Coordinate high-frequency pattern of stimulation and calcium levels control the induction of LTP in striatal cholinergic interneurons

Current evidence appoints a central role to cholinergic interneurons in modulating striatal function. Recently, a long-term potentiation (LTP) of synaptic transmission has been reported to occur in these neurons. The relationship between the pattern of cortico/thalamostriatal fibers stimulation, the consequent changes in the intracellular calcium concentration ([Ca2+]i), and the induction of synaptic plasticity was investigated in striatal cholinergic interneurons from a rat corticostriatal slice preparation by means of combined electrophysiological intracellular recordings and microfluorometric techniques. Different protocols of stimulation were considered, varying both the frequency and the duration of the train of stimuli. High-frequency stimulation (HFS) (three trains at 100 Hz for 3 sec, 20-sec interval) induced a rise in [Ca2+]i, exceeding by fivefold the resting level, and caused a LTP of synaptic transmission. Tetanic stimulation delivered at lower frequencies (5-30 Hz) failed to induce long-term changes of synaptic efficacy. The observed elevation in [Ca2+]i during HFS was primarily mediated by L-type high-voltage activated (HVA)-Ca2+ channels, as it was fully prevented by nifedipine. Conversely, blockade of NMDA and AMPA glutamate receptor did not affect either LTP or the magnitude of the [Ca2+]i rise. Interestingly, the pharmacological analysis of the post-tetanic depolarizing postsynaptic potential (DPSP) revealed that LTP was attributable, to a large extent, to the potentiation of the GABA(A)-mediated component. In conclusion, the expression of LTP in striatal cholinergic interneurons is a selective response to a precise stimulation pattern of induction requiring a critical rise in [Ca2+]i.     

DISTINGUISHING BETWEEN EXTINCTION AND PUNISHMENT EFFECTS OF RESPONSE BLOCKING: A REPLICATION

Lerman and Iwata (1996) described a method for distinguishing between sensory extinction and punishment effects of response blocking on self-injurious behavior maintained independent of social contingencies. Results of their study suggested that blocking decreased the self-injurious hand mouthing of their participant via punishment. The current replication of these procedures with the self-injurious eye poking of a woman with developmental disabilities produced patterns of responding indicating that, for this participant, blocking functioned as an extinction procedure.     

The genesis and use of exemplar vs. prototype knowledge in abstract category learning

Accurate classification of new exemplars in an abstraction paradigm may be due to their similarity to old exemplars rather than to abstract category (or prototype) knowledge. In the present study, subjects received initial training on a two-category problem before being transferred to a task in which half of the exemplar-response pairs had their responses reversed while the remaining half of the pairs were unchanged. When transfer occurred with no delay and involved old exemplars, more errors occurred for changed than for unchanged pairs. This result implies the use of exemplar-specific rather than abstract category knowledge. However, when transfer was delayed by 24 or 72 h, errors occurred equally often for changed and unchanged pairs. This result suggests that exemplar-specific knowledge is no longer used. Since subjects were still able to accurately classify exemplars prior to the transfer task at these delays, some form of abstract category knowledge is implicated.     

A comparison of human and automated instruction of autistic children

While it appears reasonable to assume that the autistic child might benefit from the development of programmed instruction and teaching machines to teach imitation, concepts, and receptive vocabulary skills, no systematic research to date has seriously investigated such possibilities. The purpose of this study was to compare the effects of automated versus teacher-controlled instruction in the education of autistic children. Four autistic children, each with extreme deficits in language, social, and self-care behaviors, were trained on a matching-to-sample task under three different instructional situations within an intrasubject replication design and multiple baseline procedure. Analysis of the data showed the following results: (1) The teacher, manually operating the teaching machine, was able to teach and maintain the matching-to-sample task; (2) the same autistic children did not acquire or maintain the task when taught by the machine alone; and (3) the teacher alone (without the machine) was able to teach and maintain the task. The results suggest that automated instruction may, at least, serve as a valuable aid to teachers of autistic children. However, before machines can be used without the participation of a trained teacher, further research appears necessary. Several areas, including the role of motivation in automated instructional settings, the saliency and effectiveness of reinforcers, and the importance of controlling antecedent stimulus conditions and off-task behavior are discussed as areas of primary concern in the development of automated instruction for autistic children.     

