Effects of cognitive load on semantic priming in patients with schizophrenia.

Schizophrenic and control participants received 2 blocks of trials in each experiment. In 1 block they were exposed to regular priming trials (doctor-nurse), and in another block a nonlexical probe was presented at prime onset for 40 ms. Regardless of stimulus onset asynchrony (SOA), the schizophrenic patients showed hyperpriming when no distrator was present.

Endogenously generated and visually guided saccades after lesions of the human frontal eye fields.

Abstract Nine patients with chronic, unilateral lesions of the dorso-lateral prefrontal cortex including the frontal eye fields (FEF) made saccades toward contralesional and ipsilesional fields. The saccades were either voluntarily directed in response to arrows in the center of a visual display, or were reflexively summoned by a peripheral visual signal. Saccade latencies were compared to those made by seven neurologic control patients with chronic, unilateral lesions of dorsolateral prefrontal cortex sparing the FEF, and by 13 normal control subjects.

Capacity demands of automatic processes in semantic priming.

In three experiments, we examined the effects of prime-target stimulus onset asynchrony (SOA) and the proportion of related primes and targets (relatedness proportion, or RP) on semantic priming when the prime was either named or was searched for a specific letter. In Experiment 1, with an RP of .50, priming occurred at SOAs of 240 and 840 msec when the prime was named, but no priming was found at either SOA when the prime was searched for a letter.

Disinhibition of automatic word reading in Parkinson's disease.

The Stroop phenomenon was studied in patients with early and late onset Parkinson's disease (PD) and in normal controls to examine the effect of this disease on generating and controlling automatic mental processes. In the Stroop task subjects are presented with color or neutral words in various colors and asked to ignore the word and name its color as fast as possible. We examined the facilitory and interference effects of the irrelevant word upon naming the color by using computerized version of the Stroop test.

Dissociation of lexical and semantic aspects in word processing.

We present data and review studies that show a dissociation between identity and semantic priming. This dissociation appears as a result of employing certain prime tasks, adding cognitive load or following brain damage. Such a dissociation suggests that while activation of the word's representation is obligatory, the spread of activation to related concepts is not.

Differential effects of semantic and identity priming in patients with left and right hemisphere lesions.

Abstract Patients with single brain lesions in the anterior or posterior left and right hemispheres and a group of controls were studied in two priming experiments. The first experiment employed associative pairs (DOCTOR-NURSE) and the second employed identical pairs (NURSE-nurse). Short and long prime-target stimulus onset asynchronies (SOAs) (i.

Controlling Stroop effects by manipulating expectations for color words.

An important characteristic of automatic processing is its uncontrollability. The Stroop phenomenon is regarded as a prototypical example of this characteristic of automatic processing, hence, the Stroop effect should not change when the percentages of color words versus neutral stimuli are manipulated to induce controlled processing. We found that Stroop interference decreased as the percentage of color words increased.

Extrageniculate contributions to reflex visual orienting in normal humans: a temporal hemifield advantage.

Evidence is presented that the phylogenetically older retin-otectal pathway contributes to reflex orienting of visual attention in normal human subjects. The study exploited a lateralized neuroanatomic arrangement of retinotectal pathways that distinguishes them from those of the geniculostriate system; namely, more direct projections to the colliculus from the temporal hemifield. Subjects were tested under monocular viewing conditions and responded to the detection of a peripheral signal by making either a saccade to it or a choice reaction time manual keypress.

Automatic processes in lexical access and spreading activation.

The semantic priming effect can be reduced or eliminated depending on how the prime word is processed. The experiments reported here investigate this prime task effect. Two experiments used identity and semantic priming tasks to determine whether the prime word is encoded at a lexical level under letter-search conditions.

Perceived temperamental characteristics and regulation of physiological stress: a study of wheezy babies.

Explored prospectively were the temperamental dimensions involved in the modulation of wheeziness in infancy. Subjects were 69 infants, 4 to 8 months old, referred to the emergency room because of wheeziness, and a control group of 30 infants, 4 to 8 months old, referred to the emergency room because of an acute illness other than wheeziness. Infant respiratory clinical score for wheeziness was registered and the Revised Infant Temperament Questionnaire and a demographic questionnaire were completed.

Performance consequences of two types of stereo picture compression.

Two algorithms for stereo picture compression were evaluated. According to one algorithm, consistent with the fusion theory of depth perception, the reduction of information in the two pictures was about equal. The other algorithm, consistent with the suppression theory of depth perception, was based on very deep compression of one picture and minimal reduction of information in the second picture.