Monthly Archives: March 2010
Biased Recognition of Positive Faces in Aging and Amnestic Mild Cognitive Impairment
We investigated age differences in biased recognition of happy, neutral, or angry faces in 4 experiments. Experiment 1 revealed increased true and false recognition for happy faces in older adults, which persisted even when changing each face’s emotional expression from study to test in Experiment 2. In Experiment 3, we examined the influence of reduced memory capacity on the positivity-induced recognition bias, which showed the absence of emotion-induced memory enhancement but a preserved recognition bias for positive faces in patients with amnestic mild cognitive impairment compared with older adults with normal memory performance. In Experiment 4, we used semantic differentials to measure the connotations of happy and angry faces. Younger and older participants regarded happy faces as more familiar than angry faces, but the older group showed a larger recognition bias for happy faces. This finding indicates that older adults use a gist-based memory strategy based on a semantic association between positive emotion and familiarity. Moreover, older adults’ judgments of valence were more positive for both angry and happy faces, supporting the hypothesis of socioemotional selectivity. We propose that the positivity-induced recognition bias might be based on fluency, which in turn is based on both positivity-oriented emotional goals and on preexisting semantic associations.
from Psychology and Aging
Everyday Memory Compensation: The Impact of Cognitive Reserve, Subjective Memory, and Stress
To determine the potential importance of several unexplored covariates of everyday memory compensation, the authors examined relations between responses on the Memory Compensation Questionnaire (a self-report measure of everyday memory compensation) and cognitive reserve (education and verbal IQ), subjective memory, and life stress in 66 older adults (mean age = 70.55 years). Key results indicated that compensation occurred in people (a) whose IQ level was greater than their education level (representing cognitive reserve “discordance”) but not in people whose IQ was commensurate with their education (representing cognitive reserve “concordance”); (b) who had greater perceived memory errors; and (c) who experienced heightened stress. Further, high-stress older adults compensated whether perceived memory errors were low or high, but low-stress older adults compensated only if they perceived high memory errors. Bootstrapped confidence intervals around model betas provided further support for estimate reliability. These results suggest boundary conditions for the concept of cognitive reserve, and highlight the importance of subjective memory and life stress for defining contexts in which compensation may occur.
from Psychology and Aging
Use of Affective Prosody by Young and Older Adults
Emotion is conveyed in speech by semantic content (what is said) and by prosody (how it is said). Prior research suggests that older adults benefit from linguistic prosody when comprehending language but that they have difficulty understanding affective prosody. In a series of 3 experiments, young and older adults listened to sentences in which the emotional cues conveyed by semantic content and affective prosody were either congruent or incongruent and then indicated whether the talker sounded happy or sad. When judging the emotion of the talker, young adults were more attentive to the affective prosodic cues than to the semantic cues, whereas older adults performed less consistently when these cues conflicted. Participants’ reading and repetition of the sentences were recorded so that age- and emotion-related changes in the production of emotional speech cues could be examined. Both young and older adults were able to produce affective prosody. The age-related difference in perceiving emotion was eliminated when listeners repeated the sentences before responding, consistent with previous findings regarding the beneficial role of repetition in conversation. The results of these experiments suggest that there are age-related differences in interpreting affective prosody but that repeating may be a compensatory strategy that could minimize the everyday consequences of these differences.
from Psychology and Aging
Motion-onset auditory-evoked potentials critically depend on history
The aim of the present study was to determine whether motion history affects motion-onset auditory-evoked potentials (motion-onset AEPs). AEPs were recorded from 33 EEG channels in 16 subjects to the motion onset of a sound (white noise) virtually moving in the horizontal plane at a speed of 60 deg/s from straight ahead to the left (−30°). AEPs for baseline and adaptation were compared. A stimulus trial comprised three consecutive phases: 2,000 ms adaptation phase, 1,000 ms stationary phase, and 500 ms test phase. During the adaptation phase of the adaptation condition, a sound source moved twice from +30° to −30° to top up preceding adaptation. In the baseline condition, neither top-up nor pre-adaptation were exerted. For both conditions, a stationary sound was presented centrally in the stationary phase, moving leftwards in the test phase. Typical motion-onset AEPs were obtained for the baseline condition, namely a fronto-central response complex dominated by a negative and a positive component, the so-called change-N1 and change-P2 after around 180 and 250 ms, respectively. For the adaptation condition, this complex was shifted significantly into the positive range, indicating that adaptation abolished a negativity within a time window of approximately 160 to 270 ms. A respective shift into the negative range was evident at occipito-parietal sites. In conclusion, while adaptation has to be taken into account as a potential confound in the design of motion-AEP studies, it might also be of benefit in order to isolate AEP correlates of motion processing.
