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Modulation of visual cortical excitability by working memory: effect of luminance contrast of mental imagery.

Cattaneo Z, Pisoni A, Papagno C, Silvanto J - Front Psychol (2011)

Bottom Line: We manipulated luminance contrast, a stimulus property known to strongly affect the magnitude of neuronal responses in early visual areas.These results point to a strong overlap in the neuronal processes underlying visual perception and mental imagery: not only does WM maintenance selectively engage neurons which are tuned to the maintained attribute (as has previously been shown), but the extent to which those neurons are activated depends on the image contrast (as is the case with visually evoked responses).From a methodological viewpoint, these results suggest that assessment of visual cortical excitability using TMS is affected by the TMS intensity used to probe the neuronal population.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Milano-Bicocca Milano, Italy.

ABSTRACT
Although much is known about the impact of stimulus properties such as luminance contrast, spatial frequency, and orientation on visually evoked neural activity, much less is known about how they modulate neural activity when they are properties of a mental image held in working memory (WM). Here we addressed this question by investigating how a parametric manipulation of an imagined stimulus attribute affects neuronal excitability in the early visual cortex. We manipulated luminance contrast, a stimulus property known to strongly affect the magnitude of neuronal responses in early visual areas. Luminance contrast modulated neuronal excitability, as assessed by the frequency of phosphenes induced by transcranial magnetic stimulation (TMS) with the exact nature of this modulation depending on TMS intensity. These results point to a strong overlap in the neuronal processes underlying visual perception and mental imagery: not only does WM maintenance selectively engage neurons which are tuned to the maintained attribute (as has previously been shown), but the extent to which those neurons are activated depends on the image contrast (as is the case with visually evoked responses). From a methodological viewpoint, these results suggest that assessment of visual cortical excitability using TMS is affected by the TMS intensity used to probe the neuronal population.

No MeSH data available.


Related in: MedlinePlus

The mean (n = 11) proportion of “Phosphene present” judgments in Experiment 4. There was no significant difference in the proportion of perceived phosphenes between the “auditory memory” and “passive listening” conditions. This shows that non-visual cognitive load did not modulate the excitability of the visual cortex. Error bars represent ±1 SEM.
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Figure 7: The mean (n = 11) proportion of “Phosphene present” judgments in Experiment 4. There was no significant difference in the proportion of perceived phosphenes between the “auditory memory” and “passive listening” conditions. This shows that non-visual cognitive load did not modulate the excitability of the visual cortex. Error bars represent ±1 SEM.

Mentions: Figure 7 shows the proportion of “Phosphene present” judgments in the Auditory memory and Passive listening conditions. In this analysis, the three response types indicating phosphene presence (i.e., responses 1, 2, and 3) are combined. A repeated-measures ANOVA with task condition (auditory memory vs. passive listening) as main factor found no significant difference between the two conditions, F(1,10) = 0.04, p = 0.86, suggesting that there was no general effect of memory load on phosphenes judgment. The mean catch trial performance was 75%, a level similar to that in the VSWM condition (80%).


Modulation of visual cortical excitability by working memory: effect of luminance contrast of mental imagery.

Cattaneo Z, Pisoni A, Papagno C, Silvanto J - Front Psychol (2011)

The mean (n = 11) proportion of “Phosphene present” judgments in Experiment 4. There was no significant difference in the proportion of perceived phosphenes between the “auditory memory” and “passive listening” conditions. This shows that non-visual cognitive load did not modulate the excitability of the visual cortex. Error bars represent ±1 SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3111229&req=5

Figure 7: The mean (n = 11) proportion of “Phosphene present” judgments in Experiment 4. There was no significant difference in the proportion of perceived phosphenes between the “auditory memory” and “passive listening” conditions. This shows that non-visual cognitive load did not modulate the excitability of the visual cortex. Error bars represent ±1 SEM.
Mentions: Figure 7 shows the proportion of “Phosphene present” judgments in the Auditory memory and Passive listening conditions. In this analysis, the three response types indicating phosphene presence (i.e., responses 1, 2, and 3) are combined. A repeated-measures ANOVA with task condition (auditory memory vs. passive listening) as main factor found no significant difference between the two conditions, F(1,10) = 0.04, p = 0.86, suggesting that there was no general effect of memory load on phosphenes judgment. The mean catch trial performance was 75%, a level similar to that in the VSWM condition (80%).

Bottom Line: We manipulated luminance contrast, a stimulus property known to strongly affect the magnitude of neuronal responses in early visual areas.These results point to a strong overlap in the neuronal processes underlying visual perception and mental imagery: not only does WM maintenance selectively engage neurons which are tuned to the maintained attribute (as has previously been shown), but the extent to which those neurons are activated depends on the image contrast (as is the case with visually evoked responses).From a methodological viewpoint, these results suggest that assessment of visual cortical excitability using TMS is affected by the TMS intensity used to probe the neuronal population.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Milano-Bicocca Milano, Italy.

ABSTRACT
Although much is known about the impact of stimulus properties such as luminance contrast, spatial frequency, and orientation on visually evoked neural activity, much less is known about how they modulate neural activity when they are properties of a mental image held in working memory (WM). Here we addressed this question by investigating how a parametric manipulation of an imagined stimulus attribute affects neuronal excitability in the early visual cortex. We manipulated luminance contrast, a stimulus property known to strongly affect the magnitude of neuronal responses in early visual areas. Luminance contrast modulated neuronal excitability, as assessed by the frequency of phosphenes induced by transcranial magnetic stimulation (TMS) with the exact nature of this modulation depending on TMS intensity. These results point to a strong overlap in the neuronal processes underlying visual perception and mental imagery: not only does WM maintenance selectively engage neurons which are tuned to the maintained attribute (as has previously been shown), but the extent to which those neurons are activated depends on the image contrast (as is the case with visually evoked responses). From a methodological viewpoint, these results suggest that assessment of visual cortical excitability using TMS is affected by the TMS intensity used to probe the neuronal population.

No MeSH data available.


Related in: MedlinePlus