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At least 631 records · Page 35Linked to original sources
PubMed2003

Impairment of odor hedonics in men with schizophrenia.

OBJECTIVE: Olfactory deficits in patients with schizophrenia, including those of odor identification, detection threshold sensitivity, discrimination, and memory, have been well described. Deficits in emotional perception, processing, and experience have also been reported, with anhedonia being one of the core features. While anatomical connections testify to the relationship between olfaction and emotion, there has been little investigation of the hedonic properties of odors in schizophrenia. This study examined intensity and hedonic judgments in patients with schizophrenia to determine whether these functions were differentially impaired. METHOD: Suprathreshold scaling of odor intensity and pleasantness was acquired by using the Suprathreshold Amyl Acetate Odor Intensity and Odor Pleasantness Rating Test given to 30 patients (15 men and 15 women) with a DSM-IV diagnosis of schizophrenia and 30 age- and sex-matched healthy comparison subjects. RESULTS: Despite virtually identical ratings of odor intensity, male patients were impaired in the assignment of odor pleasantness to amyl acetate. This gender-specific diagnostic group difference was not explained by variability in symptom severity or negative/positive symptoms. The impact of smoking status and general cognitive impairment on this deficit was also insignificant. CONCLUSIONS: Findings reveal a gender-specific disruption in the ability to attribute appropriate hedonic valence to odors in male patients with schizophrenia. This difficulty in identifying the hedonic valence of odors, despite intact intensity ratings, is consistent with clinical observations of anhedonia and points to a neural substrate that might contribute to the emotional disturbances seen in patients with schizophrenia.

Adult↗
PubMed2002

Modulation of visual event-related potentials by emotional olfactory stimuli.

The objective of the present study was to determine whether an olfactory prime could modulate behavior and visual event-related potentials (ERPs) obtained in response to a visual stimulation representing female faces. More specifically, we tested the hypothesis that a pleasant odor could have effects on face perception: behavioral effects on subjective emotional estimation of faces, and on associated response times, and electrophysiological effects on the N400 and late positive complex or LPC. Experiments were performed in which subjects had to decide whether the presented face was pleasant or not, while visual ERPs were recorded. Faces were always primed with either a pleasant odor or a neutral olfactory stimulus (pure air). In order to test the effect of subject's awareness, participants were not informed that an odor would be presented in the experimental sessions. Responses were significantly shorter for unpleasant faces. However, no behavioral effects of the pleasant odor on response time or on evaluation of face pleasantness were observed. Late ERPs evoked by faces were modulated by the presence of a pleasant odor, even when subjects were neither warned nor aware of the presence of the odor: in a frontal site and after the diffusion of the odor, the LPC (appearing 550 ms after the presentation of the visual stimulus) evoked by unpleasant faces was significantly more positive than the LPC evoked by pleasant faces. This effect could reflect an enhanced alert reaction to unpleasant faces are preceded by an (incongrous) pleasant odor.

Adult↗
PubMed2002

Long-term results of olfaction rehabilitation using the nasal airflow-inducing ("polite yawning") maneuver after total laryngectomy.

OBJECTIVES: To study the long-term results of the nasal airflow-inducing maneuver (NAIM) as an olfaction rehabilitation tool after laryngectomy and to investigate the effectiveness of a new, simpler odor detection test (ODT) called the smell disk test (SDT), or Zürcher Geruchstest. DESIGN: Intervention study. SETTINGS: National cancer center. PATIENTS: Forty-one laryngectomees who received olfaction rehabilitation training with the NAIM 4 months to 2 years earlier. This so-called polite yawning maneuver creates an "underpressure" in the oral cavity, which, in turn, generates a nasal airflow that enables odor molecules to again reach the olfactory epithelium. MAIN OUTCOME MEASURES: Olfaction acuity testing with a standard ODT, along with a questionnaire, providing a subjective olfaction score (present odor perception scale [POPS]), and the SDT, as well as assessment of the patients' correct execution of the NAIM by speech-language pathologists on video recordings made during odor testing and long-term assessment of olfaction acuity. RESULTS: The correlation between the previously used ODT-POPS combination and the SDT was kappa = 0.56 (P<.001). Based on these results, we preferred to use the much simpler SDT instead of the laborious combination of the ODT-POPS. Based on the SDT results, 19 (46%) of the 41 laryngectomees were "smellers" and could be considered normosmic. There was a significant relationship (P =.03) between the patient's correct execution of the NAIM and whether or not the laryngectomee was a smeller according to the SDT. CONCLUSIONS: The effectiveness of the NAIM, or so-called polite yawning technique, for the rehabilitation of olfaction in individuals who have undergone total laryngectomy was reconfirmed. Long-term olfaction rehabilitation was achieved in about 50% of the patients, but more intensified training may be needed to increase the percentage of successfully rehabilitated individuals. The SDT is an effective and simple test for the assessment of olfaction acuity after laryngectomy.

