E M Muro | Search PubMed

PubMed2001

Self-organized critical random Boolean networks.

Standard random Boolean networks display an order-disorder phase transition. We add to the standard random Boolean networks a disconnection rule that couples the control and order parameters. In this way, the system is driven to the critical line transition. Under the influence of perturbations the system points out self-organized critical behavior. Several numerical simulations have been done and compared with a proposed analytical treatment.

Animals↗

PubMed2001

Simulation of plasticity in the adult visual cortex.

Retinal plasticity has been shown in the adult visual nervous system in mammals. Following a retinal lesion (scotoma) there is a reorganization of the cortical receptive field distribution: cortical neurons selective to visual stimuli in the area of the visual field corresponding to the retinal lesion, become selective to other parts of the visual field. In this work, we study this effect with a self-organizing neural network. In a first stage, the network reaches a pattern of connectivity that represents normal development of neuronal selectivity. The scotoma is simulated by perturbing accordingly the properties of a region of the input layer representing the retina. The system evolves to a new receptive field distribution mainly by means of the reorganization of the intra cortical connectivity. No major change of the geniculo cortical connectivity is detected. This may explain the surprisingly short time scale of the event.

Age Factors↗