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Competing visual flicker reveals attention-like rivalry in the fly brain.

van Swinderen B - Front Integr Neurosci (2012)

Bottom Line: There is increasing evidence that invertebrates such as flies display selective attention (van Swinderen, 2011a), although parallel processing of simultaneous cues remains difficult to demonstrate in such tiny brains.Local field potential (LFP) activity in the fly brain is associated with stimulus selection and suppression (van Swinderen and Greenspan, 2003; Tang and Juusola, 2010), like in other animals such as monkeys (Fries et al., 2001), suggesting that similar processes may be working to control attention in vastly different brains.Visual competition dynamics in the fly brain were dependent on the rate of pattern presentation, suggesting that attention-like switching in insects is tuned to the pace of visual changes in the environment rather than simply the passage of time.

View Article: PubMed Central - PubMed

Affiliation: Queensland Brain Institute, The University of Queensland Brisbane, QLD, Australia.

ABSTRACT
There is increasing evidence that invertebrates such as flies display selective attention (van Swinderen, 2011a), although parallel processing of simultaneous cues remains difficult to demonstrate in such tiny brains. Local field potential (LFP) activity in the fly brain is associated with stimulus selection and suppression (van Swinderen and Greenspan, 2003; Tang and Juusola, 2010), like in other animals such as monkeys (Fries et al., 2001), suggesting that similar processes may be working to control attention in vastly different brains. To investigate selective attention to competing visual cues, I recorded brain activity from behaving flies while applying a method used in human attention studies: competing visual flicker, or frequency tags (Vialatte et al., 2010). Behavioral fixation in a closed-loop flight arena increased the response to visual flicker in the fly brain, and visual salience modulated responses to competing tags arranged in a center-surround pattern. Visual competition dynamics in the fly brain were dependent on the rate of pattern presentation, suggesting that attention-like switching in insects is tuned to the pace of visual changes in the environment rather than simply the passage of time.

No MeSH data available.


Related in: MedlinePlus

Object shape, novelty location, and image velocity modulate visual salience effects. (A) Left panels: Novelty could either be from a “+” to an “×” or vice versa. The size of either 7 Hz object is identical (30° square, 20 pixels), the surrounding 9 Hz display never changes. Right panels: the same data as in Figure 3G, partitioned into either transition sequence (indicated above the histograms). n = 12 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Only 7 Hz effects are shown. (B) Effect of novelty location/timing. Left panels: the same data as in A was divided according to where in the rotation sequence changes occurred (in front of the fly, left rose plot; behind, right rose plot), and 7 Hz power ratios (3 s after/3 s before) recalculated for each situation (right panels), n = 12 flies, P < 0.05, **P < 0.01, by t-test compared to 1.0 (dashed line). (C) 7 Hz ratios (3 s after/3 s before) for a faster moving pattern with a period of 1.5–2 s, or a slower moving pattern with a period of 4–4.5 s. n = 9 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Rose plots on left indicate positions where changes occurred for either set of experiments.
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Figure 4: Object shape, novelty location, and image velocity modulate visual salience effects. (A) Left panels: Novelty could either be from a “+” to an “×” or vice versa. The size of either 7 Hz object is identical (30° square, 20 pixels), the surrounding 9 Hz display never changes. Right panels: the same data as in Figure 3G, partitioned into either transition sequence (indicated above the histograms). n = 12 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Only 7 Hz effects are shown. (B) Effect of novelty location/timing. Left panels: the same data as in A was divided according to where in the rotation sequence changes occurred (in front of the fly, left rose plot; behind, right rose plot), and 7 Hz power ratios (3 s after/3 s before) recalculated for each situation (right panels), n = 12 flies, P < 0.05, **P < 0.01, by t-test compared to 1.0 (dashed line). (C) 7 Hz ratios (3 s after/3 s before) for a faster moving pattern with a period of 1.5–2 s, or a slower moving pattern with a period of 4–4.5 s. n = 9 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Rose plots on left indicate positions where changes occurred for either set of experiments.

Mentions: Does object shape matter? Subdividing the same dataset further revealed a similar loss of responsiveness to the 7 Hz center after 40 s, regardless of whether change had been from a “+” to an “×” or vice versa, although only increased LFP responsiveness for a “+” was significant (Figure 4A). Previous studies have shown that vertical bars are attractive in a similar paradigm (Maimon et al., 2008), which may explain the increased response to the “+,” which includes a vertical component. A different question was whether the novelty salience effects depended on where changes happened in the fly's visual field. For example, a change occurring behind the fly (where it cannot be seen) might not be as salient as a change happening in front of the fly, which might be startling. This appeared to be the case, although the peak novelty effect (at ~20 s elapsed time) was still significant (P < 0.05) for changes occurring behind the fly (Figure 4B), suggesting that this is not entirely a startle phenomenon and that the fly may be primed to respond to changes at the center of the visual display after 20 s. Together, these more detailed analyses of one frequency tag (7 Hz center) indicate that responsiveness in the brain LFP depends on elapsed time between novelty events.


