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Using time-to-contact information to assess potential collision modulates both visual and temporal prediction networks.

Coull JT, Vidal F, Goulon C, Nazarian B, Craig C - Front Hum Neurosci (2008)

Bottom Line: We also demonstrated that the temporal derivative of the perceptual index tau (tau-dot) held predictive value for making collision judgements and varied inversely with activity in primary visual cortex (V1).Finally, egocentric viewpoints provoked a response bias for reporting collisions, rather than no-collisions, reflecting increased caution for head-on approaches.Associated increases in SMA activity suggest motor preparation mechanisms were engaged, despite the perceptual nature of the task.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Neurobiologie de la Cognition, Université Aix-Marseille & CNRS Marseille, France. jennifer.coull@univ-provence.fr

ABSTRACT
Accurate estimates of the time-to-contact (TTC) of approaching objects are crucial for survival. We used an ecologically valid driving simulation to compare and contrast the neural substrates of egocentric (head-on approach) and allocentric (lateral approach) TTC tasks in a fully factorial, event-related fMRI design. Compared to colour control tasks, both egocentric and allocentric TTC tasks activated left ventral premotor cortex/frontal operculum and inferior parietal cortex, the same areas that have previously been implicated in temporal attentional orienting. Despite differences in visual and cognitive demands, both TTC and temporal orienting paradigms encourage the use of temporally predictive information to guide behaviour, suggesting these areas may form a core network for temporal prediction. We also demonstrated that the temporal derivative of the perceptual index tau (tau-dot) held predictive value for making collision judgements and varied inversely with activity in primary visual cortex (V1). Specifically, V1 activity increased with the increasing likelihood of reporting a collision, suggesting top-down attentional modulation of early visual processing areas as a function of subjective collision. Finally, egocentric viewpoints provoked a response bias for reporting collisions, rather than no-collisions, reflecting increased caution for head-on approaches. Associated increases in SMA activity suggest motor preparation mechanisms were engaged, despite the perceptual nature of the task.

No MeSH data available.


Related in: MedlinePlus

Predictive value of tau-dot for making “contact” decisions. Mean performance (averaged across subjects) on TTC and colour tasks is plotted for each value of tau-dot for (A) allocentric and (B) egocentric viewpoints. Performance is measured as the proportion of trials in which the subject made a YES response (i.e. when the subject decided that a TTC trial would result in contact, or that a colour trial contained a colour-match). As expected, and for both alloentric and egocentric viewpoints, there was a significant relationship between tau-dot and percentage of trials judged to result in contact (♦), but no significant relationship between tau-dot and the percentage of trials judged to result in a colour-match (). Specifically, the lower the tau-dot value the more likely the subject was to make a “contact” decision. Fitted curves represent the result of the logistic regression analysis. Each value of tau-dot was calculated using distances between the car and wall and the car's motion parameters (Supplementary Material 2). A tau-dot value of −0.5 represents the objective cut-off between a contact and no-contact trial.
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Figure 2: Predictive value of tau-dot for making “contact” decisions. Mean performance (averaged across subjects) on TTC and colour tasks is plotted for each value of tau-dot for (A) allocentric and (B) egocentric viewpoints. Performance is measured as the proportion of trials in which the subject made a YES response (i.e. when the subject decided that a TTC trial would result in contact, or that a colour trial contained a colour-match). As expected, and for both alloentric and egocentric viewpoints, there was a significant relationship between tau-dot and percentage of trials judged to result in contact (♦), but no significant relationship between tau-dot and the percentage of trials judged to result in a colour-match (). Specifically, the lower the tau-dot value the more likely the subject was to make a “contact” decision. Fitted curves represent the result of the logistic regression analysis. Each value of tau-dot was calculated using distances between the car and wall and the car's motion parameters (Supplementary Material 2). A tau-dot value of −0.5 represents the objective cut-off between a contact and no-contact trial.

Mentions: We then examined performance as a function of the tau-dot value for each trial (Figure 2). Logistic regression analysis revealed a significant correlation between tau-dot value and the percentage of trials judged to result in contact (a “yes” decision) for both the TTCego [R2(13) = 0.60, p < 0.001] and TTCallo [R2(13) = 0.79, p < 0.001] conditions. This indicates that the tau-dot value significantly predicted whether subjects would judge a particular scenario to result in contact or not. The lower the tau-dot value, the more likely subjects were to make a contact rather than no-contact decision. Conversely, there was no significant correlation between tau-dot value and the percentage of trials judged to result in a colour-match (a “yes” decision) for either the COLego [R2(13) = 0.03, ns] or COLallo [R2(13) = 0.002, ns] conditions. As expected, this suggests that tau-dot value had no predictive value for making colour judgements. Finally, in order to ensure that dynamic variables other than tau-dot could not also significantly predict TTC performance, we performed two additional logistic regression analyses between performance and (1) the car's final velocity and (2) the duration for which the animation was presented. Neither velocity nor duration significantly correlated with TTC performance in either the allocentric [R2(13) = 0.29 and 0.16, ns, for velocity and duration respectively] or egocentric [R2(13) = 0.13 and 0.05, ns, for velocity and duration respectively] condition.


