Dépouillements

Phonological effects on the auditory N400 event-related brain potential / Peter PRAAMSTRA in Cognitive Brain Research, 1-2 (April 1993)

Public ISBD [article]  inCognitive Brain Research > 1-2 (April 1993) . - p.73-86 Titre : Phonological effects on the auditory N400 event-related brain potential Type de document : Texte imprimé et/ou numérique Auteurs : Peter PRAAMSTRA, Auteur ; Dick F. STEGEMAN, Auteur Année de publication : 1993 Article en page(s) : p.73-86 Langues : Anglais (eng) Mots-clés : Event-related-potential Auditory-N400 Phonological-priming Lexical-decision Rhyme-matching Index. décimale : PER Périodiques Résumé : We report 3 experiments exploring the responsiveness of the auditory N400 event-related potential to the phonological relations between word or non-word targets and preceding prime words. When subjects had to decide whether primes and targets rhymed, non-rhyming words produced greater negativity in the N400 time range than rhyming words. The same effect was obtained when these targets were spoken by another voice than the prime words, suggesting that the effect is determined by phonological factors, and not merely by a physical-acoustic mismatch (Experiment 1). In the rhyming task, the differential N400 for non-rhyming vs. rhyming words was equally pronounced for non-rhyming vs. rhyming non-words (Experiment 2). In a lexical decision task on the same stimuli, a difference between non-rhyming and rhyming targets was obtained for words, but not for non-words (Experiment 3). The results show that the auditory N400 is sensitive to phonological variables. It is further proposed that phonological effects on the auditory N400 are not manifestations unique to phonological processes that demand conscious attention, but may also reflect operations that are performed automatically during auditory word recognition. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780 [article] Phonological effects on the auditory N400 event-related brain potential [Texte imprimé et/ou numérique] / Peter PRAAMSTRA, Auteur ; Dick F. STEGEMAN, Auteur . - 1993 . - p.73-86. Langues : Anglais (eng) in Cognitive Brain Research > 1-2 (April 1993) . - p.73-86 Mots-clés : Event-related-potential Auditory-N400 Phonological-priming Lexical-decision Rhyme-matching Index. décimale : PER Périodiques Résumé : We report 3 experiments exploring the responsiveness of the auditory N400 event-related potential to the phonological relations between word or non-word targets and preceding prime words. When subjects had to decide whether primes and targets rhymed, non-rhyming words produced greater negativity in the N400 time range than rhyming words. The same effect was obtained when these targets were spoken by another voice than the prime words, suggesting that the effect is determined by phonological factors, and not merely by a physical-acoustic mismatch (Experiment 1). In the rhyming task, the differential N400 for non-rhyming vs. rhyming words was equally pronounced for non-rhyming vs. rhyming non-words (Experiment 2). In a lexical decision task on the same stimuli, a difference between non-rhyming and rhyming targets was obtained for words, but not for non-words (Experiment 3). The results show that the auditory N400 is sensitive to phonological variables. It is further proposed that phonological effects on the auditory N400 are not manifestations unique to phonological processes that demand conscious attention, but may also reflect operations that are performed automatically during auditory word recognition. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780

Precision and accuracy of subjective time estimation in different memory disorders / Paolo NICHELLI in Cognitive Brain Research, 1-2 (April 1993)

