Thomas Koenig | Bern University (original) (raw)

Papers by Thomas Koenig

Recent studies suggest that computerized cognitive training leads to improved performance in rela... more Recent studies suggest that computerized cognitive training leads to improved performance in related but untrained tasks (i.e. transfer effects). However, most study designs prevent disentangling which of the task components are necessary for transfer. In the current study, we examined whether training on two variants of the adaptive dual n-back task would affect untrained task performance and the corresponding electrophysiological event-related potentials (ERPs). Forty three healthy young adults were trained for three weeks with a high or low interference training variant of the dual n-back task, or they were assigned to a passive control group. While n-back training with high interference led to partial improvements in the Attention Network Test (ANT), we did not find transfer to measures of working memory and fluid intelligence. ERP analysis in the n-back task and the ANT indicated overlapping processes in the P3 time range. Moreover, in the ANT, we detected increased parietal activity for the interference training group alone. In contrast, we did not find electrophysiological differences between the low interference training and the control group. These findings suggest that training on an interference control task leads to higher electrophysiological activity in the parietal cortex, which may be related to improvements in processing speed, attentional control, or both.

NeuroImage, 2015

Microstates (MS), the fingerprints of the momentarily and time-varying states of the brain derive... more Microstates (MS), the fingerprints of the momentarily and time-varying states of the brain derived from electroencephalography (EEG), are associated with the resting state networks (RSNs). However, using MS fluctuations along different EEG frequency bands to model the functional MRI (fMRI) signal has not been investigated so far, or elucidated the role of the thalamus as a fundamental gateway and a putative key structure in cortical functional networks. Therefore, in the current study, we used MS predictors in standard frequency bands to predict blood oxygenation level dependent (BOLD) signal fluctuations. We discovered that multivariate modeling of BOLD-fMRI using six EEG-MS classes in eight frequency bands strongly correlated with thalamic areas and large-scale cortical networks. Thalamic nuclei exhibited distinct patterns of correlations for individual MS that were associated with specific EEG frequency bands. Anterior and ventral thalamic nuclei were sensitive to the beta frequency band, medial nuclei were sensitive to both alpha and beta frequency bands, and posterior nuclei such as the pulvinar were sensitive to delta and theta frequency bands. These results demonstrate that EEG-MS informed fMRI can elucidate thalamic activity not directly observable by EEG, which may be highly relevant to understand the rapid formation of thalamocortical networks.

Frontiers in Behavioral Neuroscience, 2015

Working memory (WM) processes depend on our momentary mental state and therefore exhibit consider... more Working memory (WM) processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health. We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods. Four temporally coherent networks (TCNs)-the default mode network (DMN), the dorsal attention, the right and the left WM network-were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks' pre-stimulus activation upon retention-related EEG activity in the theta, alpha, and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing. We were able to replicate two wellknown load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be "online" synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals.

Neuropsychobiology, 2014

The attention-deficit/hyperactivity disorder (ADHD) shows an increased prevalence in delinquents ... more The attention-deficit/hyperactivity disorder (ADHD) shows an increased prevalence in delinquents compared to the normal population. In recent studies, a subgroup of subjects with ADHD as well as a subgroup of delinquents displayed excessive electroencephalography (EEG) beta activity, which has been associated with antisocial behavior in ADHD children. We investigated whether delinquent behavior in adults with ADHD symptomatology is related to excessive beta activity. We compared the resting state EEGs (eyes open/closed) of delinquent and nondelinquent subjects with ADHD symptoms and those of a control group regarding EEG power spectra and topography. Delinquents with ADHD symptomatology showed more beta power at frontal, central and parietal brain regions than nondelinquents with ADHD symptoms. Excessive beta power may thus represent a risk factor for delinquent behavior in adults with ADHD symptomatology. The awareness of such a risk factor may be helpful in the assessment of the r...

Frontiers in Psychology, 2014

To test whether humans can encode words during sleep we played everyday words to men while they w... more To test whether humans can encode words during sleep we played everyday words to men while they were napping and assessed priming from sleep-played words following waking. Words were presented during non-rapid eye movement (NREM) sleep. Priming was assessed using a semantic and a perceptual priming test. These tests measured differences in the processing of words that had been or had not been played during sleep. Synonyms to sleep-played words were the targets in the semantic priming test that tapped the meaning of sleep-played words. All men responded to sleep-played words by producing up-states in their electroencephalogram. Up-states are NREM sleep-specific phases of briefly increased neuronal excitability. The word-evoked up-states might have promoted word processing during sleep. Yet, the mean performance in the priming tests administered following sleep was at chance level, which suggests that participants as a group failed to show priming following sleep. However, performance in the two priming tests was positively correlated to each other and to the magnitude of the word-evoked up-states. Hence, the larger a participant's word-evoked up-states, the larger his perceptual and semantic priming. Those participants who scored high on all variables must have encoded words during sleep. We conclude that some humans are able to encode words during sleep, but more research is needed to pin down the factors that modulate this ability.

