g.tec medical engineering

g.HEADstage - miniaturized headstage amplifier system for single neuron spike recording

miniaturized headstage amplifier system for single neuron spike recording with g.USBamp

g.HEADstage - g.tec's miniaturized pre-amplifier

The g.tec 16-channel head-stages allow the recording of action potentials/spikes with g.USBamp. The boards are extremely small and lightweight and are connected via a very flexible cable to g.USBamp. This allows the animal to move with almost no restrictions. The electronic system has an extremely low noise level and very high input impedance for high quality recordings. The channels have very similar gain, and therefore a very high Common Mode Rejection Ratio is obtained. The head-stages can also be used for biosignal recordings like EEG or ECG in animals.

g.HEADstages are available with system connectors or with single channel connectors that can be interfaced to electrodes/wires easily. The head-stages are connected to the g.SPIKEsens power supply and filtering box that is connected to the g.USBamp. One g.SPIKEsens box supports up to 16 channels. Several head-stages can be used simultaneously. The g.SPIKEsens box filters the signal between 0.5 Hz and 6000 Hz. Voltage Noise Density at 1 kHz is only 10 nV/SQRT(Hz). Aggregation boards can be used to interface the head-stages with different electrodes like twisted wires, silicon electrodes and/or multi-electrode arrays.

An important feature of the head-stages is that the flexible cable can be disconnected. This allows you to replace the cable if it is destroyed by an animal or other cause.

The g.HEADstage is offered in two different types:

The multi-pin headstage
The golden-pin headstage

Product Highlights

Extremely small board (16 channels: 23 mm x 23 mm)
Low weight (<3 g)
Aggregation boards help interface different electrodes types
High quality neuronal activity recordings
LED slot to support easier video tracking
Very high signal-to-noise ratio

More Product Details

g.tec Headstages

Micro-wires and micro-electrode arrays (MEAs) have high impedances and must be very stable on the animal's heads. Therefore, the electrodes are connected with a very flexible cable to the input of the head-stage amplifier that has very high input impedance. It is important that this input impedance is magnitudes higher than the electrode impedance to pick up the neural activity correctly. Then, operational amplifiers with precise gain are used to amplify the spikes and to drive the cable that connects the animal to the main recording system. The precise gain is especially important for a high common-mode rejection ratio (CMRR) (100 dB). The pre-amplifiers avoid also distortions in the signal such as power line interference, electromagnetic interference, and cable artifacts.

Example: Recording of place cells in rats

In-vivo recordings of action potentials in rats can be done by using the g.HEADstages, the biosignal amplifier g.USBamp and the real-time processing software g.USBamp SIMULINK HIGH-SPEED ONLINE Processing. In the following example a rat was foraging for food in an arena measuring 80 x 80 cm. The rat's path was investigated with a video camera based tracking system that transmitted the x- and y- positions to the recording computer. Simultaneously the neuronal activity was recorded with tetrodes (electrodes consisting of 4 wires) placed in the CA1 region of the hippocampus. This is a typical setup for place and grid cell recordings. These neurons increase their firing activity only when the animal is at a specific location in its environment. A typical firing rate map (firing frequency of the neuron vs. position) of a place cell and the averaged spike are shown in the figure below.