The Journal of Neuroscience, August 2, 2006, ():
Progression of Cellular Adaptations in Medial Prefrontal and Orbitofrontal Cortex in Response to Repeated Amphetamine
J. Neurosci. Homayoun and Moghaddam
26: 8025
Supplemental data
Files in this Data Supplement:
- supplemental material
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Supplementary Figure 1. Proportion of neurons with sustained firing rate responses during early and late post-amphetamine periods. The distribution of sustained responses on days 1 and challenge 1 (Figure 5A-B) were separately calculated within two distinct windows of early (min 0-60) and late (min 60-150) post-injection periods. Compared to day 1, amphetamine challenge had a more pronounced effect on mPFC decrease responses during the late window (A), and on OFC increase responses during the early window (B). Red, increase responses, Blue, decrease responses.
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Supplementary Figure 2. Relationship between changes in neuronal firing and instrumental responding. Scatter plots depict the relative change in behavioral response rate (correct response rate post-drug compared to baseline) against average change in neuronal firing rates (inhibitory responses in mPFC, A, excitatory responses in OFC, B). The line shows the linear regression (mPFC, r = 0.72, p < 0.001, OFC, r = 0.53, p < 0.05). In both regions, the significant correlation between behavior and neuronal firing persisted even when the average firing of all units was used instead of those of the most prevalent types (data not shown).
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Supplementary Figure 3. Comparison of amphetamine effects on neuronal firing during periods of active instrumental responding. For each animal, only periods of active instrumental responding (maximum inter-response interval of 20 sec) during post-amphetamine period were selected and compared to periods of similar behavioral activity during baseline. This analysis was limited to Day 1 amphetamine data as severe behavioral impairment on subsequent treatment days did not allow similar analysis. A) Effect on average firing rate. Each bar shows the mean ± S.E.M. of average normalized firing rate of all units recorded in one region. Dotted line indicates no change from baseline. B) Distribution of response types. For this analysis, units displaying a minimum of 15% change in post-drug firing rate were considered to have a significant response (Red, increase, > 115% of baseline, Blue, decrease, < 85% of baseline). Note that this analysis does not include periods of severe behavioral impairment that are associated with maximal changes in neuronal firing (Figure 9), and therefore tends to underestimate the amphetamine effect.
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Supplementary Figure 4. Between-session comparisons of the magnitude of phasic task-related changes in firing. The normalized magnitude of significant phasic responses to food consumption and instrumental nosepoke during the baseline period were averaged and compared between sessions in mPFC (A) and OFC (B). An increase in the value of Y axis (phasic response magnitude) from 0 to 0.5 indicates an increasingly stronger phasic response (both excitatory and inhibitory). * p < 0.05 compared to all other sessions.