Perceptual Fusion Tendency of Speech Sounds
To discriminate and to recognize sound sources in a noisy, reverberant environment, listeners need to perceptually integrate the direct wave with the reflections of each sound source. It has been confirmed that perceptual fusion between direct and reflected waves of a speech sound helps listeners recognize this speech sound in a simulated reverberant environment with disrupting sound sources. When the delay between a direct sound wave and its reflected wave is sufficiently short, the two waves are perceptually fused into a single sound image as coming from the source location. Interestingly, compared with nonspeech sounds such as clicks and noise bursts, speech sounds have a much larger perceptual fusion tendency. This study investigated why the fusion tendency for speech sounds is so large. Here we show that when the temporal amplitude fluctuation of speech was artificially time reversed, a large perceptual fusion tendency of speech sounds disappeared, regardless of whether the speech acoustic carrier was in normal or reversed temporal order. Moreover, perceptual fusion of normal-order speech, but not that of time-reversed speech, was accompanied by increased coactivation of the attention-control-related, spatial-processing-related, and speech-processing-related cortical areas. Thus, speech-like acoustic carriers modulated by speech amplitude fluctuation selectively activate a cortical network for top–down modulations of speech processing, leading to an enhancement of perceptual fusion of speech sounds. This mechanism represents a perceptual-grouping strategy for unmasking speech under adverse conditions.
from the Journal of Cognitive Neuroscience
Auditory and cognitive abilities of children suspected of auditory processing disorder (APD)
Although children suspected of having APD do show, on average, poorer performance on a number of auditory tasks, the presence or absence of an auditory deficit appears to have little impact on the development of the verbal and non-verbal skills tested here.
from the International Journal of Pediatric Otorhinolaryngology
Evolution of communication abilities after cochlear implantation in prelingually deaf children
Many different factors influence the evolution of communication abilities of cochlear implanted children.
Investigating the cause of hearing loss, presence of associated disabilities and residual hearing before surgery may help to predict outcome and plan appropriate care to those children with negative predictive factors.
from the International Journal of Pediatric Otorhinolaryngology
Movement goals and feedback and feedforward control mechanisms in speech production
Studies of speech motor control are described that support a theoretical framework in which fundamental control variables for phonemic movements are multi-dimensional regions in auditory and somatosensory spaces. Auditory feedback is used to acquire and maintain auditory goals and in the development and function of feedback and feedforward control mechanisms. Several lines of evidence support the idea that speakers with more acute sensory discrimination acquire more distinct goal regions and therefore produce speech sounds with greater contrast. Feedback modification findings indicate that fluently produced sound sequences are encoded as feedforward commands, and feedback control serves to correct mismatches between expected and produced sensory consequences.
from the Journal of Neurolinguistics
Does cortical mapping protect naming if surgery includes hippocampal resection?
Despite cortical language mapping with preservation of visual naming sites from resection, removal of an intact dominant hippocampus will likely result in visual naming decline postoperatively. ANN NEUROL 2010;67:345-352
from the Annals of Neurology
Reduced interhemispheric coherence in dyslexic adults
The deviant pattern of functional connectivity in dyslexics is suggestive of an altered development of neural circuitry that may lead to deficits in magnocellular processing.
from Cortex
Reduced interhemispheric coherence in dyslexic adults
The deviant pattern of functional connectivity in dyslexics is suggestive of an altered development of neural circuitry that may lead to deficits in magnocellular processing.
from Cortex
Overgeneral autobiographical memory in Parkinson’s disease
Autobiographical memory (AM) concerns the ability to remember past events from one’s own life and consists of autobiographical knowledge (personal facts) and autobiographical incidents (personal events). The novelty of this research was to assess both personal factual and personal event AM in Parkinson’s disease (PD) for specified lifetime periods. An autobiographical fluency task was used in which participants were asked to recall personal events and personal facts from five separate lifetime periods. Previous findings as well the brain regions affected in PD lead to the hypothesis that Parkinson’s patients would recall less autobiographical memories especially for the most recent lifetime periods. Sixteen non-demented and non-depressed Parkinson’s patients and sixteen age-education-matched controls participated. The results showed a temporal gradient for the recall of personal events in Parkinson’s patients as they recalled fewer events for recent time periods. The PD group also had more difficulties in recalling autobiographical events rather than an autobiographical knowledge. The difficulty in recalling autobiographical events was characterized by overgenerality, with PD patients failing to generate specific episodic memories.
from Cortex
Language dominance, handedness and sex: Recessive X-linkage theory and test
The possibility is investigated that cerebral dominance for language and handedness share a common X-linkage and that the relation between the two is therefore a function of sex. In particular, an X-linked recessive account is shown to predict an overall configuration of language dominance, handedness and sex within which there is a sex effect in the pattern of language dominance among right-handed but not left-handed people. The recent accurate determination of cerebral dominance among relatively large samples of the general population by means of functional transcranial Doppler ultrasonography makes it possible to test this new theory rigorously, and its parameter-free pattern of predictions is found to be supported.
from Cortex
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