Cross-orientation transfer of adaptation for facial identity is asymmetric: A study using contrast-based recognition thresholds

AbstractRecent studies suggest that adaptation effects for face shape and gender transfer from upright to inverted faces more than the reverse. We investigated whether a similar asymmetry occurred for face identity, using a recently developed adaptation method based on contrast-recognition thresholds. When adapting and test stimuli shared the same orientation, aftereffects were similar for upright and inverted faces. When orientation differed, there was significant transfer of aftereffects from upright adapting to inverted test faces, but none from inverted to upright faces. We show that asymmetric cross-orientation transfer of face aftereffects generalize across two distinct face adaptation paradigms: the previously used perceptual-bias methodology and the recently introduced contrast-threshold based adaptation paradigm. These results also represent a generalization from aftereffects for face shape and gender to aftereffects for face identity. While these results are consistent with the dual-mode hypothesis, they can also be accounted for by a single population of units of varying orientation selectivity

The nature of upright and inverted face representations: an adaptation-transfer study of configuration

Published online xxx Keywords: Face inversion effect t r a c t It is considered that whole-face processing of spatial structure may only be possible in upright faces, with only local feature processing in inverted faces. We asked whether this was due to impoverished representations of inverted faces. We performed two experiments. In the first, we divided faces into segments to create 'exploded' faces with disrupted second-order structures, and 'scrambled' faces with altered first-order relations; in the second we shifted features within intact facial outlines to create equivalent disruptions of spatial structure. In both we assessed the transfer of adaptation between faces with altered structure and intact faces. Scrambled adaptors did not adapt upright or inverted intact faces, indicating that a whole-face configuration is required at either orientation. Both upright and inverted faces showed a similar decline in aftereffect magnitude when adapting faces had altered second-order structure, implying that this structure is present in both upright and inverted face representations. We conclude that inverted faces are not represented simply as a collection of features, but have a whole-face configuration with second-order structure, similar to upright faces. Thus the qualitative impairments induced by inversion are not due to degraded inverted facial representations, but may reflect limitations in perceptual mechanisms. ª 2011 Elsevier Srl. All rights reserved. Faces are processed by the human visual system in a manner that is sufficiently precise and efficient to allow us to rapidly identify thousands of individual faces, some at a single glance. This expert processing is orientation-dependent, in that recognition of faces is far better when faces are viewed in the customary upright orientation than when seen inverted, i.e., rotated in the picture plan

THE USAGE OF GELATIN AND POLYVINYL ALCOHOL AS A HARDENER İN THE CADAVERS THAT İS FİXED WITH FIXATION-PRESERVATION SOLUTION (SEFS) CONSISTING OF LIQUID FOAM SOAP, ALCOHOL, CITRIC ACID, AND ANTISEPTIC

