Cortical synaptic circuitry develops rapidly in the second postnatal week, simultaneous with experience-dependent turnover of dendritic spines. To relate the emergence of sensory maps to synaptogenesis, we recorded synaptic potentials evoked by whisker deflection in layer 2/3 neurons from postnatal day (P) 12 to 20. At P12, synaptic responses were undetectable. Only 2 days later in life (P14), ...

Homeostatic plasticity is important to maintain a set level of activity in neuronal circuits and has been most extensively studied in cell cultures following activity blockade. It is still unclear, however, whether activity changes associated with mechanisms of homeostatic plasticity occur in vivo, for example after changes in sensory input. Here, we show that activity levels in the visual cort...

The Late Pleistocene Shanidar 1 older adult male Neandertal is known for the crushing fracture of his left orbit with a probable reduction in vision, the loss of his right forearm and hand, and evidence of an abnormal gait, as well as probable diffuse idiopathic skeletal hyperostosis. He also exhibits advanced external auditory exostoses in his left auditory meatus and larger ones with complete...

Sensory loss leads to widespread adaptation of brain circuits to allow an organism to navigate its environment with its remaining senses, which is broadly referred to as cross-modal plasticity. Such adaptation can be observed even in the primary sensory cortices, and falls into two distinct categories: recruitment of the deprived sensory cortex for processing the remaining senses, which we term...