Details

Autor(en) / Beteiligte

• Parry, N.R.A
• Murray, I.J
• Hadjizenonos, C

Titel

Spatio-temporal tuning of VEPs: effect of mode of stimulation

Ist Teil von

• Vision research (Oxford), 1999-10, Vol.39 (21), p.3491-3497

Ort / Verlag

Oxford: Elsevier Ltd

Erscheinungsjahr

1999

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• The spatial tuning function of the 8 Hz reversal Visual Evoked Potential (VEP) is frequently bimodal. This amplitude ‘notch’ largely disappears with 16 Hz pattern onset–offset (on–off) stimulation. To investigate the effect of temporal frequency on this phenomenon, we tested seven subjects using a range of rates centred on 8 Hz (reversal) and 16 Hz (on–off). With reversal, a deep notch was present at all temporal frequencies. A much shallower notch was evident with on–off. The on–off and reversal functions differed only in their low spatial frequency branches (below 4.5 c deg −1) where, as temporal frequency decreased, the reversal response was reduced by 50%, whilst the on–off responses doubled in amplitude. Thus, although they behave differently with on–off and reversal, multiple spatial frequency mechanisms are evident with both forms of stimulation.