Amaç: Bu çalışmanın amacı; sıvı köpük sabun, etanol, sitrik asit karışımı ve benzalkonyum klorür den oluşan fiksasyon-preservasyon solüsyonunu (SEFS) geliştirerek uzun süre bozulmadan saklanabilen, eğitim ve araştırma amacıyla çalışılabilen kadavralar hazırlamaya imkân veren pratik ve ekonomik bir kadavra hazırlama yöntemine ulaşmaktır. Gereç ve Yöntem: Bu amaç için 6 adet Yeni Zelanda tavşanı ve 4 adet Saanen oğlak kullanılmıştır. Hayvanlar iki gruba ayrılarak modifiye edilmiş SEFS kullanılarak tespit edilmiştir. Tespit işleminin ardından damar yolundan bir gruba çeşme suyu, sığır jelatini ve gliserin karışımı (jelatin-Gls); diğer gruba ise çeşme suyu, sığır jelatini ve polivinil alkol (jelatin-PVA) karışımı uygulanmıştır. Hazırlanan kadavralar klasik diseksiyon yöntemi ile diseke edilerek diseksiyona uygunluklarına ait bulgular alınmıştır. Kadavralardan alınan doku örneklerinde renk ve sertlik analizleri, ayrıca bazı eklemlerde eklem hareket aralığı ölçümleri yapılarak her iki grupta bulunan kadavralar 12 aylık sürede karşılaştırmalı olarak değerlendirilmiştir. Bulgular: Kadavralar tespit edildikten 3 ay sonra diseksiyonlarına başlandı. Kadavraların deri diseksiyonlarına başlamadan yapılan gözlemde dokunsal ve görsel özellikleri hem grup I (jelatin-Gls) de hem de grup II (jelatin-PVA) de in vivo görünüm ve kıvamda oldukları tespit edildi. Deri kası ve deri altı bağ dokusunun doğal renginde olduğu; deri altında hiçbir alanda hipostatik konjesyona benzer sıvı birikimleri tespit edilmedi. Kasların dokunsal ve görsel muayenelerinde doğal renklerine çok yakın, canlı bir renk tonuna sahip oldukları ve sübjektif olarak kıvamlarının formaldehitle tespit edilmiş kadavraya nazaran daha yumuşak ve esnek oldukları görüldü. Pleura, akciğerler ve kalbin doğal renklerinde olduğu görüldü Akciğerler kollabe olmamış; kalp sahip olduğu normal görüntü ve hacmindeydi. Kalp içi boşluklu yapısını korumuş atriumlar ve ventriküllerin duvarları içe doğru çökmemişti. Grup II (jelatin-PVA)’nin hem göğüs hem de karın organlarının hacimlerinin korunması konusunda özellikle, kalp, akciğer, karaciğer, dalak ve böbreklerde grup I’e göre daha iyi sonuç verdiği görüldü. Sonuç: Çalışma sonuçlarına göre bir tespit solüsyonu olarak SEFS ve jelatin-PVA karışımının kadavradan beklenen bazı özellikler açısından daha üstün olduğu tespit edilmiştir.KABUL VE ONAY .................................................................................................. i TEŞEKKÜR .............................................................................................................. ii İÇİNDEKİLER .......................................................................................................... iii SİMGELER VE KISALTMALAR DİZİNİ .............................................................. vi ŞEKİLLER DİZİNİ ................................................................................................... vii RESİMLER DİZİNİ .................................................................................................. ix TABLOLAR DİZİNİ .................................................................................................. xi ÖZET ......................................................................................................................... xiii ABSTRACT .............................................................................................................. xv 1. GİRİŞ ………………............................................................................................. 1 2. GENEL BİLGİLER ............................................................................................... 5 2.1. Kadavra ve Tespit ……………………………………………………………... 2.2. Kadavra ve Tespit İşleminin Kısa Tarihçesi …………………………………. 2.2.1. Sık Kullanılan Formaldehitli Tespit Solüsyonları ………………………….. 2.2.2. Formaldehit İçermeyen Tespit Solüsyonları ………………………………... 2.3. Tespit İşlemi ………………………………………………………………….. 2.3.1. Amino Asitler ……………………………………………………………….. 2.3.2. Proteinleri Oluşturan Bağlar ……………………………..………………….. 2.3.3. Proteinler ………………………………………………..………………….. 2.3.3.1. Birinci (Primer) Yapı ………………………………………………..…….. 2.3.3.2. İkincil (Sekonder) Yapı ……………………………………………..…….. 2.3.3.3. Üçüncül (Tersiyer) Yapı ……………………………………………..…….. 2.3.3.4. Dördüncül (Kuaterner) Yapı ………………………………………..…….. 2.4. Denaturasyon ……….......…….………………………………………………. 2.4.1. Aldehitler ve Ketonların Denaturasyon Etkisi .……………………….……. 2.4.2. Asit ve Bazları Denaturasyon Etkisi .............................................………….. 2.4.3. Organik Çözücüler, Nötral Tuzlar ve Deterjanların Denaturasyon Etkisi ….. 2.4.4. İndirgeyicilerin Denaturasyon Etkisi …………….………………………….. 2.5. Tespit Solüsyonlarının İçeriği ………………………………………………….. 2.5.1. Protein Sabitleyiciler ..……………………..………………………………… 2.5.2. Antiseptikler ...…………………….………………………………………….. 2.5.3. Renk Koruyucular - İyileştiriciler ….………………………………………… 2.5.4. Yüzey Aktif Maddeler ….………………………….………………………… 2.5.5. Nemlendiriciler (Yumuşatıcılar) ….……………………..…………………… 2.5.6. Antikoagulanlar ….……………………………….…………………………… 2.5.7. Tamponlar ….………………………………………….……………………… 2.6. İyonik Sıvılar ….………………………………………………………………… 3. GEREÇ VE YÖNTEM ….…………………………...…………………………… 3.1. Gereç ………………………………….………………………………………… 3.2. Yöntem ……………………………….………………………………………… 3.2.1. Tespit (Pefüzyon), Saklama (İmmersiyon) Solüsyonları ve Tespit İşlemi …… 3.2.2. Verilerin Toplanması ve Değerlendirilmesi …...……………………………… 4. BULGULAR ...………………………….………………………………………… 4.1. Kadavraların Dokunsal ve Görsel Değerlendirme Sonuçları …………………… 4.2. Renk ve Sertlik Analiz Sonuçları .…….………………………………………… 4.3. Gonyometrik Ölçüm Sonuçları ............................................................…….…… 5 5 7 8 11 11 13 15 15 16 17 17 17 19 20 20 21 21 21 22 23 24 24 25 25 25 27 27 27 27 31 34 34 47 55 5. TARTIŞMA ………………………………………………………………………. 61 6. SONUÇ VE ÖNERİLER …………………………………………………………. 68 KAYNAKLAR ………………………………………………………………………. 69 EKLER ………………………………………………………………………………. 80 Ek 1 (ADÜ HADYEK) ……………………………………………………………… 80 BİLİMSEL ETİK BEYANI ......................................................................................... 81 ÖZ GEÇMİŞ ................................................................................................................ 8

