Wilson, M.A. and McNaughton, B.L. (1994). Reactivation of hippocampal ensemble memories during sleep. Science, 265, 676-679.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... the hippocampal representation for the stored pattern is activated (hippocampal pattern completion) and, consequently, the stored E P pattern gets reinstated; 3) during consolidation, the patterns stored in the HC are activated intrinsically and randomly (this may happen during slow wave sleep [11]) which leads to the reinstatement of cortical patterns in the same way as during completion, at least given appropriate weights. Prior to the end of consolidation, the hippocampus guides the process of probabilistic pattern completion by providing something like a very strong prior over the ....

Wilson, M.A. and McNaughton, B.L. (1994). Reactivation of hippocampal ensemble memories during sleep. Science, 265, 676-679.

....strategy assumes information read out from the hippocampus in these experiments to be continuous. The findings in the current analysis are consistent with this assumption. In cases in which information read out may be discontinuous, such as hippocampal reactivation during sleep (Buszaki, 1989; Wilson and McNaughton, 1994; Skaggs and McNaughton, 1996) the Bayes filter could give misleading results, and analysis with the ML algorithm may be more appropriate. Decoding stage: a statistical paradigm for neural spike train decoding Our decoding analysis offers analytic results not provided by other procedures. ....

Wilson MA, McNaughton BL (1994) Reactivation of hippocampal ensemble memories during sleep. Science 265:676 -- 679.

....be achieved accidentally or incidentally, while the robot is moving to fulfill some other goal. All of these potential differences between intent (selected action) and actual behaviour are also applicable to animals. However, except in special (usually invasive) experiments (e.g. Tanji 1996, Wilson McNaughton 1994), the selection of the act cannot be registered independent of its successful completion. This was the motivation for the methodological decision by the behaviourists to use the act as their level of description and experimentation it was considered the only level of description open to ....

....faces, but not both same time. From (Gleitman 1995, p. 213) Neurological Evidence of Hierarchical Control The most promising area of research in examining mental context is the very recent advance in neuroscience of multi cell recordings of various brain regions, most typically the hippocampus (Wilson McNaughton 1994, Wiener 1996) The hippocampus is a particularly interesting brain region because it has extremely sparse representations that is, relatively few cells are firing in any particular context. This is believed to be an attribute of its function, where it seems to be involved in the fast ....

Wilson, M. & McNaughton, B. (1994), `Reactivation of hippocampal ensemble memories during sleep', Science 261, 1227--1232.

....sample rate, the cycle rate increases by an order of magnitude. This suggests that the robot should engage in phased periods of activity, for example switching between sense intensive work like exploration and compute intensive work like map learning. This strategy is found in most mammals (e.g. (Wilson McNaughton 1994)) and is something the Edmund drive system should facilitate. We intend to model this in the near future. In ENRL the object metaphor, particularly encapsulation, does break down in relation to sensing. This is not surprising given that external to the robot, information is flowing in streams. ....

....My starting hypothesis is that episodic memory is not stored with chronological ordering. Recent events are clearer simply because of decay caused by interference, which is aggravated by change in context. We know that changing context changes the indexing of the place cells in the hippocampus (Wilson McNaughton 1994), a memory organ implicated in storing episodic memory (McClelland, McNaughton O Reilly 1995) Recent research indicates that human sequence learning can best be modeled by associating elements of the sequence graded relation to its start and end (Henson 1996) Consolidated motor sequence memory ....

Wilson, M. & McNaughton, B. (1994), `Reactivation of Hippocampal Ensemble Memories During Sleep', Science 261, 1227--1232.

....converges to a certain value. We are feeding the recorded place vectors of the same run several times consequently into the neural network. In doing so, the result of the data is more comparable, additionally, it also resembles the playing back of neural states in the hippocampus during REM sleep (Wilson and McNaughton, 1994). In gure 15, the activity of the winner neuron is plotted over a run of 100 place vector readings. The dotted line shows the rst iterations of the run, the solid line shows the 100 th iteration. The certainty of being at a certain place increases over time. In gure 16, ten learning runs of ....

Wilson, J. and McNaughton, B. L. (1994). Reactivation of Hippocampal Ensemble Memories During Sleep. Science, 265:676-679.

....input provides a method for obtaining a distributed representation. There is evidence that in natural systems, information is also represented in a distributed format. As can, for instance, be shown in experiments with rats, the hippocampus seems to use an ensemble code for location information [Wilson and McNaughton, 1994]. Properties: In the input state network, the self recurrent feedback loops are used to fulfil the continuity requirement described in Section 3. The strength of this network model is that the actual input is delayed and combined with the new input at the next time step. Thus the original input ....

M.A. Wilson and B.L. McNaughton. Reactivation of Hippocampal Ensemble Memories During Sleep. Science, 265, 1994. 29. July 1994.

....is not stored with chronological ordering. Recent events are clearer simply because of decay caused by interference, which may be aggravated by change in context. Neurophysiological research demonstrates that a change of context alters the indexing of the place cells in the hippocampus in rats (Wilson McNaughton 1994). Recent psychological research indicates that human sequence learning can best be modeled by associating elements of the sequence graded relation to its start and end (Henson 1996) Consolidated motor sequence memory has particular cells dedicated to units of behavior and to motor transitions ....

Wilson, M. & McNaughton, B. (1994), `Reactivation of Hippocampal Ensemble Memories During Sleep', Science 261, 1227--1232.

