Apperceptive agnosia and face recognition

Abstract

Are faces and objects recognized by separate visual recognition systems or might a single system subserve the recognition of both classes of input? Recognition of faces and objects by a single system predicts that prosopagnosics, who selectively lose the ability to recognize faces due to brain damage, should also lose the ability to recognize objects. Contrary to this prediction, case studies of prosopagnosia have reported intact object recognition. Further support for separate visual recognition systems comes from the case of HH reported here. Following a stroke involving the left posterior cortex, HH has a severe apperceptive visual agnosia for visually presented objects and an alexia for words. Yet, he shows relatively spared visual face processing. Such a performance pattern completes a double dissociation between face and object processing when coupled with prosopaganosia. More importantly, HH is the first apperceptive visual object agnosic to demonstrate spared face processing. The severity of his object-processing deficit is such that from the earliest levels in the visual processing hierarchy, distinct neural substrates must be responsible for processing some objects and faces. These results are discussed as support for Farah's model (Visual agnosia: disorders of object recognition and what they tell us about normal vision. Cambridge, MA: MIT Press, 1990) of object, face and word recognition.     

The Pneumonia Etiology Research for Child Health Project: a 21st century childhood pneumonia etiology study

The Pneumonia Etiology Research for Child Health (PERCH) project is a 7-country, standardized, comprehensive evaluation of the etiologic agents causing severe pneumonia in children from developing countries. During previous etiology studies, between one-quarter and one-third of patients failed to yield an obvious etiology; PERCH will employ and evaluate previously unavailable innovative, more sensitive diagnostic techniques. Innovative and rigorous epidemiologic and analytic methods will be used to establish the causal association between presence of potential pathogens and pneumonia. By strategic selection of study sites that are broadly representative of regions with the greatest burden of childhood pneumonia, PERCH aims to provide data that reflect the epidemiologic situation in developing countries in 2015, using pneumococcal and Haemophilus influenzae type b vaccines. PERCH will also address differences in host, environmental, and/or geographic factors that might determine pneumonia etiology and, by preserving specimens, will generate a resource for future research and pathogen discovery.     

Intraoperative Diagnosis Using Sentinel Node Biopsy with Indocyanine Green Dye in Gastric Cancer Surgery: An Institutional Trial by Experienced Surgeons

Background

Reliable indicators that can intraoperatively determine the absence of nodal metastasis are in great demand to avoid unnecessary lymphadenectomy. However, little has been reported about the intraoperative diagnostic performance of sentinel node (SN) biopsy.

Methods

Sentinel node biopsy by subserosal or submucosal injection of indocyanine green (ICG) was performed in 241 patients with American Joint Committee on Cancer tumor, node, metastasis staging system, 7th edition, clinical T1 (n = 190) and T2 (n = 51) gastric cancer by two experienced surgeons. All nodes that stained green (green node, GN), representing SNs, were excised before gastrectomy and were sliced into 2-mm sections for intraoperative histological examinations with hematoxylin and eosin staining. The sliced GNs were also examined simultaneously by imprint cytology.

Results

The GNs were detectable in 240 patients (3.8 ± 2.4 nodes per patient; range 1–17 nodes; median 3 nodes), and the success rate of detection was 99.6 % (240 of 241). Of 240 patients with a successful detection, 29 were found to have lymph node (LN) metastases; 16 were diagnosed with LN metastases in both GNs and non-GNs, 12 in GNs alone, and 1 in non-GNs alone. The false-negative rate based on the SN concept was 3.4 % (1 of 29). However, two patients with cT1 gastric cancer were diagnosed as intraoperative GN negative but were later confirmed as GN positive by histological examinations of paraffin sections. As an intraoperative diagnosis, the false-negative rate was 10.3 % (3 of 29).

Conclusions

Sentinel node biopsy using ICG could be performed intraoperatively within reasonable limits under certain conditions, such as multiplanes for detection, combination use of imprint cytology, and open surgery by experienced surgeons.