The successor representation was introduced into reinforcement learning by Dayan ( 1993 ) as a means of facilitating generalization between states with similar successors. Although reinforcement learning in general has been used extensively as a model of psychological and neural processes, the psychological validity of the successor representation has yet to be explored. An interesting possibility is that the successor representation can be used not only for reinforcement learning but for episodic learning as well.
View Article and Find Full Text PDFPrevious research on the superior temporal sulcus (STS) has shown that it responds more to facial expressions than to neutral faces. Here, we extend our understanding of the STS in two ways. First, using targeted high-resolution fMRI measurements of the lateral cortex and multivoxel pattern analysis, we show that the response to seven categories of dynamic facial expressions can be decoded in both the posterior STS (pSTS) and anterior STS (aSTS).
View Article and Find Full Text PDFPerceptual categorization is a fundamental cognitive process that gives meaning to an often graded sensory environment. Previous research has subdivided the visual pathway into posterior regions that processes the physical properties of a stimulus, and frontal regions that process more abstract properties such as category information. The superior temporal sulcus (STS) is known to be involved in face and emotion perception, but the nature of its processing remains unknown.
View Article and Find Full Text PDFWe investigated the influence of distinctive encoding on the Jacoby and Whitehouse (1989) illusion. Subjects studied visually presented words that were associated with either an auditory presentation of the same word (nondistinctive encoding) or a picture of the object (distinctive encoding). In both conditions, words were visually presented on the recognition test, and half were preceded by brief repetition primes.
View Article and Find Full Text PDFSeminal vesicle cysts associated with other genitourologic abnormalities are rare. We describe the first known robot-assisted excision of a cystic seminal vesicle associated with ipsilateral renal agenesis in a symptomatic pediatric patient. The patient was discharged home on postoperative day 1 and remains symptom free after 9 months' follow-up.
View Article and Find Full Text PDFThe authors investigated two retrieval-monitoring processes. Subjects studied red words and pictures and then decided whether test words had been studied in red font (red word test) or as pictures (picture test). Memory confusions were lower on the picture test than on the red word test, implicating a distinctiveness heuristic.
View Article and Find Full Text PDFA patient who had previously undergone radical cystoprostatectomy and ileal neobladder with the Studer technique presented with a recurrence of urothelial carcinoma in the neobladder and urethra. Surgical treatment consisted of resection of the neobladder, urethrectomy, and creation of an ileal conduit using a separately isolated segment of ileum. Pathologic analysis revealed high-grade urothelial carcinoma implants to the Studer pouch and urethra, with spread to the mesenteric lymph nodes draining the pouch.
View Article and Find Full Text PDFExpertise can increase working memory (WM) performance, but the cognitive and neural mechanisms of these improvements remain unclear. Here, we used functional magnetic resonance imaging to assess the degree to which expertise acquisition is supported by tuning of occipitotemporal object representations and tuning of prefrontal and parietal networks that may support domain-specific WM skills. We trained subjects to become experts in a novel category of complex visual objects and examined brain activity while they performed a WM task with objects from the expert category and from an untrained category.
View Article and Find Full Text PDFGadolinium-enhanced magnetic resonance imaging is a diagnostic modality widely used in urologic practice. We report on a 54-year-old woman in whom a critically low serum calcium level was measured with standard colorimetric assay after gadodiamide-enhanced magnetic resonance imaging. The same phenomenon was noted in 2 other patients seen in our practice.
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