O Koenig

University of Lyon, Lyons, Rhône-Alpes, France

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Publications (12)28.61 Total impact

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    ABSTRACT: The effects of odor processing were investigated at various analytical levels, from simple sensory analysis to deep or semantic analysis, on a subsequent task of odor naming. Students (106 women, 23.6 +/- 5.5 yr. old; 65 men, 25.1 +/- 7.1 yr. old) were tested. The experimental procedure included two successive sessions, a first session to characterize a set of 30 odors with criteria that used various depths of processing and a second session to name the odors as quickly as possible. Four processing conditions rated the odors using descriptors before naming the odor. The control condition did not rate the odors before naming. The processing conditions were based on lower-level olfactory judgments (superficial processing), higher-level olfactory-gustatory-somesthetic judgments (deep processing), and higher-level nonolfactory judgments (Deep-Control processing, with subjects rating odors with auditory and visual descriptors). One experimental condition successively grouped lower- and higher-level olfactory judgments (Superficial-Deep processing). A naming index which depended on response accuracy and the subjects' response time were calculated. Odor naming was modified for 18 out of 30 odorants as a function of the level of processing required. For 94.5% of significant variations, the scores for odor naming were higher following those tasks for which it was hypothesized that the necessary olfactory processing was carried out at a deeper level. Performance in the naming task was progressively improved as follows: no rating of odors, then superficial, deep-control, deep, and superficial-deep processings. These data show that the deepest olfactory encoding was later associated with progressively higher performance in naming.
    Perceptual and Motor Skills 03/2004; 98(1):197-213. · 0.49 Impact Factor
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    Pascale Michelon, Olivier Koenig
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    ABSTRACT: Two priming experiments using a perceptual identification task were conducted to explore the functional and representational overlap between visual imagery and visual perception. The first experiment included a study phase in which primes were either perceived or imaged objects and a test phase in which targets were parts of studied and non-studied objects. Imagery primed identification when subjects were instructed to count the parts of the imaged objects in the study phase but not when they were instructed to focus on the global shape of the imaged objects. This result suggests that imagery involves perceptual representations identical to those involved in perception. It also suggests that the representational overlap between imagery and perception depends on the type of images generated, as some images may consist in global shapes only, whereas others may consist in detailed, multi-part shapes. In the second experiment, we used whole objects as target stimuli, which provided subjects with more information to identify masked targets and thereby reduced top-down processing. Priming from imagery fell beneath significance, suggesting that this sort of priming is elicited in a large part by a transfer of top-down processes from study to test.
    European Journal of Cognitive Psychology 01/2002; 14(2):161-184. · 1.09 Impact Factor
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    O Koenig, G Bourron, J P Royet
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    ABSTRACT: Sixty-four subjects participated in an olfactory priming experiment comprising separate study and test phases. Priming was measured within the olfactory modality (intramodal condition) and from the visual modality to the olfactory modality (intermodal condition). In the study phase of the intramodal condition, subjects were exposed twice to a series of odours: once performing a semantic orientation task (deciding which of seven categories odour stimuli belonged to) and once performing a perceptual orientation task (judging the intensity, the hedonicity and the familiarity of odour stimuli). Half of the odour stimuli corresponded to edible products, the other half did not. The study phase of the intermodal condition was similar, with the exception that the names of the odours (instead of the odours themselves) were presented. In the test phase, subjects were presented with primed and non-primed odour targets and had to decide as fast as possible whether the target corresponded to an edible product or not. Response times and types were recorded by a computer. The analysis of response times revealed a priming effect in the intramodal condition only. Results are discussed in terms of separate perceptual and semantic subsystems that store odour representations.
