Smell

Kin recognition requires the ability to discriminate between one's own genetic relatives and non-relatives. There are two mechanisms that aid in kin discrimination: phenotype matching and familiarity. Dogs may be a good model for assessing these mechanisms as dogs are a promiscuous social species with a keen sense of smell. Domestic dogs of both sexes were presented with two scents (close kin, distant-kin) and preference was assessed through three measures (latency to approach, number of visits, time spent). Experiment 1 explored the possibility of phenotype matching as subjects had no contact with sires, whose scent was presented alongside a control male's scent. Experiment 2 explored recognition of siblings raised with the subjects and then separated at seven weeks of age. Whereas female dogs in this experiment did not show a statistically significant preference, male dogs showed a preference for distant-kin when presented with sire and female sibling samples.

This paper presents “Tainted”, a first-person 3D adventure game that enables players to experience a traditional horror folklore using visual-auditory-olfactory interactions. The system consists of a computer to play the game and a smell-emitting module that contains four different scents (jasmine, pineapple, mango and banana). The information provided by the additional olfactory stimuli delivers an immersive gaming experience by providing game narrative and signaling predefined game conditions (e.g. imminent threat, game hints). At the same time, smell stimuli attempt to invoke emotional responses such as fear and curiosity. Experiments were carried out to 1) validate the design of the device and 2) measure user enjoyment and experience with and without the added smell feedback using an adapted questionnaire from the GameFlow model. The results show that the provided olfactory stimuli are more informative to users and provoked greater emotions, as compared to the use of visual and auditory cues alone. The majority of participants preferred to have the added feedback device in the game (95% neutral and positive). However, approximately 26% of participants also noted that the smells are not distinct from each other. Nevertheless, it is suggested that the olfactory information is closely coupled with players’ experience and enjoyment of the narrative, as well as the smell-driven gameplay. Future studies of these factors will enable us to establish a framework to support multisensory game developers in the design of olfaction-enhanced games and other multimedia applications. (IJHCS Volume 125, May 2019, Pages 7-18)

The search for symmetry in nonhuman subjects has been successful in recent studies in pigeons (e.g., Urcuioli, 2008). The key to these successes has been the use of successive discrimination procedures and combined training on identity, as well as arbitrary, baseline relations. The present study was an effort to extend the findings and theoretical analysis developed by Urcuioli and his colleagues to rats using olfactory rather than visual stimuli. Experiment 1 was a systematic replication of Urcuioli's (2008) demonstration of symmetry in pigeons. Rats were exposed to unreinforced symmetry probes following training with two arbitrary and four identity conditional discriminations. Response rates on symmetry probe trials were low and provided little evidence for emergent symmetry in any of the seven rats tested. In Experiment 2, a separate group of six rats was trained on four identity relations and was then exposed to probe trials with four novel odor stimuli. Response rates were high on identity probe trials, and low on nonmatching probe trials. The similar patterns of responding on baseline and probe trials that were shown by most rats provided a demonstration of generalized identity matching. These findings suggest that the development of stimulus control topographies in rats with olfactory stimuli may differ from those that emerge in pigeons with visual stimuli. Urcuioli's (2008) theory has been highly successful in predicting conditions necessary for stimulus class formation in pigeons, but may not be sufficient to fully understand determinants of emergent behaviors in other nonhuman species.

Humans are gifted at detecting and discriminating odors, yet we have difficulty identifying even the most prevalent everyday odors by name. This paper offers a new explanation for the puzzling discrepancy between our olfactory capacities for discrimination and identification by weaving together recent neuroscientific findings regarding the cortical connectivity of the olfactory system, the olfactory system's proprietary semantic integration center, and recent philosophical research on the olfactory system's compositional format of representation. The paper combines these areas of research to develop the comprehensive explanation that we cannot readily deploy conceptual resources in naming odorants, because of an incompatibility of compositional formats employed by our conceptual semantic resources and the olfactory system.

A comparative study between the perception and recognition thresholds of volatile components calculated for an electronic nose and a human sensory panel is presented. The electronic nose is home-developed for wine purposes and is based on thin film semiconductor sensors. The human sensory panel is formed by 25 tasters with previous experience in wine tasting. Both systems were trained in parallel to detect 17 volatile compounds involved in aromatic and off-flavor notes (grouped under 9 aromatic descriptors) from the threshold concentrations found in the literature (T) to increasing concentrations (T, 2T, and 4T). The results showed that the perception level of the human nose is superior in relation to the electronic nose, but the electronic nose gave better results in the recognition threshold of the some aroma. According to these results, it can be concluded that the electronic nose could be a useful complementary tool to sensory human panels.

