?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Attention+deficit+disorder+and+hyperkinetic+syndrome%3A+biological+perspectives&rft.creator=Oades%2C+R.D.&rft.subject=Behavioral+Neuroscience&rft.subject=Neuropsychiatry&rft.subject=Psychobiology&rft.description=The+condition%2C+biological+indicators+and+animal+models+of+the+symptoms+and+the+disorder+are+briefly+reviewed.%0ACondition%3A+No+single+symptom+is+indispensable+to+diagnosis.+But+measures+of+the+condition+include+motor+activity%2C+attention%2C+motivation+and+psychostimulant+responsiveness.Caveat%3A+In+the+study+of+the+condition%2C+measuring+biological+correlates+of+unusual+function+may+prove+useful+for+management+of+the+condition%2C+but+could+mislead+in+the+search+for+causes.%0A%0ABiological+indicators%3A+Investigation+of+attention-related+function+and+associated+regional+cerebral+activity+would+be+improved+by+the+careful+application+of+the+results+of+neuropsychological+and+psychophysiological+study.+A+more+extensive+use+of+within+subject+protocols+would+greatly+assist+interpretation+of+the+relevance+of+physiological+states+and+the+contribution+of+activity+in+different+transmitter+systems.Why+are+MHPG+levels+low%2C+and+lower+in+stimulant+responders%3A+HVA%2FMHPG+ratios+high+in+responders+and+nonresponders+alike%3F+However%2C+the+author+sees+the+paradox+to+lie+less+with+the+induced+(sic)+metabolic+changes+as+with+the+inability+to+mimic+the+changes+with+other+catecholaminergic+agents.+Attention+is+drawn+to+the+trophic+effects+of+the+monoamines.+Attention+is+also+drawn+to+the+colocalisation+of+neuropeptide+Y+in+NA+neurons+and+the+possibility+that+alterations+in+this+relationship+could+underlie+other+ADHD+characteristics+such+as+thirst+(1).%0A%0AModels%3A+Symptom-models+attempt+to+investigate+the+determinants+a+single+feature+of+the+illness.+Examples+have+been+recent+demonstrations+that+where+NA+activity+is+low+or+depleted+selective+attention+may+be+impaired+(e.g.+latent+inhibition).+An+interesting+observation+here+is+that+where+NA+activity+is+low%2C+learning+in+a+variety+of+situations+occurs+at+normal+rates+to+a+modest+criterion%2C+but+then+slows+severely+before+eventually+reaching+good+stringent+criteria.+It+is+suggested+that+this+is+consistent+with+an+NA+role+in+%22tuning%22+(2).Discussion+of+the+various+roles+of+DA+must+make+mention+of+the+specific+improvement+seen+after+amphetamine+treatment+in+those+children+who+only+achieve+a+low+response+criterion%3A+in+contrast+in+animals+amphetamine+promotes+the+impulsive+response+lowering+beta-criterion.+The+resolution+oif+the+enigma+may+well+lie+in+a+better+understanding+of+the+interactions+of+the+mesolimbic+with+the+mesocortical+DA+system.+Mesocortical+activity+can+suppress+mesolimbic+activity%2C+impairment+of+frontal+function+releases+the+mesolimbic+system+-+a+change+that+can+be+countered+by+psychostimulant+treatment.%0ADisorder-models+are+concerned+with+mimicking+a+whole+cluster+of+symptoms+if+not+the+syndrome+itself.+Claims+of+the+usefulness+of+depleting+catecholamines+with+6-hydroxydopamine+(on+the+one+hand)+and+modifying+the+environment+in+which+young+animals+are+brought+up+(rich+andsocial+contexts+for+development)+are+elaborated+elsewhere+in+this+book.+The+similarity+of+some+of+the+features+of+hypertensive+patients+and+those+of+youngsters+with+ADHD+initiates+interest+in+the+%22spontaneously+hypertensive+rat%22+(SHR).+Encouraging+the+use+of+the+SHR+as+a+model+are+similarities+in+the+DA+and+NA+activity+and+reactivity.+Further%2C+there+are+similarities+in+between+the+responses+of+the+SHR+and+children+on+learning+schedules+requiring+the+delay+of+response%2C+-+the+delay+of+gratification+that+is+characteristic+of+many+ADHD+children%2C+and+leads+to+impulsive+responding+in+the+SHR.%0ALastly+one+should+not+overlook+the+possible+lessons+to+be+learned+in+the+comparative+approach%2C+-+namely+to+look+at+syndromes+with+more+or+fewer+comorbid+symptoms+such+as+Tourette%2C+Conduct-Disorder%2C+Autism%2C+Lesch.Nyhan+and+Phenylketonuria+(3).%0A%0A&rft.publisher=Lawrence+Erlbaum+Associates&rft.contributor=Sagvolden%2C+T&rft.contributor=Archer%2C+T&rft.date=1989&rft.type=Book+Chapter&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.identifier=http%3A%2F%2Fcogprints.org%2F1353%2F2%2FADHD1989.pdf&rft.identifier=++Oades%2C+R.D.++(1989)+Attention+deficit+disorder+and+hyperkinetic+syndrome%3A+biological+perspectives.++%5BBook+Chapter%5D+++++&rft.relation=http%3A%2F%2Fcogprints.org%2F1353%2F