    Chemical Senses 01/2001; 25(6):703-8. · 3.22 Impact Factor
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    ABSTRACT: Neural correlates of responses to emotionally valenced olfactory, visual, and auditory stimuli were examined using positron emission tomography. Twelve volunteers were scanned using the water bolus method. For each sensory modality, regional cerebral blood flow (rCBF) during presentation of both pleasant and unpleasant stimuli was compared with that measured during presentation of neutral stimuli. During the emotionally valenced conditions, subjects performed forced-choice pleasant and unpleasant judgments. During the neutral conditions, subjects were asked to select at random one of a two key-press buttons. All stimulations were synchronized with inspiration, using an airflow olfactometer, to present the same number of stimuli for each sensory modality. A no-stimulation control condition was also performed in which no stimulus was presented. For all three sensory modalities, emotionally valenced stimuli led to increased rCBF in the orbitofrontal cortex, the temporal pole, and the superior frontal gyrus, in the left hemisphere. Emotionally valenced olfactory and visual but not auditory stimuli produced additional rCBF increases in the hypothalamus and the subcallosal gyrus. Only emotionally valenced olfactory stimuli induced bilateral rCBF increases in the amygdala. These findings suggest that pleasant and unpleasant emotional judgments recruit the same core network in the left hemisphere, regardless of the sensory modality. This core network is activated in addition to a number of circuits that are specific to individual sensory modalities. Finally, the data suggest a superior potency of emotionally valenced olfactory over visual and auditory stimuli in activating the amygdala.
    Journal of Neuroscience 11/2000; 20(20):7752-9. · 6.91 Impact Factor
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    ABSTRACT: Neural correlates of responses to emotionally valenced olfactory, visual, and auditory stimuli were examined using positron emission tomography. Twelve volunteers were scanned using the water bolus method. For each sensory modality, regional cerebral blood flow (rCBF) during presentation of both pleasant and unpleasant stimuli was compared with that measured during presentation of neutral stimuli. During the emotionally valenced conditions, subjects performed forced-choice pleasant and unpleasant judgments. During the neutral conditions, subjects were asked to select at random one of a two key-press buttons. All stimulations were synchronized with inspiration, using an airflow olfactometer, to present the same number of stimuli for each sensory modality. A no-stimulation control condition was also performed in which no stimulus was presented. For all three sensory modalities, emotionally valenced stimuli led to increased rCBF in the orbitofrontal cortex, the temporal pole, and the superior frontal gyru
    J Neurosci. 01/2000; 20(20):7752-7759.
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    ABSTRACT: Two experiments were carried out to study procedural learning in Parkinson's disease (PD) patients. In Experiment 1, ten patients and their normal controls participated in a classical mirror reading task and in an inverted reading task where word-stimuli made of non inverted letters had to be processed from right to left (e.g., ygoloruen). In both tasks, reading times for new stimuli were compared to reading times for stimuli that repeated over blocks. Although PD patients and their controls exhibited learning for repeated words in both tasks, PD patients did not respond faster with practice for new words in the inverted reading task. In Experiment 2, PD patients and their controls were presented with an original dot counting task in which participants were asked to process a horizontal series of black and white dots from right to left and to indicate whether a dot that had been designated by a number at the beginning of each trial was black or white. Results showed that PD patients, in contrast to controls, did not exhibit learning in this task. Results are discussed in terms of the cognitive components involved in these tasks. It is suggested that PD patients are impaired in the acquisition of a right-to-left visual scanning skill that could be studied directly in Experiment 2.
    Neuropsychologia 10/1999; 37(10):1103-9. · 3.48 Impact Factor
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    ABSTRACT: Studying midazolam-induced amnesia offers an interesting approach to the organization of normal memory processes, since memory performance can be studied in the same subject in "on" and "off" drug conditions. The present study investigated the effect of midazolam on skill learning. The task and the experimental design we used also allowed us to assess the effect of midazolam on priming and explicit memory. Eighteen patients who underwent minor ear surgery and who were anaesthetized with intravenous midazolam, and 18 matched control subjects participated in a mirror reading task on 2 separate days. Patients were tested under midazolam on day 1 and without any medication on day 2. The mirror reading task was made of French words, some of which repeated across trial blocks, others being new. Patients under midazolam read new mirror written words faster with practice, which attested for intact skill learning. Moreover, they read repeated words faster than new words with practice, which was interpreted as reflecting intact priming abilities. These spared implicit memory capacities were observed along with severe explicit memory impairments. Learning for both new and repeated mirror written words on day 2 was similar in patients and in controls, which was interpreted as suggesting that the implicit learning that occurred on day 1 under midazolam was normal. The quality of skill learning, both in terms of speed of and lasting effect, was normal under midazolam in the task we used. In the context of the present task, midazolam offers an interesting, reversible model of amnesia.
