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Neural correlates of attentional and mnemonic processing in event-based prospective memory.

Knight JB, Ethridge LE, Marsh RL, Clementz BA - Front Hum Neurosci (2010)

Bottom Line: Specifically, the neural substrates of monitoring for an event-based cue were examined, as well as those perhaps associated with the cognitive processes supporting detection of cues and fulfillment of intentions.Analysis of the event-related potentials (ERP) revealed visual attentional modulations at 140 and 220 ms post-stimulus associated with preparatory attentional processes.Our results suggest preparatory attention may operate by selectively modulating processing of features related to a previously formed event-based intention, as well as provide further evidence for the proposal that dissociable component processes support the fulfillment of delayed intentions.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Georgia Athens, GA, USA.

ABSTRACT
Prospective memory (PM), or memory for realizing delayed intentions, was examined with an event-based paradigm while simultaneously measuring neural activity with high-density EEG recordings. Specifically, the neural substrates of monitoring for an event-based cue were examined, as well as those perhaps associated with the cognitive processes supporting detection of cues and fulfillment of intentions. Participants engaged in a baseline lexical decision task (LDT), followed by a LDT with an embedded PM component. Event-based cues were constituted by color and lexicality (red words). Behavioral data provided evidence that monitoring, or preparatory attentional processes, were used to detect cues. Analysis of the event-related potentials (ERP) revealed visual attentional modulations at 140 and 220 ms post-stimulus associated with preparatory attentional processes. In addition, ERP components at 220, 350, and 400 ms post-stimulus were enhanced for intention-related items. Our results suggest preparatory attention may operate by selectively modulating processing of features related to a previously formed event-based intention, as well as provide further evidence for the proposal that dissociable component processes support the fulfillment of delayed intentions.

No MeSH data available.


(A) Grand-averaged ERP waveforms for LDT/PM-nonwords, lures, LDT/PM-words, and cues for the 350 ms, 400 ms (marked with black arrow), and 520 ms (white arrow) components.  ERP waveforms were derived from electrode Cz which best represented each component. Negative is plotted up. (B) Topographical voltage distributions averaged within time windows centered on the peak latency of each component for which there were significant effects. Positive isopotential lines are in red, negative isopotential lines are in blue. Isopotential line scales are: 0.32 μV/step for 400 ms and 0.29 μV/step for 520 ms ERPs. Due to differences in between condition t-value distributions, lures versus LDT/PM-nonwords and cues versus LDT/PM-words are presented separately for the 400 ms effect. At 520 ms post-stimulus, these comparisons only revealed a significant effect for cues versus LDT/PM-words. (C) Plots of t-values (absolute value taken) over the head surface indicate the sensor clusters for which there were significant effects in comparisons of lures versus LDT/PM-nonwords and cues versus LDT/PM-words for the 400 and 520 ms components. The critical t-value (t = 2.3281) is marked on the scale. (D) Topographical voltage distribution averaged within a time window centered on the 350 ms peak. Isopotential line scale is: 0.31 μV/step. Due to similarities in topographic distributions, Cues and lures are averaged and presented as one topography for the 350 ms ERP that was only elicited by intention-related items.
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Figure 4: (A) Grand-averaged ERP waveforms for LDT/PM-nonwords, lures, LDT/PM-words, and cues for the 350 ms, 400 ms (marked with black arrow), and 520 ms (white arrow) components. ERP waveforms were derived from electrode Cz which best represented each component. Negative is plotted up. (B) Topographical voltage distributions averaged within time windows centered on the peak latency of each component for which there were significant effects. Positive isopotential lines are in red, negative isopotential lines are in blue. Isopotential line scales are: 0.32 μV/step for 400 ms and 0.29 μV/step for 520 ms ERPs. Due to differences in between condition t-value distributions, lures versus LDT/PM-nonwords and cues versus LDT/PM-words are presented separately for the 400 ms effect. At 520 ms post-stimulus, these comparisons only revealed a significant effect for cues versus LDT/PM-words. (C) Plots of t-values (absolute value taken) over the head surface indicate the sensor clusters for which there were significant effects in comparisons of lures versus LDT/PM-nonwords and cues versus LDT/PM-words for the 400 and 520 ms components. The critical t-value (t = 2.3281) is marked on the scale. (D) Topographical voltage distribution averaged within a time window centered on the 350 ms peak. Isopotential line scale is: 0.31 μV/step. Due to similarities in topographic distributions, Cues and lures are averaged and presented as one topography for the 350 ms ERP that was only elicited by intention-related items.

