Relationship Between the Activities of Gloss-Selective Neurons in the Macaque Inferior Temporal Cortex and the Gloss Discrimination Behavior of the Monkey.

In the macaque monkey, neurons that selectively respond to specific gloss are present in a restricted region of the central part of the inferior temporal (IT) cortex. Although the population activity of these neurons is known to represent the perceptual gloss space, the involvement of their activity in gloss perception has not been directly tested. In the present study, we examined the causal relationship between the activities of gloss-selective neurons and gloss perception by applying electrical microstimulation or injection of small amounts of muscimol (GABAA agonist) to manipulate neural activities while monkeys performed a gloss discrimination task. We found that microstimulation within or in the vicinity of the region where gloss-selective neurons were recorded induced bias toward higher gloss judgment. With muscimol injection, gloss discrimination performance was degraded in one monkey after the first injection into the region where gloss-selective neurons were recorded. These results suggest that gloss discrimination behavior is mediated by the activities of a gloss-selective network that includes the gloss-selective region in the central IT cortex examined here.

Structure and function of neural circuit related to gloss perception in the macaque inferior temporal cortex: a case report.

The inferior temporal (IT) cortex of the macaque monkey plays a pivotal role in the visual recognition of objects. In the IT cortex, a feature-selective network formed by connecting subregions specialized for common visual features seems to be a basic strategy for processing biologically important visual features. Gloss perception plays an important role in the judgment of materials and conditions of objects and is a biologically significant visual function. In the present study, we attempted to determine whether a neural circuit specialized for processing information related to gloss perception exists in the IT cortex in one monkey. We injected retrograde tracer into a gloss-selective subregion in the IT cortex where gloss-selective neurons were clustered in the neural recording experiment, and anatomically examined its neural connections. We observed that retrogradely labeled neurons were densely accumulated in multiple locations in the posterior and anterior IT cortices. Based on the results of this case study, we will discuss the possibility that, together with the injection site, the sites with a dense cluster of labeled neurons form feature-selective neural circuits for the processing of gloss information in the IT cortex.

Computational Model for Human 3D Shape Perception From a Single Specular Image.

In natural conditions the human visual system can estimate the 3D shape of specular objects even from a single image. Although previous studies suggested that the orientation field plays a key role for 3D shape perception from specular reflections, its computational plausibility, and possible mechanisms have not been investigated. In this study, to complement the orientation field information, we first add prior knowledge that objects are illuminated from above and utilize the vertical polarity of the intensity gradient. Then we construct an algorithm that incorporates these two image cues to estimate 3D shapes from a single specular image. We evaluated the algorithm with glossy and mirrored surfaces and found that 3D shapes can be recovered with a high correlation coefficient of around 0.8 with true surface shapes. Moreover, under a specific condition, the algorithm's errors resembled those made by human observers. These findings show that the combination of the orientation field and the vertical polarity of the intensity gradient is computationally sufficient and probably reproduces essential representations used in human shape perception from specular reflections.

Perceptual gloss parameters are encoded by population responses in the monkey inferior temporal cortex.

There are neurons localized in the lower bank of the superior temporal sulcus (STS) in the inferior temporal (IT) cortex of the monkey that selectively respond to specific ranges of gloss characterized by combinations of three physical reflectance parameters: specular reflectance (ρs), diffuse reflectance (ρd), and spread of specular reflection (α; Nishio et al., 2012). In the present study, we examined how the activities of these gloss-selective IT neurons are related to perceived gloss. In an earlier psychophysical study, Ferwerda et al. (2001) identified a perceptually uniform gloss space defined by two axes where the c-axis corresponds to a nonlinear combination of ρs and ρd and the d-axis corresponds to 1 - α. In the present study, we tested the responses of gloss-selective neurons to stimuli in the perceptual gloss space defined by the c- and d-axes. We found that gloss-selective neurons systematically changed their responses in the perceptual gloss space, and the distribution of the tuning directions of the population of gloss-selective neurons is biased toward directions in which perceived gloss increases. We also found that a set of perceptual gloss parameters as well as surface albedo can be well explained by the population activities of gloss-selective neurons, and that these parameters are likely encoded by the gloss-selective neurons in this area of the STS to represent various glosses. These results thus provide evidence that the IT cortex represents perceptual gloss space.

Repair of orbital fracture: the antral balloon with implantable reservoir technique.

