A highlight from Prof. Marty Woldorff, Professor of Psychiatry and Behavioral Sciences at Duke University


Mike yesterday's custodial dove who is psychiatric behavioral sciences at duke university. He's focus on advancing or understanding of the neural and psychological mechanisms underlying human attentional processes and to be fixed on cognitive functions. belco mark. yeah thanks for doing so. I want to start birth. One of your older peepers From the ninety entitled modulation of early sensory processing human auditory cortex during auditory selective attention. You sit neural. Mcphee recorded from human subjects as it isn't selectivity to sequences of rapidly presented tones in one year while league noting tolan suffered different pitch in the opposite ear and so is he getting himself auditory stimuli. And then you're measuring what's happening in the rain. That's right that's right. yeah so we. We are trying to understand the neuro mechanisms by which we End moral mechanism by which we accomplish. mental functions such as selective attention And so we measure brain activity while they're engaged in these tasks. This particular task was meant to simulate. What's called the cocktail party. Effect Where you can be a cocktail party in this different conversations going on and you can tune selectively to one conversation and tune out the other one and This is meant to simulate that by having the stimuli coming rapidly to the two years so twenty years like one conversation and the other is is the other conversation and the the the rapidly presented stimuli are simulating in a way that we can do a lab to the two conversations to track what how are differentially processing and attended conversation versus unattended stimulus. Input subjects are instructed to do this right from the beginning some different ron say either attend to the stimuli coming into the the left ear or stimuli coming into the right ear and then what we have then as we attending to the last year. They're selectively Listening to that here that's the tended side and the other side is unattended. And then we switched we get the reverse so we can compare the same physical stimuli say stimulated the left ear the responses in the brain when you're attending to that input versus when you're attending elsewhere everything else controlled stimuli identical. The overall rows will sustain but we want to see is the selective focusing of attention and what that does and there were long standing arguments based on behavioral work as to how much attention affects processing. So there were early selection series and late selection theories that went on for a long time just based on trying to standards based on button presses and and other sorts of behavioral responses. Where early or late selection theories found felt that all stimuli process to considerable censoring perceptual detail and then at some late stage processing what's relevant to you enters consciousness and you process it at a higher level. Early selection theorist held that there was a selective filtering mechanism that the higher levels of the brain could impose to modulate incoming information that much earlier levels. So these are had to be based on the behavior on reaction time after at the end of a of a five hundred. Six hundred milliseconds but by measuring bringing active. We could we. Could we see when exactly in the in the processing attention would affect that. Didn't affect early in the first ten milliseconds when the brain stem activity or when i hit auditory cortex or hundred milliseconds afterwards and this study and the study the preceded at e. g. study found. That indeed you could affect stimulus processing very early in before The the the stimulus processing had gone very far. And what could infer from that that they're descending pathways from higher levels of the brain. They're making these decisions the kind of turn up the game on the stuck. You're interested in and very early levels and turn it down on interested that that's really fascinating so one thing i was wondering marty though in a cocktail party is. Isn't there a difference in you. Know sort of naturally doing it and in an experimental setting you are asked to just focus on your left or the right year. Ignore the other. Wouldn't there be some complications because they don't behave like that. That's true that's true we do have this. As a general issues as we have phenomenon the real world that. We're trying to do a selective study of with to try to figure out mechanism and so we have to constrain at bam One of the advances of these studies were the stimuli came very rapidly and they were very. You had to attend one ear to pick out the slightly fainter distinct or an occasional Deviant tone in that ear so fast and And more difficult to do the task in so you really couldn't do

Coming up next