Public ISBD [article]  inCognitive Brain Research > 1-2 (April 1993) . - p.87-93 Titre : Precision and accuracy of subjective time estimation in different memory disorders Type de document : Texte imprimé et/ou numérique Auteurs : Paolo NICHELLI, Auteur ; Jordan GRAFMAN, Auteur ; Annalena VENNERI, Auteur ; Mariangela MOLINARI, Auteur ; Federica TAVANI, Auteur Année de publication : 1993 Article en page(s) : p.87-93 Langues : Anglais (eng) Mots-clés : Time-perception Neuropsychology Amnesia Frontal-lobe Alzheimer's-dementia Index. décimale : PER Périodiques Résumé : The aim of this study was to evaluate how different memory disorders affect subjective time durations. For this purpose we studied prospective time estimations in 4 amnesic (A) and in 15 Alzheimer's disease (AD) patients, and compared their performance with that of 5 matched young normal controls (YC) and 15 elderly subjects (EC). For the short-time durations we asked the subject to repeatedly reproduce a standard interval of 1 s. To test how subjects evaluated longer time durations, we choose a verbal estimation procedure. The subjects' task was to read either 5, 10, 20, or 40 digits appearing one at a time, while concurrently keeping the rhythm of 1 key press per second. At the end of each sequence, subjects had to judge the elapsed time from the beginning of the trial. Results showed that amnesics can correctly reproduce 1-s intervals. However, their accuracy of verbal estimates of longer durations was severely impaired. AD patients showed increased variability on repeated reproduction of 1-s intervals and were both inaccurate and imprecise in their verbal estimate of longer durations. Using the framework of the Scalar Timing Model, we conclude that amnesic patients exhibit a deficit in encoding and storing the current time for intervals that exceed their short-term memory range, while AD patients show a pattern of deficit that is explained by a more widespread involvement of both the clock, the memory, and the decisional mechanisms. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780 [article] Precision and accuracy of subjective time estimation in different memory disorders [Texte imprimé et/ou numérique] / Paolo NICHELLI, Auteur ; Jordan GRAFMAN, Auteur ; Annalena VENNERI, Auteur ; Mariangela MOLINARI, Auteur ; Federica TAVANI, Auteur . - 1993 . - p.87-93. Langues : Anglais (eng) in Cognitive Brain Research > 1-2 (April 1993) . - p.87-93 Mots-clés : Time-perception Neuropsychology Amnesia Frontal-lobe Alzheimer's-dementia Index. décimale : PER Périodiques Résumé : The aim of this study was to evaluate how different memory disorders affect subjective time durations. For this purpose we studied prospective time estimations in 4 amnesic (A) and in 15 Alzheimer's disease (AD) patients, and compared their performance with that of 5 matched young normal controls (YC) and 15 elderly subjects (EC). For the short-time durations we asked the subject to repeatedly reproduce a standard interval of 1 s. To test how subjects evaluated longer time durations, we choose a verbal estimation procedure. The subjects' task was to read either 5, 10, 20, or 40 digits appearing one at a time, while concurrently keeping the rhythm of 1 key press per second. At the end of each sequence, subjects had to judge the elapsed time from the beginning of the trial. Results showed that amnesics can correctly reproduce 1-s intervals. However, their accuracy of verbal estimates of longer durations was severely impaired. AD patients showed increased variability on repeated reproduction of 1-s intervals and were both inaccurate and imprecise in their verbal estimate of longer durations. Using the framework of the Scalar Timing Model, we conclude that amnesic patients exhibit a deficit in encoding and storing the current time for intervals that exceed their short-term memory range, while AD patients show a pattern of deficit that is explained by a more widespread involvement of both the clock, the memory, and the decisional mechanisms. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780

Motor imagery activates the cerebellum regionally. A SPECT rCBF study with 99mTc-HMPAO / Erik RYDING in Cognitive Brain Research, 1-2 (April 1993)

Public ISBD [article]  inCognitive Brain Research > 1-2 (April 1993) . - p.94-99 Titre : Motor imagery activates the cerebellum regionally. A SPECT rCBF study with 99mTc-HMPAO Type de document : Texte imprimé et/ou numérique Auteurs : Erik RYDING, Auteur ; Jean DECETY, Auteur ; Hans SJOHOLM, Auteur ; Georg STENBERG, Auteur ; David H. INGVAR, Auteur Année de publication : 1993 Article en page(s) : p.94-99 Langues : Anglais (eng) Mots-clés : Motor-imagery Cerebellum Regional-cerebral-blood-flow SPECT 99mTc-HMPAO Index. décimale : PER Périodiques Résumé : Our earlier findings of a cerebellar activation during motor imagery (Brain Res., 535 (1990) 313-317) were made with a technique with low regional resolution. Therefore we could not elucidate the distribution of the cerebellar activation. In the present study the cerebellar regional cerebral blood flow (rCBF) changes during motor imagery (MI) was measured with a single photon emission computed tomography (SPECT) rCBF method (99mTc-HMPAO) with higher regional resolution during (1) silent counting, and (2) MI (which included silent counting) in 17 normal subjects. Comparing the SPECT results from the two tasks revealed the regional activations during MI. We confirmed that the most pronounced regional activations during MI were found in the cerebellum, especially in its infero-lateral parts on both sides. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780 [article] Motor imagery activates the cerebellum regionally. A SPECT rCBF study with 99mTc-HMPAO [Texte imprimé et/ou numérique] / Erik RYDING, Auteur ; Jean DECETY, Auteur ; Hans SJOHOLM, Auteur ; Georg STENBERG, Auteur ; David H. INGVAR, Auteur . - 1993 . - p.94-99. Langues : Anglais (eng) in Cognitive Brain Research > 1-2 (April 1993) . - p.94-99 Mots-clés : Motor-imagery Cerebellum Regional-cerebral-blood-flow SPECT 99mTc-HMPAO Index. décimale : PER Périodiques Résumé : Our earlier findings of a cerebellar activation during motor imagery (Brain Res., 535 (1990) 313-317) were made with a technique with low regional resolution. Therefore we could not elucidate the distribution of the cerebellar activation. In the present study the cerebellar regional cerebral blood flow (rCBF) changes during motor imagery (MI) was measured with a single photon emission computed tomography (SPECT) rCBF method (99mTc-HMPAO) with higher regional resolution during (1) silent counting, and (2) MI (which included silent counting) in 17 normal subjects. Comparing the SPECT results from the two tasks revealed the regional activations during MI. We confirmed that the most pronounced regional activations during MI were found in the cerebellum, especially in its infero-lateral parts on both sides. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780

