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Anatoli Gorchetchnikov and Michael E. Hasselmo (2002) "A model of hippocampal circuitry mediating goal-driven navigation in a familiar environment." Neurocomputing, Volumes 44-46, Pages 423-427 
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[Abstract]
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"we present a detailed model of how the components of hippocampal circuitry might guide movement toward flexible goal locations in a familiar environment."
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"The model contains the following features: (1) Route planning is based on the spread of activation; (2) The spread of activation is gated by environmental constraints; (3) Multiple goals are visited sequentially; (4) Spatial representation is goal-independent; (5) Place cells predict the future position by about one \theta-cycle; (6) The model selects the shorter path among alternatives.

[Introduction]
"Many models have focused on the role of the hippocampus in spatial navigation toward particular goal locations [2{4,7]."


   [2] K. I. Blum and L. F. Abbott, A model of spatial map formation in the
        hippocampus of the rat, Neural Computation, 8 (1996) 85-93.

   [3] M. A. Brown and P. E. Sharp, Simulation of spatial learning in the Morris water
       maze by a neural network model of the hippocampal formation and nucleus
       accumbens, Hippocampus, 5 (1995) 171-188.

   [4] N. Burgess, J. G. Donnett, K. J. Jeffery, and J. O'Keefe, Robotic and neuronal
       simulation of the hippocampus and rat navigation, Philosophical Transactions
       of Royal Society: Biological Sciences, 352 (1997) 1535{1543.

   [7] W. Gerstner and L. F. Abbott, Learning navigational maps through
       potentiation and modulation of hippocampal place cells, Journal of
       Computational Neuroscience, 4, 1 (1997) 79-94.

"... most previous models utilize the same long-term memory representations for both the spatial environment and the goal location. For example, the strength of CA3 recurrent connections might depend upon the direction to the goal [2,7] or output connections from hippocampal place cells are directly modffied to store the direction to the goal [3,4]."

"These representations would be very dicult to utilize in navigation tasks where goal location changes on a regular basis, as in the 8-arm radial maze [12], or the Morris water maze [11] with day to day changes in platform location.


   [11] R. Morris et al., Place navigation impaired in rats with hippocampal lesions,
        Nature, 297, 5868 (1982) 681{683.

   [12] D. Olton et al., Hippocampus, space and memory, Behavioral and Brain
        Sciences, 2 (1979) 313-365.

"Recordings show that at least in rodents many of hippocampal neurons have spatial receptive elds. These place cells were identied in all regions of the hippocampus and dentate gyrus [10], as well as in the entorhinal cortex [13], the subiculum [14], and parasubiculum [15]."


"Evidence suggests that the hippocampal place code preserves the topology of adjacent locations at the cost of absolute distance, and, therefore, the hippocampal formation itself is responsible for route following navigation [16]."

   [16] M. A. Wilson, The neural correlates of place and direction, in: M. Gazzaniga, ed., 
        The New Cognitive Neurosciences, (The MIT Press, Cambridge, MA, 1999) 589-599.


[Metohd]
"The general theoretical foundations for the model were discussed in the greater detail elsewhere [9]."

   [9] M. E. Hasselmo, J. Hay, M. Ilyn, and A. Gorchetchnikov, Neuromodulation, theta rhythm 
       and hippocampal spatial navigation, Neural Networks. (in press).


"ECII activation propagates to CA3, and also provides the feedback to EC-III, which prevents the further spreading of activation in the neighborhood of current location, so that only the adjacent locations that belong to the first found (and most likely the shortest) path to the goal are activated."


[Discussion]
"In addition, the model uses activity timing dependent upon the relative timing
of  frequency oscillations in the hippocampus, which appear during exploration
[5] and are phase locked to stimulus acquisition in working memory [8]."

     [5] G. Buzsaki, L.-W. S. Leung, and C. H. Vanderwolf, Cellular bases of
         hippocampal EEG in the behaving rat, Brain Research Reviews, 6 (1983) 139-171.

     [8] B. Givens, Stimulus-evoked resetting of the dentate theta rhythm: Relation to
         working memory, Neuroreport, 8 (1996) 159{163.

[Conclusion]
"These modifications will make this model a full scale implementation
of the theoretical background provided by Hasselmo et al [9]." => see avobe