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Cortical responses elicited by luminance and compound stimuli modulated by pseudo-random sequences: comparison between normal trichromats and congenital red-green color blinds.

Risuenho BB, Miquilini L, Lacerda EM, Silveira LC, Souza GS - Front Psychol (2015)

Bottom Line: Trichromats and color-blinds had similar VECP amplitude for compound pattern-reversal K1 and compound pattern-onset K2.2, as well as for all luminance conditions.The cross-correlation analysis showed high similarity between waveforms of compound pattern-onset K2.1 and pattern-reversal K2.2 as well as pattern-reversal K2.1 and K2.2.We suggest that compound pattern-reversal K2.1 is an appropriate response to study red-green color-opponent activity.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciências Biológicas - Universidade Federal do Pará Belém, Brazil.

ABSTRACT
Conventional pattern-reversal visual evoked cortical potential (VECP) shows positivity for luminance and chromatic equiluminant stimuli while conventional pattern-onset VECP shows positivity for luminance pattern-onset and negativity for chromatic pattern-onset. We evaluated how the presentation mode affects VECPs elicited by luminance and compound (luminance plus chromatic) pseudo-random stimulation. Eleven normal trichromats and 17 red-green color-blinds were studied. Pattern-reversal and pattern-onset luminance and compound (luminance plus red-green) gratings were temporally modulated by m-sequence. We used a cross-correlation routine to extract the first order kernel (K1) and the first and second slices of the second order kernel (K2.1 and K2.2, respectively) from the VECP response. We integrated the amplitude of VECP components as a function of time in order to estimate its magnitude for each stimulus condition. We also used a normalized cross-correlation method in order to test the similarity of the VECP components. The VECP components varied with the presentation mode and the presence of red-green contrast in the stimuli. In trichromats, for compound conditions, pattern-onset K1, K2.1, and K2.2, and pattern-reversal K2.1 and K2.2 had negative-dominated waveforms at 100 ms. Small negativity or small positivity were observed in dichromats. Trichromats had larger VECP magnitude than color-blinds for compound pattern-onset K1 (with large variability across subjects), compound pattern-onset and pattern-reversal K2.1, and compound pattern-reversal K2.2. Trichromats and color-blinds had similar VECP amplitude for compound pattern-reversal K1 and compound pattern-onset K2.2, as well as for all luminance conditions. The cross-correlation analysis showed high similarity between waveforms of compound pattern-onset K2.1 and pattern-reversal K2.2 as well as pattern-reversal K2.1 and K2.2. We suggest that compound pattern-reversal K2.1 is an appropriate response to study red-green color-opponent activity.

No MeSH data available.


Magnitude of the VECP elicited by compound stimuli in trichromats and color blinds. Pattern-reversal K2.1, and pattern-reversal K2.2 had higher values for trichromats than color-blinds. Asterisks (*) were used to mark statistically significant differences. Box-plots represent medians (middle horizontal lines), first quartiles (lower horizontal lines), third quartiles (upper horizontal lines), maximum values (upper vertical lines), and minimum values (lower vertical lines).
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Figure 6: Magnitude of the VECP elicited by compound stimuli in trichromats and color blinds. Pattern-reversal K2.1, and pattern-reversal K2.2 had higher values for trichromats than color-blinds. Asterisks (*) were used to mark statistically significant differences. Box-plots represent medians (middle horizontal lines), first quartiles (lower horizontal lines), third quartiles (upper horizontal lines), maximum values (upper vertical lines), and minimum values (lower vertical lines).

Mentions: Figures 5–6 show box-plots representing the recording total power in the first 500 ms elicited by luminance (Figure 5) or compound (Figure 6) stimuli. Results from normal trichromats are compared with those from red-green color-blinds dichromats. Protans and deutans were grouped together for this comparison with normal trichromats. For luminance stimuli (Figure 5) there were no significant differences (p > 0.05) for both pattern-onset and pattern-reversal stimulation modes and for the three kernels: pattern-onset K1, p = 0.7; pattern-onset K2.1, p = 0.16; pattern-onset K2.2, p = 0.35; pattern-reversal K1, p = 0.47; pattern-reversal K2.1, p = 0.12; pattern-reversal K2.2, p = 0.98.