The antral balloon technique is a useful procedure for the treatment of orbital fracture. Its advantages include being able to apply it without any donor-site morbidity. However, the saline injection catheter, which is inserted nasally from the natural ostium, sometimes causes discomfort. We present our new antral balloon technique with an implantable reservoir dome. This technique did not cause patient discomfort because no saline injection catheter was inserted nasally. It contributed to long-term placement of the antral balloon. Of 30 patients, satisfactory symmetries were achieved in 27 patients and the others required subsequent calvarial bone grafting for correction because of residual enophthalmos.

Intraoperative acquired pressure ulcer on lower lip: a complication of rhinoplasty.

Device-related pressure ulcers are not rare. However, few studies have reported pressure ulcers of the lower lip. We encountered 2 patients with an intraoperative pressure ulcer on the lower lip caused by an endotracheal tube during rhinoplasty. A 46-year-old man showed a deviated nose and nasal obstruction. Surgery was performed under general anesthesia with endotracheal intubation. The surgery time was 270 minutes. A 23-year-old man also showed a deviated nose and nasal obstruction. Surgery was performed under general anesthesia in the same fashion. The surgery time was 273 minutes. A preformed endotracheal tube was inserted and positioned over the mandible and secured with polyurethane film intraoperatively. Both patients had pressure ulcers on their lower lip. One showed a slightly visible scar. Care must be taken to avoid ulcers of the lower lip in rhinoplasty patients.

Neural selectivity and representation of gloss in the monkey inferior temporal cortex.

When we view an object, its appearance depends in large part on specific surface reflectance properties; among these is surface gloss, which provides important information about the material composition of the object and the fine structure of its surface. To study how gloss is represented in the visual cortical areas related to object recognition, we examined the responses of neurons in the inferior temporal (IT) cortex of the macaque monkey to a set of object images exhibiting various combinations of specular reflection, diffuse reflection, and roughness, which are important physical parameters of surface gloss. We found that there are neurons in the lower bank of the superior temporal sulcus that selectively respond to specific gloss. This neuronal selectivity was largely maintained when the shape or illumination of the object was modified and perceived glossiness was unchanged. By contrast, neural responses were significantly altered when the pixels of the images were randomly rearranged, and perceived glossiness was dramatically changed. The stimulus preference of these neurons differed from cell to cell, and, as a population, they systematically represented a variety of surface glosses. We conclude that, within the visual cortex, there are mechanisms operating to integrate local image features and extract information about surface gloss and that this information is systematically represented in the IT cortex, an area playing an important role in object recognition.

Aggressive remodelling with pedicled skin flaps of the volar surface for the release of contractures of the fingers.

We treated contractures of fingers with one or several pedicled skin flaps on one or both sides of the scar, depending on the site and spread of the scar. The length of the flap was equivalent to half the circumference of the unaffected finger, or the distance between bilateral midlateral lines. The width of the flap was the same as the distance between the scar and the midlateral line. A subcutaneous pedicle including one or several vessels is left at the proximal or distal end of each flap. After the scar has been excised the flaps are rotated about 90° and both ends of the flaps are sutured on the bilateral midlateral line. The skin defect that remains between the flaps is covered with a full-thickness skin graft from the non-weight-bearing area of the sole. In all cases, the flaps and skin grafts survived perfectly. Because of the flexibility of the subcutaneous flaps, the skin defects are effectively divided to avoid recontraction without disadvantages such as excess trimming of normal skin, extensive dog ears, or formation of scars on the dorsal surface. The method seems to be less invasive than the procedures used currently, and to yield a satisfactory aesthetic appearance.

Early prediction of response to neoadjuvant chemotherapy for locally advanced breast cancer using MRI.

Neoadjuvant chemotherapy (NAC) is the favored treatment of choice among locally advanced breast cancer patients because it significantly increases the possibility of breast-conserving surgery. However, for non-responders, an early prediction of response to NAC is essential. The purpose of this study was to determine whether an early prediction of response to NAC is possible using MRI. Eleven breast cancer patients (12 lesions) scheduled to receive NAC were recruited for this study. The patients were examined by MRI prior to and after the first and fourth courses of anthracycline-containing chemotherapy and after subsequent taxane-containing chemotherapy. Lesions were divided into 2 types (mass type and non-mass type) based on contrast MRI prior to chemotherapy. Among 8 mass types, 6 were responders (R) and 2 were non-responders (NR). R cases showed either an increased apparent diffusion coefficient (ADC) or volume reduction after the first course of NAC, whereas NR cases showed neither (p < 0.005). Of the 4 non-mass types, 2 were R and 2 were NR. Changes in ADC or volume after the first course of NAC may indicate chemo-sensitivity for mass-type breast cancer. However, the same method cannot be used to predict the response to NAC for non-mass types.

