Communication of gender from human breath odors: Relationship to perceived intensity and pleasantness

During five consecutive daily test sessions, 10 men and women rated the relative intensity and pleasantness of breath odors from 14 males and 19 females on a no-oral-hygiene regimen. In addition, the likely gender of the donor of each odor was also estimated. The breath odors of males were rated, on the average, as more intense and less pleasant than the breath odors of females. Women consistently gave lower pleasantness ratings to the odors than did men. Both the male and female judges assigned the breath odors to the correct gender classes at a frequency unlikely due to chance, although the females were more accurate in this regard. An inverse relation between breath odor intensity and pleasantness was noted. Systematic changes in the rated intensity and pleasantness of the odors were present across the 5 days of the study period. These data suggest that differences exist between the breath odors of men and women, and that humans, like many other mammals, may be capable of assessing gender from oral odors. However, such assignments conceivably reflect the strategy of assigning stronger and less pleasant odors to the male category, and weaker and less unpleasant odors to the female category, regardless of the true sex of the odor donor.     

Selection of odorants for memory tests on the basis of familiarity,perceived complexity,pleasantness, similarity and identification

In a procedure for the selection of two equivalent sets of familiar and two equivalent sets of unfamiliar odours for use in odour memory studies, 24 na?ve subjects were first asked to rate the familiarity, perceived complexity and pleasantness of 54 a priori unfamiliar odours and 57 a priori familiar odours and to identify the latter. After selection of the 40 most familiar and the 40 least familiar odours, the subjects sorted each of these two sets into groups of similar odours. Their results were analysed by multidimensional scaling and cluster analysis and each set was divided into two recognition sets that had the same degree of similarity between target and distractor odours and that had similar values of familiarity, pleasantness, perceived complexity (familiar and unfamiliar sets) and identifiability (familiar sets). Finally, recognition tasks were performed in order to check the equivalence in memory performance of both the two familiar and the two unfamiliar recognition sets.     

Perception of odors by a nonlinear model of the olfactory bulb

The behavior of the olfactory bulb is modeled as a network of interconnected cells with nonlinear dynamics. External inputs from sensory neurons are introduced as perturbations to subsets of cells within the network. We describe the attractors of the system and show how they can be classified and ordered according to their varying degrees of symmetry. By studying networks of attractors in the system's phase space, it is shown how different perturbations may evoke specific switches between various patterns of behavior. This ensures that different odors, even if present at extremely low concentrations, are able to evoke a specific spatio-temporal behavior in the olfactory bulb, permitting their unique perception. The model incorporates many of the processes proposed to mediate perception, such as the topographic organisation of sensory systems, destabilization of cortex by sensory input and synchronisation between neurons. It is also consistent with the character of the olfactory electroencephalogram.     

Structure-activity relation for synthetic phenoxazone drugs: evidence for a direct correlation between DNA and pro-apoptotic activity.

The structure-activity relations of a series of synthetic phenoxazone drugs with aminoalkyl side chains of variable length and different terminal groups were investigated by examining their biological activity and DNA complexation affinity. Biological activity was determined from their ability to induce apoptosis and cell cycle perturbations (activation of cell cycle checkpoints) using the human malignant MOLT-3 cell line. The thermodynamic parameters of drug-DNA complexation were determined by differential scanning calorimetry. By comparing the activities of compounds with different terminal groups (amino, dimethylamino and diethylamino), we found that the existence of a terminal dimethylamino group in the alkylamino side chain is an important factor for anti-tumour activity. Minor modifications in the dimethylaminoalkyl side chain (e.g. elongation by one methylene group) led to notable changes in both the anti-tumour activity and DNA-binding properties of the drug, providing unambiguous evidence of a marked structure-activity relation.     