Effects of collateral inhibition in a model of the immature rat cerebellar cortex: multineuron correlations / C. BERNARD in Cognitive Brain Research, 1-2 (April 1993)

Public ISBD [article]  inCognitive Brain Research > 1-2 (April 1993) . - p.120-122 Titre : Effects of collateral inhibition in a model of the immature rat cerebellar cortex: multineuron correlations Type de document : Texte imprimé et/ou numérique Auteurs : C. BERNARD, Auteur ; H. AXELRAD, Auteur ; B.G. GIRAUD, Auteur Année de publication : 1993 Article en page(s) : p.120-122 Langues : Anglais (eng) Mots-clés : Cerebellar-Cortex Purkinje-cell Collateral-inhibition Multineuron-correlation Crosscorrelogram Informational-entropy Index. décimale : PER Périodiques Résumé : A model of the immature rat cerebellar cortex is used to simulate the effect of the inhibitory recurrent collateral axons of the Purkinje cells on the spike trains in the network. Inhibition induces an important overall change in the statistical characteristics of individual spike trains. It is also instrumental in producing a strong cooperativity between the different neurons. Moreover, a functional spatial anisotropy appears. A specific entropy index is used to analyze levels of information transfer between clustered and faraway neurons in the network. The formatting effect of recurrent collateral inhibition on spike trains and on network functional dynamics is studied by means of a model of the newborn rat cerebellar cortex. This immature structure has simpler morphological characteristics and fewer physiological parameters than the adult one. It is thus a good candidate for the comparison between experimental and theoretical data. The model network is made of 256 formal neurons (FN), arranged in a square lattice. Each neuron is coupled to its eight nearest neighbors by inhibitory links. All the parameters of the different elements of the model — in particular integration of inhibitory and excitatory inputs — are given anatomical and physiological values derived from biological data. Activities of single FNs and correlations between spatially distant ones are analyzed with classical statistical techniques as well as with a specific informational entropy method we introduce. Simulation results indicate that inhibition is instrumental in: (1) the transformation of the spike train characteristics. This includes a lengthening of the mean interspike interval as well as an overall change in the statistical distribution of intervals, with an emergence of long-lasting ones; (2) the functional structuration of the network. Inhibitory connections between nearest neighbors induce a strong cooperativity between FNs. Furthermore a clear spatial anisotropy occurs in the functioning of the network, with inhibitory effects extending beyond local connectivity in preferential directions. We propose an interpretation of this functional structuration in terms of the various routes followed by the inhibition, including relay effects. The parameters of the model (levels of activities, inhibition rules and connectivities) were varied in order to test the robustness of the above results. Finally, the results are compared with those obtained in an experimental situation. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780 [article] Effects of collateral inhibition in a model of the immature rat cerebellar cortex: multineuron correlations [Texte imprimé et/ou numérique] / C. BERNARD, Auteur ; H. AXELRAD, Auteur ; B.G. GIRAUD, Auteur . - 1993 . - p.120-122. Langues : Anglais (eng) in Cognitive Brain Research > 1-2 (April 1993) . - p.120-122 Mots-clés : Cerebellar-Cortex Purkinje-cell Collateral-inhibition Multineuron-correlation Crosscorrelogram Informational-entropy Index. décimale : PER Périodiques Résumé : A model of the immature rat cerebellar cortex is used to simulate the effect of the inhibitory recurrent collateral axons of the Purkinje cells on the spike trains in the network. Inhibition induces an important overall change in the statistical characteristics of individual spike trains. It is also instrumental in producing a strong cooperativity between the different neurons. Moreover, a functional spatial anisotropy appears. A specific entropy index is used to analyze levels of information transfer between clustered and faraway neurons in the network. The formatting effect of recurrent collateral inhibition on spike trains and on network functional dynamics is studied by means of a model of the newborn rat cerebellar cortex. This immature structure has simpler morphological characteristics and fewer physiological parameters than the adult one. It is thus a good candidate for the comparison between experimental and theoretical data. The model network is made of 256 formal neurons (FN), arranged in a square lattice. Each neuron is coupled to its eight nearest neighbors by inhibitory links. All the parameters of the different elements of the model — in particular integration of inhibitory and excitatory inputs — are given anatomical and physiological values derived from biological data. Activities of single FNs and correlations between spatially distant ones are analyzed with classical statistical techniques as well as with a specific informational entropy method we introduce. Simulation results indicate that inhibition is instrumental in: (1) the transformation of the spike train characteristics. This includes a lengthening of the mean interspike interval as well as an overall change in the statistical distribution of intervals, with an emergence of long-lasting ones; (2) the functional structuration of the network. Inhibitory connections between nearest neighbors induce a strong cooperativity between FNs. Furthermore a clear spatial anisotropy occurs in the functioning of the network, with inhibitory effects extending beyond local connectivity in preferential directions. We propose an interpretation of this functional structuration in terms of the various routes followed by the inhibition, including relay effects. The parameters of the model (levels of activities, inhibition rules and connectivities) were varied in order to test the robustness of the above results. Finally, the results are compared with those obtained in an experimental situation. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780

