Electroencephalography (EEG) is a non-invasive neuroimaging technique that measures the electrical activity of the brain. This method relies on the remarkable electrical communication that occurs within the brain's intricate network of neurons. Neurons, the fundamental building blocks of the nervous system, communicate by transmitting electrical impulses called action potentials. These electrical signals are generated when there is a change in the neuron's membrane potential due to the movement of ions across the cell membrane.
When neurons in the brain are active, they produce these action potentials in response to various stimuli and cognitive processes. In the cortex, this collective neuronal activity adds up and generates larger electrical fields. EEG electrodes, strategically placed on the scalp's surface, detect these electrical fields and record them as voltage fluctuations over time. These fluctuations give rise to the characteristic waveforms observed in EEG recordings, such as alpha waves during relaxed wakefulness, delta waves during deep sleep, or event-related potentials (ERPs) in response to specific sensory or cognitive events.
EEG's exceptional temporal resolution, capturing changes in electrical activity within milliseconds, makes it an invaluable tool for researchers studying the real-time dynamics of brain function. It is used to investigate a wide range of cognitive and neurological processes, including memory, attention, perception, and action control. With its ability to directly unveil the patterns in the brain's electrical activity, EEG continues to advance our understanding of the human brain and how it functions.
128-channel Brain Vision BrainAmps DC amplifier in shielded and soundproof cabin
- EasyCap and ActiCap
- Brain Vision recording software
- Latest-version software (e.g. BESA, Brain Vision Analyzer, Matlab)
- Eye tracking (Eyegaze Edge 600 Series)
Biological and Clinical Psychology
40-channel Bittium NeurOne Tesla amplifier
- Eye tracking (Tobii X3-120)
Functional Near-Infrared Spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in blood oxygenation in the brain. It capitalizes on the close physiological relationship between neural activity and local blood flow. When neurons in the brain become more active, they require additional oxygen to support their metabolic demands. In response to this heightened neural activity, local blood vessels dilate to deliver more oxygen-rich blood to the active brain regions. This process is known as neurovascular coupling.
fNIRS leverages the principle that hemoglobin, the oxygen-carrying molecule in blood, absorbs and scatters near-infrared light differently depending on its oxygenation state. By emitting near-infrared light into the brain tissue and measuring the reflected light, fNIRS can detect changes in the concentration of oxygenated and deoxygenated hemoglobin. These changes in hemoglobin concentration serve as an indirect marker of neural activity, allowing researchers to infer which areas of the brain are engaged during specific cognitive tasks or the processing of certain stimuli.
This real-time monitoring of neural activity and its close link to blood flow regulation make fNIRS a powerful tool for studying cognitive processes, such as attention, action-control, and decision-making. Its non-invasive nature, portability, and suitability for various populations, including infants and individuals with mobility limitations, have positioned fNIRS as a valuable technology in neuroscience research, neurorehabilitation, and the development of brain-computer interfaces. fNIRS can give us unique insights into neural processing in life-like situations and can add to our understanding of processes observed in the laboratory because it can easily be combined with other neural measurement methods.
This following video gives a short introduction into the physiological basics of the fNIRS measurement, as well as fNIRS measurement technique and application.
portable NIRSportTM NIRS system (NIRx Medizintechnik GmbH) with time-multiplexed double-wavelength LED control
- 8 sources and 8 detectors
- Flexible optode layout on a standard 10-05-EEG cap
- Easy to combine with other methods like EEG or HD-tDCS
- NIRStar recording software
Neuropsychology & Biological Psychology
Gowerlab LUMO 54
- 54 sources and 162 Detectors
- Full-head coverage
- Built for High-density Diffusion Optical Tomography (HD-DOT)
- Light-wight and fast setup, even with infants and todlers
Functional Magnetic Resonance Imaging (fMRI) is a powerful neuroimaging technique that provides insights into brain function by measuring changes in blood flow and oxygenation. It relies on the close relationship between neural activity and the brain's vascular response. When neurons in the brain become active, they require more oxygen and nutrients to support their functions. In response, local blood vessels dilate to increase blood flow and oxygen delivery to the active regions. This phenomenon, known as the hemodynamic response, is the basis of fMRI.
What sets fMRI apart is its ability to combine structural and functional imaging seamlessly. In addition to mapping brain activity, fMRI can be integrated with structural MRI scans, providing high-resolution anatomical images of the brain's structure. This combination of functional and structural data allows researchers to not only identify which brain regions are active during specific tasks but also precisely localize these regions within the individual's brain anatomy. This integration is invaluable for studying the relationship between brain structure and function, aiding in the identification of abnormalities, lesions, or structural variations that may be associated with specific cognitive or clinical conditions.
