P.S. The location is STBIO (1205 Docteur Penfield Avenue), Room S3/4
On Fri, Sep 23, 2016 at 11:08 AM, Anna Zamm anna.zamm@mail.mcgill.ca wrote:
Dear all,
A reminder that there is a Cognitive Colloquium today (Sep 23) at 3:30 PM. See abstract below.
*Effects of combined attention on early visual cortical processing: An ERP investigation*
Christopher David Blair & Jelena Ristic
Previous attention research has shown that certain types of attentional cues (such as those combining exogenous and endogenous effects, like predictive arrows) can produce behavioral effects that are additive or super-additive as compared to those produced by attentional cues that are only either exogenous (such as non-predictive arrows) or endogenous (such as predictive non-directional shapes). We sought to further examine these effects when targets were presented at longer and shorter stimulus onset asynchronies (SOAs), and to look at the accompanying brain activity in the form of the P1 evoked potential using electroencephalography (EEG). At both shorter and longer SOAs, we replicated a significant effect of cue validity, by which participants responded faster to cued targets in all cueing conditions. This effect was additive for predictive arrows at the shorter SOAs and super additive at longer SOAs as compared to non-predictive arrows and predictive shapes. Overall, our P1 data also showed a significant effect for cue validity, and our additivity measures reflect a pattern similar to our behavioral results at the shorter SOAs. However, it appears that there may be an opposing effect at the longer SOAs, with predictive arrows producing an underadditive P1 amplitude difference. Given these results, we extended our analyses to examine the frequency information present in our EEG data, focusing on the alpha band where higher power and synchronization is thought to be representative of suppression. Time frequency analysis of lateralized alpha power following cue onset showed higher power recorded at electrode sites corresponding to the hemisphere ipsilateral to cue direction, but only for predictive and non-predictive arrow conditions. A similar pattern is observed when comparing alpha power in response to cued and uncued target appearance. Thus, we have yet to find a neural measure that perfectly correlates with the relationship observed between behavioral measures of attention related to cues that produce combined, exogenous, and endogenous effects.
On Mon, Sep 19, 2016 at 10:17 AM, Anna Zamm anna.zamm@mail.mcgill.ca wrote:
Dear all,
Post-doctoral fellow *Dr. Christopher Blair *(Ristic Lab) will be giving the first Fall 2016 Cognitive Area Seminar talk this *Friday, September 23rd, 3:30 - 5 PM *(Room S3/4, Stewart Biology Building, 1205 Docteur Penfield Avenue). The talk is titled, "Effects of combined attention on early visual cortical processing: An ERP investigation."
For a full abstract, see below the dashed line. Please join us at this event!
If you are unable to attend this week's talk, there will be more opportunities. Please see our full talk schedule @: http://www.mcgill.ca/psychology/events-colloquia-0/brownbag-series.
Looking forward to an exciting semester, and hope that you are able to attend!
*Effects of combined attention on early visual cortical processing: An ERP investigation*
Christopher David Blair & Jelena Ristic
Previous attention research has shown that certain types of attentional cues (such as those combining exogenous and endogenous effects, like predictive arrows) can produce behavioral effects that are additive or super-additive as compared to those produced by attentional cues that are only either exogenous (such as non-predictive arrows) or endogenous (such as predictive non-directional shapes). We sought to further examine these effects when targets were presented at longer and shorter stimulus onset asynchronies (SOAs), and to look at the accompanying brain activity in the form of the P1 evoked potential using electroencephalography (EEG). At both shorter and longer SOAs, we replicated a significant effect of cue validity, by which participants responded faster to cued targets in all cueing conditions. This effect was additive for predictive arrows at the shorter SOAs and super additive at longer SOAs as compared to non-predictive arrows and predictive shapes. Overall, our P1 data also showed a significant effect for cue validity, and our additivity measures reflect a pattern similar to our behavioral results at the shorter SOAs. However, it appears that there may be an opposing effect at the longer SOAs, with predictive arrows producing an underadditive P1 amplitude difference. Given these results, we extended our analyses to examine the frequency information present in our EEG data, focusing on the alpha band where higher power and synchronization is thought to be representative of suppression. Time frequency analysis of lateralized alpha power following cue onset showed higher power recorded at electrode sites corresponding to the hemisphere ipsilateral to cue direction, but only for predictive and non-predictive arrow conditions. A similar pattern is observed when comparing alpha power in response to cued and uncued target appearance. Thus, we have yet to find a neural measure that perfectly correlates with the relationship observed between behavioral measures of attention related to cues that produce combined, exogenous, and endogenous effects.
-
Anna Zamm