European Archives of Psychiatry and Clinical Neuroscience, 1999

Momentary brain electric field configurations are manifestations of momentary global functional s... more Momentary brain electric field configurations are manifestations of momentary global functional states of the brain. Field configurations tend to persist over some time in the sub-second range (“microstates”) and concentrate within few classes of configurations. Accordingly, brain field data can be reduced efficiently into sequences of re-occurring classes of brain microstates, not overlapping in time. Different configurations must have been

Biological Psychiatry, 1998

Background: Schizophrenic symptoms commonly are felt to indicate a loosened coordination, i.e. a ... more Background: Schizophrenic symptoms commonly are felt to indicate a loosened coordination, i.e. a decreased connectivity of brain processes.Methods: To address this hypothesis directly, global and regional multichannel electroencephalographic (EEG) complexities (omega complexity and dimensional complexity) and single channel EEG dimensional complexities were calculated from 19-channel EEG data from 9 neuroleptic-naive, first-break, acute schizophrenics and 9 age- and sex-matched controls. Twenty

were matched for age, sex, education, and handedness. SurJ;ace potential and Laplacian maps were ... more were matched for age, sex, education, and handedness. SurJ;ace potential and Laplacian maps were generated. We obtained the following results: (1) the Laplacian maps show two separate fronto-lateral maxima of the PINV in all groups; (2) the PINV is larger following ambiguous as compared to clear matching in all groups; (3) both control groups exhibit a strong and quickly developing right-frontal predominance of the P[NV, while schizophrenic and high-schizotypal participants exhibit a more symmetric distribution (group differences were statistically confirmed); (4) dipole analyses (BESA) suggest bilateral anterior-temporal PINV sources. Our results indicate that schizophrenic patients and schizotypal subjects differ from control subjects in the cortical generator structures of the PINV.

Recent studies suggest that computerized cognitive training leads to improved performance in rela... more Recent studies suggest that computerized cognitive training leads to improved performance in related but untrained tasks (i.e. transfer effects). However, most study designs prevent disentangling which of the task components are necessary for transfer. In the current study, we examined whether training on two variants of the adaptive dual n-back task would affect untrained task performance and the corresponding electrophysiological event-related potentials (ERPs). Forty three healthy young adults were trained for three weeks with a high or low interference training variant of the dual n-back task, or they were assigned to a passive control group. While n-back training with high interference led to partial improvements in the Attention Network Test (ANT), we did not find transfer to measures of working memory and fluid intelligence. ERP analysis in the n-back task and the ANT indicated overlapping processes in the P3 time range. Moreover, in the ANT, we detected increased parietal activity for the interference training group alone. In contrast, we did not find electrophysiological differences between the low interference training and the control group. These findings suggest that training on an interference control task leads to higher electrophysiological activity in the parietal cortex, which may be related to improvements in processing speed, attentional control, or both.

NeuroImage, 2015

Microstates (MS), the fingerprints of the momentarily and time-varying states of the brain derive... more Microstates (MS), the fingerprints of the momentarily and time-varying states of the brain derived from electroencephalography (EEG), are associated with the resting state networks (RSNs). However, using MS fluctuations along different EEG frequency bands to model the functional MRI (fMRI) signal has not been investigated so far, or elucidated the role of the thalamus as a fundamental gateway and a putative key structure in cortical functional networks. Therefore, in the current study, we used MS predictors in standard frequency bands to predict blood oxygenation level dependent (BOLD) signal fluctuations. We discovered that multivariate modeling of BOLD-fMRI using six EEG-MS classes in eight frequency bands strongly correlated with thalamic areas and large-scale cortical networks. Thalamic nuclei exhibited distinct patterns of correlations for individual MS that were associated with specific EEG frequency bands. Anterior and ventral thalamic nuclei were sensitive to the beta frequency band, medial nuclei were sensitive to both alpha and beta frequency bands, and posterior nuclei such as the pulvinar were sensitive to delta and theta frequency bands. These results demonstrate that EEG-MS informed fMRI can elucidate thalamic activity not directly observable by EEG, which may be highly relevant to understand the rapid formation of thalamocortical networks.

