Spiking neural P system is a computing device recently introduced as a bridge between spiking neural nets and membrane computing. In this paper we focus on normal forms of these systems while preserving their computational power. We show that certain combinations of existing normal forms are possible without loss of computational power, thus answering partially open problems stated in [3,8]. We...

A new method of designing a robust nonlinear observer is presented for a class of neural mass models by using the Lur'e system theory and the projection lemma. The observer is robust towards input uncertainty and measurement noise. It is applied to estimate the unmeasured membrane potential of neural populations from the electroencephalogram (EEG) produced by the neural mass models. An illustra...

Cortical neurons in vivo fire quite irregularly. Previous studies about the origin of such irregular neural dynamics have given rise to two major models: a balanced excitation and inhibition model, and a model of highly synchronized synaptic inputs. To elucidate the network mechanisms underlying synchronized synaptic inputs and account for irregular neural dynamics, we investigate a spatially e...

PURPOSE The retinal pigment epithelium (RPE) lines the interface between the neural retina and the choroid. Early in chicken development, the beta 1 family of integrins resides in the apical (facing the neural retina) and basolateral (facing the choroid) membranes of RPE. Later in development, integrins reside only in the basolateral membranes, which is more typical of simple transporting epith...

In the neurogenic phase of CNS development, the proliferating progenitors are found medially within the neuroepithelium. The adherens junctions on the apical membrane of proliferating neural progenitors allow for cell-cell adhesion and medial stratification. In contrast, differentiating neuronal precursors delaminate and migrate laterally, establishing the laminar layers. Apical adherens juncti...

We have previously identified a molecule (named cell adhesion molecule [CAM]) that is involved in the in vitro aggregation of neural cells from chick embryos. In the present report, specific anti-CAM antibodies have been used to demonstrate that CAM is localized in neural tissues, and is associated with the plasma membrane of retinal cells and neurites. Furthermore, it has been shown by antibod...

The combination of biological neurons with microelectronic devices, such as transistors, in circuits affords the potential for development of robust neural prosthetic devices. Successful implementation of the technology will rely on the improvement of the electrical characteristics of the neural electronic interface. In a recent study, we investigated the impact of various factors on the fideli...

We have developed a closed-eye technique for transplanting cultured rabbit retinal epithelial cells to Bruch's membrane of the rabbit. A glass micropipette containing a suspension of 3H-thymidine-labeled, cultured retinal pigment epithelial (RPE) cells is inserted through a pars plana incision and positioned adjacent to the neural retina. A jet stream from the pipette is used to make a small re...

Lectins (SBA and PSA) were used to provoke crowding and structural modifications of the presumptive ectoderm cell surface in order to investigate the role of the membrane organization of the competent target cells in neural induction. Are specific characteristics of the cell surface essential for this phenomenon to occur? From amphibian gastrulae, it is possible to obtain neural induction in vi...

Lectins (SBA and PSA) were used to provoke crowding and structural modifications of the presumptive ectoderm cell surface in order to investigate the role of the membrane organization of the competent target cells in neural induction. Are specific characteristics of the cell surface essential for this phenomenon to occur? From amphibian gastrulae, it is possible to obtain neural induction in vi...