Lim SL, Padmala S, Pessoa L.
Neuropsychologia, in press
It has been hypothesized that the amygdala mediates the processing advantage of emotional items. In the present study, we employed functional magnetic resonance imaging (fMRI) to investigate how fear conditioning affected the visual processing of task-irrelevant faces. We hypothesized that faces previously paired with shock (threat faces) would more effectively vie for processing resources during conditions involving spatial competition. To investigate this question, following conditioning, participants performed a letter-detection task on an array of letters that was superimposed on task-irrelevant faces. Attentional resources were manipulated by having participants perform an easy or a difficult search task. Our findings revealed that threat fearful faces evoked stronger responses in the amygdala and fusiform gyrus relative to safe fearful faces during low-load attentional conditions, but not during high-load conditions. Consistent with the increased processing of shock-paired stimuli during the low-load condition, such stimuli exhibited increased behavioral priming and fMRI repetition effects relative to unpaired faces during a subsequent implicit-memory task. Overall, our results suggest a competition model in which affective significance signals from the amygdala may constitute a key modulatory factor determining the neural fate of visual stimuli. In addition, it appears that such competitive advantage is only evident when sufficient processing resources are available to process the affective stimulus.
Showing posts with label processing load. Show all posts
Showing posts with label processing load. Show all posts
Tuesday, January 29, 2008
Thursday, December 20, 2007
ARTICLE UPDATE - Neural response to emotional pictures is unaffected by concurrent task difficulty: An event-related potential study.
Hajcak G, Dunning JP, Foti D.
Behavioural Neuroscience, 121, 1156-1162
The late positive potential (LPP) is an event-related potential that is enhanced when viewing arousing (pleasant and unpleasant) pictures compared to neutral pictures. The affective modulation of the LPP is believed to reflect the increased attention to, and perceptual processing of, emotional stimuli. The present study examined whether concurrent task difficulty (performing mathematics) would modulate the LPP while participants viewed emotionally arousing stimuli. Results indicated that the LPP was larger following pleasant and unpleasant stimuli than it was following neutral stimuli; moreover, the magnitude of this increase was not influenced by concurrent task difficulty. This finding suggests that the affective modulation of neural activity during picture viewing is relatively automatic and is insusceptible to competing task demands. Results are further discussed in terms of the LPP's role in motivated attention and implications for research on emotion regulation.
Behavioural Neuroscience, 121, 1156-1162
The late positive potential (LPP) is an event-related potential that is enhanced when viewing arousing (pleasant and unpleasant) pictures compared to neutral pictures. The affective modulation of the LPP is believed to reflect the increased attention to, and perceptual processing of, emotional stimuli. The present study examined whether concurrent task difficulty (performing mathematics) would modulate the LPP while participants viewed emotionally arousing stimuli. Results indicated that the LPP was larger following pleasant and unpleasant stimuli than it was following neutral stimuli; moreover, the magnitude of this increase was not influenced by concurrent task difficulty. This finding suggests that the affective modulation of neural activity during picture viewing is relatively automatic and is insusceptible to competing task demands. Results are further discussed in terms of the LPP's role in motivated attention and implications for research on emotion regulation.
Thursday, April 05, 2007
ARTICLE UPDATE - Time course of attentional modulation on automatic emotional processing
Sonia Doallo, Fernando Cadaveira and Socorro Rodríguez Holguín
Neuroscience Letters, in press
In a previous study using event-related potentials (ERPs) [S. Doallo, S. Rodríguez Holguín, F. Cadaveira, Attentional load affects automatic emotional processing: evidence from event-related potentials, Neuroreport 17 (2006) 1797–1801], we reported that differential responses to unattended peripheral affective pictures, as reflected by N1-P2 modulations at posterior regions, are modulated by attentional load at fixation. Here, new analyses of these data were performed to evaluate whether a sustained, broadly distributed, negative shift in the unattended pictures ERP waveforms, which displayed larger amplitudes for emotional stimuli, reflects an additional differential response to the emotional content. Under low-load conditions, unpleasant (versus neutral) pictures elicited greater negativities in the 80–140 ms latency range over frontocentral sites and more centroparietally distributed from 200 to 280 ms. These findings provide further evidence of the time course of emotional processing at unattended locations and its modulation by attentional load.
