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Probing of Brain States in Real-Time: Introducing the ConSole Environment.

Hartmann T, Schulz H, Weisz N - Front Psychol (2011)

Bottom Line: However such offline analyses are disadvantageous as they are correlational by drawing conclusions in a post hoc-manner and stimulus presentation is random with respect to the feature of interest.The software is also independent from the EEG/MEG system, as long as a driver can be written (currently two EEG systems are supported).Besides a general introduction, we present benchmark data regarding performance and validity of the calculations used, as well as three example applications of ConSole in different settings.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Universität Konstanz Konstanz, Germany.

ABSTRACT
Recent years have seen huge advancements in the methods available and used in neuroscience employing EEG or MEG. However, the standard approach is to average a large number of trials for experimentally defined conditions in order to reduce intertrial-variability, i.e., treating it as a source of "noise." Yet it is now more and more accepted that trial-to-trial fluctuations bear functional significance, reflecting fluctuations of "brain states" that predispose perception and action. Such effects are often revealed in a pre-stimulus period, when comparing response variability to an invariant stimulus. However such offline analyses are disadvantageous as they are correlational by drawing conclusions in a post hoc-manner and stimulus presentation is random with respect to the feature of interest. A more direct test is to trigger stimulus presentation when the relevant feature is present. The current paper introduces Constance System for Online EEG (ConSole), a software package capable of analyzing ongoing EEG/MEG in real-time and presenting auditory and visual stimuli via internal routines. Stimulation via external devices (e.g., transcranial magnetic stimulation) or third-party software (e.g., PsyScope X) is possible by sending TTL-triggers. With ConSole it is thus possible to target the stimulation at specific brain states. In contrast to many available applications, ConSole is open-source. Its modular design enhances the power of the software as it can be easily adapted to new challenges and writing new experiments is an easy task. ConSole is already pre-equipped with modules performing standard signal processing steps. The software is also independent from the EEG/MEG system, as long as a driver can be written (currently two EEG systems are supported). Besides a general introduction, we present benchmark data regarding performance and validity of the calculations used, as well as three example applications of ConSole in different settings. ConSole can be downloaded at: http://console-kn.sf.net.

No MeSH data available.


Related in: MedlinePlus

Comparison between the classic offline and the proposed online approach. By targeting the presentation of events and/or stimuli to hypothesized brain states, the hypothesis can be more easily verified or falsified.
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Figure 1: Comparison between the classic offline and the proposed online approach. By targeting the presentation of events and/or stimuli to hypothesized brain states, the hypothesis can be more easily verified or falsified.

Mentions: All these studies nonetheless face a major limitation: although they aim to show a direct relationship between certain features of cortical oscillations and an assumed functional state on a trial-by-trial basis, their conclusions are drawn ex post facto. Since the direct (real-time) control of cortical oscillations is difficult in vivo (an interesting avenue may be the recently reported “entrainment” paradigms; e.g., Mathewson et al., 2010; Romei et al., 2010), even though it is not resolved how “entrained” oscillations are really associated to genuinely spontaneously produced oscillations), the experimental setup that comes closest to allowing causal inferences is to temporally trigger events as close as possible to the hypothetically relevant brain activity feature, which fluctuates over the course of an experiment. A real-time framework even holds advantages for the more conventional offline analysis approach, including a clearer distinction between high and low alpha trials that enables a better contrast between the hypothesized brain state and its assumed behavioral impact (e.g., on reaction time). Currently, the presentation of stimuli is entirely random with respect to features of ongoing brain oscillations and the conclusions that can be drawn from it are correlational (see Figure 1).


Probing of Brain States in Real-Time: Introducing the ConSole Environment.

Hartmann T, Schulz H, Weisz N - Front Psychol (2011)

Comparison between the classic offline and the proposed online approach. By targeting the presentation of events and/or stimuli to hypothesized brain states, the hypothesis can be more easily verified or falsified.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3110935&req=5

Figure 1: Comparison between the classic offline and the proposed online approach. By targeting the presentation of events and/or stimuli to hypothesized brain states, the hypothesis can be more easily verified or falsified.
Mentions: All these studies nonetheless face a major limitation: although they aim to show a direct relationship between certain features of cortical oscillations and an assumed functional state on a trial-by-trial basis, their conclusions are drawn ex post facto. Since the direct (real-time) control of cortical oscillations is difficult in vivo (an interesting avenue may be the recently reported “entrainment” paradigms; e.g., Mathewson et al., 2010; Romei et al., 2010), even though it is not resolved how “entrained” oscillations are really associated to genuinely spontaneously produced oscillations), the experimental setup that comes closest to allowing causal inferences is to temporally trigger events as close as possible to the hypothetically relevant brain activity feature, which fluctuates over the course of an experiment. A real-time framework even holds advantages for the more conventional offline analysis approach, including a clearer distinction between high and low alpha trials that enables a better contrast between the hypothesized brain state and its assumed behavioral impact (e.g., on reaction time). Currently, the presentation of stimuli is entirely random with respect to features of ongoing brain oscillations and the conclusions that can be drawn from it are correlational (see Figure 1).

Bottom Line: However such offline analyses are disadvantageous as they are correlational by drawing conclusions in a post hoc-manner and stimulus presentation is random with respect to the feature of interest.The software is also independent from the EEG/MEG system, as long as a driver can be written (currently two EEG systems are supported).Besides a general introduction, we present benchmark data regarding performance and validity of the calculations used, as well as three example applications of ConSole in different settings.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Universität Konstanz Konstanz, Germany.

ABSTRACT
Recent years have seen huge advancements in the methods available and used in neuroscience employing EEG or MEG. However, the standard approach is to average a large number of trials for experimentally defined conditions in order to reduce intertrial-variability, i.e., treating it as a source of "noise." Yet it is now more and more accepted that trial-to-trial fluctuations bear functional significance, reflecting fluctuations of "brain states" that predispose perception and action. Such effects are often revealed in a pre-stimulus period, when comparing response variability to an invariant stimulus. However such offline analyses are disadvantageous as they are correlational by drawing conclusions in a post hoc-manner and stimulus presentation is random with respect to the feature of interest. A more direct test is to trigger stimulus presentation when the relevant feature is present. The current paper introduces Constance System for Online EEG (ConSole), a software package capable of analyzing ongoing EEG/MEG in real-time and presenting auditory and visual stimuli via internal routines. Stimulation via external devices (e.g., transcranial magnetic stimulation) or third-party software (e.g., PsyScope X) is possible by sending TTL-triggers. With ConSole it is thus possible to target the stimulation at specific brain states. In contrast to many available applications, ConSole is open-source. Its modular design enhances the power of the software as it can be easily adapted to new challenges and writing new experiments is an easy task. ConSole is already pre-equipped with modules performing standard signal processing steps. The software is also independent from the EEG/MEG system, as long as a driver can be written (currently two EEG systems are supported). Besides a general introduction, we present benchmark data regarding performance and validity of the calculations used, as well as three example applications of ConSole in different settings. ConSole can be downloaded at: http://console-kn.sf.net.

No MeSH data available.


Related in: MedlinePlus