A controlled study of formal thought disorder in children with autism and multiple complex developmental disorders

Along with well-defined categories in classification systems (e.g., autistic disorders and attention-deficit/hyperactivity disorder (ADHD)), practitioners are confronted with many children showing mixed forms of developmental psychopathology. These clusters of symptoms are on the borderlines of more defined categories. The late Donald Cohen proposed heuristic criteria to study a group defined by impaired social sensitivity, impaired regulation of affect, and thinking disorders under the name multiple complex developmental disorders (MCDD). Although these children meet criteria for pervasive developmental disorder--not otherwise specified (PDD-NOS), they have additional important clinical features, such as thought disorder. After highlighting similarities and differences between MCDD and comparable groups (e.g., multidimensionally impaired children), this paper presents the findings of a study comparing formal thought disorder scores in children with MCDD to children with autism spectrum diagnoses, such as autistic disorder (AD), and to children with nonspectrum diagnoses, such as ADHD and anxiety disorders. METHODS: Videotaped speech samples of four groups of high-functioning, latency-aged children with MCDD, AD, ADHD, and anxiety disorders were compared to a control group of normal children using the Kiddie Formal Thought Disorder Rating Scale (K-FTDS). RESULTS: High formal thought disorder scores were found both in the AD and MCDD groups, low rates in the ADHD groups, and no thought disorder in the anxiety disorder and normal control groups. The severity of formal thought disorder was related to verbal IQ scores within the AD and MCDD groups. CONCLUSION: High formal thought scores in children with complex developmental disorders, such as AD and MCDD, appear to reflect impaired communication skills rather than early signs of psychosis.     

Uncoupling of hormone-dependence from chaperone-dependence in the L701H mutation of the androgen receptor

The mechanisms underlying androgen receptor (AR)-mediated progression of prostate cancer following androgen ablation have yet to be fully determined. On this basis we screened naturally occurring mutants of human AR for hormone-independent activity using a yeast model system. An initial screen of 43 different mutants revealed that ARs having a Leu701His mutation (AR(L701H)) exhibited hormone-independent activation of a lacZ reporter gene. The AR(L701H) mutant bound dihydrotestosterone to a similar extent as did wild type AR, although its ability to be induced by hormone for transactivation was reduced substantially. Subsequent studies focused on the dependence of AR(L701H) on molecular chaperones for folding to the active state. We found that AR(L701H) was highly dependent on Hsp90 for its hormone-independent activation, suggesting that this chaperone functions in AR(L701H) folding. However, the mutant did not respond specifically to increased levels of FKBP52, suggesting that this chaperone functions at the hormone-dependent activation stage in the folding process. Further studies of AR(L701H) in PC3 cells suggested that this mutant is prohibited from hormone-independent transactivation in mammalian cells. However, basal expression of a reporter gene by AR(L701H) was not impaired by the presence of 17-allylamino-17-demethoxygeldanamycin as was wild type AR, suggesting differential interactions of these receptors with molecular chaperones in animal cells.     

Distinct patterns of brain oscillations underlie two basic parameters of human maze learning.

We examine how oscillations in the intracranial electroencephalogram (iEEG) relate to human maze learning. Theta- band activity (4-12 Hz in rodents; 4-8 Hz in humans) plays a significant role in memory function in rodents and in humans. Recording intracranially in humans, we have reported task-related, theta-band rhythmic activity in the raw trace during virtual maze learning and during a nonspatial working memory task. Here we analyze oscillations during virtual maze learning across a much broader range of frequencies and analyze their relationship to two task variables relevant to learning. We describe a new algorithm for detecting oscillatory episodes that takes advantage of the high signal-to-noise ratio and high temporal resolution of the iEEG. Accounting for the background power spectrum of the iEEG, the algorithm allows us to directly compare levels of oscillatory activity across frequencies within the 2- to 45-Hz band. We report that while episodes of oscillatory activity are found at various frequencies, most of the rhythmic activity during virtual maze learning occurs within the theta band. Theta oscillations are more prevalent when the task is made more difficult (manipulation of maze length). However, these oscillations do not tend to covary significantly with decision time, a good index of encoding and retrieval operations. In contrast, lower- and higher-frequency oscillations do covary with this variable. These results suggest that while human cortically recorded theta might play a role in encoding, the overall levels of theta oscillations tell us little about the immediate demands on encoding or retrieval. Finally, different patterns of oscillations may reflect distinct underlying aspects of memory function.     

Aphasic disorders of syntactic comprehension and working memory capacity

Abstract

Miyake, Carpenter, and Just (1994) present results of two sentence comprehension experiments using RSVP in normal subjects, which they say simulate important features of aphasic patients' comprehension of syntactic structures. On this basis, they claim that normal and aphasic subjects' performance represents a continuum of limitations in working memory capacity. In this paper, we argue that the Miyake et al. data do not resemble the performance of aphasic patients in crucial respects, and that their results provide evidence for the opposite conclusion…namely, that the processing resource system that underlies syntactic processing and that is affected in aphasia is substantially separate from the one used for other verbal tasks, such as reasoning and problem solving, which is tested In tasks such as the Daneman and Carpenter (1980) reading span task.     

A case study of reproduction conduction aphasia I: Word production

Abstract

We present data regarding word production and short-term auditory verbal memory in a patient, RL, who falls into the class of “reproduction conduction aphasia”. RL shows similar disturbances of single word production in naming, repetition, and reading aloud. He shows qualitatively similar and quantitatively worse performance in repetition of nonwords. His STM is good on tasks (pointing and recognition) which do not require verbal output. We conclude that his disturbance lies at a stage of word production, rather than in the process of perception or in the transfer of perceived representations to motor planning processes. We discuss existing models of the deficit in conduction aphasia and models of word recognition and production in the light of RL's performance, and we argue that none can account for the pattern of his results. We suggest that a model which incorporates two stages of phonological representations, in accordance with contemporary linguistic theory, is supported by the pattern of RL's performances.     

Gastric parietal cell acid secretion in mice can be regulated independently of H/K ATPase endocytosis

BACKGROUND & AIMS: Gastric parietal cells secrete acid into the lumen of the stomach. They express a proton pump, the gastric H(+)/K(+) ATPase, the activity of which is tightly regulated. The H(+)/K(+) ATPase traffics between an intracytoplasmic compartment (tubulovesicles) in quiescent parietal cells and the apical plasma membrane in activated cells. These trafficking events are considered to contribute to the control of acid secretion by modulating access to apical K(+) and Cl(-) conductances that are required for transmembrane H(+) ion transport by the H(+)/K(+) ATPase. Here, we have determined whether the control of acid secretion in vivo requires membrane trafficking of the H(+)/K(+) ATPase. METHODS: We developed mice that only express an H(+)/K(+) ATPase beta subunit in which a putative tyrosine-based endocytosis motif in the cytoplasmic tail is mutated. Location of the H(+)/K(+) ATPase and parietal cell ultrastructure and gastric acid secretion were then examined. RESULTS: Parietal cells of these mice lacked a tubulovesicular compartment, and the H(+)/K(+) ATPase was resident exclusively on the apical plasma membrane. Despite the inability of the H(+)/K(+) ATPase to be endocytosed, the gastric acid secretory response to histamine or an antagonist was very similar to that of wild-type mice, indicating that control of H(+)/K(+) ATPase activity can occur independently of intracellular trafficking. CONCLUSIONS: We were able to dissociate the regulation of H(+)/K(+) ATPase activity from intracellular trafficking of the protein. Thus, it is likely that direct regulation of apical K(+) and Cl(-) conductances are sufficient to control gastric acid secretion.