Performance of mice in discrimination of liquor odors: behavioral evidence for olfactory attention

We examined performance of mice in discrimination of liquor odors by Y-maze behavioral assays. Thirsty mice were initially trained to choose the odor of a red wine in the Y-maze. After successful training (>70% concordance for each trained mouse), the individual mice were able to discriminate the learned red wine from other liquors, including white wine, rosé wine, sake, and plum liqueur. However, when the mice were tested to distinguish fine differences between 2 brands of red wine, their performance significantly varied among the individual trained mice. Among 10 mice tested, 2 mice were able to discriminate between the red wines (>75% concordance) whereas 6 mice failed to distinguish between them (50-67% concordance, where chance could be assumed to be 50%). More importantly, 2 other mice exhibited lower than 30% concordance, indicating that they were more attracted to the nonrewarded red wine compared with the learned one. This result suggested that the individual mice directed attention to different subsets of volatile components emanating from the rewarded red wine, when they were trained to choose the liquor odor in the Y-maze. Selective attention of mice was also observed in Y-maze behavioral assays using the mixtures of 3 or less pure odorants. Additionally, we also observed that the olfactory attention of mice could be modified through their learning experiences.     

Sulfation of gastrin in Zollinger-Ellison sera: evidence for association between sulfation and proteolytic processing

Sulfated gastrins were quantitated in sera from 15 patients with the Zollinger-Ellison syndrome (ZES) by specific radioimmunoassays. The total concentration of gastrin varied from 174 to 285000 pmol/1. Sulfated gastrins constituted $\text{44.8±5.5\%}$ (mean ± S.E.M.) of the gastrins in ZES sera compared with $\text{37.7±1.9\%}$ in sera from 100 control subjects ($\text{P>0.1}$). There was no correlation between gastrin concentration and sulfation ($\text{r=0.40}$). Gel and ion-exchange chromatography showed that up to 90% of the gastrins could be in the sulfated form. The highest degree of sulfation was found in sera where the small gastrin components dominated. Thus, the percentage of small gastrins (G-17 and G-14) correlated with the degree of sulfation ($\text{N = 15}$, $\text{r=0.75}$, $\text{P<0.01}$). We suggest therefore that proteolytic processing of the gastrin precursor and sulfation of tyrosyl are associated.     

Olfactory information processing in the brain: Encoding chemical and temporal features of odors

A fundamental problem in studying the neural mechanisms of odor recognition and discrimination in the olfactory system lies in determining the features or “primitives” of an odor stimulus that are analyzed by glomerular circuits at the first level of processing in the brain. Several recent studies support the idea that it is not simply the molecular features of odors that contain important information, but also the intermittent pattern of their presentation to the olfactory epithelium that helps determine the behavioral response to odor. © 1996 John Wiley & Sons, Inc.     

Pollen advertisement: chemical contrasts between whole-flower and pollen odors

Odors of pollen and whole flowers were compared in taxonomically unrelated species that offer pollen as the only food reward to pollinators. Volatiles were collected using headspace adsorption and analyzed by gas chromatography and mass spectrometry. The odor of pollen was found to be chemically distinct from the total flower odor, and this pollen-odor distinctness varied among the three species. In Papaver rhoeas (Papaveraceae), the contrast between pollen and whole-flower odors was most subtle, with differences observed only in the proportions of individual volatiles (almost exclusively aliphatic hydrocarbons). In Filipendula vulgaris (Rosaceae), pollen volatiles were fewer than in the flowers (comprising mainly benzenoids and fatty-acid derivatives) and their relative proportions produced an odor dominated by 2-heptadecanone that contrasted strikingly with the flower odor dominated by 2-phenyl ethanol. In Lupinus polyphyllus (Fabaceae), the pollen odor contained fewer volatiles and in differing proportions than the flower fragrance (comprising almost exclusively isoprenoids). The findings add to earlier chemical evidence of odor contrasts between pollen and other flower parts in two other species. Drawing on information from pollination studies of these various species, it is suggested that pollen odor is used by pollen-foraging insects both to discriminate between plant species and to assess reward availability in individual flowers, and that it might in addition serve a protective function against destructive flower-feeding insects and pathogens.     

