An assessment of daily production and significance of thyroidal secretion of 3, 3'', 5''-triiodothyronine (reverse T3) in man

The present study was designed to determine if frequency of repetitive photic stimulation could affect the response rate of an operant upon which such stimulation was made contingent. To test this hypothesis, we trained retarded and autistic children, equated for mental age, to pull a lever to obtain photic stimulation of different frequencies. It was found that (a) response rates of autistic children were related to the frequency of stimulation, while retarded children showed no such consistency. (b) The two groups did not differ in the average duration of time they engaged in stereotypies. (c) During a subsequent extinction session, two autistic children ceased responding, but one of two retarded children did not. (d) Noncontingent photic stimulation suppressed a food-motivated operant in one autistic child. These results were interpreted as evidence for frequency-dependent properties of repetitive visual feedback in autistic children. In addition, support was given to the position that performance deficits in autistic children correlating with the occurrence of stereotypies result from competition of different sources of reinforcement.     

Selective responding by autistic children to multiple sensory input.

Reinforced 6 autistic, 5 retarded, and 5 normal children for responding to a complex stimulus involving the simultaneous presentation of auditory, visual, and tactile cues. After discrimination was established, elements of the complex were presented separately to assess which aspects of the complex stimulus had acquired control over the S's behavior. It was found that (a) the autistics responded primarily to only 1 of the cues, normals to all 3 cues, and retardates to 2 cues; and (b) conditions could be arranged such that a cue which had remained nonfunctional when presented in association with other cues could be established as functional when trained separately. Data fail to support theories that any 1 sense modality is impaired in autistic children. When presented with a stimulus complex, autistic Ss' attention was overselective. Findings are related to the literature on selective attention. Since much learning involves contiguous or near-contiguous pairing of 2 or more stimuli, failure to respond to 1 of the stimuli may be an important factor in the development of autism. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electroencephalographic signs of compensatory reactions following stroke with location of the focus in the right and left cerebral hemispheres

The authors studied 41 patients with acute disorders of cerebral circulation, a focus in the right hemisphere and 14 with foci in the left hemisphere. The traits of compensatory reactions were studied according to the background and functional EEG, depending upon the severity, stage, localization and lateralization of focal vascular brain lesions. The authors indicate to a rigidity of clinical and EEG changes in patients with right hemispheric localization of the focus which is explained by the authors by disturbances of the higher cortical functions in these patients.     

Efficiency of callosal transfer and hemispheric interaction.

The corpus callosum (CC) is essential to hemispheric interaction, but it is unclear how individual callosal properties affect interaction between the cerebral hemispheres. A number of studies have demonstrated some relationship between morphology or structure of the CC and measures of hemispheric interaction. However, to the authors' knowledge, none of these studies has been able to show a clear, direct relationship between a behavioral measure of transfer speed through the CC, interhemispheric transfer time (IHTT), and a behavioral measure of hemispheric interaction. Eighty participants were tested over 6 sessions on 2 tasks assessing IHTT and hemispheric interaction. The Poffenberger paradigm was used to measure IHTT, and a divided split-visual-field letter-matching task was used to assess hemispheric interaction. A significant correlation that could not be accounted for by other factors such as functional lateralization, handedness, age, sex, or attention was found between these 2 measures. These results are discussed in relation to CC morphology and structure and functional and structural hemispheric lateralization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Language lateralization of Chinese-English bilingual patients with temporal lobe epilepsy: A functional MRI study.

