normal and pathological development of the nervous system
TRANSCRIPT
Editorial
Normal and pathological development of the nervous system
The 80th annual meeting of the ARNMD was devoted
to the study of normal and pathological development. Drs
Judith Rapoport and Guy McKhann joined me in organiz-
ing the meeting. It proved to be an excellent moment for
discussion of this topic. Recent years have seen a decisive
move in neuroscience toward an understanding of plasti-
city and change. While plasticity is a lifelong phenom-
enon, the organization of the nervous system prior to
birth and in the years of infancy and childhood provide
striking changes in behavior that relate to the development
of neural circuits. A theme of the meeting was to view
pathology in relation to these normal developmental
processes.
The meeting began with evidence of changes in neurons
and synapses that might illuminate the circuitry involved in
developmental disorders. Two of these papers presented by
Hastings and by McKay are contained in this volume. The
startling discoveries of life long neurogenesis and the abil-
ity to form working synapses from cultured stem cells
provided a dramatic backdrop to the potentials that might
become available for aiding human function and treating
disorders.
The next session dealt with genetics in relation to normal
development and developmental disorders. Papers were
presented on learning and memory (Silva), dyslexia (Gala-
burda), Williams disease (Bellugi & Klima), Alzheimer's
dementia (Reiman) and attention de®cit/hyperactivity disor-
der (Swanson) which taken together illustrated a variety of
methods for discovering the genetic basis of functions
and disorders. The importance of careful de®nition of
phenotypes and the speci®cation of pathways to link muta-
tions to affected brain pathways were basic to all the talks.
The possibility of using asymptomatic patients in the early
treatment of disorders and the need to combine the study of
human disorders with the use of animal and cellular
approaches were among the many issues raised in these
papers.
The ®nal session of the ®rst day emphasized the devel-
opment of normal functions of perception, attention and
language. Studies of children who had cataracts removed
at varying ages revealed quite different time periods sensi-
tive to the role of experience for various aspects of visual
acuity (Maurer). Dr Neville presented a similar theme.
Individuals born blind or deaf were studied to examine
the in¯uence of sensory deprivation. Experiments suggest
that the impact of sensory experience seemed to differ
between dorsal and ventral visual and perhaps auditory
information processing streams.
The ®rst day was concluded with the Salmon lecture.
In this lecture I presented studies conducted at the Sackler
institute that involved aspects of the development of
attention apparent at three periods of infancy and child-
hood. In discussing the future of the Institute I sought
to tie attentional networks to cellular and genetic mechan-
isms on the one hand and, on the other hand, to the
acquisition of high level skills learned in school such as
literacy.
The second day of the meeting was concerned with
studies of speci®c clinical syndromes. Casey outlined the
role of striatal-frontal circuits in a number of developmental
disorders. She illustrated how these disorders showed
distinct patterns of de®cit in stimulus and response selec-
tion. The development of regional brain areas can be traced
non-invasively in longitudinal studies using magnetic reso-
nance imaging. Rapoport reported that her team of research-
ers at NIMH found a very distinctive pattern of reduced
gray matter in child onset schizophrenia that appeared
®rst in posterior sites and only later in anterior regions.
Shaywitz presented brain-imaging evidence showing
that developmental dyslexia involves a dif®culty in auto-
matic activation of posterior brain regions that translate
visual input into phonolology. Nelson reported on new
studies of the concentration of neuropeptides and neurotro-
phins in neonatal blood of normal children compared to
those later diagnosed with autism, mental retardation, or
cerebral palsy. Some quite speci®c indicants of autism
were found that could be used for early diagnosis of the
disorder.
Overall the meeting was characterized by a feeling of
great optimism. This was fostered by ability to communi-
cate across many levels of analysis that was illustrated by
the meeting and by the papers in this volume. It was clear
that new methods and ®ndings were rapidly increasing our
understanding of both normal and pathological conditions in
Clinical Neuroscience Research 1 (2001) 173±174
1566-2772/01/$ - see front matter q 2001 Association for Research in Nervous and Mental Disease. Published by Elsevier Science B.V. All rights reserved.
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the development of the human brain and in some cases
providing us with the tools to develop and assess new meth-
ods of treatment. I hope that the readers of these papers will
share a similar feeling of excitement and progress of those
that attended and presented at the meeting.
Michael I. Posner
Sackler Institute, Weill Medical College,
1300 York Avenue, Box 140,
New York NY 10021,
USA
Editorial174
E-mail address: [email protected] (M.I. Posner).