Using time-to-contact information to assess potential collision modulates both visual and temporal prediction networks.

Coull JT, Vidal F, Goulon C, Nazarian B, Craig C - Front Hum Neurosci (2008)

Predictive value of tau-dot for making “contact” decisions. Mean performance (averaged across subjects) on TTC and colour tasks is plotted for each value of tau-dot for (A) allocentric and (B) egocentric viewpoints. Performance is measured as the proportion of trials in which the subject made a YES response (i.e. when the subject decided that a TTC trial would result in contact, or that a colour trial contained a colour-match). As expected, and for both alloentric and egocentric viewpoints, there was a significant relationship between tau-dot and percentage of trials judged to result in contact (♦), but no significant relationship between tau-dot and the percentage of trials judged to result in a colour-match (). Specifically, the lower the tau-dot value the more likely the subject was to make a “contact” decision. Fitted curves represent the result of the logistic regression analysis. Each value of tau-dot was calculated using distances between the car and wall and the car's motion parameters (Supplementary Material 2). A tau-dot value of −0.5 represents the objective cut-off between a contact and no-contact trial.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2572212&req=5

Figure 2: Predictive value of tau-dot for making “contact” decisions. Mean performance (averaged across subjects) on TTC and colour tasks is plotted for each value of tau-dot for (A) allocentric and (B) egocentric viewpoints. Performance is measured as the proportion of trials in which the subject made a YES response (i.e. when the subject decided that a TTC trial would result in contact, or that a colour trial contained a colour-match). As expected, and for both alloentric and egocentric viewpoints, there was a significant relationship between tau-dot and percentage of trials judged to result in contact (♦), but no significant relationship between tau-dot and the percentage of trials judged to result in a colour-match (). Specifically, the lower the tau-dot value the more likely the subject was to make a “contact” decision. Fitted curves represent the result of the logistic regression analysis. Each value of tau-dot was calculated using distances between the car and wall and the car's motion parameters (Supplementary Material 2). A tau-dot value of −0.5 represents the objective cut-off between a contact and no-contact trial.
Mentions: We then examined performance as a function of the tau-dot value for each trial (Figure 2). Logistic regression analysis revealed a significant correlation between tau-dot value and the percentage of trials judged to result in contact (a “yes” decision) for both the TTCego [R2(13) = 0.60, p < 0.001] and TTCallo [R2(13) = 0.79, p < 0.001] conditions. This indicates that the tau-dot value significantly predicted whether subjects would judge a particular scenario to result in contact or not. The lower the tau-dot value, the more likely subjects were to make a contact rather than no-contact decision. Conversely, there was no significant correlation between tau-dot value and the percentage of trials judged to result in a colour-match (a “yes” decision) for either the COLego [R2(13) = 0.03, ns] or COLallo [R2(13) = 0.002, ns] conditions. As expected, this suggests that tau-dot value had no predictive value for making colour judgements. Finally, in order to ensure that dynamic variables other than tau-dot could not also significantly predict TTC performance, we performed two additional logistic regression analyses between performance and (1) the car's final velocity and (2) the duration for which the animation was presented. Neither velocity nor duration significantly correlated with TTC performance in either the allocentric [R2(13) = 0.29 and 0.16, ns, for velocity and duration respectively] or egocentric [R2(13) = 0.13 and 0.05, ns, for velocity and duration respectively] condition.

Bottom Line: We also demonstrated that the temporal derivative of the perceptual index tau (tau-dot) held predictive value for making collision judgements and varied inversely with activity in primary visual cortex (V1).Finally, egocentric viewpoints provoked a response bias for reporting collisions, rather than no-collisions, reflecting increased caution for head-on approaches.Associated increases in SMA activity suggest motor preparation mechanisms were engaged, despite the perceptual nature of the task.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Neurobiologie de la Cognition, Université Aix-Marseille & CNRS Marseille, France. jennifer.coull@univ-provence.fr

ABSTRACT
Accurate estimates of the time-to-contact (TTC) of approaching objects are crucial for survival. We used an ecologically valid driving simulation to compare and contrast the neural substrates of egocentric (head-on approach) and allocentric (lateral approach) TTC tasks in a fully factorial, event-related fMRI design. Compared to colour control tasks, both egocentric and allocentric TTC tasks activated left ventral premotor cortex/frontal operculum and inferior parietal cortex, the same areas that have previously been implicated in temporal attentional orienting. Despite differences in visual and cognitive demands, both TTC and temporal orienting paradigms encourage the use of temporally predictive information to guide behaviour, suggesting these areas may form a core network for temporal prediction. We also demonstrated that the temporal derivative of the perceptual index tau (tau-dot) held predictive value for making collision judgements and varied inversely with activity in primary visual cortex (V1). Specifically, V1 activity increased with the increasing likelihood of reporting a collision, suggesting top-down attentional modulation of early visual processing areas as a function of subjective collision. Finally, egocentric viewpoints provoked a response bias for reporting collisions, rather than no-collisions, reflecting increased caution for head-on approaches. Associated increases in SMA activity suggest motor preparation mechanisms were engaged, despite the perceptual nature of the task.

No MeSH data available.


Related in: MedlinePlus