Event-related potentials and repetition priming in young, middle-aged and elderly normal subjects / Frini KARAYANIDIS in Cognitive Brain Research, 1-2 (April 1993)

Public ISBD [article]  inCognitive Brain Research > 1-2 (April 1993) . - p.123-134 Titre : Event-related potentials and repetition priming in young, middle-aged and elderly normal subjects Type de document : Texte imprimé et/ou numérique Auteurs : Frini KARAYANIDIS, Auteur ; Sally ANDREWS, Auteur ; Philip B. WARD, Auteur ; Neil MCCONAGHY, Auteur Année de publication : 1993 Article en page(s) : p.123-134 Langues : Anglais (eng) Mots-clés : Aging Word-recognition Repetition-priming Lag-effect Event-related-potential Late-positive-component N400 Index. décimale : PER Périodiques Résumé : Although the structure of semantic memory appears to be unaffected with increasing age, there is evidence that older adults are less efficient at accessing stored memory representations. Aging also results in a decline in the ability to use contextual information effectively, suggesting a deficit in episodic memory processes. The present experiment examines the effects of age on memory retrieval of stored representations and the use of contextual information. Event-related potentials (ERP) were recorded to immediate and delayed word repetition during a lexical decision task. Three groups of subjects were tested: young (mean = 27.3 years), middle (mean = 46.7 years) and old (mean = 67.4 years). Behavioral facilitation due to repetition did not significantly differ across groups. With increasing age, the ERP waveform showed a positive shift which began around 300–400 ms post-stimulus and was apparent across all stimulus types and response conditions. This positive shift may reflect an age-related decrease in cortical excitation. Although the onset of the ERP repetition effect was not affected by age, its duration for both immediate and delayed repetition was significantly prolonged. In the light of recent models of ERP word repetition effects, these results suggest that processes related to accessing stored representations in memory are unaffected by age. The extended duration of the repetition effect and the increase in the magnitude of the effect of delayed repetition with age suggest that aging effects processes related to the retrieval and use of contextual information in integrating a stimulus with its context. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780 [article] Event-related potentials and repetition priming in young, middle-aged and elderly normal subjects [Texte imprimé et/ou numérique] / Frini KARAYANIDIS, Auteur ; Sally ANDREWS, Auteur ; Philip B. WARD, Auteur ; Neil MCCONAGHY, Auteur . - 1993 . - p.123-134. Langues : Anglais (eng) in Cognitive Brain Research > 1-2 (April 1993) . - p.123-134 Mots-clés : Aging Word-recognition Repetition-priming Lag-effect Event-related-potential Late-positive-component N400 Index. décimale : PER Périodiques Résumé : Although the structure of semantic memory appears to be unaffected with increasing age, there is evidence that older adults are less efficient at accessing stored memory representations. Aging also results in a decline in the ability to use contextual information effectively, suggesting a deficit in episodic memory processes. The present experiment examines the effects of age on memory retrieval of stored representations and the use of contextual information. Event-related potentials (ERP) were recorded to immediate and delayed word repetition during a lexical decision task. Three groups of subjects were tested: young (mean = 27.3 years), middle (mean = 46.7 years) and old (mean = 67.4 years). Behavioral facilitation due to repetition did not significantly differ across groups. With increasing age, the ERP waveform showed a positive shift which began around 300–400 ms post-stimulus and was apparent across all stimulus types and response conditions. This positive shift may reflect an age-related decrease in cortical excitation. Although the onset of the ERP repetition effect was not affected by age, its duration for both immediate and delayed repetition was significantly prolonged. In the light of recent models of ERP word repetition effects, these results suggest that processes related to accessing stored representations in memory are unaffected by age. The extended duration of the repetition effect and the increase in the magnitude of the effect of delayed repetition with age suggest that aging effects processes related to the retrieval and use of contextual information in integrating a stimulus with its context. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=780