    Psychopharmacology 08/1999; 145(2):139-43. · 4.06 Impact Factor
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    ABSTRACT: Functional magnetic resonance imaging (fMRI) was applied to determine the involvement of the angular gyri in the processing of categorical and coordinate spatial relations. In a categorical task, subjects were asked to judge whether a dot was presented above or below a horizontal line. In a coordinate task, they were asked to judge whether or not the distance between the dot and the bar was within a reference distance. Results showed stronger activation of the left than of the right angular gyrus in the categorical task, and stronger activation, initially, of the right than of the left angular gyrus in the coordinate task. In addition, in the latter task, the involvement of the right angular gyrus decreased with practice while that of the left angular gyrus increased. These results are interpreted in terms of the development of new categorical representations with practice in the coordinate task.
    Neuroreport 05/1999; 10(6):1373-8. · 1.40 Impact Factor
  • B Boudia, O Koenig, N Bedoin, L Collet
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    ABSTRACT: Our research is a first attempt to study phonological representations in postlingually deaf subjects using a multichannel cochlear implant. Before deafness, these subjects had developed normal language. The present study investigated how phonological representations are assessed through cochlear implant inputs by comparing priming within the auditory modality, and priming in a visual-auditory, cross-modal, condition. Two postlingually deafened adults participated in two lexical decision experiments where word primes were phonologically paired with a word target (e.g. vedette/dette), or a pseudoword target (e.g. banane/nane). The same word primes were also paired with non phonologically related target words (e.g. vedette/chat) and pseudowords (e.g. banane/repe). In addition, the same targets were used in phonologically-related pairs and in phonologically-unrelated ones. Results showed different priming effects for each patient. In one patient, priming was observed for word targets in the unimodal condition only. In the other patient, priming was observed for word targets and interference was observed for pseudoword targets in the cross-modal condition, whereas no effect was observed in the unimodal condition. In addition, this last patient made more errors for pseudowords than for words in the cross-modal condition. These results were interpreted as suggesting that lexical phonological representations participated to priming effects. Moreover, our results suggest that phonological word forms can be activated by visual primes via cochlear implants.
    International Journal of Pediatric Otorhinolaryngology 03/1999; 47(2):157-64. · 1.35 Impact Factor
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    ABSTRACT: 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.
    Journal of Cognitive Neuroscience 02/1999; 11(1):94-109. · 4.49 Impact Factor
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    ABSTRACT: Micro-rods have been observed in indurated carbonate horizons (30 cm thick) that overlie a periglacial chalk formation, in contact with the present-day soil (Champagne, France). They are numerous in the upper part of the hardened layers. Variations in micro-rod morphologies are related to progressive biomineralization of organic matter, transforming purely organic rods into calcite. Mineralized rods undergo diagenesis and their arrangement evolves from a random mesh fabric to recrystallized micritic platelets to microsparite. Two types of organic micro-rods have been observed: bacilliform and thread-like bacteria. Mineralogically, micro-rods are low-magnesian calcite. Crystallographically, their length is parallel to the (104) axis and they grow along the {010} plane. Micro-rods can be associated with needle-fiber calcite. They increase the CaCO3 content of the primary matrix and infill its microporosity. Their diagenetic evolution into microsparite contributes to soil layer induration.
    Sedimentary Geology 01/1999; 126(1). · 1.80 Impact Factor
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    ABSTRACT: Organic amnesia is typically associated with lesions in either the diencephalic or medial temporal regions of the brain. However, amnesia can result from other kinds of lesions, in particular those resulting from an aneurysm of the anterior communicating artery (ACoA). In the present study, 7 patients who became amnesic following a ruptured and operated ACoA aneurysm were comparated neuropsychologically with 11 patients with ruptures but no cognitive complaints and 18 normal control subjects. They were submitted to explicit and implicit memory tests and to tests claimed to be sensitive to frontal lobe dysfunction. The performance of the 11 ACoa patients without cognitive complaints revealed evidence for a functional frontal dysfunction (test of Stroop) and a partial deficit of explicit memory (free recall and long-term recall). The performance of the 7 ACoa amnesics revealed evidence for a functional frontal dysfunction and a deficit of explicit memory (safe in recognition). Anosognosia was also observed. The performance of all patients revealed the preservation of implicit memory in procedural tasks (serial reaction time and mirror reading) as diencephalic and temporal amnesia. The functionnal nature of the syndrome is discussed.
    Neurochirurgie 02/1996; 42(1):54-60. · 0.32 Impact Factor