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Scaling behavior of human locomotor activity amplitude: association with bipolar disorder.

Indic P, Salvatore P, Maggini C, Ghidini S, Ferraro G, Baldessarini RJ, Murray G - PLoS ONE (2011)

Bottom Line: Scale invariance is a feature of complex biological systems, and abnormality of multi-scale behaviour may serve as an indicator of pathology.The hypothalamic suprachiasmatic nucleus (SCN) is a major node in central neural networks responsible for regulating multi-scale behaviour in measures of human locomotor activity.A proposed index of scaling behaviour (Vulnerability Index [VI]) derived from such data distinguished between: [i] healthy subjects at high versus low risk of mood disorders; [ii] currently clinically stable BD patients versus matched controls; and [iii] among clinical states in BD patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America. Premananda.Indic@umassmed.edu

ABSTRACT
Scale invariance is a feature of complex biological systems, and abnormality of multi-scale behaviour may serve as an indicator of pathology. The hypothalamic suprachiasmatic nucleus (SCN) is a major node in central neural networks responsible for regulating multi-scale behaviour in measures of human locomotor activity. SCN also is implicated in the pathophysiology of bipolar disorder (BD) or manic-depressive illness, a severe, episodic disorder of mood, cognition and behaviour. Here, we investigated scaling behaviour in actigraphically recorded human motility data for potential indicators of BD, particularly its manic phase. A proposed index of scaling behaviour (Vulnerability Index [VI]) derived from such data distinguished between: [i] healthy subjects at high versus low risk of mood disorders; [ii] currently clinically stable BD patients versus matched controls; and [iii] among clinical states in BD patients.

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Estimated multi-scale rhythms of motility data obtained by wavelet analysis.(a) Raw data in arbitrary units (a.u) along with the rhythms detected at three different time scales. (b) The detected rhythm (grey line) along with its amplitude (blue line) for a scale of 0.2 h. (c) The corresponding rhythm and amplitude for a scale of 1.04 h. (d) The same measure at a scale of 23.48 h. Wavelet amplitudes are in normalized arbitrary units.
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pone-0020650-g001: Estimated multi-scale rhythms of motility data obtained by wavelet analysis.(a) Raw data in arbitrary units (a.u) along with the rhythms detected at three different time scales. (b) The detected rhythm (grey line) along with its amplitude (blue line) for a scale of 0.2 h. (c) The corresponding rhythm and amplitude for a scale of 1.04 h. (d) The same measure at a scale of 23.48 h. Wavelet amplitudes are in normalized arbitrary units.

Mentions: Rhythms were observed at circadian (∼24 h) as well as other temporal ranges (minutes or hours). Figure 1 represents an example of motility data along with the multi-scale rhythms obtained using wavelet analysis. The amplitude of rhythms at shorter time scales appeared to be random; to check whether such fluctuation was simply due to noise in the data, we plotted the distribution of amplitudes at a range of time-scales. The distribution of amplitudes obtained at very short time-scales (≤2.0 h) had an apparent long-tail and was nearly collapsed (Figure 2 (a–d)). Such a long-tail distribution is characteristic of nonlinear complex systems near critical points, and the collapse of amplitude distribution represents the scale-invariant feature of such systems [25].


Scaling behavior of human locomotor activity amplitude: association with bipolar disorder.

Indic P, Salvatore P, Maggini C, Ghidini S, Ferraro G, Baldessarini RJ, Murray G - PLoS ONE (2011)

Estimated multi-scale rhythms of motility data obtained by wavelet analysis.(a) Raw data in arbitrary units (a.u) along with the rhythms detected at three different time scales. (b) The detected rhythm (grey line) along with its amplitude (blue line) for a scale of 0.2 h. (c) The corresponding rhythm and amplitude for a scale of 1.04 h. (d) The same measure at a scale of 23.48 h. Wavelet amplitudes are in normalized arbitrary units.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3105113&req=5

pone-0020650-g001: Estimated multi-scale rhythms of motility data obtained by wavelet analysis.(a) Raw data in arbitrary units (a.u) along with the rhythms detected at three different time scales. (b) The detected rhythm (grey line) along with its amplitude (blue line) for a scale of 0.2 h. (c) The corresponding rhythm and amplitude for a scale of 1.04 h. (d) The same measure at a scale of 23.48 h. Wavelet amplitudes are in normalized arbitrary units.
Mentions: Rhythms were observed at circadian (∼24 h) as well as other temporal ranges (minutes or hours). Figure 1 represents an example of motility data along with the multi-scale rhythms obtained using wavelet analysis. The amplitude of rhythms at shorter time scales appeared to be random; to check whether such fluctuation was simply due to noise in the data, we plotted the distribution of amplitudes at a range of time-scales. The distribution of amplitudes obtained at very short time-scales (≤2.0 h) had an apparent long-tail and was nearly collapsed (Figure 2 (a–d)). Such a long-tail distribution is characteristic of nonlinear complex systems near critical points, and the collapse of amplitude distribution represents the scale-invariant feature of such systems [25].

Bottom Line: Scale invariance is a feature of complex biological systems, and abnormality of multi-scale behaviour may serve as an indicator of pathology.The hypothalamic suprachiasmatic nucleus (SCN) is a major node in central neural networks responsible for regulating multi-scale behaviour in measures of human locomotor activity.A proposed index of scaling behaviour (Vulnerability Index [VI]) derived from such data distinguished between: [i] healthy subjects at high versus low risk of mood disorders; [ii] currently clinically stable BD patients versus matched controls; and [iii] among clinical states in BD patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America. Premananda.Indic@umassmed.edu

ABSTRACT
Scale invariance is a feature of complex biological systems, and abnormality of multi-scale behaviour may serve as an indicator of pathology. The hypothalamic suprachiasmatic nucleus (SCN) is a major node in central neural networks responsible for regulating multi-scale behaviour in measures of human locomotor activity. SCN also is implicated in the pathophysiology of bipolar disorder (BD) or manic-depressive illness, a severe, episodic disorder of mood, cognition and behaviour. Here, we investigated scaling behaviour in actigraphically recorded human motility data for potential indicators of BD, particularly its manic phase. A proposed index of scaling behaviour (Vulnerability Index [VI]) derived from such data distinguished between: [i] healthy subjects at high versus low risk of mood disorders; [ii] currently clinically stable BD patients versus matched controls; and [iii] among clinical states in BD patients.

Show MeSH
Related in: MedlinePlus