Spike Train Statistics from Empirical Facts to Theory: The Case of the Retina - Modeling in Computational Biology and Biomedicine - page 251

Chapter 8
Spike Train Statistics from Empirical Facts
to Theory: The Case of the Retina

Bruno Cessac and Adrian G. Palacios

8.1 Introduction

Given a stimulus from the external world (e.g., visual scene, sound or smell)
biological sensors at the periphery of the nervous system are able to transduce
the physical manifestations of this stimulus (light emission, air pressure variations,
chemical concentrations) into sequences of action potentials (spike trains), which
propagate through the nervous system. Then, the brain is able to analyze those
spike trains and infer crucial information on the nature of the stimulus. Critical—
yet unsolved—questions in neuroscience are How is the physical signal encoded
by the nervous system? How does the brain analyze the spike trains? What are
the underlying computational coding principles? At the current stage of scientific
knowledge, answering those questions is still a challenge for biology and computa-
tional neuroscience.
Among sensory systems the retina provides functionality such as detection of
movement, orientation, temporal and spatial prediction, response to flash omissions
and contrast, that were up to recently viewed as the exclusive duty of higher brain
centers [ 24 ]. The retina is an accessible part of the brain [ 15 ] and a prominent
system to study the neurobiology and the underlying computational capacity of the
neural coding. As a matter of fact, there is currently a wide research activity in
understanding how the retina encodes visual information. However, basic questions
are still open, such as: Are the ganglion cells (which send spikes from the eyes to the

B. Cessac ( )
Inria Sophia Antipolis Mediterranee, Neuromathcomp project-team, 2004 Route des Lucioles,
Sophia Antipolis 06902, France
e-mail: [e-mail]
A.G. Palacios
CINV-Centro Interdisciplinario de Neurociencia de Valparaiso, Universidad de Valparaiso,
Harrington 287, Valparaiso 2360102, Chile
e-mail: [e-mail]