphatic alcohol group and the aliphatic acid group of the esters; and (iii) that iso- and n-amyl acetate were perceived as qualitatively similar despite different steric conformation. Using a triple-forced choice procedure, 20 human subjects were tested on the same tasks in parallel and showed a very similar pattern of discrimination performance compared with the squirrel monkeys. Thus, the results of this study provide evidence of well-developed olfactory discrimination ability in squirrel monkeys for aliphatic esters and support the assumption that human and non-human primates may share common principles of odor quality perception.

Adult↗
PubMed1997

[Odor perception in relation to age, general health, nutritional status, and dental status].

Many studies have shown that odour perception declines with age. Considering the possible role of age-related phenomena such as general health, dental health and nutrition in such a decline, their joint effect on variability in odour perception was evaluated in the present study. 73 apparently healthy adults aged from 53 to 86 years (median age = 66), living in the community, took part in this study. The SENIEUR protocol was used to assess the general health status and anthropometric measures were obtained to assess the nutritional status. The sensory detection threshold for isoamylacetate (banana odour) was determined as the lowest detectable odour concentration. Dental status was assessed by a questionnaire on the presence of natural teeth and wearing of dentures. Those in poor general health had significantly higher mean odour thresholds (2.35, SD = 1.34), where threshold concentration was expressed as -log(mol/l), than those in good (3.47, SD = 1.46) or reasonably general health (3.75, SD = 1.02). Partial denture wearers had significantly higher odour thresholds (2.99, SD = 1.12) than those having only natural teeth (4.24, SD = 1.43). Significant correlations between age and anthropometrical values were found, indicating that with age, muscle mass particularly in women decreases (r = -0.50). Odour perception of women correlated significantly inversely with triceps skinfold thickness (r = -0.42), indicating that poor sense of small is associated with high body content of fat. Our results indicate that general health and dental state are important age-associated factors in odour perception. Since age does not show a significant independent effect, neither in an analysis of variance, nor in a multiple regression analysis, such factors tend to become more important than chronological age per se.

Aged↗
PubMed1996

Manual laterality in spider monkeys (Ateles geoffroyi) solving visually and tactually guided food-reaching tasks.

The purpose of this study was to assess the occurrence of manual laterality in Ateles geoffroyi and in particular to test the influence of visual and tactual control on preferential hand use. Thirteen spider monkeys were presented with three different food-reaching tasks and assessed for hand preferences with a minimum of 100 reaches per animal. In all three tasks a significant lateral bias towards use of the left hand at the group level was found. Performance in visually and tactually guided reaching tasks did not differ with regard to direction or degree of manual laterality. Males and females showed no significant differences in performance with the exception that males used their mouths to retrieve food when the task permitted, significantly more often than females. The results suggest a possible right-hemisphere specialization in the spider monkey for both visually and tactually guided reaching.

Animals↗
PubMed1996

A study of long-term odor memory in squirrel monkeys (Saimiri sciureus).

Five squirrel monkeys (Saimiri sciureus) were trained to discriminate between pairs of odors, and their ability to recognize these as positive or negative was tested at intervals of up to 7 months. Retention was excellent up to 15 weeks and remained significantly above chance even after 30 weeks. Good performance at the shorter intervals was not due to rapid relearning, although at the longer intervals considerable savings were demonstrated by the animals' ability to reach criterion more rapidly than with novel odors. Thus, squirrel monkeys possess a robust memory for odors and show flat forgetting curves consistent with reports for human subjects.

Animals↗
PubMed1996

Sensory detection of food odour in relation to dental status, gender and age.

The aim of this study was to investigate to what extent declining odour perception can be ascribed to dental status and oral hygiene habits, taking into account gender and age. Apparently healthy adults (n = 182), ranging from 53 to 93 years (mean age = 68.4) were tested. Information about oral hygiene habits (brushing teeth and cleaning dentures) and dental status was obtained by questionnaires. A validated objective procedure was used to measure sensory detection thresholds for isoamylacetate by an ascending method of limits. A significant negative correlation of odour perception with age was shown by the edentulous subjects which might reflect their wider age spread with many subjects over age 75. The evaluation of odour perception as a function of dental status shows no significant difference in odour perception between persons partial denture wearers, with natural teeth only or complete dentures. However, a tendency for lower odour perception was observed among male partial denture wearers, especially those reporting less frequent oral hygiene, which justifies further more detailed study.