Functional MRI was used to examine language lateralization of Chinese characters and English words associated with temporal lobe epilepsy (TLE) in Chinese-English bilinguals with left or right TLE. The results suggest that the neural basis of processing Chinese and English seems to be different, as normal controls demonstrated left hemispheric lateralization in reading English words but bi-hemispheric lateralization in reading Chinese characters. This difference in the neural bases of Chinese and English processing was found to affect the patterns in change-of-language processing associated with TLE. That is, whereas left-TLE patients were more likely than right-TLE patients to demonstrate a bi-hemispheric language involvement in reading English, both left- and right-TLE patients demonstrated primarily bilateral hemispheric involvement for reading Chinese characters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of diagnosis, race, and puberty on platelet serotonin levels in autism and mental retardation

OBJECTIVE: To reevaluate platelet serotonin (5-HT) levels in autism, measuring and controlling for effects of race and puberty. The specificity of hyperserotonemia for autism versus cognitive impairment is also assessed. METHOD: Platelet 5-HT levels were measured in 77 individuals, aged 2 through 37 years, with autistic disorder; 65 normal controls; and 22 mentally retarded or otherwise cognitively impaired (MR/CI) prepubertal children. Effects of diagnosis, race, and pubertal status were evaluated by analysis of variance in separate pre- and postpubertal groups. 5-HT levels were expressed as ng/mL blood and ng/microL platelet volume. RESULTS: Among prepubertal children, significant effects of diagnosis (ng/mL; F2,109 = 5.9, p = .004) and race (F2,109 = 14.7, p < .0005) were found. Autistic youngsters had significantly higher 5-HT concentrations than controls, although the elevation (25%) was less than typically reported; MR/CI children had levels very similar to those of controls. White children had significantly lower 5-HT levels than black or Latino youngsters, regardless of diagnosis. Diagnosis and race effects were nonsignificant in the postpubertal group. Postpubertal subjects had lower 5-HT concentrations than prepubertal subjects (ng/mL; F1,114 = 28.5, p < .0005). CONCLUSIONS: The data underscore the importance of matching for race and pubertal status in neuropsychiatric research and suggest that the prevalence of hyperserotonemia in autistic individuals may have been overestimated because of a failure to control for both variables. Hyperserotonemia was not found in MR/CI youngsters without autistic features.     

Cognitive processes in normal and hyperactive children and their response to amphetamine treatment.

14 normal (mean age 10.1 yrs) and 15 hyperactive (mean age 9.4 yrs) children were compared on cognitive tasks following placebo or amphetamine administration (.5 mg/kg) in a double-blind crossover study. A no-treatment control group of normal children who were matched with the hyperactive Ss on age, IQ, and socioeconomic status were also tested on the cognitive measures. In the undrugged state, normals remembered more information under free-recall retrieval conditions than did hyperactives; cued recall did not differentiate between the 2 groups. Both normals and hyperactives demonstrated similar, amphetamine-related increases in the recall of semantically and acoustically processed words. This enhancement of cognition occurred along with improvements in attention but was independent of such attentional changes. The pattern of amphetamine-induced changes in cognition is generally similar in normal and hyperactive children. Differences in response to amphetamine that do appear involve components of cognition that distinguish these children in the undrugged state (e.g., semantic processing, organization in recall, and free retrieval of information). (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reverse micellar extraction of antibiotics from aqueous solutions

PURPOSE: We reviewed 1,360 EEG reports for all patients studied in two different neurophysiology laboratories during 1 calendar year to determine whether epileptiform discharges have a hemispheric dominance. METHODS: Both inpatients and outpatients, with or without epilepsy, were included. RESULTS: Ninety-four records (6.9%) demonstrated generalized epileptiform activity. Of 95 EEG reports indicating spikes solely from one hemisphere, spikes arose from the left in 61 and from the right in 34. Among 50 other records with bilateral independent spikes with lateralization, 40 were left hemisphere dominant and 10 were right hemisphere dominant. CONCLUSIONS: These findings raise the possibility that the left cerebral hemisphere may generate focal epilepsy more frequently than the right.     