Although several studies have been performed to detect cancer using canine olfaction, none have investigated whether canine olfaction trained to the specific odor of one cancer is able to detect odor related to other unfamiliar cancers. To resolve this issue, we employed breast and colorectal cancer in vitro, and investigated whether trained dogs to odor related to metabolic waste from breast cancer are able to detect it from colorectal cancer, and vice versa. The culture liquid samples used in the cultivation of cancerous cells (4T1 and CT26) were employed as an experimental group. Two different breeds of dogs were trained for the different cancer odor each other. The dogs were then tested using a double-blind method and cross-test to determine whether they could correctly detect the experimental group, which contains the specific odor for metabolic waste of familiar or unfamiliar cancer. For two cancers, both dogs regardless of whether training or non-training showed that accuracy...

To investigate the differences in regions of brain activation in response to olfactory stimulation by functional magnetic resonance imaging in conditions of prior warning of an odor and without. Participants were 17 normal right-handed volunteers; 8 participants received prior warning of the odor (informed condition) and 9 participants were not pre-warned (naïve condition). The odorant used was isovaleric acid. In the informed condition with prior warning, activation was observed in the putamen extending to the insula, amygdala, and inferior frontal gyrus, and there was instant reification of the odor, while in the naïve condition without prior warning, activation was observed in the anterior cingulate cortex, entorhinal cortex, putamen and inferior frontal gyrus, and recognition of the odor was difficult. These results suggest that the condition prior to olfactory stimulation, i.e., with or without prior warning, can affect recognition and regions of brain activation in response to olfactory stimulation using isovaleric acid. Differences in recognition and regions of brain activation between both conditions could be associated with response latencies, or degree of attention, expectation and/or concentration.

The mechanism of the sense of smell has long been a subject for theory and speculation. More recently, the notion of odorant recognition by stereospecific protein receptors has gained wide acceptance, but the receptor molecules remained elusive. The recognition molecules are believed to be quite diverse, which would partly explain the unusual difficulties encountered in their isolation by conventional ligand-binding techniques. An alternative approach would be to probe the receptors through transductory components that may be common to all receptor types. Here we report the identification of one such transductory molecular component. This is an odorant-sensitive adenylate cyclase, present in very large concentrations in isolated dendritic membranes of olfactory sensory neurones. Odorant activation of the enzyme is ligand and tissue specific, and occurs only in the presence of GTP, suggesting the involvement of receptor(s) coupled to a guanine nucleotide binding protein (G-protein). The olfactory G-protein is independently identified by labelling with bacterial toxins, and found to be similar to stimulatory G-proteins in other systems. Our results suggest a role for cyclic nucleotides in olfactory transduction, and point to a molecular analogy between olfaction and visual, hormone and neurotransmitter reception. Most importantly, the present findings reveal new ways to identify and isolate olfactory receptor proteins.

This paper presents a rationale for the place of incense in the Divine Service (DS) with a view of what this means to engage all five senses to the highest level. Focussing particularly on the least considered bodily sense, the nose and smell, it argues from a biblical, systematic, liturgical and historical perspective, considering specific passages from Isaiah and John's revelations, and Old Testament scriptures (OT). It concludes that incense is prescriptive in OT worship, descriptive in New Testament (NT) and Church History (CH), but again prescriptive for worship in the heavens and the age to come. While incense is considered to be adiaphora in NT worship since the fall of the Temple (70AD), the Church has redeemed it for use in the DS since the fifth century for the sake of good order (1 Cor. 7:35) and its liturgical function.

Aim of this study was to investigate whether intranasal anatomy plays a role in intranasal trigeminal sensitivity. A total of 65 healthy subjects (30 female, 35 male) participated in this study (age range 18-35 years). Nasal cavities were assessed using magnetic resonance imaging (MRI). The area of the nasal cavity was measured in 5 coronal sections distributed across the length of the nasal cavity. Trigeminal function was assessed by determining thresholds for CO2, and responses to suprathreshold stimulation with CO2 and menthol (intensity ratings; event-related potentials). In addition, rhino-manometric measures were obtained. A positive correlation was found between the size of the nasal cavity and trigeminal event-related potentials in response to suprathreshold CO2 and menthol stimuli. By contrast, no such correlations were found between nasal cavity size and CO2 thresholds. Results from rhino-manometry correlated only with the size of the nasal cavity in the nasal valve area. These data suggest that, at least at a suprathreshold level, nasal anatomy plays a significant role in determining interindividual differences in the sensitivity to trigeminal stimuli.