A fruity note: crossmodal associations between odors and musical notes

Odors are notoriously difficult to describe, but they seem prone to a variety of crossmodal associations. In the present study, we generalize the previously-shown association between odors (from perfumery) and pitch (Belkin et al. 1997) to odors related to food and drink (in this case those associated with wine). We also demonstrate that, to a lesser extent (25% of the odor tested), participants preferentially match specific odors to certain types of instruments. The ratings of the odors along a number of dimensions are used in principal components analysis (PCA) to explore the psychological dimensions underlying the odor-pitch associations. The results demonstrate that both pleasantness and complexity, but not intensity, appear to play a role when choosing a pitch to match an odor. Our results suggest that these features of odor stimuli constitute psychological dimensions that can be consistently matched to auditory features.     

fMRI evidence for a cortical hierarchy of pitch pattern processing

Pitch patterns, such as melodies, consist of two levels of structure: a global level, comprising the pattern of ups and downs, or contour; and a local level, comprising the precise intervals that make up this contour. An influential neuropsychological model suggests that these two levels of processing are hierarchically linked, with processing of the global structure occurring within the right hemisphere in advance of local processing within the left. However, the predictions of this model and its anatomical basis have not been tested in neurologically normal individuals. The present study used fMRI and required participants to listen to consecutive pitch sequences while performing a same/different one-back task. Sequences, when different, either preserved (local) or violated (global) the contour of the sequence preceding them. When the activations for the local and global conditions were contrasted directly, additional activation was seen for local processing in right planum temporale and posterior superior temporal sulcus (pSTS). The presence of additional activation for local over global processing supports the hierarchical view that the global structure of a pitch sequence acts as a "framework" on which the local detail is subsequently hung. However, the lateralisation of activation seen in the present study, with global processing occurring in left pSTS and local processing occurring bilaterally, differed from that predicted by the neuroanatomical model. A re-examination of the individual lesion data on which the neuroanatomical model is based revealed that the lesion data equally well support the laterality scheme suggested by our data. While the present study supports the hierarchical view of local and global processing, there is an evident need for further research, both in patients and neurologically normal individuals, before an understanding of the functional lateralisation of local and global processing can be considered established.     

Social learning in nest-building birds: a role for familiarity

It is becoming apparent that birds learn from their own experiences of nest building. What is not clear is whether birds can learn from watching conspecifics build. As social learning allows an animal to gain information without engaging in costly trial-and-error learning, first-time builders should exploit the successful habits of experienced builders. We presented first-time nest-building male zebra finches with either a familiar or an unfamiliar conspecific male building with material of a colour the observer did not like. When given the opportunity to build, males that had watched a familiar male build switched their material preference to that used by the familiar male. Males that observed unfamiliar birds did not. Thus, first-time nest builders use social information and copy the nest material choices when demonstrators are familiar but not when they are strangers. The relationships between individuals therefore influence how nest-building expertise is socially transmitted in zebra finches.     

Spatial language processing in the blind: evidence for a supramodal representation and cortical reorganization

Neuropsychological and imaging studies have shown that the left supramarginal gyrus (SMG) is specifically involved in processing spatial terms (e.g. above, left of), which locate places and objects in the world. The current fMRI study focused on the nature and specificity of representing spatial language in the left SMG by combining behavioral and neuronal activation data in blind and sighted individuals. Data from the blind provide an elegant way to test the supramodal representation hypothesis, i.e. abstract codes representing spatial relations yielding no activation differences between blind and sighted. Indeed, the left SMG was activated during spatial language processing in both blind and sighted individuals implying a supramodal representation of spatial and other dimensional relations which does not require visual experience to develop. However, in the absence of vision functional reorganization of the visual cortex is known to take place. An important consideration with respect to our finding is the amount of functional reorganization during language processing in our blind participants. Therefore, the participants also performed a verb generation task. We observed that only in the blind occipital areas were activated during covert language generation. Additionally, in the first task there was functional reorganization observed for processing language with a high linguistic load. As the visual cortex was not specifically active for spatial contents in the first task, and no reorganization was observed in the SMG, the latter finding further supports the notion that the left SMG is the main node for a supramodal representation of verbal spatial relations.     