Neuroscience Letters, in press
In a previous study using event-related potentials (ERPs) [S. Doallo, S. Rodríguez Holguín, F. Cadaveira, Attentional load affects automatic emotional processing: evidence from event-related potentials, Neuroreport 17 (2006) 1797–1801], we reported that differential responses to unattended peripheral affective pictures, as reflected by N1-P2 modulations at posterior regions, are modulated by attentional load at fixation. Here, new analyses of these data were performed to evaluate whether a sustained, broadly distributed, negative shift in the unattended pictures ERP waveforms, which displayed larger amplitudes for emotional stimuli, reflects an additional differential response to the emotional content. Under low-load conditions, unpleasant (versus neutral) pictures elicited greater negativities in the 80–140 ms latency range over frontocentral sites and more centroparietally distributed from 200 to 280 ms. These findings provide further evidence of the time course of emotional processing at unattended locations and its modulation by attentional load.
Friday, December 15, 2006
ARTICLE UPDATE - Attentional load affects automatic emotional processing: evidence from event-related potentials.
Doallo S, Holguin SR, Cadaveira F.
Neuroreport, 17, 1797-1801
One open question on the relation between attention and emotion concerns the automatic processing of emotional visual stimuli outside the focus of attention. This study examined to what extent the emotional processing at unattended locations is modulated by the processing load at attended locations. Event-related potentials were measured to task-irrelevant unpleasant and neutral pictures briefly presented at peripheral locations while participants performed a visual central task varying in load (low and high load). Unpleasant pictures elicited larger amplitudes of N1-P2 at parietoccipital and occipital sites than that of neutral pictures. This effect was only significant in the low-load condition. Data suggest that brain responses to affective value of task-irrelevant peripheral pictures are modulated by attentional load at fixation.
Neuroreport, 17, 1797-1801
One open question on the relation between attention and emotion concerns the automatic processing of emotional visual stimuli outside the focus of attention. This study examined to what extent the emotional processing at unattended locations is modulated by the processing load at attended locations. Event-related potentials were measured to task-irrelevant unpleasant and neutral pictures briefly presented at peripheral locations while participants performed a visual central task varying in load (low and high load). Unpleasant pictures elicited larger amplitudes of N1-P2 at parietoccipital and occipital sites than that of neutral pictures. This effect was only significant in the low-load condition. Data suggest that brain responses to affective value of task-irrelevant peripheral pictures are modulated by attentional load at fixation.
ARTICLE UPDATE - The impact of processing load on emotion.
D.G.V. Mitchell, M. Nakic, D. Fridberg, N. Kamel, D.S. Pine and R.J.R. Blair
NeuroImage, in press
This event-related fMRI study examined the impact of processing load on the BOLD response to emotional expressions. Participants were presented with composite stimuli consisting of neutral and fearful faces upon which semi-transparent words were superimposed. This manipulation held stimulus-driven features constant across multiple levels of processing load. Participants made either (1) gender discriminations based on the face; (2) case judgments based on the words; or (3) syllable number judgments based on the words. A significant main effect for processing load was revealed in prefrontal cortex, parietal cortex, visual processing areas, and amygdala. Critically, enhanced activity in the amygdala and medial prefrontal cortex seen during gender discriminations was significantly reduced during the linguistic task conditions. A connectivity analysis conducted to investigate theories of cognitive modulation of emotion showed that activity in dorsolateral prefrontal cortex was inversely related to activity in the ventromedial prefrontal cortex. Together, the data suggest that the processing of task-irrelevant emotional information, like neutral information, is subject to the effects of processing load and is under top-down control.
NeuroImage, in press
This event-related fMRI study examined the impact of processing load on the BOLD response to emotional expressions. Participants were presented with composite stimuli consisting of neutral and fearful faces upon which semi-transparent words were superimposed. This manipulation held stimulus-driven features constant across multiple levels of processing load. Participants made either (1) gender discriminations based on the face; (2) case judgments based on the words; or (3) syllable number judgments based on the words. A significant main effect for processing load was revealed in prefrontal cortex, parietal cortex, visual processing areas, and amygdala. Critically, enhanced activity in the amygdala and medial prefrontal cortex seen during gender discriminations was significantly reduced during the linguistic task conditions. A connectivity analysis conducted to investigate theories of cognitive modulation of emotion showed that activity in dorsolateral prefrontal cortex was inversely related to activity in the ventromedial prefrontal cortex. Together, the data suggest that the processing of task-irrelevant emotional information, like neutral information, is subject to the effects of processing load and is under top-down control.
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