Aspects of temporal information processing: A dimensional analysis

A major controversy in the field of prospective temporal information processing refers to the question of whether performance in various temporal tasks can be accounted for by the general assumption of an internal clock rather than by distinct, task-specific timing mechanisms. Therefore, the present study was designed to identify dimensions of temporal information processing. For this purpose, 120 subjects performed eight psychophysical temporal tasks. Correlational and principal factor analyses suggested a common pacemaker-based interval timing mechanism involved in duration discrimination, temporal generalization, and temporal order judgment. On the other hand, rhythm perception and perceived simultaneity/successiveness appeared to be controlled by task-specific processes unrelated to interval-based timing.     

Evidence for episodic retrieval of inadequate prime responses in auditory negative priming

Four experiments are reported in which the mechanisms underlying auditory negative priming were investigated. In Experiments 1A and 1B, preprime-prime intervals and prime-probe intervals were manipulated. The ratio between the 2 intervals determined the size of the negative priming effect. Results are compatible with the episodic retrieval account, according to which the retrieval of inappropriate response information associated with the previous distractor slows down responding when that stimulus becomes the target. Experiment 2 tested a variant of this account, according to which the retrieval of the prime response rather than the retrieval of nonresponse information interferes with responding. Consistent with this variant, participants erroneously responded with the prime response more frequently in the ignored repetition condition than in the control condition. Experiment 3 replicated this finding and generalized it to the visual modality. The authors conclude that the retrieval of the inappropriate prime response is a determinant of the negative priming phenomenon.     

ERP correlates of auditory negative priming

Negative priming refers to slowed down reactions when the distractor on one trial becomes the target on the next. Following two popular accounts, the effect might be due either to inhibitory processes associated with the frontal cortex, or to an ambiguity in the retrieval of episodic information. We used event-related brain potentials (ERPs) to identify the processing stage primarily associated with negative priming. In an auditory categorization task, reactions in negative priming trials were compared to reactions in a standard control (unrelated primes and probes) and a repetition control (attended prime=ignored probe) condition. Reactions were slower for negative priming than for standard control (Delta32 ms) and repetition control trials (Delta64 ms). The corresponding ERP effect was reflected in an attenuation of a sustained parietal positivity extending from 300 to 600 ms. Because corresponding ERP components were found to be sensitive to stimulus recognition and familiarity, the results may be interpreted to support an episodic retrieval account of negative priming.     

Syntactic frame and verb bias in aphasia: plausibility judgments of undergoer-subject sentences

This study investigates three factors that have been argued to define "canonical form" in sentence comprehension: Syntactic structure, semantic role, and frequency of usage. We first examine the claim that sentences containing unaccusative verbs present difficulties analogous to those of passive sentences. Using a plausibility judgment task, we show that a mixed group of aphasics performed significantly better on unaccusatives than on passives. We then turn to the observation that passives are generally harder than actives for aphasics. We show that this effect is modulated by lexical bias, i.e., the likelihood that a verb appears in a given syntactic structure: Passives of passive-bias verbs were significantly easier than passives of active-bias verbs. More generally, sentences whose structure matches the lexical bias of the main verb are significantly easier than sentences in which structure and lexical bias do not match. These findings suggest that "canonical form" reflects frequency and lexical biases.     

Hemispheric lateralization of the EEG during wakefulness and REM sleep in young healthy adults

EEG recordings confirm hemispheric lateralization of brain activity during cognitive tasks. The aim of the present study was to investigate spontaneous EEG lateralization under two conditions, waking and REM sleep. Bilateral monopolar EEG was recorded in eight participants using a 12-electrode montage, before the night (5 min eyes closed) and during REM sleep. Spectral analysis (0.75-19.75 Hz) revealed left prefrontal lateralization on total spectrum amplitude power and right occipital lateralization in Delta activity during waking. In contrast, during REM sleep, right frontal lateralization in Theta and Beta activities and right lateralization in occipital Delta activity was observed. These results suggest that spontaneous EEG activities generated during waking and REM sleep are supported in part by a common thalamo-cortical neural network (right occipital Delta dominance) while additional, possibly neuro-cognitive factors modulate waking left prefrontal dominance and REM sleep right frontal dominance.     

Frequency effects with visual words and syllables in a dyslexic reader

The present study investigated the nature of the inhibitory syllable frequency effect, recently reported for normal readers, in a German-speaking dyslexic patient. The reading impairment was characterized as a severe deficit in naming single letters or words in the presence of spared lexical processing of visual word forms. Three visual lexical decision experiments were conducted with the dyslexic patient, an unimpaired control person matched to the patient and a control group: Experiment 1 manipulated the frequency of words and word-initial syllables and demonstrated systematic effects of both factors in normal readers and in the dyslexic patient. The syllable frequency effect was replicated in a second experiment with a more strictly controlled stimulus set. Experiment 3 confirmed the patient's deficit in activating phonological forms from written words by demonstrating that a pseudohomophone effect as observed in the unimpaired control participants was absent in the dyslexic patient.     

Emotion recognition in stroke patients with left and right hemispheric lesion: results with a new instrument-the FEEL Test

The aim of this study was to investigate the effect of a stroke event on people's ability to recognize basic emotions. In particular, the hypothesis that right brain-damaged (RBD) patients would show less of emotion recognition ability compared with left brain-damaged (LBD) patients and healthy controls, was tested. To investigate this the FEEL Test (Facially Expressed Emotion Labeling) was used, a computer based psychometric test that assesses one's ability to recognize facially displayed basic emotions via a forced-choice paradigm. We examined 24 patients after a stroke event (13 RBD, 11 LBD) and compared them with a matched group of healthy controls (HC, n=29). Results showed that the stroke patients performed significantly worse in the FEEL Test than did HC (p<.001). This deficit was especially evident for negative emotions (fear, anger, sadness, and disgust). In contrast to other studies we did not find any significant differences between RBD and LBD patients in their ability to recognize emotions. These results indicate that a stroke event has a negative effect on the recognition of facially displayed emotions but suggest that this effect is apparently not dependent on the side of the brain damage.     

Are you better than me? Social comparisons in carrion crows (Corvus corone)

Animal Cognition - Comparing oneself to others is a key process in humans that allows individuals to gauge their performances and abilities and thus develop and calibrate their self-image. Little...     

Recovery of intellectual function after a brain injury: a comparison of longitudinal and cross-sectional approaches

The goal of this study was to investigate recovery of intellectual function as a function of age at the time of a brain lesion. Participants with unilateral cortical lesions were selected from an initial data base of 685 patients. Ninety-six participants formed a longitudinal cohort for a first study and 314 participants formed a cross-sectional cohort for a second study. Participants of each study were split into two age groups according to the age at the time of the lesion: (1) before 7 years, (2) 7 years or more. Results showed a significantly different recovery profile as a function of age in the longitudinal study. Older participants manifested recovery on VIQ and PIQ, while younger participants presented stable profiles. The longitudinal and cross-sectional studies revealed differing recovery profiles as a function of age. Results are discussed in the context of the Kennard principle and with regard to the methodological approaches.