4 T-fMRI study of nonspatial shifting of selective attention: cerebellar and parietal contributions

Regional blood oxygenation in the cerebellum and posterior cerebral cortices was monitored with functional magnetic resonance imaging (fMRI) at four Tesla while 16 normal subjects performed three tasks with identical visual stimulation: fixation; attention focused upon either stimulus shape or color and sustained during blocks of trials (sustained attention); and rapid, serial shifts in attention between stimulus shape or color within blocks of trials (shifting attention). The stimuli were displayed centrally for 100 ms followed by a central fixation mark for 900 ms. Each stimulus was either a circle or a square displayed in either red or green. Attention shifting required switching between color and shape information after each target detection and occurred on average once every three seconds. Subjects pressed a response key upon detecting the target; reaction time and response accuracy were recorded. Two protocols for T2*-weighted echo-planar imaging were optimized, one with a surface coil for the cerebellum alone and the other with a volume coil for imaging both cerebellum and posterior brain structures (parietal, occipital, and part of temporal cortices). Because fMRI of the cerebellum is particularly susceptible to cardiac and respiratory fluctuations, novel techniques were applied to isolate brain activation signals from physiological noise. Functional activation maps were generated for contrasts of 1) sustained attention to color minus fixation; 2) sustained attention to shape minus fixation; and 3) shifting attention minus sustained attention (to color and shape; i.e., summed across blocks of trials). Consistent with the ease of these tasks, subjects performed with >80% accuracy during both sustained attention and shifting attention. Analysis of variance did not show significant differences in false alarms or true hits across either attentional condition. A subgroup of subjects whose performance data were recorded during ten minutes of continuous practice did not show significant changes over time. Both contrasts between the conditions of sustained attention to color or to shape as compared with the fixation condition showed significant bilateral activation in occipital and inferior temporal regions (Brodmann areas 18, 19, and 37). The anterior medial cerebellum was also significantly activated ipsilateral to the finger used for responding. The principal comparison of interest, the contrast between the condition of shifting attention and the condition of sustained attention produced significant and reproducible activation: lateral cerebellar hemisphere (ansiform lobule: Crus I Anterior and Crus I Posterior; left Crus I Posterior); cerebellar folium; posterior superior parietal lobule (R and L); and cuneus and precuneus (R and L).     

Adult age differences in shifting focused attention.

Young and older adults performed a choice response task in which 1 of 2 target letters was presented visually at 1 of 4 display locations. In 2 experiments, the validity of a target location cue and the presence of nontarget characters (distractors) were varied. With target-only displays and 40% cue validity (Experiment 1), the estimated time to shift attention between display locations was essentially 0 msec for both age groups. With 70% cue validity, Experiment 2 demonstrated significant increases in the attention shift time as a function of both increased age and the presence of distractors (asterisks). The results suggest that age-related changes in the shifting of focused attention are minimal except when the processing of nontarget information is required. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention, breadth of attention, and shifting attention in chronic nonparanoid schizophrenics

Compared the performance of 16 normals (hospital employees), 16 chronic schizophrenics, and 16 hospitalized alcoholics in a reaction time task with simultaneous presentation of 2 stimuli and the offset of 1 stimulus as the signal. The stimuli were either of 1 or 2 different modalities, and the signal was known or was not known to the Ss in advance. The data were analyzed according to 2 different models of attentional deficit in chronic nonparanoid schizophrenics. No empirical support could be found for W. E. Broen's (1973) model, which attributes the difficulties that chronic nonparanoid schizophrenics experience in tasks with stimuli of different sense modalities to narrowed attention. On the other hand, M. W, Kristofferson's (see PA, Vol 42:958) findings on slower attentional shifts in chronic schizophrenics could be replicated. As an extension of her work, it is shown that this slower shifting process is confined to cross-modal shifts—no differences being found between normals, chronic schizophrenics, and alcoholics in ipsimodal shifts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Focused and shifting attention in children with heavy prenatal alcohol exposure.

Attention deficits are a hallmark of the teratogenic effects of alcohol. However, characterization of these deficits remains inconclusive. Children with heavy prenatal alcohol exposure and nonexposed controls were evaluated using a paradigm consisting of three conditions: visual focus, auditory focus, and auditory-visual shift of attention. For the focus conditions, participants responded manually to visual or auditory targets. For the shift condition, participants alternated responses between visual targets and auditory targets. For the visual focus condition, alcohol-exposed children had lower accuracy and slower reaction time for all intertarget intervals (ITIs), while on the auditory focus condition, alcohol-exposed children were less accurate but displayed slower reaction time only on the longest ITI. Finally, for the shift condition, the alcohol-exposed group was accurate but had slowed reaction times. These results indicate that children with heavy prenatal alcohol exposure have pervasive deficits in visual focused attention and deficits in maintaining auditory attention over time. However, no deficits were noted in the ability to disengage and reengage attention when required to shift attention between visual and auditory stimuli, although reaction times to shift were slower. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioning of attention as a source of autistic effects in perception.

