Biomedical subjects

A Holley

Publications and source records attributed to A Holley.

At least 19 recordsLinked to original sources

PubMed2002

Asymmetry of pleasant vs. unpleasant odor processing during affective judgment in humans.

The objective of the present study was to investigate interactions between odor hedonic tone, perceived odor intensity, olfactory judgments and stimulated nostril laterality. Subjects were stimulated in the right and the left nostril separately, with two odors: vanillin (pleasant); and indole (unpleasant). They had two tasks to perform: an intensity judgment; and an affective judgment. Two concentrations (one strong and one weak) of each odor were presented. Odors were presented for a short period corresponding to one inhalation (about 1 s). The inter-stimulus interval was always 30 s. The nostril stimulated and task presentation order were counterbalanced according to a Latin square. Odor presentation order was randomized for each subject. Results indicated that response times for unpleasant odors were significantly shorter than for pleasant odors during affective judgment and right nostril stimulation, indicating greater right hemisphere efficiency for the decoding of unpleasant affects induced by odors.

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↗

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

Psychophysiological correlates of affects in human olfaction.

Pleasantness and arousal have been identified as the main dimensions of affective responses to environment. Pleasantness is defined as the degree of favorable feelings a subject can experience under given circumstances. Arousal is defined as the degree of excitement (general activation) the subject feels under these circumstances. In visual and auditory modalities, many studies using measures such as facial electromyographic (EMG) activity and skin conductance (SC) have found those parameters to vary as a function of either pleasantness or arousal: for example, facial corrugator EMG activity covaries with the pleasantness dimension, while SC increases together with arousal. The first objective of this research is to study the possible covariation between peripheral measures and pleasantness/arousal in olfaction. We also examined the effect of odor intensity on facial and autonomic variations. The second objective was to investigate whether odors could evoke verbally specific emotions (e.g. joy, anger, fear, surprise, disgust or sadness) and also induce specific patterns of peripheral responses. Participants were exposed to 12 different odors while their facial and autonomic parameters were recorded, and estimated their intensity, pleasantness, and arousal capacity. Then, they chose between seven words for emotions (fear, anger, sadness, surprise, neutral, joy or disgust) to describe their reaction to the odor. As in vision, olfactory pleasantness covaries (negatively) with facial activity of the corrugator muscle, and arousal (positively) with skin conductance. No relationships were observed between physiological changes and variations in perceived intensity. Results also showed that emotions of "disgust" and "joy" were more frequently evoked verbally than any other emotions, and that only facial EMG activity distinguishes them (e.g. "disgust" vs. "joy" and "neutral state"). The results are discussed in terms of possible existence of two brain systems (defensive and appetitive), each of them being able to vary in metabolic arousal.

Adult↗

PubMed2002

Autonomic nervous system responses to odours: the role of pleasantness and arousal.

Perception of odours can provoke explicit reactions such as judgements of intensity or pleasantness, and implicit output such as skin conductance or heart rate variations. The main purpose of the present experiment was to ascertain: (i) the correlation between odour ratings (intensity, arousal, pleasantness and familiarity) and activation of the autonomic nervous system, and (ii) the inter-correlation between self-report ratings on intensity, arousal, pleasantness and familiarity dimensions in odour perception. Twelve healthy volunteers were tested in two separate sessions. Firstly, subjects were instructed to smell six odorants (isovaleric acid, thiophenol, pyridine, L-menthol, isoamyl acetate, and 1-8 cineole), while skin conductance and heart rate variations were being measured. During this phase, participants were not asked to give any judgement about the odorants. Secondly, subjects were instructed to rate the odorants on dimensions of intensity, pleasantness, arousal and familiarity (self-report ratings), by giving a mark between 1 (not at all intense, arousing, pleasant or familiar) and 9 (extremely intense, arousing, pleasant or familiar). Results indicated: (i) a pleasantness factor correlated with heart rate variations, (ii) an arousal factor correlated with skin conductance variations, and (iii) a strong correlation between the arousal and intensity dimensions. In conclusion, given that these correlations are also found in other studies using visual and auditory stimuli, these findings provide preliminary information suggesting that autonomic variations in response to olfactory stimuli are probably not modality specific, and may be organized along two main dimensions of pleasantness and arousal, at least for the parameters considered (i.e. heart rate and skin conductance).