Adult↗
PubMed2006

A Drosophila protein specific to pheromone-sensing gustatory hairs delays males' copulation attempts.

In insects, increasing evidence suggests that small secreted pheromone binding proteins (PBPs) and odorant binding proteins (OBPs) are important for normal olfactory detection of airborne pheromones and odorants far from their source. In contrast, it is unknown whether extracellular ligand binding proteins participate in perception of less volatile chemicals, including many pheromones, that are detected by direct contact with chemosensory organs. CheB42a, a small Drosophila melanogaster protein unrelated to known PBPs or OBPs, is expressed and likely secreted in only a small subset of gustatory sensilla on males' front legs, the site of gustatory perception of contact pheromones. Here we show that CheB42a is expressed specifically in the sheath cells surrounding the taste neurons expressing Gr68a, a putative gustatory pheromone receptor for female cuticular hydrocarbons that stimulate male courtship. Surprisingly, however, CheB42a mutant males attempt to copulate with females earlier and more frequently than control males. Furthermore, CheB42a mutant males also attempt to copulate more frequently with other males that secrete female-specific cuticular hydrocarbon pheromones, but not with females lacking cuticular hydrocarbons. Together, these data indicate that CheB42a is required for a normal gustatory response to female cuticular hydrocarbon pheromones that modulate male courtship.

Animals↗
PubMed2006

Ric-8B promotes functional expression of odorant receptors.

Odorants are detected by a large family of odorant receptors (ORs) expressed in the nose. The information provided by the ORs is transmitted to specific regions of the brain, leading to odorant perception. The determination of the odorant specificities of the different ORs will contribute to the understanding of how odorants are discriminated by the olfactory system. However, to date only a few ORs have been linked to odorants they recognize, because ORs are poorly expressed on the cell surface of heterologous cells. Here we show that Ric-8B, a putative guanine nucleotide exchange factor for Galphaolf, promotes efficient heterologous expression of ORs. Our results also show that Ric-8B enhances accumulation of Galphaolf at the cell periphery, indicating that it promotes functional OR expression by improving the efficiency of OR coupling to Galphaolf. Expression systems containing Galphaolf and Ric-8B should contribute to the functional characterization of ORs.

Animals↗
PubMed2000

Odor identification: influences of age, gender, cognition, and personality.

The aim of this study was to examine the influences of age, gender, cognitive abilities, and personality styles on odor identification. Participants (N = 532) aged 45-87 years from the Swedish Adoption/Twin Study of Aging were assessed with a Swedish version of the National Geographic Smell Survey. Both detection and identification of olfactory information were impaired with age. Gender had no effect on detection or identification. Hierarchical regressions revealed that proficiency in semantic memory, intensity perception, and personality style (i.e., neuroticism, impulsivity, and lack of assertiveness) were potent predictors for successful odor identification, even when individual variations in chronological age, sex, education, and global cognitive functioning were taken into account.

Age Factors↗
PubMed2003

Effects of odors on pain perception: deciphering the roles of emotion and attention.

Emotions have been shown to alter pain perception, but the underlying mechanism is unclear since emotions also affect attention, which itself changes nociceptive transmission. We manipulated independently direction of attention and emotional state, using tasks involving heat pain and pleasant and unpleasant odors. Shifts in attention between the thermal and olfactory modalities did not alter mood or anxiety. Yet, when subjects focused attention on the pain, they perceived it as clearly more intense and somewhat more unpleasant than when they attended to the odor. In contrast, odor valence altered mood, anxiety level, and pain unpleasantness, but did not change the perception of pain intensity. Pain unpleasantness ratings correlated with mood, but not with odor valence, suggesting that emotional changes underlie the selective modulation of pain affect. These results show that emotion and attention differentially alter pain perception and thus invoke at least partially separable neural modulatory circuits.

Adolescent↗
PubMed2005

How chemical information processing interferes with face processing: a magnetoencephalographic study.

Magnetic field changes related to face encoding were recorded in 20 healthy young participants. Faces had to be deeply encoded under four kinds of simultaneous nasal chemical stimulation. Neutral room air, phenyl ethyl alcohol (PEA, rose flavor), carbon dioxide (CO2, pain), and hydrogen sulfide (H2S, rotten eggs flavor) were used as chemical stimuli. PEA and H2S represented odor stimuli, whereas CO2 was used for trigeminal stimulation (pain sensation). After the encoding of faces, the respective recognition performances were tested focusing on recognition effects related to specific chemical stimulation during encoding. The number of correctly recognized faces (hits) varied between chemical conditions. PEA stimulation during face encoding significantly increased the number of hits compared to the control condition. H2S also led to an increased mean number of hits, whereas simultaneous CO2 administration during face encoding resulted in a reduction. Analysis of the physiological data revealed two latency regions of interest. Compared to the control condition, both olfactory stimulus conditions resulted in reduced activity components peaking at about 260 ms after stimulus onset, whereas CO2 produced a strongly pronounced enhanced activity component peaking at about 700 ms after stimulus onset. Both olfactory conditions elicited only weak enhanced activities at about 700 ms, and CO2 did not show any difference activity at 260 ms after stimulus onset compared to the control condition. It is concluded that the early activity differences represent subconscious olfactory information processing leading to enhanced memory performances irrespective of the hedonic value, at least if they are only subconsciously processed. The later activity is suggested to reflect conscious CO2 perception negatively affecting face encoding and therefore leading to reduced subsequent face recognition. We interpret that conscious processing of nasal chemical stimulation competes with deep face encoding with respect to cortical resources, whereas subconscious processing of nasal chemical stimulation does not.