COMPLIANCE TRAINING AND BEHAVIORAL COVARIATION IN THE TREATMENT OF MULTIPLE BEHAVIOR PROBLEMS

The present study investigated the use of a compliance-training procedure and its effect on untreated deviant child behaviors. Three children, each generally noncompliant to adult requests and with several additional problems, such as crying, aggression, and self-injurious behavior, were trained in the compliance procedure under a multiple-baséline design across therapists. Compliance was defined as the correct response to prespecified requests. Other classes of deviant child behavior were measured continuously throughout the study but not directly reinforced. The results of the study showed that (a) increases in compliance to requests were directly related to the contingencies employed; (b) decreases in untreated deviant behaviors occurred when compliance increased, even though no direct contingencies had been placed on these behaviors; and (c) the relationship between untreated deviant behaviors and compliance appeared to be maintained by a different set of events in each of the three children. The results are discussed in terms of behavioral covariation and generalization.     

A METHOD FOR INTEGRATING AN AUTISTIC CHILD INTO A NORMAL PUBLIC-SCHOOL CLASSROOM1

This study investigated the feasibility of using behavioral techniques to integrate an autistic child into a normal public-school class with one teacher and 20 to 30 normal children. The results showed: (1) that during treatment by a therapist in the classroom, the child's appropriate verbal and social behaviors increased, and autistic mannerisms decreased; and (2) training teachers in behavioral techniques was apparently sufficient to maintain the child's appropriate school behaviors throughout kindergarten and the first grade.     

ASSESSING AND TRAINING TEACHERS IN THE GENERAUZED USE OF BEHAVIOR MODIFICATION WITH AUTISTIC CHILDREN1

This study investigated the feasibility of developing reliable, valid criteria for measuring and training the skills necessary to teach autistic children. The behaviors of 11 teachers and 12 autistic children were recorded in a series of different teaching situations. Teacher-training was initiated at different times for different teachers. The results showed: (1) it was possible to assess empirically whether a teacher was correctly using defined behavior-modification techniques; (2) generally, for any given session, systematic improvement in the child's behavior did not occur unless the teacher working in that session had been trained to use the techniques to a high criterion; (3) all 11 teachers were rapidly trained to use these techniques; and (4) the teachers learned generalized skills effective with a variety of children and target behaviors.     

Predictors of burden in spouse caregivers of individuals with Alzheimer's disease

This study used the following model of distress: Distress = [Exposure to Stress + Vulnerability]/[Psychological and Social Resources]. The constructs in the model were operationalized as (a) distress in response to caregiver experiences (burden); (b) exposure to stress (care recipient functional impairment in activities of daily living [ADLs]); (c) vulnerability (caregiver health problems, anger, and anxiety); and (d) resources (coping, outlook on life, and social supports). Long-term burden (15-18 months after entry) was predicted by several baseline variables: burden, care recipient ADLs, vulnerability and resource variables, and specific interactions of burden, ADLs, vulnerability, and resource variables. The interactions showed that caregivers with high vulnerability and low resources had higher burden scores than caregivers with other combinations of these variables.     

Formal Ontology and Mathematics. A Case Study on the Identity of Proofs

We propose a novel, ontological approach to studying mathematical propositions and proofs. By “ontological approach” we refer to the study of the categories of beings or concepts that, in their practice, mathematicians isolate as fruitful for the advancement of their scientific activity (like discovering and proving theorems, formulating conjectures, and providing explanations). We do so by developing what we call a “formal ontology” of proofs using semantic modeling tools (like RDF and OWL) developed by the computer science community. In this article, (i) we describe this new approach and, (ii) to provide an example, we apply it to the problem of the identity of proofs. We also describe open issues and further applications of this approach (for example, the study of purity of methods). We lay some foundations to investigate rigorously and at large scale intellectual moves and attitudes that underpin the advancement of mathematics through cognitive means (carving out investigationally valuable concepts and techniques) and social means (like communication, collaboration, revision, and criticism of specific categories, inferential patterns, and levels of analysis). Our approach complements other types of analysis of proofs such as reconstruction in a deductive system and examination through a proof-assistant.