?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Event-related+potentials+to+omitted+visual+stimuli+in+a+reptile&rft.creator=Prechtl%2C+James+C.&rft.creator=Bullock%2C+Theodore+H.&rft.subject=Neuroanatomy&rft.subject=Neurochemistry&rft.subject=Neurology&rft.subject=Neurophysiology&rft.subject=Neurophysiology&rft.description=Visual+omitted+stimulus+potentials+(OSPs)+were+recorded+from+awake+pond+turtles+with+arrays+of+3-20+electrodes+in+the+dorsal+cortex+(DC)%2C+dorsal+ventricular+ridge+(DVR)+and+optic+tectum.+Since+they+are+generally+longer+in+duration+than+the+interstimulus+interval+(ISI)%2C+the+standard+experiment+is+a+short+conditioning+train+of+regular+light+or+dark+flashes+(1-20+Hz)+whose+termination+elicits+the+OSP.+Tectal+surface+OSPs+after+trains+%3E7+Hz+have+two+major+positive+peaks%2C+P120-140+and+P220-250+after+the+due-time+of+the+first+omission%3B+after+%3C7+Hz+down+to+the+minimum+of+1.5+Hz+only+the+slower+peak+appears.+Some+deep+tectal+loci+also+have+one+to+three+100+ms+wide+negative+waves+peaking+at+variable+times+from+200-1300+ms.+Forebrain+OSPs+in+DC+and+DVR+are+approximately+30+ms+later+and+often+include+induced+17-25+Hz+oscillations%2C+not+phase-locked+and+attenuated+in+averages.+Both+tectal+and+forebrain+OSP+main+waves+tend+toward+a+constant+latency+after+the+due-time%2C+over+a+wide+range+of+ISIs%2C+as+though+the+system+expects+a+stimulus+on+schedule.+Jitter+of+ISI+around+the+mean+does+not+greatly+reduce+the+OSP.+At+all+loci+higher+conditioning+rates+cause+the+amplitudes+of+the+steady+state+response+(SSR)+VEPs+to+decline+and+of+the+OSPs+to+increase.+Some+similarities+and+correlations+of+regional+amplitude+fluctuations+between+OSPs+and+VEPs+are+noted.+The+OSP+dynamics+are+consistent+with+the+hypothesis+of+a+postinhibitory+rebound+of+temporally+specific+VEP+components+increasingly+inhibited+with+higher+stimulation+rates%3B+much+of+this+response+is+retinal+but+each+higher+brain+level+further+modulates.+OSPs+in+this+reptile+are+similar+to+those+known+in+fish+and+to+the+%22high+frequency%22+type+in+humans%2C+quite+distinct+in+properties+from+the+%22low+frequency%22+OSPs.+It+will+be+important+to+look+at+the+high+frequency+type+in+laboratory+mammals+to+determine+whether+they+are+present+in+the+midbrain+and+retina%2C+as+in+fish+and+reptiles.&rft.date=1994&rft.type=Journal+(Paginated)&rft.type=PeerReviewed&rft.format=text%2Fhtml&rft.identifier=http%3A%2F%2Fcogprints.org%2F118%2F1%2Fevent_reptile.htm&rft.identifier=++Prechtl%2C+James+C.+and+Bullock%2C+Theodore+H.++(1994)+Event-related+potentials+to+omitted+visual+stimuli+in+a+reptile.++%5BJournal+(Paginated)%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F118%2F