Adult↗

PubMed2001

Functional neuroanatomy of different olfactory judgments.

Humans routinely make judgments about olfactory stimuli. However, few studies have examined the functional neuroanatomy underlying the cognitive operations involved in such judgments. In order to delineate this functional anatomy, we asked 12 normal subjects to perform different judgments about olfactory stimuli while regional cerebral blood flow (rCBF) was measured with PET. In separate conditions, subjects made judgments about the presence (odor detection), intensity, hedonicity, familiarity, or edibility of different odorants. An auditory task served as a control condition. All five olfactory tasks induced rCBF increases in the right orbitofrontal cortex (OFC), but right OFC activity was highest during familiarity judgments and lowest during the detection task. Left OFC activity increased significantly during hedonic and familiarity judgments, but not during other odor judgments. Left OFC activity was significantly higher during hedonicity judgments than during familiarity or other olfactory judgments. These data demonstrate that aspects of odor processing in the OFC are lateralized depending on the type of olfactory task. They support a model of parallel processing in the left and right OFC in which the relative level of activation depends on whether the judgment involves odor recognition or emotion. Primary visual areas also demonstrated a differential involvement in olfactory processing depending on the type of olfactory task: significant rCBF increases were observed in hedonic and edibility judgments, whereas no significant rCBF increases were found in the other three judgments. These data indicate that judgments of hedonicity and edibility engage circuits involved in visual processing, but detection, intensity, and familiarity judgments do not.

Adult↗

PubMed1999

Stress induces neurogenesis in non-neuronal cell cultures of adult olfactory epithelium.

Among the basal cells of the olfactory epithelium is a stem cell which divides and whose progeny differentiate into new sensory neurons throughout adult life. Olfactory neurogenesis is highly regulated, for example it is stimulated by epithelial damage. Previous reports implicate several growth factors in progenitor cell proliferation and neuronal differentiation in vitro but these studies differ in growth conditions and age of donors making it difficult to determine precisely the roles of neurogenic stimuli and their sites of action. The aims of the present study were to develop purified basal cell cultures from adult olfactory epithelium and to stimulate neurogenesis in defined growth conditions in order to elucidate the cellular mechanisms by which neurogenesis is stimulated after epithelial damage. We show here that differentiated olfactory sensory neurons arise after biochemical or mechanical stress of rat and mouse olfactory epithelial cell cultures in the absence of growth factors, complex media (e.g., serum, conditioned media, pituitary and hypothalamic extracts), or other cells (e.g., explants, feeder layers of glia, or other non-epithelial cells). Prior to the stress, these cultures contained basal cells and supporting cells but not neurons. After the stress, some cells differentiated into bipolar neurons expressing a number of neuronal proteins including olfactory marker protein. Bromodeoxyuridine experiments show that the differentiated neurons arose from recently divided cells which did not divide again before differentiating. We conclude that stress disrupts cell surface contacts to induce the immediate neuronal precursors to undergo final differentiation into olfactory sensory neurons. This may be a mechanism for enhanced neurogenesis after epithelial damage.

Age Factors↗

PubMed1999

Functional anatomy of perceptual and semantic processing for odors.

