Current events
Date: Dec 16th
Time: 09:30 am
Place : 2nd Floor Conference Room, Gonda building.
Title : "Reevaluating the Role of LTD in Cerebellar Motor Learning"
Speaker: Paul Mathews
Summary: It is widely believed that changes in the strength of synapses underlies the cellular changes responsible for memory formation. In the Cerebellum theories regarding the location of the cellular changes necessary for motor learning have recently been of great debate. One particular hypothesis proposed by Marr, Albus and Ito is that errors in motor behavior lead to changes in the strength of parallel fiber (PF) inputs onto Purkinje neurons (PNs). These errors, which are believed to be carried by climbing fiber terminals originating from the inferior olive, are thought to drive long term depressions (LTD) of PF-PN synapses that are activated coincidentally with the error signal. This change in the cerebellar circuit is believed, at least in part to underlie the cellular mechanisms driving motor learning. Supporting this hypothesis are numerous studies in which blocking the pathways responsible for PF-PN LTD leads to a deficit in cerebellar mediated motor behaviors. However, it has been argued that since these manipulations effect targets that often play multiple cellular regulatory roles (mGlur1/PKC, PKG, and αCamKII) the changes observed in motor behavior may be due instead to alterations in processes unrelated to the abolition of LTD. In the paper for discussion this Friday the authors reevaluate the role LTD plays in cerebellar motor learning by disrupting LTD through preventing AMPA receptor endocytosis directly rather than effecting more precocious molecules. Their experiments show that while these manipulations prevent associative PF-PN LTD in vitro numerous tests fail to show any significant behavioral effect of LTD disruption. For LMP this Friday we will examine the previous data suggesting LTD in the cerebellar cortex is critical for motor learning as well as how these new negative findings potentially alter our view of LTD’s role in cerebellar mediated motor learning.
Releavant Reading Material: http://www.sciencedirect.com/science?_ob=MiamiImageURL&_cid=272195&_user=4423&_pii=S0896627311001991&_check=y&_origin=&_coverDate=14-Apr-2011&view=c&wchp=dGLbVlS-zSkzk&md5=b2315bb5e6d206c4b2b051a7e8edf789/1-s2.0-S0896627311001991-main.pdf
