Article Figures & Data
Figures
- Figure 1.
Coronal sections showing the extent of experimental lesions. Schematics of largest and smallest lesions are shown for the PER group (A) and the POR group (B). The largest lesion is shown in dark gray and the smallest lesion is shown in light gray. Scale bar: 1 mm.
- Figure 2.
Examples of experimental lesion damage in the PER and the POR. Damage was identified as missing cortex, thinning cortex, missing cells, and pyknotic cells. A, In this example from a PER subject, there was damage to the superficial layers and middle layers of the dorsoventral extent of the PER. Layer I is thinner than in control subjects. There are areas in which cells have disappeared or have become pyknotic in superficial layers and deep Layer V. B, This POR subject shows damage to deep layers exhibited as pyknotic cells as well as thinning of cortical layers. Again, secondary damage would be expected in superficial layers because of the death of deep layer cells that project to superficial layers. In both cases, there is likely secondary damage that is not apparent. See text for details. In this case, there is some damage in dorsally adjacent temporal ventral cortex (TEv) and possibly to the ventrally adjacent lateral entorhinal area (LEA). In both cases, there is likely secondary damage that is not apparent. See text for details. Scale bar: 500 μm.
- Figure 3.
Group performance during shaping. A, The PER group compared with both the SHAM and the POR groups required significantly more sessions to reach criterion. They also showed lower accuracies (B), higher omissions, especially in later shaping stages (C), and longer latencies to make an incorrect choice, especially early in shaping (D). E, The POR group also showed marginally higher premature responses than the PER group. F, The POR group differed from the SHAM group only in the pattern of perseverations, showing more perseverations at some limited holds and fewer at others. No other differences in shaping were observed. InS, initial shaping. Group differences: *p < 0.05, **p < 0.01, ***p < 0.001, #p < 0.075. POR versus SHAM, group by limited hold: p < 0.0001, xxx.
- Figure 4.
Group performance during training. A, Percent accuracy across blocks of five sessions. B, Overall percent accuracy. C, Latencies to respond on correct trails across blocks of five sessions. D, Overall latencies on correct trials. The PER group exhibited significantly lower accuracies than the POR group and marginally significantly lower accuracy than the SHAM group. The POR group exhibited significantly faster latencies on correct training trials than the PER group and marginally significantly faster latencies than the SHAM group. InS, initial shaping. Group differences: *p < 0.05, #p < 0.075.
- Figure 5.
Performance during baseline and attentional challenges. Shown in each panel are the mean of the challenge baseline sessions (Ave BL) along with mean challenge performance along with group differences. Ave BL are shown for simplicity though each challenge was compared with its own baseline. It is important to note that, because there were differences in acquisition, baselines differ across groups. A, For percent (Pct) accuracy, the PER group was significantly or marginally significantly lower than both SHAM and POR groups on Ave BL and each of the challenges. B, For Pct omissions, the PER group was marginally significantly higher than SHAM and POR groups on baseline performance, and significantly higher than both on short challenges. The PER group was also significantly higher than the POR group n variable ITI and tone challenges. C, For Pct premature responses, the ER group was significantly higher than the SHAM group on noise challenges. Group differences: *p < 0.05, **p < 0.01, ***p < 0.001, #p < 0.075. Solid lines indicate main effects of group and dashed lines indicate significant group by condition interactions.
- Figure 6.
Latencies to respond during baseline and attentional challenges. Shown in each panel are the mean average baselines (Ave BL) latencies and challenge latencies along with group differences. A, For correct trials, the POR group was significantly or marginally significantly faster than both SHAM and PER groups on baseline and challenges. For the noise challenge, there were group by condition interactions such that the PER group was faster relative to baseline than the POR or SHAM groups. B, For latencies on incorrect trials, the POR group was significantly faster than SHAM and PER on baseline performance and the tone challenge. C, For latencies to retrieve rewards there was a marginally significant group by condition interaction between the PER and POR groups for the tone challenge. The POR group was faster at baseline and the tone challenge, but the difference was less for the challenge. Significance: *p < 0.05, **p < 0.01, ***p < 0.001, #p < 0.075. Solid lines indicate main effects of group and dashed lines indicate significant group by condition interactions.
- Figure 7.
Impact of attentional challenges on accuracy, omissions, and premature responses during attentional challenges. Shown are ratios of performance on attentional challenges relative to baseline for accuracy, omitted trials, and premature responses. Differences here reflect group by condition interactions (prior baseline vs challenge). The challenge ratio is calculated as CR = (challenge – baseline)/(challenge + baseline) such that scores near zero indicate little change from baseline during the challenge. Positive and negative scores indicate increases and decreases from baseline, respectively. R is shown for the noise distraction during target presentation (A). Both the SHAM and POR groups showed significantly increased omissions relative to baseline. There were no significant group by condition interactions for shortened target presentations (B), variable ITIs (C), or the tone presented during the ITI (D). Both the SHAM and POR groups showed more omissions during the noise challenge (A). Group differences: *p < 0.05, ***p < 0.001, #p < 0.075.
- Figure 8.
Impact of attentional challenges on latencies to respond. Shown are ratios of performance on attentional challenges relative to baseline for latencies on correct and incorrect trials as well as latencies to retrieve rewards. As in Figure 7, differences here reflect group by condition interactions. The challenge ratio is calculated as CR = (challenge – baseline)/(challenge + baseline) such that scores near zero indicate little change from baseline during the challenge. Positive and negative scores indicate increases and decreases from baseline, respectively. A, For both the SHAM and POR groups, latencies changed in directions opposite that of the PER group relative to baseline. There were no significant group by condition interactions for shortened target presentations (B), variable ITIs (C), or the tone presented during the ITI (D). Both the SHAM and POR groups showed more omissions during the noise challenge (A). Group differences: *p < 0.05.
Tables
Region AP ML DV PER −3.3 5.7 −6.7 −4.3 5.7 −6.7 −5.3 5.7 −6.7 −6.3 5.7 −6.7 −7.4 5.7 −6.2 POR 0.54 5.3 −5.5 −0.46 5.3 −5.5 −1.46 5.3 −5.5 Perirhinal anteroposterior (AP) coordinates are measured in mm from bregma. Postrhinal AP coordinates are measured in mm from λ. Mediolateral (ML) coordinates are measured in mm to the left and to the right from the midline. Dorsoventral (DV) coordinates are measured in mm from skull.
Region Noise prior to target Short target Variable ITI Tone during ITI SHAM Accuracy - ↓↓↓ ↓↓↓ - Premature responses - - - - Omissions ↑↑ - ↑↑↑ - Perseverations - - - - Correct latencies - - ↑↑ - Incorrect latencies - - ↑↑↑ - Reward latencies - - ↓↓ - PER Accuracy - - - - Premature responses ↑↑↑ - ↓↓ ↑ Omissions - - - - Perseverations - - - - Correct latencies ↓ - ↑ - Incorrect latencies ↓ - ↑↑ - Reward latencies - - - - POR Accuracy - - - - Premature responses - - - - Omissions ↑↑ ↑ - - Perseverations - - - - Correct latencies ↑↑ - ↑↑↑ - Incorrect latencies ↑↑ - ↑↑↑ - Reward latencies ↑ - ↓↓ - Results of within subject repeated measures ANOVA in which each attentional challenge was compared with its own baseline for each lesion group. ↑↑↑p < 0.001, ↑↑p < 0.05, ↑p < 0.075. SHAM, controls; PER, perirhinal cortex; POR, postrhinal cortex.
In this issue