An experiment and replication are presented to demonstrate the production of autistic effects in a situation creating habitual modes of responding to a problem-solving task. The task was to locate a simple figure within a complex colored figure much like the Gottschaldt Test. The simple figure could be located in 1 of 2 different colored areas within the complex figure. During an intervening training period certain colors were rewarded and other colors punished. The Gottschaldt-like figures were then presented again, and changes in responses were observed. In both experiments Ss showed a significant change toward the rewarded colors, which was explained in terms of subliminal anticipatory responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lateralized human cortical activity for shifting visuospatial attention and initiating saccades

Lateralized human cortical activity for shifting visuospatial attention and initiating saccades. J. Neurophysiol. 80: 2900-2910, 1998. The relation between shifts of visual attention and saccade preparation was investigated by studying their electrophysiological correlates in human scalp-recorded electroencephalogram (EEG). Participants had to make saccades either to a saliently colored or to a gray circle, simultaneously presented in opposite visual hemifields, under different task instructions. EEG was measured within the short interval between stimulus onset and saccade, focusing on lateralized activity, contralateral either to the side of the relevant stimulus or to the direction of the saccade. Three components of lateralization were found: 1) activity contralateral to the relevant stimulus irrespective of saccade direction, peaking 250 ms after stimulus onset, largest above lateral parietal sites, 2) activity contralateral to the relevant stimulus if the stimulus was also the target of the saccade, largest 330-480 ms after stimulus onset, widespread over the scalp but with a focus again above lateral parietal sites, and 3) activity contralateral to saccade direction, beginning about 100 ms before the saccade, largest above mesial parietal sites, with some task-dependent fronto-central contribution. Because of their sensitivity to task variables, component 1 is interpreted as the shifting of attention to the relevant stimulus, component 2 is interpreted as reflecting the enhancement of the attentional shift if the relevant stimulus is also the saccade target, and component 3 is interpreted as the triggering signal for saccade execution. Thus human neurophysiological data provided evidence both for independent and interdependent processes of saccade preparation and shifts of visual attention.     

Motivating autistic children.

A major problem encountered in the field of autism is the children's characteristic lack of motivation. This problem is especially apparent when autistic children attempt to complete learning tasks. The purpose of this study was to investigate the influence of correct vs incorrect task completion on children's motivation to respond to such tasks. Ss were 3 autistic children aged 6 yrs 1 mo, 11 yrs 11 mo, and 12 yrs 3 mo. Results demonstrate that when Ss worked on tasks at which they were typically incorrect, their motivation for those tasks decreased to extremely low levels. However, designing treatment procedures to prompt Ss to keep responding until they completed the tasks correctly served to increase Ss' motivation to respond to those tasks. The implications of these findings are that (a) autistic children's learning handicaps (which typically lead to low levels of correct responding) may result in few or inconsistent rewards for attempting to respond at all, thus decreasing the children's motivation; and (b) treatment procedures designed to keep the children responding until they complete a task correctly may result in coincidental reinforcement for perseverance, increasing the children's motivation to respond to those tasks. Results are discussed in relation to the literature on learned helplessness. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Speech and language in high-functioning autistic individuals.

Verbal individuals with autism provide an important opportunity for investigating the qualitative nature of speech and language impairments in autism. In this study, a psychometric analysis of the language performance of 62 high-functioning autistic (HFA; Full Scale IQ and Verbal IQ?>?70) participants was compared with that of 50 control participants matched for age, IQ, gender, race, education, and family socioeconomic distribution. Tests were included to compare basic procedural linguistic skills with complex, interpretive linguistic skills. The HFA participants did as well as controls on basic procedural language tests, but significantly less well on tests of complex interpretive language abilities. This profile is consistent with neuropsychological reports of generalized deficits in complex information-processing abilities with preservation of basic skills in the same functional areas. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modal attention asymmetry in patients with schizophrenia and bipolar disorder.

