31,024 research outputs found
Visual pathways from the perspective of cost functions and multi-task deep neural networks
Vision research has been shaped by the seminal insight that we can understand
the higher-tier visual cortex from the perspective of multiple functional
pathways with different goals. In this paper, we try to give a computational
account of the functional organization of this system by reasoning from the
perspective of multi-task deep neural networks. Machine learning has shown that
tasks become easier to solve when they are decomposed into subtasks with their
own cost function. We hypothesize that the visual system optimizes multiple
cost functions of unrelated tasks and this causes the emergence of a ventral
pathway dedicated to vision for perception, and a dorsal pathway dedicated to
vision for action. To evaluate the functional organization in multi-task deep
neural networks, we propose a method that measures the contribution of a unit
towards each task, applying it to two networks that have been trained on either
two related or two unrelated tasks, using an identical stimulus set. Results
show that the network trained on the unrelated tasks shows a decreasing degree
of feature representation sharing towards higher-tier layers while the network
trained on related tasks uniformly shows high degree of sharing. We conjecture
that the method we propose can be used to analyze the anatomical and functional
organization of the visual system and beyond. We predict that the degree to
which tasks are related is a good descriptor of the degree to which they share
downstream cortical-units.Comment: 16 pages, 5 figure
A Quantitative Neural Coding Model of Sensory Memory
The coding mechanism of sensory memory on the neuron scale is one of the most
important questions in neuroscience. We have put forward a quantitative neural
network model, which is self organized, self similar, and self adaptive, just
like an ecosystem following Darwin theory. According to this model, neural
coding is a mult to one mapping from objects to neurons. And the whole cerebrum
is a real-time statistical Turing Machine, with powerful representing and
learning ability. This model can reconcile some important disputations, such
as: temporal coding versus rate based coding, grandmother cell versus
population coding, and decay theory versus interference theory. And it has also
provided explanations for some key questions such as memory consolidation,
episodic memory, consciousness, and sentiment. Philosophical significance is
indicated at last.Comment: 9 pages, 3 figure
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