Most of the investigations performed by our program group during the last five-year period belong to basic science. They complement the common human knowledge in the field of neurobiology and neuropathophysiology because nearly all of them were published in the high quality international scientific journals referenced by the SCI.In this respect, we join other developed countries which is also reflected by many common publications with foreign investigators. We investigated plasticity and regeneration in the central and periphral nervous system and muscles. Our research on the plasticity and regeneration in the central nervous system dealt with the animal models of the neurodegenerative diseases of the brain, like Parkinson's disease, with excitotoxic damage of the brain, animal models of epilepsy, organophosphate poisoning, brain repair with trophic factors and cell transplants and with prion diseases, like Creutzfeld-Jacob disease and the "mad cow disease". We investigated the mechanisms of drug addiction and related synaptic plasticity. Of special interest in this regard were the investigations of the substance LEK-8829, sythesized in Slovenia, and of an antioxydant with anticholinesterase properties, both of which might eventually lead to new brain drug development. Monoclonal antibodies specific against the pathological form of the prion protein, which had been developed in Slovenia, and other non-immunogenic substances able to bind with high affinity to the prion protein aggregates, open new diagnostic possibilities in the field of prion diseases. Investigations performed in the field of regeneration and collateral axon sprouting revealed the factors involved in these processes after peripheral nerve injury in experimental animals. Among other things, the potentials of the end-to-side nerve anastomosis technique for nerve repaire were explored. We showed that, by using this technique, it was possible to achieve sensory innervation of the denervated skin due to a permanent nerve transection, and stable recovery of its sensitivity after collateral axon sprouting through the anastomosis. Plasticity of several aspects of skeletal muscles was also investigated. A previously unknown plasticity of the neuromuscular junction in response to different patterns of muscle activation was revealed through explorations of muscle acetylcholinesterase, an indispensable component of the neuromuscular junction. Investigations of plasticity of muscle contractile proteins revealed different adaptive ranges of mature and immature (regenerating) muscle fibers in response to changing patterns of muscle activation. Studies of contractile proteins in the extraocular muscles after transient paralyis by botulinum toxin showed irreversible long tem changes in the myosin heavy chain isoform pattern. This is very important finding because long tem effects of botulinum toxin application for the therapy of strabism in humans have not been adequately explored yet. We developed the method for 3D imaging and analyisi of the cappilary net in muscles which is a considerable methodological novelty.