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Frontal midline theta oscillations during mental arithmetic: effects of stress.

Gärtner M, Grimm S, Bajbouj M - Front Behav Neurosci (2015)

Bottom Line: Additionally, it is well-established that acute stress impairs PFC function, and recent evidence suggests that FMT is decreased under stress.Our results show late-onset, sustained FMT increases during mental arithmetic.Our results suggest that FMT is associated with stimulus independent mental processes during the natural and complex PFC-dependent task of mental arithmetic, and is a possible marker for intact PFC function that is disrupted under stress.

View Article: PubMed Central - PubMed

Affiliation: Affective Neuroscience and Emotion Modulation, Department of Education and Psychology, Freie Universität Berlin Berlin, Germany ; Department of Psychiatry, Charité, Campus Benjamin Franklin Berlin, Germany.

ABSTRACT
Complex cognitive tasks such as mental arithmetic heavily rely on intact, well-coordinated prefrontal cortex (PFC) function. Converging evidence suggests that frontal midline theta (FMT) oscillations play an important role during the execution of such PFC-dependent tasks. Additionally, it is well-established that acute stress impairs PFC function, and recent evidence suggests that FMT is decreased under stress. In this EEG study, we investigated FMT oscillations during a mental arithmetic task that was carried out in a stressful and a neutral control condition. Our results show late-onset, sustained FMT increases during mental arithmetic. In the neutral condition FMT started to increase earlier than in the stress condition. Direct comparison of the conditions quantified this difference by showing stronger FMT increases in the neutral condition in an early time window. Between-subject correlation analysis showed that attenuated FMT under stress was related to slowed reaction times. Our results suggest that FMT is associated with stimulus independent mental processes during the natural and complex PFC-dependent task of mental arithmetic, and is a possible marker for intact PFC function that is disrupted under stress.

No MeSH data available.


Related in: MedlinePlus

Frontal midline theta increases during mental arithmetic in the response-locked time window. Cluster dimensions in the electrode-time-frequency space for pooled, neutral and stress conditions. (A–C) Show event-related synchronization (ERS) compared to a pre-stimulus baseline period (−1000 to 0 ms) in dB. (A) Shows the cluster dimensions in the electrode space. (B) Shows the cluster dimensions in the time-frequency space. (C) Shows the time course of the ERS. (D) Shows the distribution of random clusters in the cluster-based permutation test. The red line marks the position of the observed cluster.
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Figure 3: Frontal midline theta increases during mental arithmetic in the response-locked time window. Cluster dimensions in the electrode-time-frequency space for pooled, neutral and stress conditions. (A–C) Show event-related synchronization (ERS) compared to a pre-stimulus baseline period (−1000 to 0 ms) in dB. (A) Shows the cluster dimensions in the electrode space. (B) Shows the cluster dimensions in the time-frequency space. (C) Shows the time course of the ERS. (D) Shows the distribution of random clusters in the cluster-based permutation test. The red line marks the position of the observed cluster.

Mentions: Cluster analysis revealed significant power increases from baseline in both, the stimulus-locked and the response-locked time window. In the neutral condition and stimulus-locked time window one significant cluster (p = 0.002, cluster statistic, Figure 2) was observed. Cluster dimensions ranged from 3 to 7.5 Hz in the frequency domain, and from 740 to 3000 ms in the time domain. In the neutral condition and response-locked window one significant cluster (p = 0.001, cluster statistic, Figure 3) that ranged from 2 to 8 Hz in the frequency domain, and from −2500 to −500 ms in the time domain, was observed. In the stress condition and stimulus-locked time window one cluster reached significance (p = 0.016, cluster statistic, Figure 2). It ranged from 3.5 to 6.5 Hz in the frequency domain, and from 2015 to 3000 ms in the time domain. In the stress condition and response-locked window the observed significant cluster (p = 0.003, cluster statistic, Figure 3) incorporated frequencies from 3 to 7 Hz, and time bins from −2500 to −500 ms. In the electrode space all clusters were located over a frontal midline region centered around Fz. All cluster statistics and dimensions are summarized in Table 1. Control time-frequency analyses without ERP removal showed an additional cluster in the theta frequency range. It ranged from 1.5 to 7 Hz in the frequency range, and from 0 to 615 ms in the time domain. It was located over the complete posterior half of the cortex, centered at bilateral parieto-occipital electrodes (see Supplementary Figure 1). Exploratory time-frequency analyses for higher frequencies (8–50 Hz) revealed strong decreases in the frequency range from 8 to 48 Hz, which was strongest in the alpha (8–13 Hz), and beta (15–25 Hz) band (see Supplementary Figure 2). The decrease started in the stimulus-locked time window at stimulus onset, and remained decreased until the end of the response-locked time window. It was located over the entire posterior half of the cortex, and strongest at occipital electrode sites.


