Odors: implicit memory and performance effects. (65/8569)

In order to assess the influence of odors on human performance and implicit memory for odors, 108 subjects completed a variety of tests in weakly scented (jasmine, lavender or odorless) rooms without having been made aware of the odor. After a 30 min interval the subjects were shown slides of different surroundings, including the room they had been in, and were requested to rate how well a set of 12 odors, including a blank, would fit to these surroundings. Half of these contexts contained visual cues related to two of the presented odors (leather and coffee). After the rating of fit the subjects had to rate the odors for pleasantness, were asked to identify the odors with their correct names and to tell where and when they had last smelled these odors. One subject remembered smelling the odor (jasmine) in the room and was discarded from the analysis of the results for the rating of fit. None of the others reported recollection of the experimental odors. The results showed that in general jasmine had a negative and lavender a positive effect on test performance. If an odor-related visual cue was present in the context, the related odor was always rated highest in fit to that context. Furthermore, the subjects working in rooms with an odor subsequently assigned this odor to the visual context of that room to a significantly higher degree than subjects working in rooms with different odors. Since none of the subjects reported that they had smelled the odor in the rooms where performance testing took place, it was concluded that the memory for these odors was implicit. Further analysis showed that such memory was only found in subjects who were unable to supply the right name for the odor. The possible consequences of this latter finding for understanding the relationship between sensory (episodic) and semantic odor memory are discussed.  (+info)

Odor identification, consistency of label use, olfactory threshold and their relationships to odor memory over the human lifespan. (66/8569)

The purpose of this study was to investigate olfactory threshold, odor identification, consistency of label use and their relationships to odor memory in the context of semantic/episodic memory across the human lifespan. A total of 137 subjects aged 4-90 years were tested with several olfactory test procedures. We found that olfactory sensitivity was well developed in children despite the finding that their odor naming and odor memory were inferior to that of adults. In the elderly population, olfactory functions gradually declined, with odor memory and odor identification demonstrating the most significant decline. Semantic encoding was differentially related to odor memory over the human age span. Whereas consistency of label use was the main predictor for odor memory in children and young adults, olfactory identification ability was the main predictor in the elderly study group. We also calculated response bias for the separate age groups and found no differences between children, young adults and elderly. However, with age false alarm rates increased. We conclude that children possess equal olfactory sensitivity compared with adults; however, due to limitations in linguistic capabilities and familiarity to odorants, odor memory and odor identification performance was limited. Additionally, our data indicate major alterations of olfactory processing in advanced age with substantial losses in odor memory and odor identification performance.  (+info)

Implicit testing of odor memory: instances of positive and negative repetition priming. (67/8569)

The study provides a test and evaluation of a new repetition priming procedure designed to solve problems in investigating olfactory-specific priming. Although the results did not reveal any overall priming effect, a post-hoc analysis showed that incorrectly identified odors were more quickly processed than control odors, whereas correctly identified odors were processed more slowly These results are discussed and interpreted as instances of positive and negative repetition priming respectively.  (+info)

Responses to auditory stimuli in macaque lateral intraparietal area. II. Behavioral modulation. (68/8569)

The lateral intraparietal area (LIP), a region of posterior parietal cortex, was once thought to be unresponsive to auditory stimulation. However, recent reports have indicated that neurons in area LIP respond to auditory stimuli during an auditory-saccade task. To what extent are auditory responses in area LIP dependent on the performance of an auditory-saccade task? To address this question, recordings were made from 160 LIP neurons in two monkeys while the animals performed auditory and visual memory-saccade and fixation tasks. Responses to auditory stimuli were significantly stronger during the memory-saccade task than during the fixation task, whereas responses to visual stimuli were not. Moreover, neurons responsive to auditory stimuli tended also to be visually responsive and to exhibit delay or saccade activity in the memory-saccade task. These results indicate that, in general, auditory responses in area LIP are modulated by behavioral context, are associated with visual responses, and are predictive of delay or saccade activity. Responses to auditory stimuli in area LIP may therefore be best interpreted as supramodal responses, and similar in nature to the delay activity, rather than as modality-specific sensory responses. The apparent link between auditory activity and oculomotor behavior suggests that the behavioral modulation of responses to auditory stimuli in area LIP reflects the selection of auditory stimuli as targets for eye movements.  (+info)

Protein synthesis-dependent and mRNA synthesis-independent intermediate phase of memory in Hermissenda. (69/8569)