Competing visual flicker reveals attention-like rivalry in the fly brain.

van Swinderen B - Front Integr Neurosci (2012)

Object shape, novelty location, and image velocity modulate visual salience effects. (A) Left panels: Novelty could either be from a “+” to an “×” or vice versa. The size of either 7 Hz object is identical (30° square, 20 pixels), the surrounding 9 Hz display never changes. Right panels: the same data as in Figure 3G, partitioned into either transition sequence (indicated above the histograms). n = 12 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Only 7 Hz effects are shown. (B) Effect of novelty location/timing. Left panels: the same data as in A was divided according to where in the rotation sequence changes occurred (in front of the fly, left rose plot; behind, right rose plot), and 7 Hz power ratios (3 s after/3 s before) recalculated for each situation (right panels), n = 12 flies, P < 0.05, **P < 0.01, by t-test compared to 1.0 (dashed line). (C) 7 Hz ratios (3 s after/3 s before) for a faster moving pattern with a period of 1.5–2 s, or a slower moving pattern with a period of 4–4.5 s. n = 9 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Rose plots on left indicate positions where changes occurred for either set of experiments.
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Figure 4: Object shape, novelty location, and image velocity modulate visual salience effects. (A) Left panels: Novelty could either be from a “+” to an “×” or vice versa. The size of either 7 Hz object is identical (30° square, 20 pixels), the surrounding 9 Hz display never changes. Right panels: the same data as in Figure 3G, partitioned into either transition sequence (indicated above the histograms). n = 12 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Only 7 Hz effects are shown. (B) Effect of novelty location/timing. Left panels: the same data as in A was divided according to where in the rotation sequence changes occurred (in front of the fly, left rose plot; behind, right rose plot), and 7 Hz power ratios (3 s after/3 s before) recalculated for each situation (right panels), n = 12 flies, P < 0.05, **P < 0.01, by t-test compared to 1.0 (dashed line). (C) 7 Hz ratios (3 s after/3 s before) for a faster moving pattern with a period of 1.5–2 s, or a slower moving pattern with a period of 4–4.5 s. n = 9 flies, *P < 0.05, by t-test compared to 1.0 (dashed line). Rose plots on left indicate positions where changes occurred for either set of experiments.
Mentions: Does object shape matter? Subdividing the same dataset further revealed a similar loss of responsiveness to the 7 Hz center after 40 s, regardless of whether change had been from a “+” to an “×” or vice versa, although only increased LFP responsiveness for a “+” was significant (Figure 4A). Previous studies have shown that vertical bars are attractive in a similar paradigm (Maimon et al., 2008), which may explain the increased response to the “+,” which includes a vertical component. A different question was whether the novelty salience effects depended on where changes happened in the fly's visual field. For example, a change occurring behind the fly (where it cannot be seen) might not be as salient as a change happening in front of the fly, which might be startling. This appeared to be the case, although the peak novelty effect (at ~20 s elapsed time) was still significant (P < 0.05) for changes occurring behind the fly (Figure 4B), suggesting that this is not entirely a startle phenomenon and that the fly may be primed to respond to changes at the center of the visual display after 20 s. Together, these more detailed analyses of one frequency tag (7 Hz center) indicate that responsiveness in the brain LFP depends on elapsed time between novelty events.

Bottom Line: There is increasing evidence that invertebrates such as flies display selective attention (van Swinderen, 2011a), although parallel processing of simultaneous cues remains difficult to demonstrate in such tiny brains.Local field potential (LFP) activity in the fly brain is associated with stimulus selection and suppression (van Swinderen and Greenspan, 2003; Tang and Juusola, 2010), like in other animals such as monkeys (Fries et al., 2001), suggesting that similar processes may be working to control attention in vastly different brains.Visual competition dynamics in the fly brain were dependent on the rate of pattern presentation, suggesting that attention-like switching in insects is tuned to the pace of visual changes in the environment rather than simply the passage of time.

View Article: PubMed Central - PubMed

Affiliation: Queensland Brain Institute, The University of Queensland Brisbane, QLD, Australia.

ABSTRACT
There is increasing evidence that invertebrates such as flies display selective attention (van Swinderen, 2011a), although parallel processing of simultaneous cues remains difficult to demonstrate in such tiny brains. Local field potential (LFP) activity in the fly brain is associated with stimulus selection and suppression (van Swinderen and Greenspan, 2003; Tang and Juusola, 2010), like in other animals such as monkeys (Fries et al., 2001), suggesting that similar processes may be working to control attention in vastly different brains. To investigate selective attention to competing visual cues, I recorded brain activity from behaving flies while applying a method used in human attention studies: competing visual flicker, or frequency tags (Vialatte et al., 2010). Behavioral fixation in a closed-loop flight arena increased the response to visual flicker in the fly brain, and visual salience modulated responses to competing tags arranged in a center-surround pattern. Visual competition dynamics in the fly brain were dependent on the rate of pattern presentation, suggesting that attention-like switching in insects is tuned to the pace of visual changes in the environment rather than simply the passage of time.

No MeSH data available.


Related in: MedlinePlus