Frontal midline theta oscillations during mental arithmetic: effects of stress.

Gärtner M, Grimm S, Bajbouj M - Front Behav Neurosci (2015)

Frontal midline theta increases during mental arithmetic in the response-locked time window. Cluster dimensions in the electrode-time-frequency space for pooled, neutral and stress conditions. (A–C) Show event-related synchronization (ERS) compared to a pre-stimulus baseline period (−1000 to 0 ms) in dB. (A) Shows the cluster dimensions in the electrode space. (B) Shows the cluster dimensions in the time-frequency space. (C) Shows the time course of the ERS. (D) Shows the distribution of random clusters in the cluster-based permutation test. The red line marks the position of the observed cluster.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403551&req=5

Figure 3: Frontal midline theta increases during mental arithmetic in the response-locked time window. Cluster dimensions in the electrode-time-frequency space for pooled, neutral and stress conditions. (A–C) Show event-related synchronization (ERS) compared to a pre-stimulus baseline period (−1000 to 0 ms) in dB. (A) Shows the cluster dimensions in the electrode space. (B) Shows the cluster dimensions in the time-frequency space. (C) Shows the time course of the ERS. (D) Shows the distribution of random clusters in the cluster-based permutation test. The red line marks the position of the observed cluster.
Mentions: Cluster analysis revealed significant power increases from baseline in both, the stimulus-locked and the response-locked time window. In the neutral condition and stimulus-locked time window one significant cluster (p = 0.002, cluster statistic, Figure 2) was observed. Cluster dimensions ranged from 3 to 7.5 Hz in the frequency domain, and from 740 to 3000 ms in the time domain. In the neutral condition and response-locked window one significant cluster (p = 0.001, cluster statistic, Figure 3) that ranged from 2 to 8 Hz in the frequency domain, and from −2500 to −500 ms in the time domain, was observed. In the stress condition and stimulus-locked time window one cluster reached significance (p = 0.016, cluster statistic, Figure 2). It ranged from 3.5 to 6.5 Hz in the frequency domain, and from 2015 to 3000 ms in the time domain. In the stress condition and response-locked window the observed significant cluster (p = 0.003, cluster statistic, Figure 3) incorporated frequencies from 3 to 7 Hz, and time bins from −2500 to −500 ms. In the electrode space all clusters were located over a frontal midline region centered around Fz. All cluster statistics and dimensions are summarized in Table 1. Control time-frequency analyses without ERP removal showed an additional cluster in the theta frequency range. It ranged from 1.5 to 7 Hz in the frequency range, and from 0 to 615 ms in the time domain. It was located over the complete posterior half of the cortex, centered at bilateral parieto-occipital electrodes (see Supplementary Figure 1). Exploratory time-frequency analyses for higher frequencies (8–50 Hz) revealed strong decreases in the frequency range from 8 to 48 Hz, which was strongest in the alpha (8–13 Hz), and beta (15–25 Hz) band (see Supplementary Figure 2). The decrease started in the stimulus-locked time window at stimulus onset, and remained decreased until the end of the response-locked time window. It was located over the entire posterior half of the cortex, and strongest at occipital electrode sites.

Bottom Line: Additionally, it is well-established that acute stress impairs PFC function, and recent evidence suggests that FMT is decreased under stress.Our results show late-onset, sustained FMT increases during mental arithmetic.Our results suggest that FMT is associated with stimulus independent mental processes during the natural and complex PFC-dependent task of mental arithmetic, and is a possible marker for intact PFC function that is disrupted under stress.

View Article: PubMed Central - PubMed

Affiliation: Affective Neuroscience and Emotion Modulation, Department of Education and Psychology, Freie Universität Berlin Berlin, Germany ; Department of Psychiatry, Charité, Campus Benjamin Franklin Berlin, Germany.

ABSTRACT
Complex cognitive tasks such as mental arithmetic heavily rely on intact, well-coordinated prefrontal cortex (PFC) function. Converging evidence suggests that frontal midline theta (FMT) oscillations play an important role during the execution of such PFC-dependent tasks. Additionally, it is well-established that acute stress impairs PFC function, and recent evidence suggests that FMT is decreased under stress. In this EEG study, we investigated FMT oscillations during a mental arithmetic task that was carried out in a stressful and a neutral control condition. Our results show late-onset, sustained FMT increases during mental arithmetic. In the neutral condition FMT started to increase earlier than in the stress condition. Direct comparison of the conditions quantified this difference by showing stronger FMT increases in the neutral condition in an early time window. Between-subject correlation analysis showed that attenuated FMT under stress was related to slowed reaction times. Our results suggest that FMT is associated with stimulus independent mental processes during the natural and complex PFC-dependent task of mental arithmetic, and is a possible marker for intact PFC function that is disrupted under stress.

No MeSH data available.


Related in: MedlinePlus