Dementia offrontal lobe typeandmotorneuron disease. A Golgi study ofthefrontal cortex

Neuropathological findings ina 38year oldpatient withdementiaoffrontal lobe typeandmotorneurondisease included pyramidaltracts, myelinpallorand neuronloss, gliosis andchromatolysis in thehypoglossal nucleus, together with frontal atrophy, neuronloss, gliosis and spongiosis intheuppercortical layers of thefrontal(andtemporal) lobes. Most remaining pyramidal and nonpyramidalneurons(multipolar, bituftedandbipolar cells) intheupper layers (layers IIandIII) ofthefrontal cortex(areaB)hadreduceddendritic arbors, proximaldendritic varicosities andamputation ofdendrites asrevealed inoptimally stainedrapidGolgisections. Pyramidal cells intheselayers also showeddepletion of dendritic spines. Neuronsin the innerlayerswere preserved. Lossofreceptive surfaces in neuronsoftheuppercortical layers in the frontalcortexare indicative of neuronaldisconnection, andare"hidden"contributory morphological substrates forthedevelopment ofdementia.