Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies

Mayank Bhagat, Chitresh Bhushan, Goutam Saha, Shinsuke Shimjo, Katsumi Watanabe, Joydeep Bhattacharya

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Background: Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. Methodology/Principal Findings: Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. Conclusions/Significance: Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations.

Original languageEnglish
Article numbere7173
JournalPLoS One
Volume4
Issue number9
DOIs
Publication statusPublished - 2009 Sep 25
Externally publishedYes

Fingerprint

Flickering
Entropy
entropy
Brain
Color
brain
color
Order disorder transitions
epilepsy
Reflex Epilepsy
Brain Diseases
Photosensitivity
Epilepsy
wavelet
Display devices

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies. / Bhagat, Mayank; Bhushan, Chitresh; Saha, Goutam; Shimjo, Shinsuke; Watanabe, Katsumi; Bhattacharya, Joydeep.

In: PLoS One, Vol. 4, No. 9, e7173, 25.09.2009.

Research output: Contribution to journalArticle

Bhagat, Mayank ; Bhushan, Chitresh ; Saha, Goutam ; Shimjo, Shinsuke ; Watanabe, Katsumi ; Bhattacharya, Joydeep. / Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies. In: PLoS One. 2009 ; Vol. 4, No. 9.
@article{51b0265f1fd34fa6a9b3753d36a17238,
title = "Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies",
abstract = "Background: Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. Methodology/Principal Findings: Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. Conclusions/Significance: Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations.",
author = "Mayank Bhagat and Chitresh Bhushan and Goutam Saha and Shinsuke Shimjo and Katsumi Watanabe and Joydeep Bhattacharya",
year = "2009",
month = "9",
day = "25",
doi = "10.1371/journal.pone.0007173",
language = "English",
volume = "4",
journal = "PLoS One",
issn = "1932-6203",
publisher = "Public Library of Science",
number = "9",

}

TY - JOUR

T1 - Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies

AU - Bhagat, Mayank

AU - Bhushan, Chitresh

AU - Saha, Goutam

AU - Shimjo, Shinsuke

AU - Watanabe, Katsumi

AU - Bhattacharya, Joydeep

PY - 2009/9/25

Y1 - 2009/9/25

N2 - Background: Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. Methodology/Principal Findings: Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. Conclusions/Significance: Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations.

AB - Background: Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. Methodology/Principal Findings: Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. Conclusions/Significance: Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations.

UR - http://www.scopus.com/inward/record.url?scp=70349728567&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70349728567&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0007173

DO - 10.1371/journal.pone.0007173

M3 - Article

C2 - 19779630

AN - SCOPUS:70349728567

VL - 4

JO - PLoS One

JF - PLoS One

SN - 1932-6203

IS - 9

M1 - e7173

ER -