....measured and if the training induced shifts in synaptic efficacy, represented by DeltaW ij , are known. Unfortunately, it is not possible to measure large numbers of synaptic weights directly, but it may be possible to infer them from firing correlation measurements (Georgopoulos et al. 1994; Wilson McNaughton, 1994). If the asymmetric, short latency firing correlation matrix is used in place of DeltaW ij in equation (3.2) or (6.11) a map representing the effect of training on a neuronal representation of sensory data can be generated. Results like those in figure 1 would provide remarkable insight into the ....

Wilson, M.A. and McNaughton, B.L. 1994 Reactivation of hippocampal ensemble memories during sleep. Science 265:676-679.

....the performance. This experiment suggests that hippocampus is transiently involved in the memory storage process and that other structures maintain the permanent memories. Recent work by Wilson and McNaughton hints at interesting possibilities for the role of the hippocampus in consolidation [Wilson and McNaughton, 1994]. They developed a technique by which they can record simultaneously from about a hundred neurons in a rat hippocampus. Their recordings as the rat traversed a new environment confirmed the existence of cells in the hippocampus that are sensitive to particular locations in the environment ....

Wilson, M. A. and McNaughton, B. L. (1994). Reactivation of hippocampal ensemble memories during sleep. Science, 265:676-- 679.

....that some animals and humans may use the hippocampus for a temporary storage of episodic memories [20] Some theories of memory consolidation postulate that the episodic memories stored in the hippocampus are transferred into some regions of the neocortical systems during sleep. Recent experiments [25] on the hippocampal place cells of rats show evidence that those cells reinstate the information acquired during daytime active behavior. McClelland [17] further assumes that the hippocampus is involved in the reinstatement of the neocortical patterns in long term memory and that the hippocampus ....

M. Wilson. Reactivation of hippocampal ensemble memories during sleep. Science, Vol. 265, pp. 676-- 679, 1994.

....sample rate, the cycle rate increases by an order of magnitude. This suggests that the robot should engage in phased periods of activity, for example switching between sense intensive work like exploration and compute intensive work like map learning. This strategy is found in most mammals (e.g. [35]) and is facilitated by the Edmund drive system. We are developing a navigation system based on this for the robot have modeled such behavior in simulation. Correcting scheduling problems can also be done incrementally; switching elements between competences and drives can also occur at the ....

Matthew Wilson and Bruce McNaughton. Reactivation of hippocampal ensemble memories during sleep. Science, 261:1227--1232, 29 July 1994.

....During sleep, the recent routes are replayed because, when primed with noise, the hippocampal formation settles The Role of the Hippocampus 75 to a stable representation of a location, which then drifts along the routes stored in the CA3 recurrent connections. McNaughton, Skaggs, and Wilson (Wilson McNaughton, 1994; Skaggs McNaughton, 1996) have reported data supporting this hypothesis: simultaneous extracellular recordings from hippocampal pyramidal cells have shown that cells tend to fire in the same sequence during slow wave sleep as they did during recent experience in an environment. We discuss this ....

.... LTP in the CA3 recurrent connections combined with random exploration of an environment would produce a connection function where the learned synaptic weight is inversely related to distance between place field centers was first made by Muller et al. 1991) McNaughton, Skaggs, and Wilson (Wilson McNaughton, 1994; Skaggs McNaughton, 1996) have shown that after exploring an arena, cells with overlapping place fields in that arena are more likely to be correlated during subsequent sleep than those with nonoverlapping fields. However, none of these authors suggested the competitive dynamics that produces ....

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Wilson, M. A., & McNaughton, B. L. (1994). Reactivation of hippocampal ensemble memories during sleep. Science, 265, 676--679.

....complex pre wired connections within the hippocampus. Each place cell needs to be more strongly connected to cells with place fields nearby (in some chart) than to cells with place fields that are distant (in all charts) There is evidence that this connection structure exists after exploration [ Wilson and McNaughton, 1994 ] but the theory requires that the connection structure be in place before exploration. According to this theory, on entering a novel environment, one location on one chart (map) will win the competition among competing representations and become the preferred representation for the entry ....

....In practice, we have found that most HC cells simulated with this model show at most one place field within a reference frame, but occasionally, some cells do show two subfields. Cells with multiple subfields have been reported in real animals (e.g. O Keefe and Nadel, 1978, Muller et al. 1991a, Wilson and McNaughton, 1994, Markus et al. 1995) As the animal explores the environment, LTP occurs along the learnable (dashed) connections. We assume that this LTP is Hebbian and rectified at 0, so that synaptic strength can only increase. We do not model LTD. Returning to a familiar environment. According to the ....

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M. A. Wilson and B. L. McNaughton. Reactivation of hippocampal ensemble memories during sleep. Science, 265:676--679, 1994.

.... for most pixels (Figures 2 and 13) The independence is no longer exactly true for cells with highly overlapping place fields [cf. Eichenbaum, Wiener, Shapiro Cohen (1989) In fact, the correlations in the firing of these cells could be strengthened rapidly by Hebbian type learning process (Wilson McNaughton, 1994; Skaggs McNaughton, 1996; Blum Abbott, 1996; Mehta, Barnes McNaughton, 1997) In such a situation, the independence assumption is only a simplifying approximation for theoretical convenience. There is additional information in correlated firing that could be exploited to improve the ....

Wilson, M. A. & McNaughton, B. L. (1994). Reactivation of hippocampal ensemble memories during sleep.

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Wilson, M.A. and McNaughton, B.L. (1994) Reactivation of hippocampal ensemble memories during sleep Science 265, 676--679

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Wilson, M. (1994) 'Reactivation of hippocampal ensemble memories during sleep', Science, 265, pp. 676--679.

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