Predictive value for malignancy of suspicious breast masses of BI-RADS categories 4 and 5 using ultrasound elastography and MR diffusion-weighted imaging.

OBJECTIVE: The aim of this study is to evaluate the ability of ultrasound elastography and MR diffusion-weighted imaging (DWI) to predict malignancy of breast masses, with subsequent recommendation for biopsy. MATERIALS AND METHODS: For 115 breast masses classified as BI-RADS category 4 or 5, which were assessed according to combined findings of mammography, B-mode sonography, and dynamic contrast-enhanced MRI, two radiologists retrospectively evaluated the elasticity scores using ultrasound elastography and the apparent diffusion coefficient (ADC) values using MR DWI. The diagnostic abilities of these two techniques were analyzed by using univariate and multivariate logistic regression analysis. RESULTS: In the analysis of all 115 breast masses, the elasticity score was predictive of malignancy, whereas the ADC value was not independently predictive. In an analysis of the 52 masses assessed as BI-RADS category 4, the elasticity score was found to be a significant predictor of malignancy, compared with the ADC value, which was a nonsignificant predictor. In an analysis of the 63 masses assessed as BI-RADS category 5, neither the elasticity score nor the ADC value was a significant predictor of malignancy. CONCLUSION: Our results show that elasticity imaging provides relatively reliable predictions for malignancy, especially in BI-RADS category 4 masses, compared with MR DWI.

Uptake of 18F-FDG in acute aortic dissection: a determinant of unfavorable outcome.

UNLABELLED: Imaging with (18)F-FDG PET/CT is able to reveal vascular inflammation, and several studies have shown that increased (18)F-FDG uptake in carotid artery plaques can qualify the degree of atherosclerotic inflammation. However, clinical assessment of acute aortic dissection (AAD) by PET/CT remains largely unexplored. This study aimed to investigate the use of (18)F-FDG PET/CT to predict short- and midterm outcomes in medically controlled AAD patients. METHODS: A total of 28 medically treated AAD patients (2 Stanford type A and 26 type B, aged 69.5 +/- 11.6 y) were prospectively studied. All patients were examined by enhanced CT for diagnosis of AAD and underwent serial imaging studies during follow-up. PET/CT images were acquired 50 and 100 min after (18)F-FDG injection in all patients in the acute phase. RESULTS: Of the 28 patients, 8 who had an unfavorable outcome due to death from rupture (n = 2), surgical repair (n = 4), and progression of dissection (n = 2) were categorized as having unfavorable AAD. The remaining 20 patients were categorized as having favorable AAD. Maximum dissection diameter in the unfavorable group was significantly greater than that in the favorable group (P = 0.0207). On 50-min images, maximal and mean standardized uptake values (SUVs) at maximum aortic dissection sites were significantly greater for the unfavorable group than for the favorable group (all P < 0.01). A stepwise-forward selection procedure demonstrated that the mean SUV at sites of maximum aortic dissection on 50-min images significantly and independently predicted an unfavorable outcome for AAD (P = 0.0171; odds ratio, 7.72; 95% confidence interval, 1.44-41.4; R(2) = 0.2372). A mean SUV greater than 3.029 had significant predictive power, with sensitivity of 75.0%, specificity of 70.0%, a positive predictive value of 50.0%, a negative predictive value of 87.5%, and accuracy of 71.4%. CONCLUSION: Greater uptake of (18)F-FDG in AAD was significantly associated with an increased risk for rupture and progression. (18)F-FDG PET/CT may be used to improve AAD patient management, although more studies are still needed to clarify its role in this clinical scenario.

Neuroendocrine tumor in the breast.

A 34-year-old woman with a past history of a carcinoid tumor in the right ovary presented with a right breast mass found on contrast-enhanced computed tomography (CT) of the chest. She was asymptomatic, and her blood tests were normal. The mass measured about 2 cm. Mammography showed a lobular, circumscribed, high-density mass without microcalcifications in the upper outer quadrant of the right breast. Ultrasonography showed an irregular mass with both hypoechoic and hyperechoic components with increased vascularity. The mass was well enhanced on contrast-enhanced CT and dynamic magnetic resonance imaging. At the same time, a well-enhanced small nodule was detected in the pouch of Douglas. Both of the tumors were resected, and a primary breast neuroendocrine tumor (solid neuroendocrine carcinoma) and peritoneal dissemination of the ovarian carcinoid tumor were diagnosed.