<div dir="ltr"><div class="gmail_default" style="color:#333399">Hello Ali, some thoughts below, best wishes.</div><div class="gmail_default" style="color:#333399"><br></div><div class="gmail_default" style="color:#333399"><br></div><div class="gmail_default" style="color:#333399">A simple method is to use an experimental software such as psychtoolbox, and have it "synch up" with your eeg amplifier, and generate events with each beep.</div><div class="gmail_default" style="color:#333399"><span style="color:rgb(51,51,153);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Another more principled/accurate way to do this is to have a audio sensor that picks up the sound and records it's time. Of course the sensor also needs to be fully aligned with eeg time.</span><br></div><div class="gmail_default" style="color:#333399"><span style="color:rgb(51,51,153);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div class="gmail_default" style="color:#333399"><span style="color:rgb(51,51,153);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">If you trust your beep event times, and they are aligned with the EEG, then you might be good as you are, just import your event list into eeglab (into the eeg file).</span></div><div class="gmail_default" style="color:#333399"><br></div><div class="gmail_default" style="color:#333399"><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial;color:rgb(51,51,153)">One thing to be careful of here is that your eeg and time signal are properly aligned (find a way to make sure that 0 time is 0 time in both the eeg record and the beep events record).</div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial;color:rgb(51,51,153)">Also watch out for jitter (e.g., inaccurate event timing info, unevenly spaced beeps), and for "uncoupling or drift" of your eeg time and beep time over the whole period of the recording.</div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial;color:rgb(51,51,153)"><br></div><div class="gmail_default" style="font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial;color:rgb(51,51,153)"><br></div><br></div><div class="gmail_default" style="color:#333399"><br></div></div>