David Acunzo PhD

David Acunzo


Research Interests

I am interested in the interplay between visual attention and visual emotional stimuli processing. With John Henderson, I have used eye-tracking to study how emotional items orient overt attention in natural scenes. I am currently using psychophysical and EEG methods to investigate how emotional stimuli and attention modulate early visual processing.

I have worked with Mark van Rossum (IANC) and Graham MacKenzie (Psychology).

Publications:
2012
  Systematic biases in early ERP and ERF components as a result of high-pass filtering
Acunzo, D, MacKenzie, G & van Rossum, MCW 2012, 'Systematic biases in early ERP and ERF components as a result of high-pass filtering' Journal of Neuroscience Methods, vol 209, no. 1, pp. 212-218. DOI: 10.1016/j.jneumeth.2012.06.011
The event-related potential (ERP) and event-related field (ERF) techniques provide valuable insights into the time course of processes in the brain. Because neural signals are typically weak, researchers commonly filter the data to increase the signal-to-noise ratio. However, filtering may distort the data, leading to false results. Using our own EEG data, we show that acausal high-pass filtering can generate a systematic bias easily leading to misinterpretations of neural activity. In particular, we show that the early ERP component C1 is very sensitive to such effects. Moreover, we found that about half of the papers reporting modulations in the C1 range used a high-pass digital filter cut-off above the recommended maximum of 0.1 Hz. More generally, among 185 relevant ERP/ERF publications, 80 used cutoffs above 0.1 Hz. As a consequence, part of the ERP/ERF literature may need to be re-analyzed. We provide guidelines on how to minimize filtering artifacts.
General Information
Organisations: Institute for Adaptive and Neural Computation .
Authors: Acunzo, David, MacKenzie, G. & van Rossum, M.C.W..
Keywords: (, , . )
Number of pages: 7
Pages: 212-218
Publication Date: 2012
Publication Information
Category: Article
Journal: Journal of Neuroscience Methods
Volume: 209
Issue number: 1
Original Language: English
DOIs: 10.1016/j.jneumeth.2012.06.011
2011
  ERP evidence for very early gating of facial expression processing by sustained attention
Acunzo, DJ, MacKenzie, G & van Rossum, MCW 2011, 'ERP evidence for very early gating of facial expression processing by sustained attention' 18th Annual Meeting of the Cognitive Neuroscience Society , San Francisco, United States, 2/04/11 - 5/04/11, .
General Information
Organisations: Institute for Adaptive and Neural Computation .
Authors: Acunzo, David J., MacKenzie, Graham & van Rossum, Mark C. W..
Publication Date: 2011
Publication Information
Category: Poster
Original Language: English
  No emotional 'pop-out' effect in natural scene viewing
Acunzo, DJ & Henderson, JM 2011, 'No emotional 'pop-out' effect in natural scene viewing' Emotion, vol 11, pp. 1134-43.
It has been shown that attention is drawn toward emotional stimuli. In particular, eye movement research suggests that gaze is attracted toward emotional stimuli in an unconscious, automated manner. We addressed whether this effect remains when emotional targets are embedded within complex real-world scenes. Eye movements were recorded while participants memorized natural images. Each image contained an item that was either neutral, such as a bag, or emotional, such as a snake or a couple hugging. We found no latency difference for the first target fixation between the emotional and neutral conditions, suggesting no extrafoveal “pop-out” effect of emotional targets.
However, once detected, emotional targets held attention for a longer time than neutral targets. The failure of emotional items to attract attention seems to contradict previous eye-movement research using emotional stimuli. However, our results are consistent with studies examining semantic drive of overt attention in natural scenes. Interpretations of the results in terms of perceptual and attentional load are provided.
General Information
Organisations: Neuroinformatics DTC.
Authors: Acunzo, David J. & Henderson, J. M..
Pages: 1134-43
Publication Date: 2011
Publication Information
Category: Article
Journal: Emotion
Volume: 11
ISSN: 1528-3542
Original Language: English

Projects:
Timecourse of Allocation of Attention by Emotional Visual Stimuli (PhD)