Mentions: Data analyses were performed using programs written in Matlab. First, to identify ERP peaks that were above baseline noise level, grand averaged plots were derived for each condition. Due to interference of motor-related activations occurring after 600 ms resulting from button presses (i.e., responses began occurring around this time point for some participants), we focused our analysis on the cortical activations occurring in the first 600 ms epoch following each stimulus presentation. There were identifiable, above-baseline, peaks for each condition around 140, 220, 400, and 520 ms post-stimulus (see Figures 1–4). An additional peak was present only for the PM condition at 350 ms post-stimulus. The latencies of these peaks did not differ significantly as a function of condition. The latencies of peaks in the grand averaged data were used as guidelines for determining the individual peak time points; scalp potentials were averaged within 20 ms time windows centered on the latency of each peak. A set of planned contrasts at each ERP peak were used to evaluate the main hypotheses: (i) to test for word/nonword differences, LDT-words were compared to LDT-nonwords and PM-words were compared to PM-nonwords, (ii) to test for monitoring (preparatory attention) effects, PM-words were compared to LDT-words and PM-nonwords were compared to LDT-nonwords, and (iii) to test for cue-specific effects, PM-cues were compared to PM-lures, PM-cues were compared to (PM-words + LDT-words)/2, and PM-lures were compared to (PM-nonwords + LDT-nonwords)/2. [Due to the low percentage of cues that were missed (M = 12%), a sufficiently stable average could not be obtained for missed prospective cues, thus a comparison of detected cues to missed cues could not be conducted.]


Neural correlates of attentional and mnemonic processing in event-based prospective memory.

Knight JB, Ethridge LE, Marsh RL, Clementz BA - Front Hum Neurosci (2010)

(A) Grand-averaged ERP waveforms for LDT/PM-nonwords, lures, LDT/PM-words, and cues for the 350 ms, 400 ms (marked with black arrow), and 520 ms (white arrow) components.  ERP waveforms were derived from electrode Cz which best represented each component. Negative is plotted up. (B) Topographical voltage distributions averaged within time windows centered on the peak latency of each component for which there were significant effects. Positive isopotential lines are in red, negative isopotential lines are in blue. Isopotential line scales are: 0.32 μV/step for 400 ms and 0.29 μV/step for 520 ms ERPs. Due to differences in between condition t-value distributions, lures versus LDT/PM-nonwords and cues versus LDT/PM-words are presented separately for the 400 ms effect. At 520 ms post-stimulus, these comparisons only revealed a significant effect for cues versus LDT/PM-words. (C) Plots of t-values (absolute value taken) over the head surface indicate the sensor clusters for which there were significant effects in comparisons of lures versus LDT/PM-nonwords and cues versus LDT/PM-words for the 400 and 520 ms components. The critical t-value (t = 2.3281) is marked on the scale. (D) Topographical voltage distribution averaged within a time window centered on the 350 ms peak. Isopotential line scale is: 0.31 μV/step. Due to similarities in topographic distributions, Cues and lures are averaged and presented as one topography for the 350 ms ERP that was only elicited by intention-related items.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2821175&req=5