This cross-sectional study examined modal attention asymmetries in patients with schizophrenia (n?=?47) and bipolar disorder (n?=?42), as contrasted to a matched-sample comparison group of normal participants (n?=?89). A test of continuous auditory and visual attention was the primary measure. The data were analyzed from 2 experimental conditions: simple modal responses (auditory and visual) and modal switching responses (ipsimodal and cross-modal switching). In the simple modal condition, patients with schizophrenia demonstrated a visual over auditory asymmetry; patients with bipolar disorder showed no differences. In modal switching conditions, however, patients with bipolar disorder displayed a significant auditory over visual asymmetry. No main effect was detected between medications and attention functioning. Results are discussed in light of differentiating these 2 populations on the basis of modal specificity of attention functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptual shifting in chronic alcoholics.

Examined the inferior performance of chronic alcoholics on abstracting tasks. After, administering the Wisconsin Card Sorting Test to 24 alcoholics, it was found that alcoholics took more trials to reach criterion and made more errors than either a group of 24 hospital controls or 24 students. Error pattern analysis indicates that these differences could not be attributed to perseveration. The deficit appeared to be in sustaining a pattern of search and persistence in problem solution. Duration of drinking history was related to impairment of task persistence. Results are consistent with the hypothesis of subcortical organic involvement with a concomitant deficit in conceptual shifting tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning set acquisition in autistic children.

Compared the performance of 19 autistic 5-13 yr olds (mean MA: 4 yrs, 3 mo) on an object discrimination learning set task with that of MA and IQ matched control groups of normal and retarded Ss. All but 2 of the autistic Ss acquired a learning set. About 1/2 of the Ss in each control group also acquired a learning set. However, the mean number of problems to criterion was similar for both the autistic and control groups of Ss who acquired a learning set. It is suggested that the superior performance of autistic Ss on a task which is believed to be related to MA indicates that the MA of these children may be higher than that which is usually obtained with standard measuring techniques. Results provided somewhat equivocal evidence for a relation between MA, IQ, and learning set formation in the normal and retarded Ss. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative learning in patients with cerebellar ataxia

It has been claimed that patients with cerebellar pathology are impaired at associative learning. Patients with cerebellar ataxia (n = 7) were taught a visual-motor associative task. The task was chosen so as to allow comparisons with data currently being collected on the effects of cerebellar lesions on associative learning in monkeys. As a group the patients were as impaired at learning the task as a group of 8 patients with Huntington's disease. When each patient was individually matched with a control of the same age and IQ, some patients with cerebellar ataxia were found to be clearly impaired, but 2 were not. Of the 4 patients who were most clearly impaired, 2 had brainstem pathology and 2 did not. The relevance of these findings is discussed in relation to views concerning the functions of the cerebellum.     

Negativism in verbal and nonverbal responses of autistic children.

Studied negativism in 9 autistic, 9 behavior-disturbed, and 9 normal 5-12 yr olds in 3 different stimulus conditions (verbal requests for verbal responses, verbal requests for nonverbal responses, and nonverbal requests for nonverbal responses). Each condition included 2 tasks, which were requested 15 consecutive times. Ss demonstrated that they could perform the tasks before testing, and their responses were scored according to the similarity between the response and the request. Results demonstrate that the autistic and behavior-disturbed Ss responded similarly, except when requests required verbal responses, in which case the autistic Ss were much more negative. Results suggest applications to diagnostic and therapeutic interventions. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypnotizability and attention.

Developed an attentional explanation of cognitive hypnotic phenomena (e.g., hallucinations and amnesia) based on the ability to shift the pertinence of stored information. It was hypothesized that individuals who were successful at a difficult attentional task would also succeed on cognitive hypnotic items. The Harvard Group Scale of Hypnotic Susceptibility, Form A was used to assess hypnotizability in 42 adult night-school students. To measure pertinence-shift ability, 2 tape recordings made by the same person were played through a single sound source. One tape was designated the target tape. Amount remembered and perceived task ease were summed to form an additive score of task success. Ss above the median on the task were assigned to the good pertinence shift group (GP); those below the median were assigned to the poor pertinence shift group (PP). As predicted, GP subjects passed significantly more cognitive hypnotic items than did PP subjects. When task difficulty and compliance were controlled for, the results remained significant. Results were replicated in a 2nd study with 23 summer-school students. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The shifting definitions of acquiescence.

Asserts that the P.M. Bentler, D.N. Jackson, and S. Messick (see record 1972-21017-001) rebuttal is not responsive to the criticisms leveled earlier. The shifting over the years in the definition of acquiescence and in the kinds of evidence used to bolster the acquiescence interpretation is noted. In particular, it is noted tht highly specific and replicable evidence is required to support the presently advanced hypothesis that acceptance acquiescence importantly influences assessment procedures. The Bentler, et al., view that any evidence of response inconsistency is evidence for their "distinct species of acquiescence" is not accepted. (l8 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Divided attention in youth-onset psychosis and attention deficit/hyperactivity disorder.

