Motor imagery task discrimination using wide-band frequency spectra with Slepian tapers

Author(s):  
M Kamrunnahar ◽  
A Geronimo
Behaviour ◽  
1992 ◽  
Vol 120 (3-4) ◽  
pp. 151-163 ◽  
Author(s):  
T. Aubin ◽  
J.C. Bremond

AbstractTo examine the ethological role of signal composition in the distress calls of starlings (Sturnus vulgaris), we conducted a series of playback experiments in the field. Earlier researches revealed that frequency modulations are important features of distress calls for triggering the responses of starlings. Another feature, the harmonic structure, was thought to play a role in the coding/decoding process of the call. The aim of this work was to investigate the role of this structure. Four points emerge from these experiments: 1) Ethological message is effectively encoded in the harmonic structure. 2) Wide-band frequency spectra are preferred to narrow-band spectra. 3) Starlings examine the width of the spectrum but not the interval between frequency bands. 4) Spectra with a high intensity upper part produce a stronger response than other types of spectra. Such a coding/decoding process is discussed regarding transmission of information at long range, the ability to appreciate distance, to locate the caller and the possibility of grading the information.


2011 ◽  
Vol 29 (supplement) ◽  
pp. 352-377 ◽  
Author(s):  
Seon Hee Jang ◽  
Frank E Pollick

The study of dance has been helpful to advance our understanding of how human brain networks of action observation are influenced by experience. However previous studies have not examined the effect of extensive visual experience alone: for example, an art critic or dance fan who has a rich experience of watching dance but negligible experience performing dance. To explore the effect of pure visual experience we performed a single experiment using functional Magnetic Resonance Imaging (fMRI) to compare the neural processing of dance actions in 3 groups: a) 14 ballet dancers, b) 10 experienced viewers, c) 12 novices without any extensive dance or viewing experience. Each of the 36 participants viewed short 2-second displays of ballet derived from motion capture of a professional ballerina. These displays represented the ballerina as only points of light at the major joints. We wished to study the action observation network broadly and thus included two different types of display and two different tasks for participants to perform. The two different displays were: a) brief movies of a ballet action and b) frames from the ballet movies with the points of lights connected by lines to show a ballet posture. The two different tasks were: a) passively observe the display and b) imagine performing the action depicted in the display. The two levels of display and task were combined factorially to produce four experimental conditions (observe movie, observe posture, motor imagery of movie, motor imagery of posture). The set of stimuli used in the experiment are available for download after this paper. A random effects ANOVA was performed on brain activity and an effect of experience was obtained in seven different brain areas including: right Temporoparietal Junction (TPJ), left Retrosplenial Cortex (RSC), right Primary Somatosensory Cortex (S1), bilateral Primary Motor Cortex (M1), right Orbitofrontal Cortex (OFC), right Temporal Pole (TP). The patterns of activation were plotted in each of these areas (TPJ, RSC, S1, M1, OFC, TP) to investigate more closely how the effect of experience changed across these areas. For this analysis, novices were treated as baseline and the relative effect of experience examined in the dancer and experienced viewer groups. Interpretation of these results suggests that both visual and motor experience appear equivalent in producing more extensive early processing of dance actions in early stages of representation (TPJ and RSC) and we hypothesise that this could be due to the involvement of autobiographical memory processes. The pattern of results found for dancers in S1 and M1 suggest that their perception of dance actions are enhanced by embodied processes. For example, the S1 results are consistent with claims that this brain area shows mirror properties. The pattern of results found for the experienced viewers in OFC and TP suggests that their perception of dance actions are enhanced by cognitive processes. For example, involving aspects of social cognition and hedonic processing – the experienced viewers find the motor imagery task more pleasant and have richer connections of dance to social memory. While aspects of our interpretation are speculative the core results clearly show common and distinct aspects of how viewing experience and physical experience shape brain responses to watching dance.


2016 ◽  
Author(s):  
Yury V. Kistenev ◽  
Alexey V. Borisov ◽  
Dmitry A. Kuzmin ◽  
Anna A. Bulanova ◽  
Andrey A. Boyko ◽  
...  

2000 ◽  
Vol 123 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Nader Jalili ◽  
Ebrahim Esmailzadeh

A new approach to optimal control of vehicle suspension systems, incorporating actuator time delay, is presented. The inclusion of time delay provides a more realistic model for the actuators, and the problem is viewed from a different perspective rather than the conventional optimal control techniques. The objective here is to select a set of feedback gains such that the maximum vertical acceleration of the sprung mass is minimized, over a wide band frequency range and when subjected to certain constraints. The constraints are dictated by the vehicle stability characteristics and the physical bounds placed on the feedback gains. Utilizing a Simple Quarter Car model, the constrained optimization is then carried out in the frequency domain with the road irregularities described as random processes. Due to the presence of the actuator time delay, the characteristic equation is found to be transcendental rather than algebraic, which makes the stability analysis relatively complex. A new scheme for the stability chart strategy with fixed time delay is introduced in order to address the stability issue. The stability characteristics are also verified utilizing other conventional methods such as the Michailov technique. Results demonstrate that the suspension system, when considering the effect of the actuator time delay, exhibits a completely different behavior.


2006 ◽  
Vol 83 (11-12) ◽  
pp. 2184-2188 ◽  
Author(s):  
T. Lacrevaz ◽  
B. Fléchet ◽  
A. Farcy ◽  
J. Torres ◽  
M. Gros-Jean ◽  
...  

2021 ◽  
Author(s):  
Wenwen Chang ◽  
Wenqie Huang ◽  
Guanghui Yan ◽  
Yuchan Zhang

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