The conditioned stimulus pathway in Hermissenda has been used to examine the time-dependent mechanisms of memory consolidation following one-trial conditioning. Here we report an intermediate phase of memory consolidation following one-trial conditioning that requires protein synthesis, but not mRNA synthesis. In conditioned animals, enhanced excitability normally expressed during an intermediate phase of memory was reversed by the protein synthesis inhibitor anisomycin, but not by the mRNA synthesis inhibitor 5, 6-dichloro-1-beta-D-ribobenzimidazole (DRB). Associated with the intermediate phase of memory is an increase in the phosphorylation of a 24-kDa protein. Anisomycin present during the intermediate phase blocked the increased phosphorylation of the 24-kDa phosphoprotein, but did not block the increased phosphorylation of other proteins associated with conditioning or significantly change their baseline phosphorylation. DRB did not reverse enhanced excitability or decrease protein phosphorylation expressed during the intermediate phase of memory formation, but it did reverse enhanced excitability 3.5 h after conditioning. Phosphorylation of the 24-kDa protein may support enhanced excitability during the intermediate phase, in the transition period between short- and long-term memory.  (+info)

Electrophysiological correlates of language processing in schizotypal personality disorder. (70/8569)

OBJECTIVE: This study examined whether the electrophysiological correlates of language processing found previously to be abnormal in schizophrenia are also abnormal in schizotypal individuals. The authors used the N400 component to evaluate language dysfunction in schizotypal individuals. METHOD: Event-related potentials were recorded in 16 comparison subjects and 17 schizotypal individuals (who met full DSM-III-R criteria) to sentences presented both visually and aurally; half of the sentences ended with an expected word completion (congruent condition), and the other half ended with an unexpected word completion (incongruent condition). RESULTS: In the congruent condition, the N400 amplitude was more negative in individuals with schizotypal personality disorder than in comparison subjects in both the visual and auditory modalities. In addition, in the visual modality, the N400 latency was prolonged in the individuals with schizotypal personality disorder. CONCLUSIONS: The N400 was found to be abnormal in the individuals with schizotypal personality disorder relative to comparison subjects. The abnormality was similar to the abnormality the authors' laboratory reported earlier in schizophrenic subjects, in which the N400 amplitude was found to be more negative in both congruent and incongruent sentence completions. The N400 abnormality is consistent with the inefficient use of context.  (+info)

Nociceptin/orphanin FQ and nocistatin on learning and memory impairment induced by scopolamine in mice. (71/8569)

1. Nociceptin, also known as orphanin FQ, is an endogenous ligand for the orphan opioid receptor-like receptor 1 (ORL1) and involves in various functions in the central nervous system (CNS). On the other hand, nocistatin is recently isolated from the same precursor as nociceptin and blocks nociceptin-induced allodynia and hyperalgesia. 2. Although ORL1 receptors which display a high degree of sequence homology with classical opioid receptors are abundant in the hippocampus, little is known regarding their role in learning and memory. 3. The present study was designed to investigate whether nociceptin/orphanin FQ and nocistatin could modulate impairment of learning and memory induced by scopolamine, a muscarinic cholinergic receptor antagonist, using spontaneous alternation of Y-maze and step-down type passive avoidance tasks in mice. 4. While nocistatin (0.5-5.0 nmol mouse-1, i.c.v.) administered 30 min before spontaneous alternation performance or the training session of the passive avoidance task, had no effect on spontaneous alternation or passive avoidance behaviours, a lower per cent alternation and shorter median step-down latency in the retention test were obtained in nociceptin (1.5 and/or 5.0 nmol mouse-1, i.c.v.)-treated normal mice. 5. Administration of nocistatin (1.5 and/or 5.0 nmol mouse-1, i.c.v.) 30 min before spontaneous alternation performance or the training session of the passive avoidance task, attenuated the scopolamine-induced impairment of spontaneous alternation and passive avoidance behaviours. 6. These results indicated that nocistatin, a new biologically active peptide, ameliorates impairments of spontaneous alternation and passive avoidance induced by scopolamine, and suggested that these peptides play opposite roles in learning and memory.  (+info)

latheo encodes a subunit of the origin recognition complex and disrupts neuronal proliferation and adult olfactory memory when mutant. (72/8569)

The Drosophila latheo (lat) gene was identified in a behavioral screen for olfactory memory mutants. The original hypomorphic latP1 mutant (Boynton and Tully, 1992) shows a structural defect in adult brain. Homozygous lethal lat mutants lack imaginal discs, show little cell proliferation in the CNS of third instar larvae, and die as early pupae. latP1 was cloned, and all of the above mentioned defects of hypomorphic or homozygous lethal lat mutants were rescued with a lat+ transgene. lat encodes a novel protein with homology to a subunit of the origin recognition complex (ORC). Human and Drosophila LAT both associate with ORC2 and are related to yeast ORC3, suggesting that LAT functions in DNA replication during cell proliferation.  (+info)