The authors used pupillary dilations to test whether divided attention deficits in youth-onset psychosis and attention deficit/hyperactivity disorder (ADHD) were because of limitations in recruitment of cognitive resources or abnormalities in attention allocation. Eight- to 19-year-olds with youth-onset psychosis or ADHD were administered a divided attention test consisting of an auditory digit span (DS) task and a simple visual response time (RT) task. In 4 conditions, participants performed neither (no task), 1 (DS or RT only), or both tasks (dual). Dependent variables were DS accuracy, RT, and pupillary dilation to digits as an estimate of recruitment of cognitive resources. The authors found no evidence for an abnormal attention strategy in either disorder. Instead, results were consistent with the hypothesis that both clinical groups have limitations in resource recruitment. These limitations were more severe in psychosis than in ADHD. Findings indicate that both clinical groups had difficulties in regulating physiological arousal on a moment-to-moment basis in accordance with task demands. Findings also demonstrate the importance of taking into account difficulties that constrain performance on simple tasks before interpreting impairments on complex tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transcranial magnetic stimulation in patients with cerebellar stroke

Animals engage in a startlingly diverse array of behaviours that depend critically on the time of day or the ability to time short intervals. Timing intervals on the scale of many hours to around a day is mediated by the circadian timing system, while in the range of seconds to hours a different system, known as interval timing, is used. Recent research has illuminated some of the neural mechanisms underlying the 'internal clocks' of these two different timing systems in both animals and humans. Therapeutic applications for humans with impairments in either timing system may ultimately result from these endeavours.     

Reduced intracortical facilitation in patients with cerebellar degeneration

Susceptibility patterns of methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium obtained from various hospitals of the Tohoku district were documented. MICs of 6 antimicrobial agents against a total of 480 strains (380 strains were MRSA and 100 were E. faecium) were estimated. All MRSAs were susceptible to vancomycin, teicoplanin and quinupristin/dalfopristin, but all of them were resistant to ampicillin and benzylpenicillin. None of the E. faecium strains were found to be resistant to vancomycin, teicoplanin and quinupristin/dalfopristin. Excluding these, almost all strains of E. faecium were resistant to the remaining drugs. These data suggest that despite the emergence of vancomycin resistance to E. faecium in Europe and in the United States, vancomycin, teicoplanin and quinupristin/dalfopristin will nevertheless provide effective bactericidal activity in the Tohoku area of Japan.     

Predicting neurologic deterioration in patients with cerebellar hematomas

BACKGROUND: Patients with cerebellar hematomas may appear stable but may worsen suddenly. Whether certain clinical or CT scan findings predict worsening is not known. METHODS: We reviewed clinical and neuroimaging data in 72 patients with cerebellar hematomas at the Mayo Clinic from 1973 through 1993 to identify predictive features for neurologic deterioration. Patients presenting in coma and patients with vascular malformations or malignancies were excluded. Data were analyzed using chi-square or Fisher's exact test, with calculation of odds ratios with 95% confidence intervals. Multivariate logistic regression analysis was performed on appropriate variables. RESULTS: Thirty-three patients (46%) deteriorated, with a decrease in level of consciousness, new brainstem signs, or worsened motor response on the Glasgow Coma Scale. Clinical and neuroradiologic predictors for neurologic deterioration at p < 0.05 were admission systolic blood pressure greater than 200 mm Hg, pinpoint pupils and abnormal corneal or oculocephalic reflexes, hemorrhage extending into the vermis, hematoma size more than 3 cm in diameter, brainstem distortion, intraventricular hemorrhage, upward herniation, and acute hydrocephalus. Multivariate analysis demonstrated that hemorrhage located in the vermis (p = 0.03) and acute hydrocephalus (p = 0.0006) on admission CT scanning independently predicted deterioration. CONCLUSION: Patients with a cerebellar vermian hematoma or acute hydrocephalus are at high risk for neurologic deterioration. These patients should be carefully monitored and are more likely to require consideration for neurosurgical intervention.     

Impairment in abstract conceptualization in schizophrenia.

Discusses investigators' disagreements with K. Goldstein's (1940) and L. Vigotsky's (1934) notion that schizophrenics are impaired in abstract conceptualization. Following a review of terminological and theoretical issues, the evidence derived from investigations employing sorting test methods and principles is critically examined. Research findings are interpreted as strongly supporting the Goldstein-Vigotsky position. Critics' dissatisfaction with the early theorists' proposals appears to be based on a misunderstanding of Goldstein's and Vigotsky's ideas and a faulty assessment of the available evidence. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)