This capacity to merge structural and functional information with high spatial resolution has made fMRI a versatile tool for investigating complex cognitive processes, emotional responses, and neurological or psychiatric disorders. It provides researchers with a comprehensive view of the brain, enabling a deeper understanding of the neural basis of human behavior and cognition. Despite the specialized equipment required, fMRI is widely regarded as the gold standard for neural imaging, steadily fostering new discoveries in the field.
Scanner (at the Brüderhaus Trier)
3T Philips Ingenia Elition X equipped with
- Nordic Neurolabs Visual System HD (with binocular eye tracking) and Response Grips
- 32-Channel head coil (in order)
More Information (in German) ► here.
Transcranial Direct Current Stimulation (tDCS) and Transcranial Alternating Current Stimulation (tACS) are non-invasive neuromodulation techniques that aim to influence brain activity and connectivity. tDCS involves the application of a low, direct electrical current to specific areas of the scalp using electrodes. This modulates the resting membrane potential of neurons, making them more or less likely to fire, thereby enhancing or inhibiting neural activity. The effects of tDCS can be categorized into "online" and "offline" phases.
During the "online" phase of tDCS, which occurs while the stimulation is being applied, the electrical current induces immediate changes in neuronal excitability by altering the membrane potential. When the anode (positive electrode) is placed over a brain region of interest, it promotes neuronal depolarization, making neurons more likely to fire, while the cathode (negative electrode) has the opposite effect, leading to hyperpolarization and reduced firing.
In the "offline" phase, which occurs after tDCS has been applied, there are longer-lasting stimulation effects. Besides its direct effects on membrane potentials, tDCS can induce changes in signaling related to gamma-aminobutyric acid (GABA) and glutamate. GABA, the brain's primary inhibitory neurotransmitter, plays a crucial role in broadly reducing neuronal excitability. On the other hand, glutamate, the brain's primary excitatory neurotransmitter, broadly increases neural excitability. These effects can outlast the actual stimulation period, depending on the type of stimulation, leading to long-term depression or long-term potentiation of the stimulated brain areas.
tACS delivers oscillating electrical currents at specific frequencies to entrain neural oscillations. This rhythmic stimulation can synchronize or desynchronize brain regions, potentially enhancing communication between them.
Both tDCS and tACS have gained popularity in neuroscience research and clinical applications. tDCS is used to investigate cognitive processes, like learning, executive functioning, and motor functions, while tACS is particularly valuable for studying brain oscillations, sensory perception, and memory consolidation. These non-invasive neuromodulation techniques offer promising opportunities for exploring the neural basis of human experiencing and behavior and can within limits even be used to enhance cognitive functioning.
- Bi-polar stimulation, sinusoidal stimulation up to 250Hz
- Current selectable up to 4.5 mA
- Stimulation duration up to 30 min
- Controlled by a panel PC (1.6 GHz)
- Simulated of current flow using via HD-Explore (Sosterix medical) or SimNIBS
- Approved as a medical product in Germany
Transcranial Vagus Nerve Stimulation (tVNS) is a non-invasive neuromodulation technique that involves the application of electrical impulses to the vagus nerve, a major neural pathway connecting the brain to various organs. tVNS is typically administered using specialized devices that deliver low-frequency electrical pulses to the auricular branch of the vagus nerve, located in the outer ear. By strategically placing electrodes on the ear, tVNS targets the sensory afferent fibers of the vagus nerve, which convey information from the body to the brain.
These electrical impulses travel along the vagus nerve to reach the brainstem and then project to various brain regions, including the locus coeruleus, nucleus tractus solitarius, and other areas associated with autonomic functions and mood regulation. The precise mechanisms by which tVNS exerts its effects are still under investigation, but it is believed to modulate autonomic nervous system activity, influence inflammation pathways, and enhance neural plasticity.
tVNS has gained attention for its potential therapeutic applications, including the treatment of depression, epilepsy, and chronic pain, as well as its role in enhancing cognitive and memory functions. This non-invasive neuromodulation technique shows promise in both neuroscience research and clinical settings, offering a novel approach to understanding and modulating neural processes.
- 3 portable stimulators
- Non-invasive in-ear stimulation of afferent nerve fibers
- Freely progammable stimulation programms & possibility of triggered stimulation
- Live transmission of stimulation parameters
- Stimulation intensities from 0.1 - 5 mA