The functional anatomy of perceptual and semantic processings for odors was studied using positron emission tomography (PET). The first experiment was a pretest in which 71 normal subjects were asked to rate 185 odorants in terms of intensity, familiarity, hedonicity, and comestibility and to name the odorants. This pretest was necessary to select the most appropriate stimuli for the different cognitive tasks of the second experiment. The second one was a PET experiment in which 15 normal subjects were scanned using the water bolus method to measure regional cerebral blood flow (rCBF) during the performance in three conditions. In the first (perceptual) condition, subjects were asked to judge whether an odor was familiar or not. In the second (semantic) condition, subjects had to decide whether an odor corresponded to a comestible item or not. In the third (detection) condition, subjects had to judge whether the perceived stimulus was made of an odor or was just air. It was hypothetized that the three tasks were hierarchically organized from a superficial detection level to a deep semantic level. Odorants were presented with an air-flow olfactometer, which allowed the stimulations to be synchronized with breathing. Subtraction of activation images obtained between familiarity and control judgments revealed that familiarity judgments were mainly associated with the activity of the right orbito-frontal area, the subcallosal gyrus, the left inferior frontal gyrus, the left superior frontal gyrus, and the anterior cingulate (Brodmann's areas 11, 25, 47, 9, and 32, respectively). The comestibility minus familiarity comparison showed that comestibility judgments selectively activated the primary visual areas. In contrast, a decrease in rCBF was observed in these same visual areas for familiarity judgments and in the orbito-frontal area for comestibility judgments. These results suggest that orbito-frontal and visual regions interact in odor processing in a complementary way, depending on the task requirements.

Adult↗

PubMed1999

Implementing the right to community integration for children with disabilities in Russia: a human rights framework for international action.

Human rights organizations have documented a widespread pattern of abuse in Russia's orphanages and institutions for children with disabilities. Community integration is critical to attack the underlying causes of discrimination and abuse of children in institutions. While there is an immediate need to protect children in institutions, investment in improving orphanages may inadvertently strengthen an outmoded system of segregated services, delaying long-term reform. This article describes a response to abuses in institutions based on the internationally recognized right to community integration for all children, including children with mental and physical disabilities. While tailored to Russia, the framework for action described here applies to many countries in which children and adults with disabilities are similarly segregated from society in closed institutions.

Child↗

PubMed1998

Generation of neurons from a nonneuronal precursor in adult olfactory epithelium in vitro.

Within the olfactory epithelium is a stem cell which can divide and differentiate to produce new sensory neurons. The identity of the neuronal stem cell is unknown but one candidate is the horizontal basal cell which lies adjacent to the basement membrane and expresses keratin. Previous attempts to generate mature sensory neurons from purified horizontal basal cells in vitro were unsuccessful. We show here for the first time that olfactory neurogenesis can be reproduced in vitro from partially-purified cultures of adult rat precursor cells cultivated in a serum-free medium. Rat olfactory epithelium was dissected from the nasal septum and separated from the underlying lamina propria, and its cells were dissociated and grown in a medium containing epidermal growth factor for 5 days. Immunochemistry showed that only supporting cells (SUS1-positive) and horizontal basal cells (keratin-positive) survived for this period. At day 6, the cells were stressed either by passaging them or by a simple mechanical stress. In each case, a morphological and immunological differentiation was observed within 24-48 hr. Newly formed bipolar cells were found to be S100-, glial fibrillary acidic protein (GFAP-), neural cell adhesion molecule (N-CAM+), and/or microtubule-associated protein 5 (MAP-5+). After passaging 14% of the surviving cells were immature neurons (MAP-5+) and 4% were mature olfactory neurons (MAP-5+) and olfactory marker protein (OMP+)). In addition the same experiment was conducted on transgenic mice in which the lacZ gene was linked to the OMP promoter. Using 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal) staining we showed that OMP+ cells disappeared before day 5 in culture but reappeared after passaging. These results suggest that olfactory sensory neurons can arise from a non-neuronal precursor, probably the keratin-positive horizontal basal cell.

Animals↗

PubMed1997

Eyewitness performance in cognitive and structured interviews.

This paper addresses two methodological and theoretical questions relating to the Cognitive Interview (CI), which previous research has found to increase witness recall in interviews. (1) What are the effects of the CI mnemonic techniques when communication techniques are held constant? (2) How do trained interviewers compare with untrained interviewers? In this study, witnesses (college students) viewed a short film clip of a shooting and were questioned by interviewers (research assistants) trained in conducting the CI or a Structured Interview (SI)--similar to the CI except for the "cognitive" components--or by untrained interviewers (UI). The CI and SI groups recalled significantly more correct information compared to the UI group. However they also reported more errors and confabulated details. Theoretical and practical implications of the results are discussed in terms of precisely identifying the CI facilitatory effects and consequent good practice in the forensic setting.

