Brainvision

Brainvision EEG

Image: 200 pixels

Electroencephalography is the neurophysiological measurement of electrical activity in the brain as recorded by electrodes placed on the scalp or, in special cases, subdurally or in the cerebral cortex. The resulting traces are known as an electroencephalogram (EEG) and represent a summation of post-synaptic potentials from a large number of neurons.

The use of EEG in neuroscience research delivers a number of benefits. One is that EEG is non-invasive for the research subject. Furthermore, the need to restrict the subject‘s movements is clearly lower than in other fields of neuroscience such as functional magnetic resonance imaging (fMRI). A further benefit is that many EEG applications record spontaneous brain activity, which means that the subject does not need to be able to cooperate with the researcher (as is necessary, for instance, during behavioral testing in neuropsychology). Also, EEGs have a high temporal resolution compared with techniques such as fMRI and PET and are capable of detecting changes in electrical activity in the brain on a time scale in the millisecond region.

In conventional scalp EEG, the recording is obtained by applying electrodes to the scalp using a conductive gel or paste, usually after preparing the scalp area by light abrasion to reduce electrode-scalp impedance. Many systems typically use electrodes which are each attached to an individual wire. Some systems use caps in which electrodes are embedded. This latter method is particularly common when high-density arrays of electrodes are required.

In addition to internal artifacts such as those produced by blinking, there are many artifacts which originate from outside the patient. Movement by the patient generates huge artifacts. Sweating or changes in temperature may cause electrode drifts. Spikes can originate from a momentary change in impedance at a given electrode. Poor grounding of the EEG electrodes can cause significant 50 or 60 Hz artifacts arising from the power system‘s frequency.

Brain Products EEG amplifiers are equipped with a number of noise reduction techniques such as active noise cancellation and active electrodes. High common mode rejection as well as low amplifier noise ensure maximum data quality. Our huge product range includes a range of electrodes and caps with custom or standard montages as well as a variety of requisite accessories.

Software Documentation

Find the Brainvision analyzer manual here Media:BrainVision_Analyzer_UM.pdf

Find the Brainvision recorder manual here Media:BrainVision_Recorder_UM.pdf

Find the Brainvision macro cookbook manual here Media:Macro_Cookbook.pdf

Find the Brainvision RecView manual here Media:BrainVision_RecView_UM.pdf

Find the Brainvision Automation manual here Media:Automation_Reference_Manual.pdf

EEG Markers

Presentation

#TemplateINFO.pcl

output_port Oport = output_port_manager.get_port( 1 );

#TemplateSUBS.pcl

Oport.send_code(100);  #This is your marker code, range code 1-255
wait_interval(2);      #2ms delay for the code to be recorded by brainvision; 2ms->500hz sampling rate
Oport.send_code(0);    #Back to 0; now ready to send a new code

Python

#!/usr/bin/env python

# import the rusocsci.buttonbox module
from rusocsci import buttonbox 

# make a buttonbox
bb = buttonbox.Buttonbox()

# wait for a single button press
bb.sendMarker(100)    #This is your marker code, range code 1-255
core.wait(0.002)      #2ms delay for the code to be recorded by brainvision; 2ms->500hz sampling rate
bb.sendMarker(0)      #Back to 0; now ready to send a new code</nowiki>