| A | B |
|---|
| critical periods | the time during which a given behavior is especially susceptible to—indeed, requires—specific environmental influences in order to develop normally |
| Ocular dominance columns | oThe segregated termination patterns of thalamic inputs representing two eyes in the primary visual cortex of some mammalian species |
| Amblyopia | oDiminished visual acuity, diminished stereopisis, and problems with fusions that arise as a result of failure to establish appropriate visual cortical connections in early life. o Most often is a result of strabismus |
| strabismus | •A misalignment of the two eyes due to improper control of the direction of gaze by the eye muscles (lazy eye) |
| Esotropia | •Convergent strabismus (cross-eyed) |
| Exotropia | • Divergent strabismus |
| Hebb’s postulate | o Coordinated activity of a presynaptic terminal and a postsynaptic neuron strengthens the synaptic connection between them o Implies that synaptic terminals strengthened by correlated activity will be retained or sprout new branches, whereas those terminals that are persistently weakened by uncorrelated activity will eventually lose their hold on the postsynaptic cell |
| 3 eyed frog | o when a correlated, visually driven set of inputs is added to another set of similar inputs that normally do not segregate the higher degree of correlation of activity within each set of inputs (vs. between the inputs from the two independent eyes) leads to periodic segregation of connections |
