Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Temporal Specificity in the Cortical Plasticity of Visual Space Representation Interdisciplinary Program in Brain Science Eye Movement & Vision Research LAB Hwang, Jae Won http://www.pgd.hawaii.edu/~cecily/courses/gg313/DA_book/node94.html Cross Correlation • Autocorrelation is the correlation between two copies of the same time-series. • Autocorrelations can be high for large lags if the data “repeats”. http://www.pgd.hawaii.edu/~cecily/courses/gg313/DA_book/node95.html Cross Correlation(cont’d) • Cross Correlation is to compare two different time series at various lags rather than two identical series. • From cross correlation we would expect to learn two things: 1) The strength of the relationship between the two series 2) The lag that maximizes the coherence Spike Timing-dependent Plasticity • A→B stimulation may strengthen a→b connections weaken b→a connections • Synaptic modifications induced by A→B stimuli may cause the receptive fields of both groups to shift toward A. • The shift toward A of receptive fields should cause a rightward shift in perception. Spike Timing of Cortical Neurons Cross Correlation of Model Neurons Changes induced by Conditioning • Intragroup Correlation Changes induced by Conditioning(cont’d) • Intergroup Correlation Shifts in Receptive Fields Human Perception Localization • Conditioning-induced shifts in human perceptual localization. • Three-bar bisection test Conclusion • Asynchronous visual stimuli in different retinal regions induced rapid changes in cortical representation of visual space, which was likely mediated by spike timing-dependent modification of intracortical connections. • Spike timing-dependent modification of intracortical connections provides the most natural explanation, although mechanisms related to contrast adaptation may have caused the conditioning-induced reduction in receptive field size.