Rating of different olfactory judgements in Alzheimer's disease

Using simple successive tasks we assessed the influence of Alzheimer's disease on the processing of different odours. Fifteen patients with Alzheimer's disease, 15 old control subjects and 15 young control subjects were tested. The experiment included two sessions. Initially 12 odorants were presented, one odorant every minute. For each odour the subjects were asked to rate intensity, pleasantness, familiarity and edibility using linear rating scales. The odorants were then presented a second time and the subjects were asked to identify them. The results show that the intensity scores were lower in old control subjects and Alzheimer patients than in the young control subjects and that familiarity and identification scores were lower in Alzheimer patients than in old control and young control subjects. When we compared the five olfactory tasks the impairment of performance in Alzheimer patients was relatively higher for identification than familiarity, itself higher than the intensity judgement. No difference was observed between the three groups of subjects for pleasantness and edibility judgements.     

Ratings of overall olfactory function

The aim of this study was to investigate the accuracy of self-reported ratings of olfactory function in 83 healthy subjects. Such ratings were compared with quantitative measures of olfactory function, as well as with ratings of nasal patency. In experiment 1 subjects rated olfactory function and nasal patency before olfactory testing, whereas in experiment 2 the reverse was the case. No feedback regarding test results were provided until after completion of the testing. The principal findings were: (i) when ratings preceded measurements of olfactory function, there was no significant correlation between the two parameters. However, ratings of olfactory function correlated significantly with ratings of nasal airway patency. (ii) In contrast, when measurements of olfactory function preceded the ratings, this constellation switched. Now ratings of olfactory function correlated significantly with measured olfactory function, whereas there was no significant correlation between ratings of nasal airway patency and ratings of olfactory function. In conclusion, these data suggest that ratings of olfactory function are unreliable in healthy, untrained subjects. The ratings seem to reflect changes of nasal airway patency to a larger degree than measurable olfactory function. The results further indicate that this is mainly due to the limited attention the sense of smell receives in daily life.     

3-D Golgi and image analysis of the olfactory tubercle in schizophrenia

OBJECTIVE: To examine morphologic changes in the olfactory tubercle (OT) spiny neurons and astrocytes in schizophrenia (Sch) by means of quantitative 3-D Golgi and immunocytochemical studies. STUDY DESIGN: Free-floating vibrotome sections of postmortem brain tissue from 10 controls and 12 Sch cases were used for Golgi study and glial fibrillary acidic protein (GFAP) immunocytochemistry. A gray level image analysis was applied for quantitative estimation of GFAP-positive astrocytes on uniform, randomly sampled sections. This method is effective for low-contrast objects on an uneven background. Golgi-impregnated OT spiny neurons were analyzed both qualitatively and quantitatively in three dimensions with a semiautomated microscope-computer system. From digitized image of the neurons, various metric parameters were estimated to characterize the dendritic tree. RESULTS: In cases of Sch, degenerative changes in the dendrites of OT spiny neurons were revealed. A decrease in the maximal radius of the dendritic tree and total length of dendrites were accompanied by an increase in the length density of dendrites. Hypertrophy and a more-intensive GFAP reaction of astrocytes were found in OT of Sch. CONCLUSION: Based on these results, one can hypothesize that OT spiny neurons in Sch are involved in the process of dendritic reorganization, including degenerative changes in dendrites.     

Expression of mRNAs encoding for two different olfactory receptors in a subset of olfactory receptor neurons

Evidence has accumulated to support a model for odorant detection in which individual olfactory receptor neurons (ORNs) express one of a large family of G protein-coupled receptor proteins that are activated by a small number of closely related volatile chemicals. However, the issue of whether an individual ORN expresses one or multiple types of receptor proteins has yet to be definitively addressed. Physiological data indicate that some individual ORNs can be activated by odorants differing substantially in structure and/or perceived quality, suggesting multiple receptors or one nonspecific receptor per cell. In contrast, molecular biological studies favor a scheme with a single, fairly selective receptor per cell. The present studies directly assessed whether individual rat ORNs can express multiple receptors using single-cell PCR techniques with degenerate primers designed to amplify a wide variety of receptor sequences. We found that whereas only a single OR sequence was obtained from most ORNs examined, one ORN produced two distinct receptor sequences that represented different receptor gene families. Double-label in situ hybridization studies indicated that a subset of ORNs co-express two distinct receptor mRNAs. A laminar segregation analysis of the cell nuclei of ORNs labeled with the two OR mRNA probes showed that for one probe, the histogram of the distribution of the cell nuclei along the depth of the epithelium was bimodal, with one peak overlapping the (unimodal) histogram for the other probe. These results are consistent with co-expression of two OR mRNAs in a population of single ORNs.     

