Does priming specific syllables during tip-of-the-tongue states facilitate word retrieval in older adults?

This experiment investigated whether phonological priming of syllables helps resolve tip-of-the-tongue (TOT) states in young and older adults. Young, young-old, and old-old adults read general knowledge questions and responded "know," "TOT," or "don't know" accordingly. Participants then read a list of 10 words that included 3 phonological primes corresponding solely to the first, middle, or last syllable of the target word. Young and young-old adults resolved more TOTs after first-syllable primes, but old-old adults showed no increase in TOT resolution following any primes. These results indicate that presentation of the first syllable of a missing word strengthens the weakened phonological connections that cause TOTs and increases word retrieval, but not for old-old adults who experience greater deficits in the transmission of priming across these connections.     

Age differences in overlapping-task performance: evidence for efficient parallel processing in older adults

Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task 1 (T1) and a lexical-decision task (word or nonword) for Task 2 (T2) were used. PRP effects, response time for T2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T2 was smaller at the short SOA than at the long SOA, reflecting slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T2 in parallel with the processing of T1 at least as efficiently as younger adults.     

Polysynaptic potentiation at different levels of rat olfactory pathways following learning

This study was aimed at investigating the consequences of learning on late polysynaptic components of evoked field potential signals recorded in parallel at different levels of the olfactory pathways. For this, evoked field potentials induced by electrical stimulation of the olfactory bulb were recorded simultaneously in the anterior piriform cortex, the posterior piriform cortex, the lateral entorhinal cortex, and the dentate gyrus. The different parameters of late components were measured in each site before and after completion of associative learning in anesthetized rats. In the learning task, rats were trained to associate electrical stimulation of one olfactory bulb electrode with the delivery of sucrose (positive reward) and stimulation of a second olfactory bulb electrode with the delivery of quinine (negative reward). In this way, stimulation of the same olfactory bulb electrodes used for inducing field potentials served as a discriminative cue in the learning paradigm. The data confirmed previous observation that learning was associated with a lowering in late-component-1 intensity of induction in the posterior piriform cortex. The use of simultaneous recording allowed us to further specify the consequences of learning on late-component distribution in the studied network. Indeed the data showed that whereas before learning, late component 1 was rather uniformly distributed among the recorded sites; following learning, its expression was facilitated preferentially in the posterior piriform cortex and lateral entorhinal cortex. Furthermore, learning was accompanied by the emergence of a new late component (late component 2), which occurred simultaneously in the four recording sites. The possible involvement of potentiation of polysynaptic components in recognition and/or consolidation processes will be discussed.     

A crossmodal attentional blink between vision and touch

There is currently a great deal of interest regarding the possible existence of a crossmodal attentional blink (AB) between audition and vision. The majority of evidence now suggests that no such crossmodal deficit exists unless a task switch is introduced. We report two experiments designed to investigate the existence of a crossmodal AB between vision and touch. Two masked targets were presented successively at variable interstimulus intervals. Participants had to respond either to both targets (experimental condition) or to just the second target (control condition). In Experiment 1, the order of target modality was blocked, and an AB was demonstrated when visual targets preceded tactile targets, but not when tactile targets preceded visual targets. In Experiment 2, target modality was mixed randomly, and a significant crossmodal AB was demonstrated in both directions between vision and touch. The contrast between our visuotactile results and those of previous audiovisual studies is discussed, as are the implications for current theories of the AB.     

Odorant quality perception: a metric individual differences approach

Perceptual spaces, in which similar stimuli are located close to each other and dissimilar stimuli are located far apart, have aided in the understanding of the physiological and psychological bases for sensory quality coding. Differences in perception between individuals should be reflected by differences in the spatial relationships between stimuli. If the dimensionality of the perceptual space is small (e.g., color space), individual differences that reflect specific pathologies are readily apparent from visual inspection. On the other hand, if the dimensionality of the perceptual space is large (as is proposed for odor space), visual inspection alone may not reveal individual differences in quality perception. The present work presents an information-theory-based method for quantifying individual differences in quality perception from perceptual confusion matrices. The ability of this method to quantify individual differences in quality perception is shown in a hypothetical example of specific anosmia. Finally, the method is applied to the examination of intrasubject consistency of odorant quality perception.     

Contextual effects on word production: A lifespan study

The effect of sentence priming on picture naming was investigated across the lifespan, from age 3 to 87 years. Names that are normally acquired before 3 years of age were presented in auditory contexts that were semantically congruent, incongruent, or neutral in relation to each picture and its name. Sentential priming was present at all age levels. Facilitation (neutral vs. congruent) was significantly by 4 years of age and did not vary significantly with age. Interference (incongruent vs. neutral) was significant at all age levels, but changed nonmonotonically with age (largest in the youngest children, stable from young adulthood through age 70, with a small increase in the oldest participants). We conclude that picture naming is a useful tool for the investigation of sentential priming effects across the lifespan and that it can reveal potentially interesting developmental changes in the effects of sentential context on word retrieval.     

Immediate serial recall of words and nonwords: Tests of the retrieval-based hypothesis

In two experiments, the immediate serial recall of lists of words or nonwords was investigated under quiet and articulatory suppression conditions. The results showed better item recall for words but better order recall for nonwords, as measured with proportion of order errors per item recalled. Articulatory suppression hindered the recall of item information for both types of lists and of order information for words. These results are interpreted in light of a retrieval account in which degraded phonological traces must undergo a reconstruction process calling on long-term knowledge of the tobe-remembered items. The minimal long-term representations for nonwords are thought to be responsible for their lower item recall and their better order recall. Under suppression, phonological representations are thought to be minimal, producing trace interpretation problems responsible for the greater number of item and order errors, relative to quiet conditions. The very low performance for nonwords under suppression is attributed to the combination of degraded phonological information and minimal long-term knowledge.     

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Neural mechanisms of affective interference in schizotypy

Negatively valenced stimuli foster cognitive impairment in schizotypy and schizophrenia. To identify relevant brain mechanisms, the authors had 16 positive-schizotypy and 16 control participants perform an emotional Stroop task, judging the ink color of negative and neutral words during functional magnetic resonance imaging (fMRI) of regional brain activity. Schizotypy individuals showed increased right and decreased left activity in dorsolateral prefrontal cortex, indicating a deficit in maintenance of attentional set in the presence of negative emotional distractors. They also showed abnormal activity in ventral limbic areas, including decreased activity in nucleus accumbens and increased activity in hippocampus and amygdala, a circuit involved in the integration of cognitive and affective processes. These results indicate that aspects of emotion-cognition processes and the brain mechanisms that implement them are similar in schizotypy and schizophrenia.