To clarify the nature of auditory P50, middle latency auditory evoked potentials were recorded by using different condition of reference electrodes (linked earlobes, LE; balanced non-cephalic, BN), stimulation characteristics (tone burst, human voice) and tasks (counting, simple reaction) in 10 right- handed males (aged 21-36 years). EEG was recorded from Fz, Cz, Pz, C3, C4, T3 and T4 according to the 10-20 system. Two groups of electrode sites were made for the statistical analysis: a midline group. Fz, Cz and Pz; and a lateral group, T3, C3, Cz, C4 and T4. The results were that the P50 amplitudes with BN electrodes were significantly higher than those with LE in both groups (midline, P<0.01; lateral, P<0.01); the P50 amplitudes by voice stimulations were significantly higher than those by tone stimulation in the lateral group (P<0.05), and the P50 latencies under a simple reaction paradigm were significantly shorter than those under a counting task in both groups (midline, P<0.05; lateral, P<0.05). These results suggest that various factors including motor response affect the P50 amplitudes and latencies.
|Number of pages||5|
|Journal||Psychiatry and clinical neurosciences|
|Publication status||Published - 1997|
All Science Journal Classification (ASJC) codes
- Clinical Neurology
- Psychiatry and Mental health