Neural Systems Mediating American Sign Language: Effects of Sensory Experience and Age of Acquisition

ERPs were recorded from deaf and hearing native signers and from hearing subjects who acquired ASL late or not at all as they viewed ASL signs that formed sentences. The results were compared across these groups and with those from hearing subjects reading English sentences. The results suggest that there are constraints on the organization of the neural systems that mediate formal languages and that these are independent of the modality through which language is acquired. These include different specializations of anterior and posterior cortical regions in aspects of grammatical and semantic processing and a bias for the left hemisphere to mediate aspects of mnemonic functions in language. Additionally, the results suggest that the nature and timing of sensory and language experience significantly impact the development of the language systems of the brain. Effects of the early acquisition of ASL include an increased role for the right hemisphere and for parietal cortex and this occurs in both hearing and deaf native signers. An increased role of posterior temporal and occipital areas occurs in deaf native signers only and thus may be attributable to auditory deprivation.     

Teaching chained skills in a non-school setting using a divided half instructional format

This investigation evaluated the use of dyadic instructional arrangements in teaching chained skills to four students with moderate mental retardation. Each instructional dyad consisted of two students. Each of the three cooking skills was divided into two equal parts, and each student in a dyad received direct instruction on one part of the task analysis during each instructional session. During the following session, the two parts were reversed and a student received instruction on the second part. A constant time delay procedure was used to teach the targeted skills in an off-campus setting. A multiple probe design across skills and replicated across students evaluated the effectiveness of the instructional procedure and teaching arrangement. Results indicate that each of the four students learned the three cooking skills. Implications for future research are discussed.     

Fixed-interval schedule of cocaine reinforcement: effect of dose and infusion duration

Rhesus monkeys were trained on a fixed-interval 9-min limited-hold 3-min schedule of intravenous cocaine reinforcement. A 15-min timeout followed each reinforcement or limited-hold expiration. An identical schedule of food reinforcement was interspersed in the session to assess rate-modifying effects of the drug infusions not specific to drug reinforcement. In one experiment, response rate for cocaine reinforcement was shown to be a positive function of reinforcement magnitude for a dose range from 0 to 800 ug/kg/inj. At these doses, there was little effect on food reinforced responding except at the highest dose, where responding decreased. Results of the second experiment indicated that increasing the duration of the cocaine infusion produced a change in response rate similar to decreasing unit dose. The response rate change for a given increase in infustion duration was less at a unit dose of 400 ug/kg than at 200 ug/kg.     

Zum Zusammenhang zwischen Projektionsoperatoren und Eigenschaften

Der nichtdistributive, orthokomplementäre Verband der Projektionsoperatoren in der Quantenmechanik hat Anlaß zu mancherlei Interpretationen gegeben, so z. B. als eine von der klassischen Logik abweichende Quantenlogik, oder man deutete die Projektionsoperatoren als Eigenschaften von Mikroobjekten. Wir glauben, mit dieser Arbeit ein wesentliches Argument für die letztere Interpretation liefern zu können:Es ist nämlich möglich, in der Menge der Eigenschaftsbegriffe eine Ordnungs-relation einzuführen. Mit dieser Ordnungsrelation bildet einen nichtdistributiven, orthokomplementären Verband. D.h. bei einer solchen Interpretation werden keinerlei Veränderungen — weder im Verband der Aussagen noch im Verband der Eigenschaftsbegriffe — durch die Entdeckung der Quantenmechanik notwendig.     

Person,setting, and interaction contributions to nursery school social behavior patterns1

Within a nursery school environment, 8,930 behavioral observations were taken on 17 preschool children in six settings over a two-month period. Two different data analysis techniques were used. The aggregate analysis showed that person, setting, and interaction all contributed significantly to behavior patterns. The setting was significantly stronger than person. The individual analysis found that subjects' median Person Pattern values were correlated significantly and negatively with IQ and age, suggesting that younger children and those with lower IQ's had more consistent behavior across different settings. This was also true of children who had been at the school more than one year. Implications for predicting behavior were discussed, noting the need to study person and setting relative to one another for particular behaviors in different categories of environments.     

Neural substrates for verbal working memory in deaf signers: fMRI study and lesion case report

The nature of the representations maintained in verbal working memory is a topic of debate. Some authors argue for a modality-dependent code, tied to particular sensory or motor systems. Others argue for a modality-neutral code. Sign language affords a unique perspective because it factors out the effects of modality. In an fMRI experiment, deaf participants viewed and covertly rehearsed strings of non-sense signs; analyses focused on regions responsive in both sensory and rehearsal phases. Compared with previous findings in hearing subjects, deaf subjects showed a significantly increased involvement of parietal regions. A lesion case study indicates that this network is left-dominant. The findings support the hypothesis that linguistic working memory is supported by modality-specific neural systems, but some modality-neutral systems may also be involved.