Adolescent↗

PubMed1997

Role of verbal encoding in short- and long-term odor recognition.

The role of verbal encoding in odor recognition memory was investigated using odors of low familiarity to subjects before the experiment began. The experimental procedure included two phases--odor learning (first phase) and odor memory testing (second phase)--separated by a delay of 7 days. Five experimental conditions were established: three conditions of odor learning with names (labeling conditions), one condition of odor learning without names (sensory familiarization), and one condition of no learning prior to testing (control conditions). The labeling conditions differed from each other regarding label characteristics. The names were those of odor sources (veridical names), those personally generated by subjects (generated names), or those derived from the chemical names of the odorants (chemical names). Subjects were required to learn 20 fixed associations between odors (targets or distractors) and 20 names during two daily sessions. The learning sessions included two identification tests and ended by a verbal memory test in which subjects recalled odor names. The odor memory test was split into two parts separated by a retention interval of either 20 min (short-term memory) or 24 h (long-term memory). Data showed that olfactory recognition memory was enhanced in subjects who associated veridical or generated names to odors during the learning session. Chemical names were not appropriate to facilitate odor recognition. Similarly, the level of odor identification was higher for veridical and generated names than for chemical names, though the level of verbal memory for chemical names was substantial. Recognition response latencies were systematically longer for a target odor implying a positive response than for a distractor odor implying a negative response. Together, these data suggest that odor recognition and identification are sensitive to the semantic content of labels associated with odors. Odor memory was adversively influenced by time, but this influence was less pronounced when the names were endowed with a rich semantic content.

Adolescent↗

PubMed1995

Temporal competition between odorants: effect of different time intervals on the perception of monorhinic and dichorhinic binary mixtures.

Backward masking and its possible connection with the perception of odour mixtures has been investigated. Temporal competition between odorants in a binary mixture was tested by artificially creating a delay between one odour (the target) and a second, stronger, odour (the mask) during a single natural sniff. To test the influence of central versus peripheral competition, the same mixture was presented either monorhinically or dichorhinically. The delay (100 to 400 ms) did not influence intensity perception, indicating that intensities are integrated during the sniff irrespective of the temporal arrangement. In contrast, the number of qualities perceived was influenced by the delay: delays of 200 to 400 ms gave significant increases in the frequency of detection of a mixture, whereas synchronous mixtures favoured the perception of a single odour. Masking was also significantly stronger in dichorhinic mixtures. These effects are discussed in terms of retroactive masking which seems to be enhanced by dichorhinic mixtures, suggesting that masking has an important central component.

Adult↗

PubMed1995

Odor discrimination and recognition memory as a function of familiarization.

The role of olfactory familiarization in short-term recognition of odors was investigated. Subjects were asked to make qualitative similarity judgments regarding either identical or dissimilar odors delivered in pairs. Except for control groups, subjects got familiarized with either the first (target) or the second (distractor) or both odors from a pair. Groups also differed according to the number of familiarization sessions--one, two, or three--taking place prior to the discrimination judgments. There was no significant influence of familiarization on correct recognition scores for pairs of identical odors. The most salient finding was a marked decrease of false alarms as a function of the number of familiarization sessions, which evidenced a positive effect of familiarization on discrimination for pairs of dissimilar odors. These judgments were not dependent on an intensity criterion. False alarms did not vary according to whether subjects had been familiarized with the target or the distractor or both odors from a pair. A positive correlation found between discrimination performances and the number of odors correctly remembered as being presented during familiarization suggested that familiarization resulted in long-term storing of memory traces for familiarized odors. Since familiarization was effective despite conditions unfavorable to the use of semantic encoding, the results argue in favor of a predominantly perceptual encoding of odors in the investigated task.

Adult↗

PubMed1994

Very short term recognition memory for odors.

