### Abstract

This study investigates the possible relevance of distribution and age variation of spontaneous theta activity (4-8 Hz) in normal subjects using magnetoencephalography (MEG) recordings. Spontaneous theta was recorded with a 151-channel MEG in healthy subjects; moreover, in a group of 10 subjects, simultaneous MEG-EEG was recorded in order to compare the two methods. Theta was divided in two sub-bands: T(A) (4-6 Hz) and T(B) (6-8 Hz). The pre-processed data were transformed into the frequency domain by Fast Fourier Transform (FFT)-based software by subdividing the data in epochs of 5 sec, on which FFT amplitudes are computed. Moreover, on all trials a simple model of a single electric current embedded in a spherically symmetric conductor was fitted automatically to the magnetic fields and projected onto an averaged MRI. The results obtained show that FFT-based theta power spectrum was distributed in adults with the highest power over the posterior parietal and occipital areas with T(B) dominance. The dipole analysis resulted in a mid-sagittal distribution, though the youngest group displayed theta dipoles fitting more posteriorly respect to the adults and the elderly. These results suggest that spontaneous theta activity is a diffuse and pervasive rhythm which shows some different topographical distribution among the age groups. Whether the prevalent posterior distribution of theta is the expression of distinct networks or the outcome of complex dynamics are questions of possible relevance in the organization of higher order processes.

Original language | English |
---|---|

Pages (from-to) | 165-75 |

Number of pages | 11 |

Journal | Brain Topography |

Volume | 17 |

Issue number | 3 |

Publication status | Published - 2005 |

### Cite this

*Brain Topography*,

*17*(3), 165-75.

}

*Brain Topography*, vol. 17, no. 3, pp. 165-75.

**Age distribution of MEG spontaneous theta activity in healthy subjects.** / Puligheddu, Monica; de Munck, Jan C; Stam, Cornelis J; Verbunt, Jeroen; de Jongh, Arent; van Dijk, Bob W; Marrosu, Francesco.

Research output: Contribution to journal › Article › Academic › peer-review

TY - JOUR

T1 - Age distribution of MEG spontaneous theta activity in healthy subjects

AU - Puligheddu, Monica

AU - de Munck, Jan C

AU - Stam, Cornelis J

AU - Verbunt, Jeroen

AU - de Jongh, Arent

AU - van Dijk, Bob W

AU - Marrosu, Francesco

PY - 2005

Y1 - 2005

N2 - This study investigates the possible relevance of distribution and age variation of spontaneous theta activity (4-8 Hz) in normal subjects using magnetoencephalography (MEG) recordings. Spontaneous theta was recorded with a 151-channel MEG in healthy subjects; moreover, in a group of 10 subjects, simultaneous MEG-EEG was recorded in order to compare the two methods. Theta was divided in two sub-bands: T(A) (4-6 Hz) and T(B) (6-8 Hz). The pre-processed data were transformed into the frequency domain by Fast Fourier Transform (FFT)-based software by subdividing the data in epochs of 5 sec, on which FFT amplitudes are computed. Moreover, on all trials a simple model of a single electric current embedded in a spherically symmetric conductor was fitted automatically to the magnetic fields and projected onto an averaged MRI. The results obtained show that FFT-based theta power spectrum was distributed in adults with the highest power over the posterior parietal and occipital areas with T(B) dominance. The dipole analysis resulted in a mid-sagittal distribution, though the youngest group displayed theta dipoles fitting more posteriorly respect to the adults and the elderly. These results suggest that spontaneous theta activity is a diffuse and pervasive rhythm which shows some different topographical distribution among the age groups. Whether the prevalent posterior distribution of theta is the expression of distinct networks or the outcome of complex dynamics are questions of possible relevance in the organization of higher order processes.

AB - This study investigates the possible relevance of distribution and age variation of spontaneous theta activity (4-8 Hz) in normal subjects using magnetoencephalography (MEG) recordings. Spontaneous theta was recorded with a 151-channel MEG in healthy subjects; moreover, in a group of 10 subjects, simultaneous MEG-EEG was recorded in order to compare the two methods. Theta was divided in two sub-bands: T(A) (4-6 Hz) and T(B) (6-8 Hz). The pre-processed data were transformed into the frequency domain by Fast Fourier Transform (FFT)-based software by subdividing the data in epochs of 5 sec, on which FFT amplitudes are computed. Moreover, on all trials a simple model of a single electric current embedded in a spherically symmetric conductor was fitted automatically to the magnetic fields and projected onto an averaged MRI. The results obtained show that FFT-based theta power spectrum was distributed in adults with the highest power over the posterior parietal and occipital areas with T(B) dominance. The dipole analysis resulted in a mid-sagittal distribution, though the youngest group displayed theta dipoles fitting more posteriorly respect to the adults and the elderly. These results suggest that spontaneous theta activity is a diffuse and pervasive rhythm which shows some different topographical distribution among the age groups. Whether the prevalent posterior distribution of theta is the expression of distinct networks or the outcome of complex dynamics are questions of possible relevance in the organization of higher order processes.

KW - Adult

KW - Age Factors

KW - Aged

KW - Aged, 80 and over

KW - Aging/physiology

KW - Brain/physiology

KW - Brain Mapping

KW - Child

KW - Electroencephalography/methods

KW - Evoked Potentials/physiology

KW - Female

KW - Fourier Analysis

KW - Humans

KW - Magnetoencephalography

KW - Male

KW - Middle Aged

KW - Spectrum Analysis

KW - Statistics, Nonparametric

KW - Theta Rhythm

M3 - Article

VL - 17

SP - 165

EP - 175

JO - Brain Topography

JF - Brain Topography

SN - 0896-0267

IS - 3

ER -