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The contents of working memory (WM) steer visual attention, but the extent of this guidance can be strategically enhanced or inhibited when WM content is reliably helpful or harmful to a visual task. Current understanding of the neural substrates mediating the cognitive control over WM biases is limited, however, by the correlational nature of functional MRI approaches. A recent fMRI study provided suggestive evidence for a functional lateralization of these control processes in posterior parietal cortex (PPC): activity in left PPC correlated with the presentation of WM cues that ought to be strategically enhanced to optimize performance, while activity in the right PPC correlated with the presentation of cues that ought to be inhibited to prevent detrimental attentional biases in a visual search. Here, we aimed to directly assess whether the left and right PPC are causally involved in the cognitive control of WM biases, and to clarify their precise functional contributions. We therefore applied 1Hz repetitive transcranial magnetic stimulation (rTMS) to left and right PPC (and a vertex control site) prior to administering a behavioral task assessing WM biasing control functions. We observed that the perturbation of left PPC eliminated the strategic benefit of predictably helpful WM cueing, while the perturbation of right PPC amplified the cost of unpredictable detrimental WM cueing. Left and right PPC thus play distinct causal roles in WM-attention interactions: left PPC to maximize benefits, and right PPC to minimize costs, of internally maintained content on visual attention.

The K-ABC was administered to 21 autistic children, and scores were examined both in relation to differences in sequential and simultaneous processing scores and in comparison to the subjects' current IQ scores on the WISC-R. Results are discussed in terms of problems in interpretation of cognitive test scores.

The authors review the records of 61 patients who had clinical mammographic examination and histologic lobular carcinoma in situ in at least one breast. An analysis was done to determine the tissue counterpart of positive mammographic findings as well as the accuracy and usefulness of mammography as an adjunct in the diagnosis of in situ lobular carcinoma.

The purpose of this study was to test the feasibility of MR-guided percutaneous ethanol ablation of liver tissue on a .2-T open MR scanner. Needles were placed by MR guidance first into an ex vivo sheep liver and then into livers of three anesthetized pigs, and injection of 10 ml of 96% alcohol was performed. T1 fast low-angle shot (FLASH), T2 turbo spin echo (TSE), and T1 spin echo (SE) images were obtained after incremental volumes of injection. In one pig, simultaneous injection of saline into normal liver was also performed with subsequent pathological correlation. Ethanol-infiltrated liver was hypointense to liver on all sequences, whereas saline caused no tissue signal changes on T1 SE and either isointense or hyperintense changes on T2 TSE images. Pathological examination confirmed ethanol-induced acute liver changes as compared with the control. MR guidance of needle placement and monitoring of ethanol effects on liver tissue is feasible. This may have implications for potential MR-guided hepatic tumor ablation.

Following the detection of non‐infiltrating cancer, there have been more extensive microscopic studies for various atypical lesions of the breast. At Memorial Hospital, 296 patients with these lesions were seen during the period 1960 to 1972. These lesions were found more often in middle aged women than is the case in average cancer patients, commonly seen in nulliparous women, in patients in whom breast cancer was found in the opposite breast, and in patients with a history of breast cancer in the family. The clinical and mammographic findings are quite similar to those in non‐infiltrating cancer. Occasionally, these lesions are quite difficult to distinguish from minimal breast cancer by histologic examination. In this study, the cumulative risk of breast cancer was approximately 4‐5% at 30 months and 9% at 48 months.

Histopathological findings in filtering blebs with recurrent blebitis We report clinical courses and histopathological findings of excised blebs from two patients with recurrent blebitis.

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