Colloquia Series 2018-19

Monday, November 19, 2018

Speaker: Dr. Cheryl Sisk, Neuroscience Program, Michigan State University 

Ttitle: Not The Usual Place & Time: New Neurons & Glia Are Added To Sexually Dimoprhic Brain Regions During Puberty

Abstract:  

There is growing evidence that postnatally born neurons and glial cells are added to the rodent hypothalamus and amygdala. My talk will focus on the pubertal addition of cells to the anteroventral periventricular nucleus (AVPV) and posterodorsal medial amygdala (MePD), two sexually dimorphic cell groups that contribute to sex differences in reproductive function and social behaviors. Using BrdU as a cell birthdate marker, we initially observed sex differences in the pubertal addition of new cells that parallel sex differences in AVPV and MePD volume in rats: more pubertally born cells are added to the AVPV in females, whereas more are added to the MePD in males. These sex differences are eliminated by prepubertal gonadectomy, indicating that gonadal hormones drive sex differences in the pubertal maturation of AVPV and MePD. Using tfm mice that lack functional androgen receptors, we found that the sex difference in pubertally born MePD cells is androgen receptor-dependent. Other experiments investigated whether pubertally born cells are functionally incorporated into neural circuits mediating sex-specific behaviors. These experiments provide evidence that pubertally born AVPV cells contribute to the ovarian-hormone induced LH surge in female rats, and that pubertally born MePD cells are are activated by social interactions in male hamsters and mice. We propose that the pubertal addition of new neurons and glia to sexually dimorphic cell groups is a potential mechanism underlying adolescent maturation of sex-specific reproductive function and social behaviors.

Monday, October 15, 2018

Speaker: Dr. Andrew Leber, Department of Psychology, Ohio State University

Ttitle: Toward An Individual Profile of Goal-Directed Attention Control

Abstract:  

As humans, we are tremendously adept at controlling how we perceive the world around us.  We can choose to strategically attend to red things, round things, moving things, etc., and the choices we make effectively determine the world we experience.  While decades of research have focused on cataloging and quantifying the various attentional control abilities at our disposal, the choice part of the process has been largely understudied.  That is, how do people decide which attentional strategy to use?  Consider that lab studies typically tell people which strategy to use, which leaves much to be desired: first, participants may fail to comply, and, second, this lacks ecological validity, as we rarely are provided instructions when confronting the sensory environment in our daily lives.  To begin to address the question of choice and attentional control, we recently created the Adaptive Choice Visual Search paradigm.  In this paradigm, observers can freely choose between two search strategies on each trial, while we vary the relative efficacy of each strategy.  That is, on some trials it is faster to use the “search for red” strategy than the “search for blue” strategy, while on other trials the opposite is true.  Results using this paradigm have shown that choice behavior is far from optimal, and it appears largely determined by competing drives to maximize performance and minimize effort.  Further, individual differences in performance are stable across sessions while also being malleable to experimental manipulations that emphasize one competing drive (e.g., reward, which motivates individuals to maximize performance).  This research represents an initial step toward characterizing an individual profile of goal-directed control that extends beyond the classic understanding of attentional abilities and promises to contribute to a more accurate framework of attentional control.

Monday, September 10, 2018 

Speaker:  Dr. David Samson, Assistant Professor of Anthropology, University of Toronto Mississauga 

Ttitle: Wild Nights: Sleep and Human Evolution 

Abstract:  

What does how you sleep have to do with human evolution? Our immune strength, working memory, attention, decision-making, and visual-motor performance all depend on sleep. How then could elders’ insomnia and teenagers’ penchant for staying up late have evolved?

Find out at this free public lecture by sleep anthropologist David Samson, whose work has been featured on the BBC, Time, the New York Times, New Scientist, and the CBC. Dr. Samson describes his research using pioneering, non-invasive technology to study sleep across human cultures and primate species to answer evolutionary questions.

 


More information:
Mahnoor Mukhtar (mahnoor.mukhtar@utoronto.ca)