Scanning Faces: A Deep Learning Approach to Studying the Eye Movements of Prosopagnosic Subjects

Healthy individuals show certain biases when scanning faces, such as looking towards the eyes and the centre of the face, regions that are most informative for identifying people. Prosopagnosia is the inability to recognize faces, and some reports suggest that subjects with this condition have anomalous scanning of faces. Our goal was to determine whether a data- driven approach using artificial intelligence could identify the key scanning aspects that differentiated prosopagnosic subjects from controls

Gender in facial representations: a contrast-based study of adaptation within and between the sexes.

Face aftereffects are proving to be an effective means of examining the properties of face-specific processes in the human visual system. We examined the role of gender in the neural representation of faces using a contrast-based adaptation method. If faces of different genders share the same representational face space, then adaptation to a face of one gender should affect both same- and different-gender faces. Further, if these aftereffects differ in magnitude, this may indicate distinct gender-related factors in the organization of this face space. To control for a potential confound between physical similarity and gender, we used a Bayesian ideal observer and human discrimination data to construct a stimulus set in which pairs of different-gender faces were equally dissimilar as same-gender pairs. We found that the recognition of both same-gender and different-gender faces was suppressed following a brief exposure of 100 ms. Moreover, recognition was more suppressed for test faces of a different-gender than those of the same-gender as the adaptor, despite the equivalence in physical and psychophysical similarity. Our results suggest that male and female faces likely occupy the same face space, allowing transfer of aftereffects between the genders, but that there are special properties that emerge along gender-defining dimensions of this space

Experimental results.

<p>Threshold change ratios for the three main conditions are computed by dividing the contrast threshold in each case with the corresponding baseline threshold, such that a value of one indicates no effect of adaptation. Values below one represent lowered thresholds, i.e., a facilitation effect, and values above one represent elevated thresholds, i.e., a suppression effect. Geometric averages across nine subjects are shown. Adapting to the same face as the test face lowered thresholds below baseline performance, and adapting to a different face elevated thresholds. Most importantly, adapting to a different face elevated thresholds even more if it also differed in gender from the test face. Stars represent significant pair-wise differences. Errorbars are 68% bootstrap confidence intervals.</p

Hypothetical model predictions for magnitude of figural aftereffects in same-gender, cross-gender and gender-contingent conditions based on proximity in face space.

<p>(A) Effects of adaptation are dependent on the similarity between the adapting and test stimuli. Perceptual aftereffects peak at a neighboring location, then gradually fall off as the test stimuli become more dissimilar. For example, the effect of adapting to a contracted female face will have greater impact on a female test face (red curve, ‘a’) than a male test face (red curve, ‘d’) simply due to greater similarity between faces of the same gender compared to faces of different genders. The result is cross-gender transfer of aftereffects (‘d’) that is less than the aftereffect for the same-face (‘a’). The same logic applies to the effects of adapting to an expanded male face (blue curve). (B) Gender-contingent aftereffects are obtained by simultaneously adapting to a male and a female face with opposing figural distortions. The fact that contingent aftereffects are usually found to be smaller in magnitude than same-gender aftereffects are predicted by an additive effect of the simultaneous adaptation: Adapting to a contracted female face generates a large perceptual bias on a female test face (red curve, ‘a’), which is offset by a smaller but opposite bias caused by adapting to an expanded male face (blue curve, ‘b’). Thus the contingent aftereffect magnitude ‘c’ will be equivalent to the same-gender aftereffect ‘<i>a</i>’ reduced by the cross-gender aftereffect ‘b’.</p