Cortical responses elicited by luminance and compound stimuli modulated by pseudo-random sequences: comparison between normal trichromats and congenital red-green color blinds.

Risuenho BB, Miquilini L, Lacerda EM, Silveira LC, Souza GS - Front Psychol (2015)

Magnitude of the VECP elicited by compound stimuli in trichromats and color blinds. Pattern-reversal K2.1, and pattern-reversal K2.2 had higher values for trichromats than color-blinds. Asterisks (*) were used to mark statistically significant differences. Box-plots represent medians (middle horizontal lines), first quartiles (lower horizontal lines), third quartiles (upper horizontal lines), maximum values (upper vertical lines), and minimum values (lower vertical lines).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4309178&req=5

Figure 6: Magnitude of the VECP elicited by compound stimuli in trichromats and color blinds. Pattern-reversal K2.1, and pattern-reversal K2.2 had higher values for trichromats than color-blinds. Asterisks (*) were used to mark statistically significant differences. Box-plots represent medians (middle horizontal lines), first quartiles (lower horizontal lines), third quartiles (upper horizontal lines), maximum values (upper vertical lines), and minimum values (lower vertical lines).
Mentions: Figures 5–6 show box-plots representing the recording total power in the first 500 ms elicited by luminance (Figure 5) or compound (Figure 6) stimuli. Results from normal trichromats are compared with those from red-green color-blinds dichromats. Protans and deutans were grouped together for this comparison with normal trichromats. For luminance stimuli (Figure 5) there were no significant differences (p > 0.05) for both pattern-onset and pattern-reversal stimulation modes and for the three kernels: pattern-onset K1, p = 0.7; pattern-onset K2.1, p = 0.16; pattern-onset K2.2, p = 0.35; pattern-reversal K1, p = 0.47; pattern-reversal K2.1, p = 0.12; pattern-reversal K2.2, p = 0.98.

Bottom Line: Trichromats and color-blinds had similar VECP amplitude for compound pattern-reversal K1 and compound pattern-onset K2.2, as well as for all luminance conditions.The cross-correlation analysis showed high similarity between waveforms of compound pattern-onset K2.1 and pattern-reversal K2.2 as well as pattern-reversal K2.1 and K2.2.We suggest that compound pattern-reversal K2.1 is an appropriate response to study red-green color-opponent activity.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciências Biológicas - Universidade Federal do Pará Belém, Brazil.

ABSTRACT
Conventional pattern-reversal visual evoked cortical potential (VECP) shows positivity for luminance and chromatic equiluminant stimuli while conventional pattern-onset VECP shows positivity for luminance pattern-onset and negativity for chromatic pattern-onset. We evaluated how the presentation mode affects VECPs elicited by luminance and compound (luminance plus chromatic) pseudo-random stimulation. Eleven normal trichromats and 17 red-green color-blinds were studied. Pattern-reversal and pattern-onset luminance and compound (luminance plus red-green) gratings were temporally modulated by m-sequence. We used a cross-correlation routine to extract the first order kernel (K1) and the first and second slices of the second order kernel (K2.1 and K2.2, respectively) from the VECP response. We integrated the amplitude of VECP components as a function of time in order to estimate its magnitude for each stimulus condition. We also used a normalized cross-correlation method in order to test the similarity of the VECP components. The VECP components varied with the presentation mode and the presence of red-green contrast in the stimuli. In trichromats, for compound conditions, pattern-onset K1, K2.1, and K2.2, and pattern-reversal K2.1 and K2.2 had negative-dominated waveforms at 100 ms. Small negativity or small positivity were observed in dichromats. Trichromats had larger VECP magnitude than color-blinds for compound pattern-onset K1 (with large variability across subjects), compound pattern-onset and pattern-reversal K2.1, and compound pattern-reversal K2.2. Trichromats and color-blinds had similar VECP amplitude for compound pattern-reversal K1 and compound pattern-onset K2.2, as well as for all luminance conditions. The cross-correlation analysis showed high similarity between waveforms of compound pattern-onset K2.1 and pattern-reversal K2.2 as well as pattern-reversal K2.1 and K2.2. We suggest that compound pattern-reversal K2.1 is an appropriate response to study red-green color-opponent activity.

No MeSH data available.