Activity Patterns in Cortical Dynamics and the Illusion of Localized Representations

Fig. 1

Illustration of the dynamics of the metastable states modeled by neuropercolation; red marks show the start of the erosion of metastable states

Intentional neurodynamics is a biologically motivated connectionist approach. We employ neuropercolation model system to implement principles of intentional neurodynamics using phase transitions [2, 5]. The neuropercolation model describes various dynamical properties of metastable activity patterns in the cortical neuropil. The duration of the metastable patterns is much longer than the very rapid transition from one pattern to the other. This is illustrated in Fig. 1, where the ensemble average activity level is shown over two-dimensional neuroperolation lattices. Rewiring is a critical control parameter, which is used for tuning the characteristic length of the metastable states; for details, see [2, 8].

4 Conclusion

In this work we discuss the question of localized representations in brain recordings. We argue that metastable patterns may be perceived as localized representations with specific meaning in the context of the state of the cortex and inputs. However, such percepts are transitory illusions, and any specific pattern rapidly dissolves (within a fraction of second) and new patterns emerge. Even if the internal and external states of the system remain unchanged during such transitions, the new patterns are different form the previous one due to the changed dynamic trajectory of the brain as a dynamic system.

The proposed analysis may help to reconcile the contradictions inherent in perceived mental representations and to establish a harmony between the everlasting human desire to create tangible chunks of knowledge reflecting our limited grasp of reality and the infinite complexity of the world where our body and brain reside.

Acknowledgements

This work has been presented at the 2013 Dynamic Brain Forum (DBF), as part of ICCN2013, with the kind support of the DBF Foundation. via the Center for Integrative Mathematics, Hokkaido University, Japan. This research has been supported in part by DARPA Physical Intelligence program, through a contract with Hughes Research Laboratory (HRL), Malibu, CA (Dr. N. Srinivasa, Program Director), and by NSF CRCNS Program 13-11165.

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