Distribution of judgements in adaptive testing

In a psychophysical experiment the observer is given the task to detect a signal or to discriminate two signals; the performance of the observer in this task is to be determined as a function of the physical parameters of the stimuli presented. To increase efficiency of testing, one stimulus parameter is controlled in such a way that the task is made more difficult when the observer performs well and made easier when he doesn't. The observer then forms part of a feedback loop, a part that is characterized by stochastic behaviour. In a well-designed experiment the parameter under study will continually oscillate around its target value (i.e., the threshold of detectability or of discriminability). This paper derives an expression for the equilibrium distribution of this parameter around the target point, valid for an extremely long experiment. The observer is described as a stochastic detector with stationary characteristics. In the experiment he is subjected to a number of trials with stimuli having constant parameters. A set of rules applied to the performance of the subject in a group of trials then determines in which direction the parameter under study is to be varied for the next group of trials. For a wide class of experimental designs the desired equilibrium distribution of this parameter can be found from a recurrence formula. The derivation of this formula is given.Examples of application of this theory are presented. Equilibrium distributions computed from the recurrence formula are found to be good predictors of results of experiments carried out with a finite length. This result allows a deeper study of what constitutes the best procedural design in a given case. It is finally shown how the class of usable procedures can be enlarged by judicious combination of different types of rules.     

Neurodevelopmental involvement in schizophrenia: the olfactory epithelium as an alternative model for research

It has been suggested that disturbances during neurodevelopment may play a crucial role in the etiology of schizophrenia (SZ). This premise is supported by brain imaging, epidemiological, and pathological studies as well as the discovery of susceptibility genes for SZ that appear to be implicated in development of the central nervous system. Here, we discuss the limitations of the current methods and models for studying the neurodevelopmental implications in SZ. We agree with the proposal that the olfactory epithelium, in which neurodevelopment continues throughout life, might represent an alternative model for understanding the pathophysiology of the disorder.     

Palmar dermatoglyphics in different phenotypic manifestations of schizophrenia]

Palmar dermatoglyphics was studied in 1120 patients with schizophrenia with due regard for its form, and in 1240 healthy persons of the same population. The frequency of the AU/AC type of patterns in the hypothenar area was increased in women with schizophrenia and its paranoid form. Among men with schizophrenia and its simple form the frequency of dysplasia, true and defective patterns on the thenar was increased; in addition in men with the paranoid form the frequency of loops in the 3d interdigital areas was also increased.     

Similar numbers but different repertoires of olfactory receptor genes in humans and chimpanzees

Animals recognize their external world through the detection of tens of thousands of chemical odorants. Olfactory receptor (OR) genes encode proteins for detecting odorant molecules and form the largest multigene family in mammals. It is known that humans have fewer OR genes and a higher fraction of OR pseudogenes than mice or dogs. To investigate whether these features are human specific or common to all higher primates, we identified nearly complete sets of OR genes from the chimpanzee and macaque genomes and compared them with the human OR genes. In contrast to previous studies, here we show that the number of OR genes ( approximately 810) and the fraction of pseudogenes (51%) in chimpanzees are very similar to those in humans, though macaques have considerably fewer OR genes. The pseudogenization rates and the numbers of genes affected by positive selection are also similar between humans and chimpanzees. Moreover, the most recent common ancestor between humans and chimpanzees had a larger number of functional OR genes (>500) and a lower fraction of pseudogenes (41%) than its descendents, suggesting that the OR gene repertoires are in a phase of deterioration in both lineages. Interestingly, despite the close evolutionary relationship between the 2 species, approximately 25% of their functional gene repertoires are species specific due to massive gene losses. These findings suggest that the tempo of evolution of OR genes is similar between humans and chimpanzees, but the OR gene repertoires are quite different between them. This difference might be responsible for the species-specific ability of odor perception.     

Relative numerousness judgements in crows and pigeons in the urgent comparison of stimuli earlier linked to different amounts of reinforcement]

The ability of pigeons (Colomba livia, L.) and crows (Corvus corone cornix, L.) was studied to realize urgent numerousness judgement of reinforcement consisting of discrete elements (wheat grains and meal worm larvae, respectively). In the process of preliminary training the birds mastered the information about the conformity of the feeder colour with the definite number (1-9 for pigeons and 5-12 for crows) of reinforcement units at isolated presentation of feeders. In test at presentation of pairs formed from these feeders, pigeons and crows chose the stimulus connected with a greater quantity of reinforcement. In the range of 1-8 units the precision of choice in pigeons depended on absolute and relative differences between comparing values. In crows in the range of 6-12 this dependence was not revealed. The ability to solve the given test is considered as one of manifestations of elementary reasoning.     