Preferences for familiarity and novelty: a model for the simultaneous development of both

Many developing animals show an increasing preference for familiar companions and objects. They may also come to prefer things which are slightly different from the familiar. A model which shows how both processes can occur simultaneously is developed with particular reference to imprinting in birds. It shows how a biphasic curve would be obtained if preferences were measured in choice tests during the course of familiarization. The model predicts that shape of the preference curve will depend on the difference between the familiar and unfamiliar objects. It also predicts that the shape will be altered if inexperienced animals show a preference for one object over the other.     

Emotional cues during simultaneous face and voice processing: electrophysiological insights

Both facial expression and tone of voice represent key signals of emotional communication but their brain processing correlates remain unclear. Accordingly, we constructed a novel implicit emotion recognition task consisting of simultaneously presented human faces and voices with neutral, happy, and angry valence, within the context of recognizing monkey faces and voices task. To investigate the temporal unfolding of the processing of affective information from human face-voice pairings, we recorded event-related potentials (ERPs) to these audiovisual test stimuli in 18 normal healthy subjects; N100, P200, N250, P300 components were observed at electrodes in the frontal-central region, while P100, N170, P270 were observed at electrodes in the parietal-occipital region. Results indicated a significant audiovisual stimulus effect on the amplitudes and latencies of components in frontal-central (P200, P300, and N250) but not the parietal occipital region (P100, N170 and P270). Specifically, P200 and P300 amplitudes were more positive for emotional relative to neutral audiovisual stimuli, irrespective of valence, whereas N250 amplitude was more negative for neutral relative to emotional stimuli. No differentiation was observed between angry and happy conditions. The results suggest that the general effect of emotion on audiovisual processing can emerge as early as 200 msec (P200 peak latency) post stimulus onset, in spite of implicit affective processing task demands, and that such effect is mainly distributed in the frontal-central region.     

Oxidative damage in relation to a female plumage badge: evidence for signalling costs

Badges of status may be controlled by costs derived from increased aggression from dominant individuals. This cost could be translated into elevated metabolic levels and a concomitant disruption of oxidative balance. Some females in Iberian pied flycatcher Ficedula hypoleuca populations exhibit a white forehead patch similar to that exhibited by all males in this species, functioning in aggressive interactions between females when competing for breeding sites. To test if social stress imposes costs on signalling, we painted white patches on females without natural patches (NP) and compared them with females with natural control (NU). We also over-painted the natural patch in other females (FP) and compared to females with control natural patches (FU). We obtained for the whole sample of females data on reproductive investment, morphology and oxidative damage measured by blood malondialdehydes (MDA), and in a subsample of females variables related to parental care during incubation and the early nestling stage. FP and FU did not differ significantly in any variable which negates an effect of paint itself. However, NP females showed significant higher levels of MDA than NU females when controlling for breeding success for the whole sample, and for female incubation attendance for the parental care subsample. When including the four treatments, there was a significant interaction between the paint treatment and the presence/absence of badges before the experiment when controlling for the significant negative effect of incubation attendance on MDA. Addition of a badge to females without one leads to increased oxidative damage possibly mediated by social control. Badges of status in female pied flycatchers may operate as badges of oxidative status.     

