322025-01-24 15:20:53OlafHauk312024-04-18 13:58:10OlafHauk302024-03-20 11:55:51OlafHauk292024-03-20 11:55:09OlafHauk282024-03-20 11:53:12OlafHauk272024-03-20 11:51:57OlafHauk262021-06-23 14:29:12OlafHauk252021-01-15 11:34:03OlafHauk242013-03-08 10:02:30localhostconverted to 1.6 markup232013-02-04 15:05:24OlafHauk222012-04-19 16:53:33YaaraErez212012-04-19 16:52:13YaaraErez202012-04-19 12:46:13YaaraErez192012-04-19 12:42:54YaaraErez182012-04-10 16:46:18YaaraErez172012-04-10 16:46:06YaaraErez162010-09-15 11:46:15YaaraErez152010-04-15 12:48:35YaaraErez142010-04-15 11:57:33YaaraErez132010-04-15 11:49:19YaaraErez122010-04-15 11:49:08YaaraErez112010-04-15 11:46:40YaaraErez102010-04-15 11:44:00YaaraErez92010-04-15 11:41:58YaaraErez82010-04-15 11:38:19YaaraErez72010-04-15 11:37:54YaaraErez62010-04-15 11:36:37YaaraErez52010-04-15 11:31:55YaaraErez42010-04-15 11:28:48YaaraErez32010-04-15 11:27:08YaaraErez22010-04-15 11:24:59YaaraErez12010-04-15 11:15:27YaaraErezmrclogo.gif

Below you will find a short description of magnetometers and gradiometers, as well as our MEG sensor and EEG electrode layouts.Note we had a MEGIN Vectorview system with 70 EEG channels between 2006 and 2020, and since 20 have a MEGIN Triux neo with 64 EEG channels. The Elekta manuals are at the bottom. Figures are from the Elekta Neuromag System Hardware User's Manual.

Our Vectorview systems contains 102 magnetometers and 204 planar gradiometers. Magnetometers consist of a single coil which measures the magnetic flux perpendicular to its surface. Planar gradiometers consist of a "figure-of-eight"-type coil configuration. The measured signal is the difference between the two loops of the "eight", or the spatial gradient. There are two orthogonal planar gradiometers at each location. This arrangement is illustrated in the following figure (black: magnetometer; grey and white: two gradiometers). MagsGrads.jpg It has been shown that 3 sensors of these types at one location measure independent information (their "leadfields" are orthogonal). It is therefore more efficient than placing 3 sensors of the same type (e.g. magnetometers) close to each other (they would basically measure the same signal 3 times). Our sensor configuration therefore provides an optimal sampling of the magnetic field for a given number of sensors. The downside is that magnetometers and gradiometers often have to be treated differently during analysis or visualisation. This is the whole sensor layout, including the sensor labels used by the Neuromag software: SensorLayout.jpg SensorLabeling.jpg We routinely use a 64-electrode EEG set-up (Easycap) in combination with our MEG recordings, as depicted below. This is a subset of the previous 70-electrode configuration of the old Vectorview system. Please contact OlafHauk for more details. ElectrodeLayout_64ch.jpg

Hardware Technical Manual Hardware User's Manual Data Acquisition Manual Stimulus System Manual Sensor Tuner Manual Standard Operating Procedures