Top-down projections to the primary visual areas necessary for object recognition: A case study
نویسندگان
چکیده
We present a patient, who, following a right posterior ischemia, showed a selective deficit in visually recognising pictures, objects and faces. She was able to read and comprehend any kind of written material and could recognise letters and numbers. Her inability to recognise pictures did not arise from a deficit at the structural description level and/or from a poor semantic knowledge of the stimuli. We argue that her recognition deficit arose from an inability in combining the different elements of the visual stimuli in an unitary percept. Results are discussed in terms of dissociations between local versus global processing, as well as bottom-up versus top-down mechanisms.
منابع مشابه
A cortical mechanism for triggering top-down facilitation in visual object recognition.
The majority of the research related to visual recognition has so far focused on bottom-up analysis, where the input is processed in a cascade of cortical regions that analyze increasingly complex information. Gradually more studies emphasize the role of top-down facilitation in cortical analysis, but it remains something of a mystery how such processing would be initiated. After all, top-down ...
متن کاملTop-down facilitation of visual recognition.
Cortical analysis related to visual object recognition is traditionally thought to propagate serially along a bottom-up hierarchy of ventral areas. Recent proposals gradually promote the role of top-down processing in recognition, but how such facilitation is triggered remains a puzzle. We tested a specific model, proposing that low spatial frequencies facilitate visual object recognition by in...
متن کاملTop-down facilitation of visual object recognition: object-based and context-based contributions.
The neural mechanisms subserving visual recognition are traditionally described in terms of bottom-up analysis, whereby increasingly complex aspects of the visual input are processed along a hierarchical progression of cortical regions. However, the importance of top-down facilitation in successful recognition has been emphasized in recent models and research findings. Here we consider evidence...
متن کاملMechanisms of top-down facilitation in perception of visual objects studied by FMRI.
Prior knowledge regarding the possible identity of an object facilitates its recognition from a degraded visual input, though the underlying mechanisms are unclear. Previous work implicated ventral visual cortex but did not disambiguate whether activity-changes in these regions are causal to or merely reflect an effect of facilitated recognition. We used functional magnetic resonance imaging to...
متن کاملUrban Vegetation Recognition Based on the Decision Level Fusion of Hyperspectral and Lidar Data
Introduction: Information about vegetation cover and their health has always been interesting to ecologists due to its importance in terms of habitat, energy production and other important characteristics of plants on the earth planet. Nowadays, developments in remote sensing technologies caused more remotely sensed data accessible to researchers. The combination of these data improves the obje...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Vision Research
دوره 50 شماره
صفحات -
تاریخ انتشار 2010