Equalization of ocular dominance columns induced by an activity-dependent learning rule and the maturation of inhibition.
نویسندگان
چکیده
Early in development, the cat primary visual cortex (V1) is dominated by inputs driven by the contralateral eye. The pattern then reorganizes into ocular dominance columns that are roughly equally distributed between inputs serving the two eyes. This reorganization does not occur if the eyes are kept closed. The mechanism of this equalization is unknown. It has been argued that it is unlikely to involve Hebbian activity-dependent learning rules, on the assumption that these would favor an initially dominant eye. The reorganization occurs at the onset of the critical period (CP) for monocular deprivation (MD), the period when MD can cause a shift of cortical innervation in favor of the nondeprived eye. In mice, the CP is opened by the maturation of cortical inhibition, which does not occur if the eyes are kept closed. Here we show how these observations can be united: under Hebbian rules of activity-dependent synaptic modification, strengthening of intracortical inhibition can lead to equalization of the two eyes' inputs. Furthermore, when the effects of homeostatic synaptic plasticity or certain other mechanisms are incorporated, activity-dependent learning can also explain how MD causes a shift toward the open eye during the CP despite the drive by inhibition toward equalization of the two eyes' inputs. Thus, assuming similar mechanisms underlie the onset of the CP in cats as in mice, this and activity-dependent learning rules can explain the interocular equalization observed in cat V1 and its failure to occur without visual experience.
منابع مشابه
Supplemental Materials for “Equalization of ocular dominance columns induced by an activity-dependent learning rule and the maturation of inhibition”
متن کامل
Early development of ocular dominance columns.
The segregation of lateral geniculate nucleus (LGN) axons into ocular dominance columns is believed to involve a prolonged, activity-dependent sorting process. However, visualization of early postnatal ferret LGN axons by direct LGN tracer injections revealed segregated ocular dominance columns <7 days after innervation of layer 4. These early columns were unaffected by experimentally induced i...
متن کاملOcular dominance columns in New World monkeys.
Squirrel monkeys normally lack ocular dominance columns in V1. This study shows that squirrel monkeys can exhibit clear ocular dominance columns if they are made strabismic within a few weeks of birth. Columns were seen only in layer 4C beta and were coarser than the overlying blob pattern in the same animal. In physiological recordings from layer 4C of a normal squirrel monkey, single units we...
متن کاملSubplate Neurons: Crucial Regulators of Cortical Development and Plasticity
The developing cerebral cortex contains a distinct class of cells, subplate neurons, which form one of the first functional cortical circuits. Subplate neurons reside in the cortical white matter, receive thalamic inputs and project into the developing cortical plate, mostly to layer 4. Subplate neurons are present at key time points during development. Removal of subplate neurons profoundly af...
متن کاملNpgRJ_Nn_2008 1569..1577
Functional maturation of GABAergic innervation in the developing visual cortex is regulated by neural activity and sensory inputs and in turn influences the critical period of ocular dominance plasticity. Here we show that polysialic acid (PSA), presented by the neural cell adhesion molecule, has a role in the maturation of GABAergic innervation and ocular dominance plasticity. Concentrations o...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of neuroscience : the official journal of the Society for Neuroscience
دوره 29 20 شماره
صفحات -
تاریخ انتشار 2009