Object recognition learning differentiates the representations of objects at the ERP component N1

OBJECTIVE

Even if viewed from different angles, one can identify an object among similar distractors through learning. This study was designed to investigate the changes in neuronal activity related to learning.

METHODS

Human subjects were asked to train themselves with novel objects by performing an object recognition task, in which the images of an object had to be discriminated from those of other objects regardless of the viewpoint.

RESULTS

The ERP component-N1, the first negative peak at posterior electrodes, showed a significant increase in the amplitude variation across the objects during the learning process, while the variation across viewpoints decreased.

CONCLUSIONS

These results suggest that object recognition learning differentiates between the representations of the objects, at least, at the N1 level.

SIGNIFICANCE

The results may support the notion that object recognition differentiates among the functional representations of the trained objects in our brain.

The efficiency of performing ultrasound-guided fine-needle aspiration biopsy following mass screening for thyroid tumors to avoid unnecessary surgery

Thyroid masses are a common clinical finding, and their management remains controversial. The purpose of this study was to evaluate the clinical effect of performing routine ultrasound (US) examinations and US-guided fine-needle aspiration biopsy (US-FNAB) in the management of diffuse or nodular goiter diagnosed by mass screening. Mass screening carried out from 1993 to 1996 revealed 444 women with goiter, 322 of whom had diffuse goiter and 122 had nodular goiter. All of these patients underwent US examination, the results of which determined that 169 should undergo US-FNAB to confirm an accurate diagnosis of their thyroid tumors. Histological examinations after surgical resection revealed that 12 of the 322 patients with diffuse goiter (3.7%) and 23 of the 122 with nodular goiter (18.9%) had malignant tumors. Among the 61 thyroid tumors surgically verified, US-FNAB yielded a sensitivity rate of 93%, a specificity rate of 81%, and an accuracy rate of 90%. Insufficient aspiration was obtained from 5%. Performing US-FNAB-resulted in an elevation in the percentage of malignant tumors yielded at surgery of up to 72%. Thus, ultrasonography followed by US-guided-FNAB could be a useful routine method of evaluating thyroid tumors detected by mass screening. Moreover, a greater number of unnecessary thyroid operations can be avoided by performing US-FNAB rather than FNAB alone.

Inferior vena caval thrombosis after traumatic liver injury

We report here the case of a 35-year-old man who presented with inferior vena cava thrombosis (IVCT) after blunt hepatic trauma. The IVCT was incidentally detected by computed tomography (CT) 35 days after deep parenchymal suturing and suture approximation for liver lacerations. The patient denied any symptoms of thrombophlebitis. However, he had presented with significantly elevated values of FDP-D-dimer and a modest increase in plasminogen concentration, which indicated that he had been in a hypercoagulable and hypofibrinolytic state after the operation. He had not undergone any prophylactic anticoagulant therapy because of his concomitant subarachnoid hemorrhage and huge hepatic hematoma. The patient was treated with an emercy thrombectomy. Posttraumatic IVCT is extremely rare phenomenon. We should consider IVCT in patients with a severe hepatic injury, particularly if their coagulation system change into hypercoagulable and hypofibrinolytic state. Additionally, this case made us reflect on the treatment of traumatic liver injury.

Therapeutic experience of venomous snakebites by the Japanese viper (Agkistrodon halys Blomhoffii) with low dose of antivenin: report of 43 consecutive cases

Forty-three consecutive patients of venomous snakebite by the Japanese viper (Agkistrodon halys Blomhoffii, "Mamushi" in Japanese) were treated with an uniformly scheduled therapy from 1990 and 1994. The therapy was mainly composed of minimal dose of antivenin, methylprednisolon and cepharanthin. There were two clinical courses, i.e., the minimal envenomation course (Group A, n = 14) and the severe one (Group B, n = 29). Our treatment was so satisfactory that all patients of both groups fully recovered activities of daily living with neither organic disorders nor sequelae of the bitten extremities. The high appearance ratio of atypical lymphocytes (P < 0.05) and the increased ratio of lymphocyte count to White blood cell count (P < 0.02) could be indicators that predict which clinical courses the patients take.