Adaptation towards scale-free dynamics improves cortical stimulus discrimination at the cost of reduced detection
Fig 3
Adaptation enhances discrimination at the cost of reduced detection: LFP rate coding.
(A) TOP: Typical rasters of LFP peaks (taken from all electrodes, randomly subsampled to 10%) showing response to 13 trials with the same background movie visual stimulus (no foreground). Detection was quantified based on the LFP peak count when the movie was off (pink box) compared to when the movie was on (blue or orange box). BOTTOM: For discrimination a foreground stimulus (4 different red dots) was presented during each of four blocks with 13 trials each, all with the same background movie stimulus. The red dot was presented either during the transient period just after background stimulus onset (blue box) or later during the steady-state (orange box). Note that the different foreground stimuli were more easily distinguished by the LFP peaks in the steady-state compared with the transient, but the presence of the background stimulus is more easily detected based on strong transient response. (B) Summary (n = 14 turtles) of how well the LFP peak count can detect the presence of the background stimulus. All turtles show a decrease in detection from transient to steady-state. (C) Summary of how well the LFP peak count can discriminate the four different foreground stimuli. Most turtles showed an increase in discrimination from transient to steady-state. (D, E) A more refined explanation of detection and discrimination is obtained by comparing to δ. Generally, lower δ resulted in enhanced discrimination and poorer detection, while higher δ exhibited the opposite trend. Thus, power-law distributed (low δ) population dynamics are associated with a functional trade-off, gaining discrimination at the cost of decreased detection. The inset is an expanded view to better show the correlation between discrimination and δ during the steady-state.