Frontiers in Behavioral Neuroscience, 2015

Working memory (WM) processes depend on our momentary mental state and therefore exhibit consider... more Working memory (WM) processes depend on our momentary mental state and therefore exhibit considerable fluctuations. Here, we investigate the interplay of task-preparatory and task-related brain activity as represented by pre-stimulus BOLD-fluctuations and spectral EEG from the retention periods of a visual WM task. Visual WM is used to maintain sensory information in the brain enabling the performance of cognitive operations and is associated with mental health. We tested 22 subjects simultaneously with EEG and fMRI while performing a visuo-verbal Sternberg task with two different loads, allowing for the temporal separation of preparation, encoding, retention and retrieval periods. Four temporally coherent networks (TCNs)-the default mode network (DMN), the dorsal attention, the right and the left WM network-were extracted from the continuous BOLD data by means of a group ICA. Subsequently, the modulatory effect of these networks' pre-stimulus activation upon retention-related EEG activity in the theta, alpha, and beta frequencies was analyzed. The obtained results are informative in the context of state-dependent information processing. We were able to replicate two wellknown load-dependent effects: the frontal-midline theta increase during the task and the decrease of pre-stimulus DMN activity. As our main finding, these two measures seem to depend on each other as the significant negative correlations at frontal-midline channels suggested. Thus, suppressed pre-stimulus DMN levels facilitated later task related frontal midline theta increases. In general, based on previous findings that neuronal coupling in different frequency bands may underlie distinct functions in WM retention, our results suggest that processes reflected by spectral oscillations during retention seem not only to be "online" synchronized with activity in different attention-related networks but are also modulated by activity in these networks during preparation intervals.

Neuropsychobiology, 2014

The attention-deficit/hyperactivity disorder (ADHD) shows an increased prevalence in delinquents ... more The attention-deficit/hyperactivity disorder (ADHD) shows an increased prevalence in delinquents compared to the normal population. In recent studies, a subgroup of subjects with ADHD as well as a subgroup of delinquents displayed excessive electroencephalography (EEG) beta activity, which has been associated with antisocial behavior in ADHD children. We investigated whether delinquent behavior in adults with ADHD symptomatology is related to excessive beta activity. We compared the resting state EEGs (eyes open/closed) of delinquent and nondelinquent subjects with ADHD symptoms and those of a control group regarding EEG power spectra and topography. Delinquents with ADHD symptomatology showed more beta power at frontal, central and parietal brain regions than nondelinquents with ADHD symptoms. Excessive beta power may thus represent a risk factor for delinquent behavior in adults with ADHD symptomatology. The awareness of such a risk factor may be helpful in the assessment of the r...

Frontiers in Psychology, 2014

To test whether humans can encode words during sleep we played everyday words to men while they w... more To test whether humans can encode words during sleep we played everyday words to men while they were napping and assessed priming from sleep-played words following waking. Words were presented during non-rapid eye movement (NREM) sleep. Priming was assessed using a semantic and a perceptual priming test. These tests measured differences in the processing of words that had been or had not been played during sleep. Synonyms to sleep-played words were the targets in the semantic priming test that tapped the meaning of sleep-played words. All men responded to sleep-played words by producing up-states in their electroencephalogram. Up-states are NREM sleep-specific phases of briefly increased neuronal excitability. The word-evoked up-states might have promoted word processing during sleep. Yet, the mean performance in the priming tests administered following sleep was at chance level, which suggests that participants as a group failed to show priming following sleep. However, performance in the two priming tests was positively correlated to each other and to the magnitude of the word-evoked up-states. Hence, the larger a participant's word-evoked up-states, the larger his perceptual and semantic priming. Those participants who scored high on all variables must have encoded words during sleep. We conclude that some humans are able to encode words during sleep, but more research is needed to pin down the factors that modulate this ability.

European Archives of Psychiatry and Clinical Neuroscience, 1999

Momentary brain electric field configurations are manifestations of momentary global functional s... more Momentary brain electric field configurations are manifestations of momentary global functional states of the brain. Field configurations tend to persist over some time in the sub-second range (“microstates”) and concentrate within few classes of configurations. Accordingly, brain field data can be reduced efficiently into sequences of re-occurring classes of brain microstates, not overlapping in time. Different configurations must have been

Biological Psychiatry, 1998

Background: Schizophrenic symptoms commonly are felt to indicate a loosened coordination, i.e. a ... more Background: Schizophrenic symptoms commonly are felt to indicate a loosened coordination, i.e. a decreased connectivity of brain processes.Methods: To address this hypothesis directly, global and regional multichannel electroencephalographic (EEG) complexities (omega complexity and dimensional complexity) and single channel EEG dimensional complexities were calculated from 19-channel EEG data from 9 neuroleptic-naive, first-break, acute schizophrenics and 9 age- and sex-matched controls. Twenty

were matched for age, sex, education, and handedness. SurJ;ace potential and Laplacian maps were ... more were matched for age, sex, education, and handedness. SurJ;ace potential and Laplacian maps were generated. We obtained the following results: (1) the Laplacian maps show two separate fronto-lateral maxima of the PINV in all groups; (2) the PINV is larger following ambiguous as compared to clear matching in all groups; (3) both control groups exhibit a strong and quickly developing right-frontal predominance of the P[NV, while schizophrenic and high-schizotypal participants exhibit a more symmetric distribution (group differences were statistically confirmed); (4) dipole analyses (BESA) suggest bilateral anterior-temporal PINV sources. Our results indicate that schizophrenic patients and schizotypal subjects differ from control subjects in the cortical generator structures of the PINV.