用不同实验小鼠品系建立精神分裂症的动物模型

基于精神分裂症的谷氨酸功能紊乱假说,实验用N-甲基-D-天门冬氨酸(NMDA)非竞争性受体拮抗剂MK801(5-甲基二氢二苯并环庚稀亚氨马来酸或地卓西平马来酸盐)作用于实验小鼠,观察到类似精神分裂症的症状：移动加快(hyperlocomotion)和刻板性动作(stereotypy),建立了可用仪器测定的两项量化指标。根据作用于近交系BALB/c小鼠的MK801的剂量优化结果,用0．6mg／kg体重的MK801剂量初步建立了精神分裂症小鼠模型,并用近交系C57BL／6小鼠成功重复了上述实验。进一步用系列剂量的MK801作用于远交群ICR小鼠,同样也诱发了类似精神分裂症的症状。用目前临床上常用的抗精神分裂症药物利培酮作用于已建立的BALB／c小鼠和C57BL／6小鼠的精神分裂症模型,结果表明利培酮能显著地抑制两品系模型小鼠的类似精神分裂症的症状。实验结果证明：用MK801作用于实验小鼠建立精神分裂症动物模型是可行的。     

A candidate olfactory receptor subtype highly conserved across different insect orders

Candidate olfactory receptors of the moth Heliothis virescens were found to be extremely diverse from receptors of the fruitfly Drosophila melanogaster and the mosquito Anopheles gambiae, but there is one exception. The moth receptor type HR2 shares a rather high degree of sequence identity with one olfactory receptor type both from Drosophila (Dor83b) and from Anopheles (AgamGPRor7); moreover, in contrast to all other receptors, this unique receptor type is expressed in numerous antennal neurons. Here we describe the identification of HR2 homologues in two further lepidopteran species, the moths Antheraea pernyi and Bombyx mori, which share 86-88% of their amino acids. In addition, based on RT-PCR experiments HR2 homologues were discovered in antennal cDNA of the honey bee (Apis mellifera; Hymenoptera), the blowfly (Calliphora erythrocephala; Diptera) and the mealworm (Tenebrio molitor; Coleoptera). Comparison of all HR2-related receptors revealed a high degree of sequence conservation across insect orders. In situ hybridization of antennal sections from the bee and the blowfly support the notion that HR2-related receptors are generally expressed in a very large number of antennal cells. This, together with the high degree of conservation suggests that this unique receptor subtype may fulfill a special function in chemosensory neurons of insects.     

Effects of context on judgements of odor intensities in humans

This study evaluated whether the intensity of previously smelled odors could unintentionally influence the subsequent judgement of odor intensity. The predicted context effect was based on the adaptation- level theory. Before and 25 min after either WEAK or STRONG biasing odor concentrations, 51 subjects were required to rate the intensity of 10 different odor concentrations of California Orange Oil. After the WEAK bias, subjects judged the odor intensity as being stronger than they did after the STRONG bias. Thus the intensity of odors smelled 25 min earlier can unintentionally influence subsequent odor intensity judgement. The findings are discussed in the light of two alternative explanations, namely, a central implicit memory process and a stimulus- level-based change at the peripheral level.      

Identification of different types of serotonin-like immunoreactive olfactory interneurons in four infraorders of decapod crustaceans

Summary An antiserum raised against serotonin (5HT) was applied to the brains of representatives of four different infraorders of decapod crustaceans, and revealed two morphological classes of olfactory interneurons. They were classified by the position and size of their cell bodies, and by their connection pattern. One class consisted of giant olfactory interneurons and the other of globuli cells. They were regarded as input and intrinsic interneurons, respectively, because of their morphology. The two classes displayed a similar pattern in two of the infraorders, whereas only one class appeared in the other two infraorders.     

Effects of different ionic environments on the responses of single olfactory receptors in the lamprey

• 1.1. Effects of different ionic environments on the lamprey olfactory receptor response were studied by the analysis of frequency histograms of unitary spikes recorded extracellularly.
• 2.2. The magnitude of the receptor response to l-arginine stimulus was a function of Ca ion concentration in the external solution. The receptor response was completely blocked in Ca-free solution containing EGTA. Na and K ion concentration changes did not influence the receptor activity.
• 3.3. The receptor response was suppressed by La and Co ions. La ions had much stronger effects than Co ions. The suppression by these ions disappeared in the presence of Ca ions in the solution.
• 4.4. The results suggest that Ca ions on the apical receptor surface play an important role for the generation of olfactory receptor potential, probably as inward current carriers through the apical receptor membrane.