Human long-latency responses to brief interaural disparities of intensity

The electroencephalographic responses to abrupt changes in interaural differences of time (ITD) and intensity (IID) should provide important information on the dynamic characteristics and integrity of the binaural mechanisms detecting the azimuthal shifts of a sound image. However, a change in either or both of these cues to sound lateralization would stimulate not only the binaural mechanisms but also the monaural ones. There are several reports evidencing that in the case of ITD changes this problem can be overcome by using time-shifted noise or repetitive clicks. Any change in IID, however, will inevitably have a stimulating effect also on purely monaural mechanisms. Therefore, the stimulation techniques described in the literature so far for recording the long-latency responses related to IID mechanism cannot be regarded as being specific for binaural mechanisms. We used dichotically presented 100/s click trains which were amplitude modulated with a random sequence of 50 or 100 ms square wave-intervals, so that the sound intensities at the two ears simultaneously alternated between 60 dB and 80 dB levels except during brief periods of time (50 ms) in which the interaural intensity balance was impaired, leading to an IID of 20 dB every 2 s. Owing to the fact that the cortical mechanisms remain unresponsive to repetitive stimuli presented with intervals shorter than a certain recovery period, this stimulus did not evoke any significant potential when it was presented monotically or diotically, yet it could produce lateral sound image shifts and therefore evoke pronounced long-latency responses when presented dichotically. The main components N1 and P2 of these shift responses and those of the pip responses, also recorded from the same subjects, were compared with respect to their midline distributions and hemispheric or bilateral asymmetries. The significant differences found between the shift and pip responses indicated that those evoked by the IID stimulation we designed should not be considered simply as a non-specific vertex potential.     

Neuro-ophthalmic complications of acute varicella

In 16 patients suffering from migraine without aura, we examined quantitative EEG and steady-state visual evoked potentials (SSVEPs) at 27 Hz stimulation during the critical phase of migraine and in attack-free periods. The main spontaneous EEG abnormalities found during the critical phase were the slowing and asymmetry of the dominant frequency in the alpha range. The amplitude of the SSVEP F1 component was significantly reduced during the attack phase compared with the intercritical phase; in the latter condition the visual reactivity to 27 Hz stimulus was increased over almost the entire scalp compared with normal subjects. The EEG abnormalities confirm a fluctuating modification of alpha activity during the migraine attack, probably related to a functional disorder. The suppression of visual reactivity during the migraine attack could be related to a phenomenon of neuronal depolarization such as spreading depression, occurring in a situation of central neuronal increased excitability predisposing to migraine attacks.     

Stimulation seeking in antisocial preadolescent children.

Determined whether antisocial preadolescent male children display more stimulation seeking than normals or neurotics in a situation intentionally designed to be boring. Ss were asked to view a monotonous sequence of photographic slides. They were allowed to control the rate of slide presentation, and viewing time was taken as an inverse measure of stimulation seeking. Results support the prediction that antisocial children would exceed normals and that normals would exceed neurotics in stimulation seeking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parental perception of emotional expressiveness in children with autism.

Parents' perceptions of their children's emotional expressiveness, and possible bases for these perceptions, were investigated in a study comparing older, nonretarded autistic and normal children and in another study comparing young autistic, mentally retarded, and normal children. Both groups of autistic children were perceived as showing more negative emotion and less positive emotion than comparison children. In the younger sample, parental perceptions correlated with the children's attention and responsiveness to others' displays of emotion in 2 laboratory situations. Findings contradict the view that autism involves the "absence of emotional reaction." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Letters as spatial-oriented shapes and/or graphemic signs: a developmental study of left- and right-handed girls during the period of learning to read

This study is concerned with the problem of hemispheric specialization and/or cooperation in relation to development and manual laterality. The processing of alphabetic signs and its relationship to interhemispheric transfer and functional hemispheric asymmetries were studied by comparing left- and right-handed girls during acquisition of reading. The children perform matching tasks with letters having different orientations and with meaningless forms having the same orientations as the letters. Each subject performed the matching under three conditions: right/left intermanual transfer, left/right intermanual transfer, and dichaptic exploration. Results indicate: (1) A differentiated development between the two handednesses. (2) The functional lateralization change was different for left- and right-handed girls, a greater effect of the ability to identify the letter on matching tasks was observed for the right-handed children than for the left-handed children. These last results are discussed with regard to inter-hemispheric transfer and functional hemispheric asymmetry changes. We hypothesized a strategy difference between left- and right-handed girls and a difference in their ability to change their cognitive strategy (left-handers continue to favor a spatial coding with letters).     