Aged↗
PubMed1994

Olfactory function in patients with hypogonadotropic hypogonadism: an all-or-none phenomenon?

Hypogonadotropic hypogonadism (HH) refers to an endocrine defect of hypothalamic origin resulting in gonadal hypoplasia and frequently associated with anosmia or severely impaired olfactory function (Kallmann's syndrome). This apparently results from a disruption in the migration of neurons from the olfactory placode to the bulb and hypothalamus early in development, and so provides a unique opportunity to investigate olfactory function in human subjects with congenitally incomplete peripheral systems. Olfactory performance in 37 HH patients and 37 age-matched controls was compared using a modified version of the Munich Olfaction Test. This test is based on the sniff-bottle method and includes tests of (i) odor quality discrimination, (ii) intensity discrimination, (iii) detection thresholds, and (iv) recognition, hedonic evaluation and identification ability. The patients could be divided into two distinct groups differing significantly on all four subtests and showing no overlap in performance: 20 anosmics, conforming to Kallmann's syndrome, and 17 apparent normosmics whose performance was slightly poorer, but not significantly different to that of the controls. The unexpected failure to find a continuum of olfactory dysfunction now raises the question whether HH with or without anosmia represents two syndromes with distinct etiologies, or rather reflects the ability of the olfactory system to function well despite morphological impairment.

Adult↗
PubMed1993

Maturation of auditory evoked potentials in young guinea pigs with binaural conductive hearing loss.

A reversible conductive hearing loss produced during the first 4 weeks post partum caused marked alterations in the development of click-evoked auditory brainstem (ABR) and middle latency (MLR) responses in guinea pigs. The early component PI in the ABR in controls showed adult-like latencies at the time of birth, while the later ABR components PIII and PV and all components investigated in the MLR showed postnatal development characterized by a shortened latency that persisted for the whole period of investigation. The course of the ABR latencies showed the sharpest decrease during the first 2-3 weeks of life, while that for the MLR took place during the first 5 weeks. In addition to the increased ABR thresholds and lengthened ABR latencies due to the conductive hearing loss, development of the ABR inter-peak latencies (IPL) and MLR latencies was retarded. The IPL reached control values 1 week after the end of the deprivation phase, while the delay in MLR started later (4th week) and lasted longer than did that in the ABR. These findings showed that a long-lasting postnatal conductive hearing loss does not generate sustained impairment at the level of the brainstem but can evoke longer-lasting deficiencies at higher stations of the auditory pathway.

Aging↗
PubMed1993

Discriminating parts from the whole: determinants of odor mixture perception in squirrel monkeys, Saimiri sciureus.

In a task designed to simulate olfactory-guided foraging, the ability of squirrel monkeys to discriminate an artificial 12-component odorant from 3-, 6-, 9- or 11-component submixtures was investigated. A combination of factors was found to contribute to the animals' performance: 1. Discriminability generally decreased as the number of components in the submixture increased. 2. Submixtures did not contribute equally to mixture perception, and one component in particular (cineole) disproportionately influenced stimulus discriminability. 3. Interactive effects between submixtures resulted in marked deviations from the general pattern of discriminability. 4. Changes in the relative concentration of submixtures could also influence discriminability. 5. Finally, individual differences in responsiveness to particular stimuli were apparent. These findings demonstrate that the interaction between components in odor mixtures can be complex and that seemingly small changes in composition can strongly affect perception and thus potential signal function. It is therefore suggested that in future investigations of squirrel monkey semiochemistry, the method of systematically varying submixtures may be particularly useful in defining the contribution of components to a signal.

Adult↗