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Inevitable evolutionary temporal elements in neural processing: a study based on evolutionary simulations.

Yerushalmi U, Teicher M - PLoS ONE (2008)

Bottom Line: In repeating evolutionary sessions, there was a significant increase during evolution in the mutual information between the evolved agent's temporal neural representation and the external environment.These results suggest that in some fitness landscapes the emergence of temporal elements in neural computation is almost inevitable.Future research using similar evolutionary simulations may shed new light on various biological mechanisms.

View Article: PubMed Central - PubMed

Affiliation: The Leslie and Susan Gonda Interdisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel. uri.yerushalmi@gmail.com

ABSTRACT
Recent studies have suggested that some neural computational mechanisms are based on the fine temporal structure of spiking activity. However, less effort has been devoted to investigating the evolutionary aspects of such mechanisms. In this paper we explore the issue of temporal neural computation from an evolutionary point of view, using a genetic simulation of the evolutionary development of neural systems. We evolve neural systems in an environment with selective pressure based on mate finding, and examine the temporal aspects of the evolved systems. In repeating evolutionary sessions, there was a significant increase during evolution in the mutual information between the evolved agent's temporal neural representation and the external environment. In ten different simulated evolutionary sessions, there was an increased effect of time-related neural ablations on the agents' fitness. These results suggest that in some fitness landscapes the emergence of temporal elements in neural computation is almost inevitable. Future research using similar evolutionary simulations may shed new light on various biological mechanisms.

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Behavioral development during evolution.Red: Proportion of reproduction triggered by agent contacts (as opposed to reproductions initiated by the system when the number of agents was too low). Black: Proportion of agents that developed a basic network (as defined in the text). Blue: Proportion of agent death events triggered by the system because of crowding (as opposed to deaths due to completing the life span period). The values are average proportions measured every 5 generations.
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pone-0001863-g002: Behavioral development during evolution.Red: Proportion of reproduction triggered by agent contacts (as opposed to reproductions initiated by the system when the number of agents was too low). Black: Proportion of agents that developed a basic network (as defined in the text). Blue: Proportion of agent death events triggered by the system because of crowding (as opposed to deaths due to completing the life span period). The values are average proportions measured every 5 generations.

Mentions: As a first step, we tested for changes in the agents' behavior along generations. As shown in Figure 2, the percentage of reproduction resulting from agent contact rose over generations. However, such a development could be a result of collective competence unrelated to individual neural mechanisms. In order to insure that this phenomenon was also based on individual competence, we saved the chromosome data from 200 randomly chosen agents during evolution, and tested each chromosome phenotype in a different environment that had two kinds of static objects: one with a “mate” odor, and the other with a “self” odor. The findings show a significant improvement over evolution in the average proportion of agent-mate contacts each 100 generations. (P = 1.80×10−3, r = 0.58, Spearman's Rank Correlation Test). Thus, during the evolutionary session there was some improvement in individual fitness.


Inevitable evolutionary temporal elements in neural processing: a study based on evolutionary simulations.

Yerushalmi U, Teicher M - PLoS ONE (2008)

Behavioral development during evolution.Red: Proportion of reproduction triggered by agent contacts (as opposed to reproductions initiated by the system when the number of agents was too low). Black: Proportion of agents that developed a basic network (as defined in the text). Blue: Proportion of agent death events triggered by the system because of crowding (as opposed to deaths due to completing the life span period). The values are average proportions measured every 5 generations.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2268971&req=5

pone-0001863-g002: Behavioral development during evolution.Red: Proportion of reproduction triggered by agent contacts (as opposed to reproductions initiated by the system when the number of agents was too low). Black: Proportion of agents that developed a basic network (as defined in the text). Blue: Proportion of agent death events triggered by the system because of crowding (as opposed to deaths due to completing the life span period). The values are average proportions measured every 5 generations.
Mentions: As a first step, we tested for changes in the agents' behavior along generations. As shown in Figure 2, the percentage of reproduction resulting from agent contact rose over generations. However, such a development could be a result of collective competence unrelated to individual neural mechanisms. In order to insure that this phenomenon was also based on individual competence, we saved the chromosome data from 200 randomly chosen agents during evolution, and tested each chromosome phenotype in a different environment that had two kinds of static objects: one with a “mate” odor, and the other with a “self” odor. The findings show a significant improvement over evolution in the average proportion of agent-mate contacts each 100 generations. (P = 1.80×10−3, r = 0.58, Spearman's Rank Correlation Test). Thus, during the evolutionary session there was some improvement in individual fitness.

Bottom Line: In repeating evolutionary sessions, there was a significant increase during evolution in the mutual information between the evolved agent's temporal neural representation and the external environment.These results suggest that in some fitness landscapes the emergence of temporal elements in neural computation is almost inevitable.Future research using similar evolutionary simulations may shed new light on various biological mechanisms.

View Article: PubMed Central - PubMed

Affiliation: The Leslie and Susan Gonda Interdisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel. uri.yerushalmi@gmail.com

ABSTRACT
Recent studies have suggested that some neural computational mechanisms are based on the fine temporal structure of spiking activity. However, less effort has been devoted to investigating the evolutionary aspects of such mechanisms. In this paper we explore the issue of temporal neural computation from an evolutionary point of view, using a genetic simulation of the evolutionary development of neural systems. We evolve neural systems in an environment with selective pressure based on mate finding, and examine the temporal aspects of the evolved systems. In repeating evolutionary sessions, there was a significant increase during evolution in the mutual information between the evolved agent's temporal neural representation and the external environment. In ten different simulated evolutionary sessions, there was an increased effect of time-related neural ablations on the agents' fitness. These results suggest that in some fitness landscapes the emergence of temporal elements in neural computation is almost inevitable. Future research using similar evolutionary simulations may shed new light on various biological mechanisms.

Show MeSH
Related in: MedlinePlus