Adult↗
PubMed2000

PET shows that odors are processed both ipsilaterally and contralaterally to the stimulated nostril.

The olfactory nerve is the only cranial nerve with established ipsilateral primary cerebral anatomical projections. Whether these projections correspond to the functional pathways for monorhinal processing of odor perception is, however, unknown. We therefore studied cerebral blood flow (rCBF) with [15O]butanol-PET in 18 healthy females during monorhinal smelling of single odors (OS) and odorless air (AS). Compared with AS, OS activated right amygdala and piriform cortex (confluent cluster), right orbitofrontal cortex, left insula, right thalamus, and anterior cingulate. A post hoc analysis showed that the first three regions were activated independently of the stimulated side, but that right orbitofrontal rCBF was higher during the right nostril stimulations. Left insula was activated mainly by the right nostril stimuli, and right thalamus by the left nostril stimuli. Odors seem to be processed both ipsi and contralaterally, with a right hemisphere preponderance irrespective of the stimulated nostril.

Adult↗
PubMed2002

Influence of affective and cognitive judgments on autonomic parameters during inhalation of pleasant and unpleasant odors in humans.

Hedonic tone is so salient in odor perception that several authors have used odors to induce affective states. Various studies have shown that the electrophysiological and psychophysiological response patterns induced by olfactory stimuli are different for pleasant and unpleasant odors, and that these types of odor activate brain structures differentially. These results suggest that odors are first categorized according to pleasantness. The objective of the present work was to study the possible existence of an involuntary affective categorization in olfaction. Given that certain variations in the autonomic system, such as skin conductance amplitude and heart rate, are not under the voluntary control of human subjects, we used such psychophysiological methods for this investigation. Our results indicate that unpleasant odors provoke heart-rate acceleration during both a smelling task (control condition: a task in which subjects had only to inhale odors) and a pleasantness judgment, but not during a familiarity judgment. These results suggest that subjects involuntarily categorize odors by their pleasantness.

Adult↗
PubMed1998

Semantic mediation of age-related deficits in episodic recognition of common odors.

In the present research, the relationship between various semantic memory functions and episodic odor memory across the adult life span is addressed. In contrast to earlier evidence that odors may be encoded and stored as unique, nonlinguistic whole percepts, the present work suggests that episodic odor information is mediated by factors that can be subsumed under the rubric of semantic memory. Specific olfactory knowledge, such as perceived familiarity and identifiability, is strongly and positively related to episodic odor memory performance. In contrast to research using verbal and visual stimuli, proficiency in complex verbal intellectual abilities, such as vocabulary and fluency, seems to be of minor importance in memory for olfactory information. In agreement with earlier findings, this research indicates that episodic odor memory deteriorates across the adult life span. A similar negative age trend was observed for odor naming. Most importantly, statistical control of odor naming resulted in the elimination of age-related odor memory deficits. These results suggest that age-related failures in accessing specific semantic information of odors determine largely age-related deficits in episodic odor recognition.

Adult↗
PubMed2001

Human breathing and eye blink rate responses to airborne chemicals.

Increased levels of air pollution have been linked with morbidity and mortality, but mechanisms linking physiologic responses to quality of life and productivity issues remain largely unknown. Individuals often report irritation of the nose and/or eyes upon exposures to environmental contaminants. Evaluation of these self-reports would be greatly aided by the development of valid physiological markers. Chamber studies (unencumbered exposures) of nonsmoker responses to environmental tobacco smoke offer two candidate end points: (a) Tidal volume increases and breathing frequency declines with stimuli that elicit only moderate irritation. (b) Eye blink rate increases only with a concentration sufficiently high to cause progressive worsening of eye irritation with prolonged exposure. Experiments with very brief nasal-only presentations also suggest the value of breathing changes as sensitive markers of irritation: (a) Tidal volume is inversely related to perceived nasal irritation (NI) intensity in both normal and anosmic (lacking olfactory input) individuals, although normals exhibit greater NI sensitivity. (b) Inhalation duration, in both groups, declines only with trigeminal activation sufficient to cause readily perceptible NI in anosmics. Changes in eye blink rate and breathing may be useful in the investigation of irritation and other effects of air pollution, and could be quite useful in investigations of mixtures of volatile organic compounds.

Air Pollutants↗