Functional hierarchy of coronary circulation: direct evidence of a structure-function relation

The heart muscle is nourished by a complex system of blood vessels that make up the coronary circulation. Here we show that the design of the coronary circulation has a functional hierarchy. A full anatomic model of the coronary arterial tree, containing millions of blood vessels down to the capillary vessels, was simulated based on previously measured porcine morphometric data. A network analysis of blood flow through every vessel segment was carried out based on the laws of fluid mechanics and appropriate boundary conditions. Our results show an abrupt change in cross-sectional area that demarcates the transition from epicardial (EPCA) to intramyocardial (IMCA) coronary arteries. Furthermore, a similar pattern of blood flow was observed with a corresponding transition from EPCA to IMCA. These results suggest functional differences between the two types of vessels. An additional abrupt change occurs in the IMCA in relation to flow velocity. The velocity is fairly uniform proximal to these vessels but drops significantly distal to those vessels toward the capillary branches. This finding suggests functional differences between large and small IMCA. Collectively, these observations suggest a novel functional hierarchy of the coronary vascular tree and provide direct evidence of a structure-function relation.     

3' end processing of mouse histone pre-mRNA: evidence for additional base-pairing between U7 snRNA and pre-mRNA.

We have analysed the extent of base-pairing interactions between spacer sequences of histone pre-mRNA and U7 snRNA present in the trans-acting U7 snRNP and their importance for histone RNA 3' end processing in vitro. For the efficiently processed mouse H4-12 gene, a computer analysis revealed that additional base pairs could be formed with U7 RNA outside of the previously recognised spacer element (stem II). One complementarity (stem III) is located more 3' and involves nucleotides from the very 5' end of U7 RNA. The other, more 5' located complementarity (stem I) involves nucleotides of the Sm binding site of U7 RNA, a part known to interact with snRNP structural proteins. These potential stem structures are separated from each other by short internal loops of unpaired nucleotides. Mutational analyses of the pre-mRNA indicate that stems II and III are equally important for interaction with the U7 snRNP and for processing, whereas mutations in stem I have moderate effects on processing efficiency, but do not impair complex formation with the U7 snRNP. Thus nucleotides near the processing site may be important for processing, but do not contribute to the assembly of an active complex by forming a stem I structure. The importance of stem III was confirmed by the ability of a complementary mutation in U7 RNA to suppress a stem III mutation in a complementation assay using Xenopus laevis oocytes. The main role of the factor(s) binding to the upstream hairpin loop is to stabilise the U7-pre-mRNA complex. This was shown by either stabilising (by mutation) or destabilising (by increased temperature) the U7-pre-mRNA base-pairing under conditions where hairpin factor binding was either allowed or prevented (by mutation or competition). The hairpin dependence of processing was found to be inversely related to the strength of the U7-pre-mRNA interaction.     

Insulin binding and processing by H4IIEC3 hepatoma cells: ultrastructural and biochemical evidence for a unique route of internalization and processing

Biochemical and ultrastructural studies of insulin binding and cellular processing by cultured H4IIEC3 hepatoma cells were performed. Insulin binding and intracellular accumulation were rapid and after 30 min at 37 degrees C, 65% of the total cell-associated 125I-insulin was in an acid-stable compartment. Chloroquine had no significant effect on the amount of total cell-associated insulin or the percentage of insulin in the acid-stable compartment or cell-associated insulin degradation under those conditions, but after 60-min incubations, it slightly decreased the rate of dissociation of internalized hormone. Ultrastructural analysis revealed that monomeric ferritin-insulin (Fm-I) initially bound to single or paired receptors on microvilli. Within 5 min occupied insulin receptors microaggregated and migrated to the intervillous cell surface. During the next 5-10 min occupied receptors aggregated into large clusters on the plasma membrane. Large amounts of insulin were internalized by macropinocytosis and the majority of internalized Fm-I was found in phagosomes. Less than 10% of the membrane-bound insulin was associated with pinocytotic invaginations or coated pits and less than 5% of the total cell-associated insulin was found in lysosomes. Chloroquine had no detectable effect on the amount of Fm-I or its distribution among the intracellular organelles. These studies demonstrated that, compared to previous studies with rat adipocytes or 3T3-L1 adipocytes, insulin interalization and intracellular processing in this hepatoma cell were unique. These differences provide further evidence that insulin binding and processing may be controlled by cell-specific mechanisms and that substantial heterogeneity exists in pathways previously presumed to be similar for all cell types.