[Histological lesions and changes in neurotransmitter systems in the aged brain. Discussion of their pathogenic role].

The histological lesions of cerebral senescence are varied. Some, like congophil angiopathy, are specific to pathological ageing while others, such as neurofibrillary degeneration or senile plaques, are common to all senescence processes. All these lesions reflect disorders in neuron metabolism and synaptic function. Concomitant biochemical disturbances indicate perturbations in neurotransmitter systems with decreased activity, and these are instrumental to the pathogenesis of the clinical symptoms observed in cerebral ageing. All these changes occurring during senescence seem to result from disturbances in cerebral metabolism the triggering factor of which has yet to be discovered.