Psychobiological heterogeneity of familial and sporadic schizophrenia

BACKGROUND: Although schizophrenia is presumed to be heterogeneous, there has been limited success distinguishing familial from sporadic cases. We used psychobiological measures to examine heterogeneity, as they may be closer to neurobiology than symptoms. Smooth pursuit eye movement quality (SPEM) and dichotic listening (DL) tests to tones and words were used to assess hemispheric laterality asymmetry. METHODS: Forty-six research unit patients participated in assessments of family history (FH) and physiological measures. FH was categorized by three exclusive groups: FH-1 patients had a chronic schizophrenia-related psychosis in a first-degree relative, FH-2 had it in second-degree relative, and FH-3 had no family member with a reoccurrence. RESULTS: Analysis of variance showed a significant group difference for SPEM and DL tones. SPEM was significantly worse in all three schizophrenia groups than for the normal comparison subjects. Among the schizophrenia groups, the nonfamilial group (FH-3) had the worst SPEM quality, FH-2 had intermediate quality, and FH-1 had the best quality. Conversely, only the nonfamilials (FH-3) had normal right hemispheric lateralization for tones, whereas familials did not, and FH-2 again had intermediate values. The lateralization quotient for DL words did not significantly differ among the groups. CONCLUSIONS: SPEM was affected most in sporadic, not familial schizophrenia, whereas dichotic listening was most affected in familial schizophrenia. This double dissociation supports the utility of the familial/sporadic distinction and suggests that etiological factors in different forms of schizophrenia may impact principally on distinct neurobiological substrates, despite similar patient phenomenology.     

Overselectivity, developmental level, and overtraining in autistic and normal children

Thirteen autistic children were compared to 13 normal children matched to them in mental age, on performance of a visual discrimination task. Form, color, and size were relevant and redundant cues. The groups did not differ significantly in mean trials to reach criterion or in breadth of learning, and both groups increased their breadth of learning after 50 trials of overtraining. Form was preferred to color and size by both autistic and normal children. Within each group, rank on mental age was highly correlated with rank in breadth of learning. Verbal and nonverbal autistic children did not differ in breadth of learning or in dimensional preference. Even nonverbal autistics equaled the performance of their normal controls. Our results suggest that overselective attention is better understood as part of a general developmental lag in cognition in autistic children than as a specific deficit underlying psychotic behavior.     

Interhemispheric EEG coherence in men with abnormal sexual behavior

Interhemispheric interactions were examined in individuals with abnormal sexual behaviour by means of method of evaluation of coherent EEG properties in symmetric points of two hemispheres in different levels of awakening and in elaboration of cognitive tests related with preferential activation of one of two hemispheres. It was determined that EEG of the individuals who had committed sexual deliquency and had the signs of paraphilia was characterized by diffuse elevation of the degree of interhemispheric coherence in alpha-activity in the state of both passive and active awakening and by its local elevation in theta-activity. The results obtained might testify to the disorders either in cortical-subcortical interactions and in the cortical processes and permitted to suppose the decrease of degree of functional hemispheric lateralization in persons with paraphilias.     

Restricted stimulus control and inferred attentional deficits in autistic and retarded children.