Figure 4: (A) Grand-averaged ERP waveforms for LDT/PM-nonwords, lures, LDT/PM-words, and cues for the 350 ms, 400 ms (marked with black arrow), and 520 ms (white arrow) components. ERP waveforms were derived from electrode Cz which best represented each component. Negative is plotted up. (B) Topographical voltage distributions averaged within time windows centered on the peak latency of each component for which there were significant effects. Positive isopotential lines are in red, negative isopotential lines are in blue. Isopotential line scales are: 0.32 μV/step for 400 ms and 0.29 μV/step for 520 ms ERPs. Due to differences in between condition t-value distributions, lures versus LDT/PM-nonwords and cues versus LDT/PM-words are presented separately for the 400 ms effect. At 520 ms post-stimulus, these comparisons only revealed a significant effect for cues versus LDT/PM-words. (C) Plots of t-values (absolute value taken) over the head surface indicate the sensor clusters for which there were significant effects in comparisons of lures versus LDT/PM-nonwords and cues versus LDT/PM-words for the 400 and 520 ms components. The critical t-value (t = 2.3281) is marked on the scale. (D) Topographical voltage distribution averaged within a time window centered on the 350 ms peak. Isopotential line scale is: 0.31 μV/step. Due to similarities in topographic distributions, Cues and lures are averaged and presented as one topography for the 350 ms ERP that was only elicited by intention-related items.
Mentions: Data analyses were performed using programs written in Matlab. First, to identify ERP peaks that were above baseline noise level, grand averaged plots were derived for each condition. Due to interference of motor-related activations occurring after 600 ms resulting from button presses (i.e., responses began occurring around this time point for some participants), we focused our analysis on the cortical activations occurring in the first 600 ms epoch following each stimulus presentation. There were identifiable, above-baseline, peaks for each condition around 140, 220, 400, and 520 ms post-stimulus (see Figures 1–4). An additional peak was present only for the PM condition at 350 ms post-stimulus. The latencies of these peaks did not differ significantly as a function of condition. The latencies of peaks in the grand averaged data were used as guidelines for determining the individual peak time points; scalp potentials were averaged within 20 ms time windows centered on the latency of each peak. A set of planned contrasts at each ERP peak were used to evaluate the main hypotheses: (i) to test for word/nonword differences, LDT-words were compared to LDT-nonwords and PM-words were compared to PM-nonwords, (ii) to test for monitoring (preparatory attention) effects, PM-words were compared to LDT-words and PM-nonwords were compared to LDT-nonwords, and (iii) to test for cue-specific effects, PM-cues were compared to PM-lures, PM-cues were compared to (PM-words + LDT-words)/2, and PM-lures were compared to (PM-nonwords + LDT-nonwords)/2. [Due to the low percentage of cues that were missed (M = 12%), a sufficiently stable average could not be obtained for missed prospective cues, thus a comparison of detected cues to missed cues could not be conducted.]

Bottom Line: Specifically, the neural substrates of monitoring for an event-based cue were examined, as well as those perhaps associated with the cognitive processes supporting detection of cues and fulfillment of intentions.Analysis of the event-related potentials (ERP) revealed visual attentional modulations at 140 and 220 ms post-stimulus associated with preparatory attentional processes.Our results suggest preparatory attention may operate by selectively modulating processing of features related to a previously formed event-based intention, as well as provide further evidence for the proposal that dissociable component processes support the fulfillment of delayed intentions.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Georgia Athens, GA, USA.

ABSTRACT
Prospective memory (PM), or memory for realizing delayed intentions, was examined with an event-based paradigm while simultaneously measuring neural activity with high-density EEG recordings. Specifically, the neural substrates of monitoring for an event-based cue were examined, as well as those perhaps associated with the cognitive processes supporting detection of cues and fulfillment of intentions. Participants engaged in a baseline lexical decision task (LDT), followed by a LDT with an embedded PM component. Event-based cues were constituted by color and lexicality (red words). Behavioral data provided evidence that monitoring, or preparatory attentional processes, were used to detect cues. Analysis of the event-related potentials (ERP) revealed visual attentional modulations at 140 and 220 ms post-stimulus associated with preparatory attentional processes. In addition, ERP components at 220, 350, and 400 ms post-stimulus were enhanced for intention-related items. Our results suggest preparatory attention may operate by selectively modulating processing of features related to a previously formed event-based intention, as well as provide further evidence for the proposal that dissociable component processes support the fulfillment of delayed intentions.

No MeSH data available.