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Behavioral states may be associated with distinct spatial patterns in electrocorticogram.

Panagiotides H, Freeman WJ, Holmes MD, Pantazis D - Cogn Neurodyn (2010)

Bottom Line: Moments of maximal spatial variance are shown to cluster by behavior.Comparisons between conditions using a permutation test reveal significantly different spatial patterns for each behavior.We conclude that ECoG recordings obtained on the cortical surface with optimal high spatial frequency resolution reveal distinct local spatial patterns that reflect different behavioral states, and we predict that similar patterns will be found in many if not most cortical areas on which a microgrid is placed.

View Article: PubMed Central - PubMed

ABSTRACT
To determine if behavioral states are associated with unique spatial electrocorticographic (ECoG) patterns, we obtained recordings with a microgrid electrode array applied to the cortical surface of a human subject. The array was constructed with the intent of extracting maximal spatial information by optimizing interelectrode distances. A 34-year-old patient with intractable epilepsy underwent intracranial ECoG monitoring after standard methods failed to reveal localization of seizures. During the 8-day period of invasive recording, in addition to standard clinical electrodes a square 1 × 1 cm microgrid array with 64 electrodes (1.25 mm separation) was placed on the right inferior temporal gyrus. Careful review of video recordings identified four extended naturalistic behaviors: reading, conversing on the telephone, looking at photographs, and face-to-face interactions. ECoG activity recorded with the microgrid that corresponded to these behaviors was collected and ECoG spatial patterns were analyzed. During periods of ECoG selected for analysis, no electrographic seizures or epileptiform patterns were present. Moments of maximal spatial variance are shown to cluster by behavior. Comparisons between conditions using a permutation test reveal significantly different spatial patterns for each behavior. We conclude that ECoG recordings obtained on the cortical surface with optimal high spatial frequency resolution reveal distinct local spatial patterns that reflect different behavioral states, and we predict that similar patterns will be found in many if not most cortical areas on which a microgrid is placed.

No MeSH data available.


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Average topographic distributions of normalized voltages  across the microgrid. First row average of topographies for time points corresponding to the bottom right clusters of Fig. 5, separately for each condition. Second row average of top left clusters of Fig. 5. Thirdrow summation of above. Topographies on first and second rows are nearly opposite. Also, there is great similarity of topographies between conditions, but also visible differences
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Fig6: Average topographic distributions of normalized voltages across the microgrid. First row average of topographies for time points corresponding to the bottom right clusters of Fig. 5, separately for each condition. Second row average of top left clusters of Fig. 5. Thirdrow summation of above. Topographies on first and second rows are nearly opposite. Also, there is great similarity of topographies between conditions, but also visible differences

Mentions: To focus on topographic patterns rather than voltage level differences, we normalized the voltage measurements into zero mean and unit variance across electrodes, as in Eq. 4. Then, we averaged the microgrid measurements corresponding to each cluster separately. Figure 6 shows the average topographic voltage maps for the bottom right clusters (first row), top left clusters (second row), and their summation (third row). The average topographic voltage maps revealed that the two distributions are symmetrically opposite to each other in each condition. Also, despite the great resemblance of topographies across conditions, differences are still visible. Our MDA and permutation test analysis explored whether these differences are significant.Fig. 6


Behavioral states may be associated with distinct spatial patterns in electrocorticogram.

Panagiotides H, Freeman WJ, Holmes MD, Pantazis D - Cogn Neurodyn (2010)

Average topographic distributions of normalized voltages  across the microgrid. First row average of topographies for time points corresponding to the bottom right clusters of Fig. 5, separately for each condition. Second row average of top left clusters of Fig. 5. Thirdrow summation of above. Topographies on first and second rows are nearly opposite. Also, there is great similarity of topographies between conditions, but also visible differences
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3045495&req=5

Fig6: Average topographic distributions of normalized voltages across the microgrid. First row average of topographies for time points corresponding to the bottom right clusters of Fig. 5, separately for each condition. Second row average of top left clusters of Fig. 5. Thirdrow summation of above. Topographies on first and second rows are nearly opposite. Also, there is great similarity of topographies between conditions, but also visible differences
Mentions: To focus on topographic patterns rather than voltage level differences, we normalized the voltage measurements into zero mean and unit variance across electrodes, as in Eq. 4. Then, we averaged the microgrid measurements corresponding to each cluster separately. Figure 6 shows the average topographic voltage maps for the bottom right clusters (first row), top left clusters (second row), and their summation (third row). The average topographic voltage maps revealed that the two distributions are symmetrically opposite to each other in each condition. Also, despite the great resemblance of topographies across conditions, differences are still visible. Our MDA and permutation test analysis explored whether these differences are significant.Fig. 6

Bottom Line: Moments of maximal spatial variance are shown to cluster by behavior.Comparisons between conditions using a permutation test reveal significantly different spatial patterns for each behavior.We conclude that ECoG recordings obtained on the cortical surface with optimal high spatial frequency resolution reveal distinct local spatial patterns that reflect different behavioral states, and we predict that similar patterns will be found in many if not most cortical areas on which a microgrid is placed.

View Article: PubMed Central - PubMed

ABSTRACT
To determine if behavioral states are associated with unique spatial electrocorticographic (ECoG) patterns, we obtained recordings with a microgrid electrode array applied to the cortical surface of a human subject. The array was constructed with the intent of extracting maximal spatial information by optimizing interelectrode distances. A 34-year-old patient with intractable epilepsy underwent intracranial ECoG monitoring after standard methods failed to reveal localization of seizures. During the 8-day period of invasive recording, in addition to standard clinical electrodes a square 1 × 1 cm microgrid array with 64 electrodes (1.25 mm separation) was placed on the right inferior temporal gyrus. Careful review of video recordings identified four extended naturalistic behaviors: reading, conversing on the telephone, looking at photographs, and face-to-face interactions. ECoG activity recorded with the microgrid that corresponded to these behaviors was collected and ECoG spatial patterns were analyzed. During periods of ECoG selected for analysis, no electrographic seizures or epileptiform patterns were present. Moments of maximal spatial variance are shown to cluster by behavior. Comparisons between conditions using a permutation test reveal significantly different spatial patterns for each behavior. We conclude that ECoG recordings obtained on the cortical surface with optimal high spatial frequency resolution reveal distinct local spatial patterns that reflect different behavioral states, and we predict that similar patterns will be found in many if not most cortical areas on which a microgrid is placed.

No MeSH data available.


Related in: MedlinePlus