Seven autistic, 7 Down's syndrome, and 7 normal children (mean CAs 83.1, 65.7, and 45.3 mo; mean MAs 42, 36.7, and 50.6 mo; mean IQs 46.3, 45.3, and 98.6, respectively) were initially trained on a single dimension, simultaneous match-to-sample problem. Following criterion performance, each S's simultaneous matching of 4 new dimensions (2 attributes/dimension) was assessed in order to clarify the relation between autism, retardation, and attentional deficits. The Down's syndrome Ss matched significantly fewer attributes than did the autistic and normal Ss, who were equivalent in their performances. Based on these results, it is suggested that Down's syndrome and not autistic children suffer from attentional deficits. Performance in this simultaneous match-to-sample paradigm, which better assesses attentional mechanisms, was related to performances in previous serial and simultaneous discrimination paradigms, in which autistic children reportedly evidenced overselective attention. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single photon emission computed tomography-EEG relations in temporal lobe epilepsy

The role of single photon emission computed tomography (SPECT) as an independent confirmation test in presurgical evaluation of medically intractable temporal lobe epilepsy has not been critically investigated. Because spreading ictal discharges may cause a concomitant increase of cerebral blood flow in remote cerebral regions, a careful analysis of peri-injection EEG patterns and their relation to ictal SPECT may be important in evaluating the reliability of ictal SPECT. Both interictal and ictal EEG and SPECT were reviewed in 19 patients with temporal lobe epilepsy who achieved a successful seizure outcome after surgery. Patients were divided into unitemporal and bitemporal groups according to the lateralization of interictal epileptiform discharges (IED). Ictal EEG features were classified into lateralized and nonlateralized groups. The concordance between SPECT and EEG lateralizations was examined in each patient and correlated to the documented epileptogenic temporal lobe. Interictal SPECT correctly lateralized in eight of nine patients with unitemporal IED and in five of 10 patients with bitemporal IED. Ictal SPECT was highly concordant with the peri-injection ictal EEG but correctly lateralized the epileptogenic region in only 11 of 19 patients. When both pre- and postinjection EEG epochs lateralized ipsilaterally, all ictal SPECT images showed concordant lateralization. If pre- and postinjection EEG epochs were either different in lateralization or nonlateralization, ictal SPECT images often showed complex patterns of cerebral perfusion with a high incidence of false lateralization. Interictal SPECT was more sensitive and reliable in patients with unitemporal IED than in patients with bitemporal IEDs. Ictal SPECT was closely related with peri-injection EEG epochs but with frequent false lateralization. The role of ictal SPECT as an independent confirmation test in presurgical evaluation should be reappraised.     

Video-task assessment of stimulus novelty effects on hemispheric lateralization in baboons (Papio papio).

In a video matching-to-sample task, we examined the effects of stimulus novelty on hemispheric specialization in 6 baboons (Papio papio). After familiarization with a set of 8 composite stimuli, baboons were tested with either familiar stimuli paired in a novel way, novel stimuli composed of familiar elements, or novel stimuli differing in structure from the previous stimuli. Analyses focused on visual field differences between initial and later trials in each condition. The findings reflected shorter left than right visual half-field response times for initial but not for terminal trials. With regard to accuracy, scores were smaller for the initial trials than for the later ones, but there was no significant difference between left and right visual half-fields. Overall, this study suggests that hemispheric lateralization changes with practice and that the right hemisphere of the baboon plays a critical role in the processing of novelty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive and language skills in autistic, mentally retarded, and normal children.

Compared the sensorimotor skills and play behaviors of 16 normal 16–25 mo old children, 16 mentally retarded children (CA 32–80 mo, MA 17–38 mo), and 16 autistic children (CA 39–74 mo, MA 18–38 mo) to identify deficits in object knowledge specific to autism. There were no differences in sensorimotor skills between the 3 groups except that the autistic Ss were deficient in the capacity to imitate gestures and vocalizations. Autistic Ss showed less diverse functional play, particularly directed toward dolls, and less symbolic play both spontaneously and after cuing. Although functional and symbolic play and the ability to imitate were correlated with receptive language for all 3 groups, sensorimotor skills were associated with receptive language only for the normal and the mentally retarded groups. The observation that autism involves deficits in certain cognitive concepts and not others suggests that representational thought may be manifested in 2 systems, only one of which is impaired in the autistic child. Another hypothesis is that the cognitive deficits manifested by autistic children may be related to their impaired social development, because all the areas of cognitive deficit involve significant social components. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)