Upcoming talks

The Center for the Neural Basis of Cognition

                              Cognitive Brown-bag

Speaker: Dr. Class Glymour
	 Department of Philosophy, CMU
	 Department of History and Philosophy of Science, Pitt
Title: "On the Methods of Cognitive Neuropsychology"
Time:  Noon, 11/9/94
Location: 9th floor, LRDC

Abstract:

     Caramazza has criticized the use of group studies to identify normal
cognitive architecture from neuropsychological deficits, and he has
argued that double dissociations have no special importance as evidence
in single case studies. Bub and Bub have responded that Caramazza's
arguments depend on a "hypothetico-deductive" model of scientific
inquiry, and that the author's "bootstrapping" framework is more
appropriate. Shallice has responded against Caramazza that double
dissociations establish the existence of distinct functional modules
underlying two or more capacities when distinct capacities put
different computational demands on the same module, whereas data on
dissociations and associations do not.
    This paper studies these issues from the perspective of computational
learning theory; the results are independent of any particular
conception of scientific confirmation or testing. I find that several
of Caramazza's claims are essentially correct, but so is at least one
of Shallice's: in particular: (1) if damage to a functional module
underlying two cognitive capacities must interfere with both capacities
if with either, then under general assumptions like Caramazza's,
individual case studies can identify important aspects of cognitive
architecture; (2) under the same assumptions, there is no clear sense
in which double dissociations are more or less important than
associations and dissociations; (3) if Shallice's assumption is
made--injury to a module underlying two cognitive capacities can
interfere with one of these capacities but not the other--then double
dissociations can establish the existence of distinct functional
modules; (4) under Shallice's assumption, absent very strong background
knowledge, individual data give reduced information about cognitive
architecture. Issues of group versus individual studies are not
considered here.

Statistics seminar
 
Wednesday November 9th 4pm Adamson Wing Baker Hall
 
Speaker: Greg Campbell
Chief, Analytical Biometrics
Biometry and Field Studies Branch
National Institute of Neurological Disorders and Stroke
 
STATISTICAL ISSUES IN NEUROIMAGING
 
Statistics can play a major role in the design and analysis of medical
imaging experiments, especially neuroimaging.  Both Positron Emission
Tomography (PET) and Magnetic Resonance (MR) brain images can be
acquired digitally.  The challenges to statistical science for such
enormous data sets (sure to grow larger as resolution increases) are
nontrivial.  Statistical research areas include image reconstruction,
normalization (deformation), segmentation, object identification,
registration, statistical inference, the design of neuroimaging
experiments, and evaluation of imaging modalities.  Areas of
particular interest in inference relate to comparative experiments and
correlational issues in space and, for functional MRI, also in time.
One way to evaluate imaging modalities is Receiver Operating
Characteristic (ROC) methodology.  Some recent advances in ROC work
are reviewed.  Numerous examples from NIH studies illustrate the talk.
 

           Department of Neuroscience  Colloquium Series

                              presents
                    
                     Wycliffe C. Abraham, Ph.D.

                   who will give a talk entitled

Metaplasticity:  Activity-Dependent Regulation of Synaptic Plasticity

                        on 22 November 1994

             4:00 pm in Langley Hall A221, U Pittsburgh


Dr. Abraham has contributed greatly to our current understanding
of various forms of synaptic plasticity in the hippocampus.  His
research is characterized by carefully designed, clever experiments
conducted on the hippocampus in vivo as well as in vitro.
Some recent publications from his laboratory include:

Cristie BR, Kerr DS & Abraham WC (1994) Flip side of synaptic
plasticity:  Long-term depression mechanisms in the hippocampus.
HIPPOCAMPUS, 4: 127-135.

Abraham WC, Mason SE, Demmer J, et al. (1993) Correlations between 
immediate early gene induction and the persistence of long-term
potentiation. NEUROSCIENCE, 56: 717-727.

Cristie BR & Abraham WC (1992) Priming of associative long-term 
depression in the detate gyrus by theta frequency synaptic activity.
NEURON, 9: 79-84.

Christie BR & Abraham WC (1992) NMDA-dependent heterosynaptic
long-term depression in the dentate gyrus of anesthetized rats.
SYNAPSE, 10: 1-6.

Abraham WC & Wickens JR (1991) Heterosynaptic long-term 
depression is facilitated by blockade if inhibition in area CA1 of
the hippocampus. BRAIN RESEARCH, 546: 336-40.


Some influential earlier publications by Dr. Abraham include: 

Kairiss EW, Abraham WC, Bilkey DK & Goddard GV (1987) Field
potential evidence for long-term potentiation of feed-forward 
inhibition in the rat dentate gyrus.  BRAIN RESEARCH, 401: 87-94.

Abraham WC, Gustafsson B & Wigstrom H (1987) Long-term potentiation
involves enhanced synaptic excitation relative to synaptic
inhibition in guinea-pig hippocampus. J PHYSIOLOGY, 394: 367-380.

Abraham WC, Bliss, TVP & Goddard GV (1985) Heterosynaptic changes 
accompany long-term but not short-term potentiation of the perforant
path in the anaesthetized rat. J PHYSIOLOGY, 363: 335-349.

Abraham WC & Goddard GV (1983) Asymmetric relationships between
homosynaptic long-term potentiation and heterosynaptic long-term 
depression. NATURE, 305: 717-719.    


Dr. Abraham will be in Pittsburgh from the early afternoon of 
21 November (Monday) to the evening of 22 November (Tuesday).
If you wish to meet with him, please contact Floh Thiels at

thiels@neuronet.pitt.edu  

Please specify the date, time, and location that would be 
convenient for you.