Reversal of scopolamine-induced amnesia by the GABAB receptor antagonist CGP 35348 in the mouse / Mauro BIANCHI in Cognitive Brain Research, 1-2 (April 1993)

Public ISBD [article]  inCognitive Brain Research > 1-2 (April 1993) . - p.135-136 Titre : Reversal of scopolamine-induced amnesia by the GABAB receptor antagonist CGP 35348 in the mouse Type de document : Texte imprimé et/ou numérique Auteurs : Mauro BIANCHI, Auteur ; Alberto E. PANERAI, Auteur Année de publication : 1993 Article en page(s) : p.135-136 Langues : Anglais (eng) Mots-clés : GABA-B-receptor CGP-35348 Memory Passive-avoidance Scopolamine-induced-amnesia Index. décimale : PER Périodiques Résumé : We studied the effects of CGP 35348, a centrally active blocker of GABAB receptors, on scopolamine-induced amnesia for a passive avoidance response in the mouse. Both pre-training or post-training intraperitoneal administration of the GABAB antagonist (75, 150 and 300 mg/kg i.p.) significantly reduces the amnesic effect of scopolamine (1.0 mg/kg i.p.). Our results are in agreement with previous observations indicating a role for the GABAB receptors in the modulation of memory function, and suggest a possible role of GABAB receptor antagonists as nootropic drugs. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=781 [article] Reversal of scopolamine-induced amnesia by the GABAB receptor antagonist CGP 35348 in the mouse [Texte imprimé et/ou numérique] / Mauro BIANCHI, Auteur ; Alberto E. PANERAI, Auteur . - 1993 . - p.135-136. Langues : Anglais (eng) in Cognitive Brain Research > 1-2 (April 1993) . - p.135-136 Mots-clés : GABA-B-receptor CGP-35348 Memory Passive-avoidance Scopolamine-induced-amnesia Index. décimale : PER Périodiques Résumé : We studied the effects of CGP 35348, a centrally active blocker of GABAB receptors, on scopolamine-induced amnesia for a passive avoidance response in the mouse. Both pre-training or post-training intraperitoneal administration of the GABAB antagonist (75, 150 and 300 mg/kg i.p.) significantly reduces the amnesic effect of scopolamine (1.0 mg/kg i.p.). Our results are in agreement with previous observations indicating a role for the GABAB receptors in the modulation of memory function, and suggest a possible role of GABAB receptor antagonists as nootropic drugs. Permalink : https://www.cra-rhone-alpes.org/cid/opac_css/index.php?lvl=notice_display&id=781