     

具有不同嗅觉学习能力的工蜂的遗传背景分析

【目的】蜜蜂是由不同亚家系组成的社会性群居昆虫,为了研究具有不同嗅觉学习能力的工蜂的遗传背景差异。【方法】本试验以中华蜜蜂Apis cerana cerana为材料,通过微卫星技术分析了两组嗅觉学习能力不同工蜂的亚家系分布情况。【结果】同一蜂群中拥有两种不同学习能力的工蜂在各亚家系的分布不存在显著差异(P>0.05)。【结论】蜜蜂嗅觉学习能力可能与亚家系组成无关,而由更精确的遗传因子调控。     

When maths trumps logic: probabilistic judgements in chimpanzees

When searching for hidden food, do chimpanzees take into account both the number of hidden items and the number of potential hiding locations? We presented chimpanzees with two trays, each of them containing a different food/cup ratio and therefore a different likelihood of finding a baited cup among empty alternatives. Subjects'' performance was directly influenced by the relative difference (probability ratio (PR)) between the two given probabilities. Interestingly, however, they did not appreciate the special value of a truly safe option (with P = 1.0). Instead, they seemed to ‘blindly’ rely on the PR between the two options, systematically preferring the more likely one once a certain threshold had been reached. A control condition ruled out the possibility of low-level learning explanations for the observed performance.     

Wildlife conservation in churchyards: a case-study in ethical judgements

Groups promoting wildlife in churchyards or other sites, discover that they face normative questions that have no scientific answers. The language of management is used for handling these questions, but this metaphor has unhelpful associations with predetermined goals, a culture of control and self-centredness. Using a case-study approach, conflicts between conserving natural entities or natural processes (e.g. transplanting scarce plants); between caring for the individual organism or for the system (e.g. felling trees); and between conserving the natural or the cultural heritage (e.g. repointing walls) are examined. These cases of conflicts of duty illustrate the value of attention to circumstances, proportionality, and compromise. The social mechanisms of moral debate include legal protection and the power of stories to give meaning and vision. Ethics is a communal activity. By listening to others and attending to nature our sensibilities will become more refined and our ethical judgements will develop.     

Morphological phenotypes of olfactory ensheathing cells display different migratory responses upon Slit-2

Olfactory ensheathing cells (OECs) are a type of glial cells with morphological plasticity in the olfactory system. Cultured OECs display the process-bearing and flattened shape. Our previous studies have shown that the frontal application of Slit-2 gradient induced the collapse of leading front, and reversed the soma translocation of process-bearing OECs. However, the migratory properties of flattened OECs upon Slit-2 gradient remain elusive. Here, we found that Slit-2 gradient induced the collapse of their plasma membrane, and inhibited migration of flattened OECs. Upon to Slit-2 gradient, the leading front of flattened type 1 OECs firstly showed collapse and retraction, then gradually re-grew a new lamellipodia, finally, showed collapse again (this phenomenon was called as adaptation), while flattened type 2 OECs only showed collapse of plasma membrane. These different migratory responses upon Slit-2 stimulation were possibly due to their different sub-cellular distribution of Robo receptor. Furthermore, F-actin at the peripheral region of leading front was more sensitive to the Slit-2 stimulation than microtubules and the loss of F-actin might be implicated in initiating the collapse of flattened OECs. Finally, the adaptation of flattened type 1 OECs induced by Slit-2 was independent on protein synthesis. Taken together, these results demonstrate that morphological phenotypes of OECs display different migratory properties upon Slit-2 and an unexpected finding that the protein synthesis-independent adaptation in OECs induced by Slit-2.     

Removal of olfactory bulbs in rats of different ages: repercussion on some metabolic constants.

The object of this investigation is to study effects of bulbectomy on female rats operated on at 15 and 30 days of age (prepubescent), 50 days (pubescent) and 120 days (adult), with respect to various parameters: these comprise corporal weight, liver weight, blood sugar, liver glycogen, glucose tolerance test and serum free fatty acid. Results were as follows. Body weight: in all groups this was significantly less than in controls except for rats operated on at adult age. Liver weight: (% of body weight) decreases in all groups, but significantly only in animals operated on when 15 days old. Blood sugar: significantly lessened in rats operated on when 30 and 120 days old. Liver glycogen: lessens in rats operated on at 30 and 120 days of age, but significantly only in the former. Glucose tolerance test: the coefficient k is found to increase in rats operated on at 15, 30 and 120 days of age; there is a significant increase in the first two groups. Serum free fatty acids: no marked alterations in any of the groups.