PubMed · 6898856
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F Hekelman. Writing behavorial objectives: a beginning knowledge base.. https://pubmed.ncbi.nlm.nih.gov/6898856/
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PURPOSE: A multi-institutional trial was conducted by the Radiation Therapy Oncology Group (RTOG) to test the feasibility of performing a test battery consisting of five neurocognitive measures and a quality-of-life instrument in patients with brain metastases. METHODS AND MATERIALS: The major eligibility requirements included histologic proof of a primary malignancy, measurable single or multiple brain metastases, Zubrod performance status of 0-1, neurologic function status of 0-2, and "certification" for administration of neurocognitive assessments. This certification process required either attendance at an RTOG neurocognitive assessment training workshop or review of an instructional video, followed by submission of an audiotape of mock/simulated test sessions for central review. The test battery included the following measures: the Mini-Mental Status Examination, Hopkins Verbal Learning Test, Verbal Fluency/Controlled Word Association Test, Ruff 2 and 7 test, Trailmaking Test, and Profile of Mood States-Short Form. The primary objective of this trial was to establish whether patients were able to complete this test battery. Compliance was defined as successful completion of a test measure. The test battery was to be administered just before, at completion of, and 1 month after whole brain radiotherapy to 37.5 Gy at 2.5 Gy/fraction once daily. Fifty-nine patients were enrolled in the trial. RESULTS: The patient characteristics included 32% > or =65 years; 44% with Zubrod performance status of 0; and 81% with multiple brain metastases. The overall compliance rate for administration and completion of the five neurocognitive measures and a quality-of-life instrument before treatment, at treatment completion, and 1 month after treatment was > or =95%, > or =84%, and > or =70%. The most common causes of noncompliance were patient-related factors (e.g., performance status or inability to understand test instructions) and not institutional error. CONCLUSION: Neurocognitive evaluation of patients with brain metastases in a multi-institutional and cooperative group setting is feasible using the test battery and certification process used in this study. This battery and certification process will be incorporated into future RTOG brain tumor trials.
The binding problem requires a solution at the level of individual neurons, but no definite mechanism has yet be given. Therefore, the neuronal level is as yet inadequate for modeling cognitive processes in which binding plays a crucial role. Moreover, the neuronal level involves too many details that are unlikely to be essential for understanding cognition. A general model of cognitive brain functioning is described in which cognitive tasks are represented in a network of cell assemblies. In the network, binding is functionally defined in a way that is compatible with the neuronal level. A computer simulation of the model clarifies how the binding of location and identity of a set of simultaneously presented letters takes place and how questions about the location and identity of the letters are answered. From the simulation of the task three predictions on the logistics of neural processes are derived: 1. When the cell assembly representing a letter participates in more than one temporary excitation loop, it will reach its critical threshold faster. At the behavioral level this means that as the number of identical letters in the display increases, responses will be faster. 2. In order to answer questions about the location and identity of presented letters cell assemblies representing the target location and the target identity have to become bound to their appropriate values. As a consequence the facilitatory effect of identical letters will be stronger if they involve the target location or the target identity than when identical non-targets are involved. 3. Negative identifications are more dependent on the presentation time of the letters than positive identifications because the excitation loops involved take more time to reach the critical threshold. Therefore, the facilitatory effect of identical letters is stronger when the external activation is relatively strong, i.e., when presentation time of the letters is sufficiently long. The reaction times obtained in three behavioral experiments support these hypotheses. Effects of binding can therefore be predicted on the basis of the general logistics of neural processes, without assumptions about a specific binding mechanism at the neuronal level.
Previous research demonstrates that people with schizophrenia have abnormally 'restricted' visual scanpaths to face and facial expression stimuli, which appear to be diagnostically specific to schizophrenia [Schizophr. Res. 55 (2002) 159; Biol. Psychiatry 52 (2002) 338]. This study examined the familial transmission of 'restricted' scanpaths in first-degree relatives of schizophrenia subjects. We recorded visual scanpaths for 65 schizophrenia subjects, 37 biological first-degree relatives and 61 nonrelated 'healthy' control subjects in two experiments: 'face recognition' and 'facial affect recognition'. Concurrent behavioral tasks were face matching and expression matching, each under two multiple-choice conditions (seven or three options). As predicted, first-degree relatives generally showed an attenuated form of the markedly 'restricted' scanpaths of schizophrenia subjects across all face stimuli. The notable exception to this pattern was the relatives' extreme avoidance of facial features (compared to both schizophrenia and healthy control groups). Our results offer the first evidence that some components of visual scanpath dysfunction may represent a trait marker in the familial transmission of schizophrenia, but that first-degree relatives may have additional disturbances in social cognition associated with the perception of facial features.