3 types of - 3 types of refinement Topography convergence and postsynaptic compartment Synaptic refinement 1 Increase specificity 2 Mediate

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
3 types of refinement: Topography, convergence, and postsynaptic compartment Synaptic refinement: 1. Increase specificity 2. Mediate Experience-dependent plasticity Refinement in Lateral Geniculate Nucleus First refinement: Eliminate branches in the wrong layer Second refinement: Further prune extra branches in the correct layer Monocular and Binocular Neurons Monocular neurons: cortical neurons responding to only one eye. Mainly in layer IV. Binocular neurons: majority of cortical neurons outside layer IV respond to both eyes. Binocular Deprivation Turns wiring back to normal Suggest that competition is necessary for synapse elimination in monocular deprivation. Similar competition applies to cortical-spinal projections as well. Synaptic Competition Hypothesis Co-activated synapses are stabilized; Inactive synapses, particularly those that are inactive while others are active (firing action potentials), become weakened and in many cases eliminated. The more the use, the stronger it is. Strabismus: Competition Depends on Timing In strabismic kittens, visual stimuli activate different positions on the two retinas, so that cortical neurons are rarely activated by both eyes at the same time. The time delay of retinal synaptic input makes neurons respond stronger to one eye.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/26/2011 for the course BIOL 426 taught by Professor Profgongchen during the Spring '08 term at Pennsylvania State University, University Park.

Page1 / 2

3 types of - 3 types of refinement Topography convergence and postsynaptic compartment Synaptic refinement 1 Increase specificity 2 Mediate

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online