Electro-/Psychophysiology

Introduction

Nerve cells in the brain transmit information through fine electrical potentials. This electrical activity can be measured with the EEG. The EEG is measured non-invasively from the scalp and is thus harmless. In the psychiatric everyday life, the EEG it is being used to find out whether psychiatric symptoms arise because there are primary organic reasons or influene of substances that impair the functionality of the brain (e.g. toxic substances, epilepsy or a tumor). In psychiatric research, the EEG can be employed to distinguish different states of information processing that are activated during specifically designed experiments. These information processing steps are observed in certain conditions and with certain tasks. It is of particular interest to know which processing steps are changed in specific  groups of patients and how these changes relate to the psychopathological symptoms. In the University Hospital and Polyclinic for Psychiatry in Bern, we have separate laboratories for clinical routine investigations and for research.

Clinical EEG Laboratory

For the clinical EEG, a 32-Kanal digital EEG system is used. Per year, approx. 600 routine measurements are accomplished. Apart from these routine measurements, further standardized investigations (P300, CPT) are available. For the evaluation of the recording, analysis PCs, specialized programs and a data base are available. We have also begun to implement automatic classifications of the EEGs to different diagnoses. The clinical EEG measurements are accomplished by trained medical-technical assistants.

Involved team members: Yvonne Fontana, Thomas Koenig, Xiaxia Zhang-Wu

EEG applications in research

In research, the primary focus is not the diagnosis and treatment but the insight into the mechanisms that lead to psychopathological symptoms. Research projects need the approval of an ethics commission and are always voluntary for the examined persons. Independent of their causes, psychiatric symptoms result from a misfit between the brain's information processing and the environment, which leads to inadequate experiences and behavior (this implies that both patient and environment must be considered.) With neurophysiological methods, it is possible to assess and influence not only the experiences and behavior of a subject, but also the processing steps that produce them.

State dependent information processing

Human perception and cognition depend critically on age, arousal, clinical and pharmacological conditions, cognitive and motivational state, and previous experience. Our hypothesis is that many of the symptoms observed in psychiatry may be understood as the result of an interaction between situational information and abnormal patterns of pre-activation of the brain. Specifically, we want to clarify the interaction of resting and pre-stimulus brain states with cognitive capacities and performance in a broad range of normal and clinical populations and under various experimental conditions.

Involved team members: Anja Bänninger, Laura Díaz Hernàndez, Thomas Koenig

Perception, cognition and emotion

We use EEG and event related potentials to investigate a series of tasks and brain functions that are relevant in a psychiatric context. This includes auditory processing in the context of auditory verbal hallucinations, language processing, perceptual feature binding, emotional evaluation, and memory functions.

Involved team members: Anja Bänninger, Laura Díaz Hernàndez, Kathryn Heri, Thomas Koenig

Neurofeedback

Given that perceptual experience and cognition result from an interaction of momentary brain state and incoming information, and given that we have a reasonable knowledge about which brain states may account for psychiatric symptoms, we investigate whether these brain states are accessible to specific modifications thru neurofeedback, and whether these modifications improve psychiatric symptoms.

Involved team members: Laura Díaz Hernàndez, Kathryn Heri, Thomas Koenig

Methods

Apart from addressing specific research questions, we are constantly improving our analysis tools to improve the sensitivity and specificity of our methods, and we integrate emerging technologies such as near infrared spectroscopy and multimodal (EEG-fMRI, EEG-TMS) imaging.

Involved team members: Anja Bänninger, Laura Díaz Hernàndez, Kathryn Heri, Thomas Koenig

For research purposes, we have:

  • an EEG recording chamber with a 32-channel modular neurofeedback system
  • an EEG recording chamber with a 96-channel digital EEG system and a variety of soft- and hardware for stimulation
  • a 96 channel fMRI-compatible EEG system
  • a total of 4 modular 32-channel amplifiers
  • Analysis software and PCs
  • Regular introductory courses in the analysis of EEG data
  • Support for design, data acquisition,analysis and interpretation of experiments