An investigation of very short term olfactory recognition memory was made with odors of low familiarity to subjects. The experimental procedure was that currently used to make qualitative similarity judgments on odors delivered in paired succession. Subjects made similarity judgments in a yes/no recognition paradigm on odors that were either identical or different. The dependence of recognition performance upon the degree of qualitative similarity was assessed by using two sets of dissimilar odor pairs: slightly dissimilar pairs (S1) and very dissimilar pairs (S2). Performance in terms of correct judgments (hits, correct rejections) was rather good for identical pairs in both sets and was nearly perfect for very dissimilar pairs with a delay of 2-300 sec, suggesting no effect of time or similarity on performance. However, for slightly dissimilar pairs, false alarms increased in number, thereby indicating a dependence of the recognition score on the qualitative distance between odors. In addition, false alarms tended to increase with the lengthening of the retention interval. It was suggested that the subjects based their responses on their capability to detect differences between odors rather than recognizing their similarities. Correct identifications were thus preserved at the cost of increasing false alarms when the discrimination task was made more difficult by closer similarity between odors (S1) or by the fading of memory traces with time. Studying the congruence between the similarity judgments and the kind of evocations associated with paired odors gives some support to the view that recognition performances had some cognitive/semantic basis.

Adult↗

PubMed1993

Involvement of the olfactory bulb in consolidation processes associated with long-term memory in rats.

In a daily training paradigm, rats were trained to discriminate between spatially distinct electrical stimulations delivered to one olfactory bulb. Xylocaine injections were used to disrupt the olfactory bulb functioning in the region close to the electrode tips for 1 hr after training session. The treatment started either just after the session or 2 hr later. When compared with the performance of saline-injected rats, the performance of Xylocaine-injected rats was unimpaired except when the treatment started just after the daily session. In that case, acquisition of the task was slightly altered, and retention over a 5-day period was dramatically impaired. We therefore concluded that, within about 1 hr following training, the olfactory bulb is engaged in consolidation processes critical for long-term retention of learned olfactory cues.

Animals↗

PubMed1992

Morphological variations among output neurons of the olfactory bulb in the frog (Rana ridibunda).

Morphological properties of putative output cells have been studied in detail in the olfactory bulb of frogs (Rana ridibunda). Intracellular injection of Lucifer Yellow was used to reconstruct individual neurons. Ten different anatomical features related to cell shape and position were studied quantitatively. The results show that output cells, generally considered to be a homogeneous group in the olfactory bulb of amphibians, are, in fact, quite different in their morphology. Using multidimensional analysis to examine differences among the output neurons, we found that they might be divided into at least two groups. In one group, the cell somata were located near the glomerular layer and the dendrites lay at large angles with respect to each other. In the other group, the cell somata were farther from the glomerular layer and their dendrites lay at smaller angles. From their morphology, these two cell groups appear to be homologous, respectively, to the superficial/middle tufted cells and deep tufted/mitral cells of mammals.

Animals↗

PubMed1992

Some properties of receptive fields of olfactory mitral/tufted cells in the frog.

1. Different regions of the frog's olfactory epithelium were stimulated with nine glass micropipettes either individually or simultaneously in different combinations. The stimulus was a positive electrical pulse (4 s) consisting of a progressive increase, a plateau, and a progressive decrease in current intensity. Extra- and intracellular recordings were made from olfactory bulb mitral/tufted cells. Some of these cells were identified by intracellular injection of Lucifer yellow. 2. The action potential response patterns of mitral/tufted cells during the different phases of the stimulation were coded according to whether the activity was increased or decreased compared with its spontaneous level just before stimulation. Neural responses were classified into 11 types: individual neurons responded with different response types to stimuli delivered at different epithelial sites. On the basis of these response types, it was found that neurons could be classified into two groups. All response types in one group included an initial phase of increased discharge (excitation), whereas all types in the other group included an initial phase of decreased activity (suppression). Neurons that displayed response types belonging to one group never displayed those of the other group. It was thus concluded that a given neuron responded either always with an increased activity or always with a decreased activity, whatever the location of the stimulus. 3. The receptive field of a mitral/tufted cell appeared to be homogenous and not divided into areas of different properties, at least under the present experimental conditions. The extent of a receptive field was estimated by determining the number of effective epithelial sites (where an electrical stimulus evoked a response from a bulbar neuron).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