A&P Day 5
Association Lecture
Prefrontal Cortex and the Fractionation of Supervisory Control
Tim Shallice, Institute of Cognitive Neuroscience, University College London
and SISSA, Trieste
Evidence will be briefly reviewed that non-routine cognitive
operations require the modulation of more posteriorly localised
systems (which enable routine operations) by a prefrontally located
Supervisory System. It will then be argued that such a Supervisory
System can be internally fractionated with subcomponent systems having
abstract functions concerned with different aspects of confronting
non-routine situations. The functions of left and right dorsolateral
frontal cortex will then be considered from this perspective. The
left is held to be primarily involved in top-down strategic modulation
of lower-level systems with the right being more concerned with the
control of checking that on-going behaviour accords with task goals.
This postulated checking function will be supported by evidence on
right prefrontal processes related to (i) bias parameters, (ii) the
time course of activation, (iii) the prevention of capture errors and
(iv) the allocation of cognitive effort generally. Finally the role
of anterior prefrontal cortex will be briefly discussed in relation to
the holding and realising of intentions.
What have we learned (or can we learn) from cognitive neuroscience about developmental change?
This session will evaluate the progress of the field in understanding
developmental change, particularly from methods of cognitive
neuroscience. The expertise of the speakers will span a range of
techniques in cognitive neuroscience that have informed developmental
study. Speakers will be asked to evaluate what we have learned from
cognitive neuroscience about developmental change, by describing
existing work as well as commenting on the work presented at this
meeting. A Discussant with a broad perspective on the study of
cognitive development will evaluate the overall state of the field in
understanding developmental change.
Cross-species comparisons in development: The case of the spatial "module"
Lynn Nadel and Almut Hupbach, University of Arizona
The study of spatial navigation allows us to compare humans and other
species in a rich cognitive domain about which a great deal is already
known. Following upon seminal findings in rats, recent work examining
the way in which young children reorient in space has led to claims
about modularity, and development of the ability to integrate
information from multiple sources (eg., landmarks and geometric
features of the environment) in solving this task. We will
selectively review this work, discuss some of our own recent work with
young children, and conclude that any constraints on the integration
of landmark and geometric information are limited to the reorientation
situation, and even then only under certain conditions. We discuss
what this means for broader claims about modularity, the way in which
spatial cognition develops, and cross-species comparisons in
development.
Learning about learning and development with modern imaging technology
BJ Casey, Dima Amso and Matthew C. Davidson, Sackler Institute
for Developmental Psychobiology
Development is a careful balance between certain amounts of plasticity
as well as stability. Too much plasticity can hinder long-term forms
of learning. A system that is too stable, particularly in the case
where atypical behaviors and neural representations have formed, can
be devastating to the normal functioning of the organism. If modern
imaging techniques are to inform developmental theories, then they
must be used in the context of explaining change or progressions of a
dynamic system. Thus understanding the cognitive and neural basis of
learning in the developing organism is key in elucidating mechanisms
of development and constraining current cognitive developmental
theories. A premise of this paper is that learning to predict
temporal and contextual information is a key component of cognitive
development. Knowing when, what or where to expect an event is
critical for the organism in planning and maintaining appropriate
thoughts and actions in different contexts over time. Adjusting
behavior when these expectations are violated is an essential element
of cognitive control. We will describe behavioral and imaging studies
that examine the cognitive and neural processes underlying learning
and their role in the development of cognitive control. Specifically
we will emphasize the development of frontostriatal, frontocerebellar
and frontohippocampal circuits implicated in learning about temporal
and contextual information.
Spatial development following early focal brain injury: Evidence for
adaptive change in brain and cognition
Joan Stiles, Brianna Paul, and John Hesselink, University of California, San Diego
The field of developmental cognitive neuroscience has grown
exponentially over the last two decades. The body of findings from
both animal and human studies that has emerged has fundamentally
changed the way we think about development. The age-old question of
nature vs. nurture, is rapidly losing relevance as study after study
demonstrates the essential role of the interaction between biology and
experience in development. Development is principled, but dynamic,
relying on the careful balance between progressive commitment to
stable basic functional systems, while retaining the capacity for
adaptation when the demands on the organism change. Further, human
development is a protracted process extending at least into
adolescence, indeed, there is substantial evidence that the mammalian
brain retains considerable capacity for adaptive reorganization
throughout the lifespan.
The study of children with early occurring focal brain injury provides
a model for articulating and specifying this dynamic, adaptive and
protracted view of development. The children in the studies described
in this paper suffered focal brain insult (typically stroke) in the
pre- or perinatal period, long before the acquisition of higher
cognitive functions. In most, though not all cases, the injuries
affect substantial portions of one cerebral hemisphere, resulting in
patterns of neural damage that would compromise cognitive ability in
adults. However, longitudinal behavioral studies of this population of
children have revealed only mild cognitive deficits, and preliminary
data from functional brain imaging studies suggest that alternative
patterns of functional organization emerge in the wake of early
injury. It is argued that the capacity for adaptation is not the
result of early insult. Rather, it reflects normal developmental
processes operating against a backdrop of serious perturbation of the
neural substrate. Two examples illustrating profiles of spatial
cognitive development and related profiles of functional neural
activation provide evidence for adaptive change.
What have we learned (or can we learn) from atypical development about
developmental change?
Annette Karmiloff-Smith, Neurocognitive Development Unit, Institute of Child Health, UC London
In this talk I will argue that if the atypical brain were a normal
brain with parts intact and parts impaired, then atypical development
would be a direct window on normal developmental change, with
clear-cut single and double dissociations. Such a view emanates from
the model of adult neuropsychological patients whose brains were fully
and normally developed until their brain insult. However, the
developing brain is very different. It is neither localised nor
specialised at birth, and many months and years are required for the
progressive modularisation of the adult brain to occur. Because the
brain is a dynamically self-structuring organism that develops as a
whole, atypical development therefore needs to be considered with some
caution when generalising to the normal case. Once these reservations
have been taken on board, the study of atypical patients can be
informative about genotype/phenotype relations, the complexities of
gene expression, the importance of developmental timing and of
synchronies across developing domains as developmental change
progressively occurs.
Computational models in developmental cognitive neuroscience: where are
we?
Mark S. Seidenberg, Department of Psychology, University of Wisconsin-Madison, and
Jason D. Zevin, Sackler Institute for Developmental Psychobiology,
Weill Medical College of Cornell University
Computational models -- particularly connectionist models -- have been
applied to a variety of phenomena concerning normal and atypical
development and their brain bases. The models have had some notable
successes -- e.g., in explaining how stagelike behavior arises from
gradual learning processes; in unifying acquisition and skilled
performance within a common theoretical framework; in suggesting
solutions to longstanding puzzles such as how language is acquired in
light of the poverty of the stimulus. Modeling either does or could
play a crucial role in all of the other methodologies discussed in this
session: neuroimaging; studies of other species; studies of atypical
development; studies of early focal brain injury.
At the same time these models have generated considerable resistance. A
brief summary of the concerns might include: the models don't work; the
models are too powerful and can handle any pattern of data; the models
are not powerful enough and so do not apply to important aspects of
language and cognition; and so on.
We think both the advances and concerns are important, and will
discuss them in the context of a specific case: our own recent work on
critical period phenomena. This research presents an interesting
alternative to standard views of the bases of critical period effects
in language learning and other domains. However, it is also subject to
many of the concerns that loom over the connectionist enterprise.
Discussant: Dick Aslin, University of Rochester