Biology Reference
In-Depth Information
Chapter 10
S
YNAPTIC
P
LASTICITY AND
M
NEMONIC
E
NCODING
BY
H
IPPOCAMPAL
F
ORMATION
P
LACE
C
ELLS
M. Tsanov
1
, J. R. Brotons-Mas
1,2
, M. V. Sanchez-Vives
2,3
and S. M. O'Mara
1
1
Institute of Neuroscience, Trinity College, Dublin 2, Ireland
2
Instituto de Neurociencias de Alicante, Universidad Miguel Hernandez-CSIC,
San Juan de Alicante, Spain
3
ICREA-Institut d'Investigacios Biomediques August Pi i Sunyer,
Villarroel 170, 08036, Barcelona, Spain
A
BSTRACT
In order to guide behavior, sensory information has to be analyzed in the context of
previous memory and attention-related episodes. Such episodes can represent sequences
of sensory items in space and time and the learning of such sequences is known as
episodic memory. The formation of this memory is believed to be mediated in the
hippocampal region, and is generated by the changes in neuronal efficacy known as long-
term synaptic plasticity.
In this chapter we will
review some of the up-to-date
models of
synaptic plasticity and their relation to the structural and functional memory processes
demonstrated by
behavioral and electrophysiological experiments. The main aim of this
chapter is to describe how neuroplastic mechanisms work together to create network
representations of previous experiences. Here, we specifically consider experience-
dependent modulation of hippocampal cell firing in the context of spatial memory
formation. The information encoded by the firing patterns of these neurons represents
sequences of events and places that will be stored in a long-term manner. However, the
precise connection between the neuronal firing rate changes and long-term synaptic
plasticity is still controversial. A significant challenge remains to reveal how the
processing, encoding and storage of highly-integrated sensory information occurs within
the circuitry of the hippocampus.
Recent electrophysiological findings in combination
with computational memory models have allowed us to obtain closer insight into how
