---
_id: '8028'
abstract:
- lang: eng
text: 'Transmission of signals within the brain is essential for cognitive function,
but it is not clear how neural circuits support reliable and accurate signal propagation
over a sufficiently large dynamic range. Two modes of propagation have been studied:
synfire chains, in which synchronous activity travels through feedforward layers
of a neuronal network, and the propagation of fluctuations in firing rate across
these layers. In both cases, a sufficient amount of noise, which was added to
previous models from an external source, had to be included to support stable
propagation. Sparse, randomly connected networks of spiking model neurons can
generate chaotic patterns of activity. We investigate whether this activity, which
is a more realistic noise source, is sufficient to allow for signal transmission.
We find that, for rate-coded signals but not for synfire chains, such networks
support robust and accurate signal reproduction through up to six layers if appropriate
adjustments are made in synaptic strengths. We investigate the factors affecting
transmission and show that multiple signals can propagate simultaneously along
different pathways. Using this feature, we show how different types of logic gates
can arise within the architecture of the random network through the strengthening
of specific synapses.'
article_processing_charge: No
article_type: original
author:
- first_name: Tim P
full_name: Vogels, Tim P
id: CB6FF8D2-008F-11EA-8E08-2637E6697425
last_name: Vogels
orcid: 0000-0003-3295-6181
- first_name: L. F.
full_name: Abbott, L. F.
last_name: Abbott
citation:
ama: Vogels TP, Abbott LF. Signal propagation and logic gating in networks of integrate-and-fire
neurons. Journal of Neuroscience. 2005;25(46):10786-10795. doi:10.1523/jneurosci.3508-05.2005
apa: Vogels, T. P., & Abbott, L. F. (2005). Signal propagation and logic gating
in networks of integrate-and-fire neurons. Journal of Neuroscience. Society
for Neuroscience. https://doi.org/10.1523/jneurosci.3508-05.2005
chicago: Vogels, Tim P, and L. F. Abbott. “Signal Propagation and Logic Gating in
Networks of Integrate-and-Fire Neurons.” Journal of Neuroscience. Society
for Neuroscience, 2005. https://doi.org/10.1523/jneurosci.3508-05.2005.
ieee: T. P. Vogels and L. F. Abbott, “Signal propagation and logic gating in networks
of integrate-and-fire neurons,” Journal of Neuroscience, vol. 25, no. 46.
Society for Neuroscience, pp. 10786–10795, 2005.
ista: Vogels TP, Abbott LF. 2005. Signal propagation and logic gating in networks
of integrate-and-fire neurons. Journal of Neuroscience. 25(46), 10786–10795.
mla: Vogels, Tim P., and L. F. Abbott. “Signal Propagation and Logic Gating in Networks
of Integrate-and-Fire Neurons.” Journal of Neuroscience, vol. 25, no. 46,
Society for Neuroscience, 2005, pp. 10786–95, doi:10.1523/jneurosci.3508-05.2005.
short: T.P. Vogels, L.F. Abbott, Journal of Neuroscience 25 (2005) 10786–10795.
date_created: 2020-06-25T13:12:33Z
date_published: 2005-11-16T00:00:00Z
date_updated: 2021-01-12T08:16:37Z
day: '16'
doi: 10.1523/jneurosci.3508-05.2005
extern: '1'
external_id:
pmid:
- '16291952'
intvolume: ' 25'
issue: '46'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6725859/
month: '11'
oa: 1
oa_version: Published Version
page: 10786-10795
pmid: 1
publication: Journal of Neuroscience
publication_identifier:
issn:
- 0270-6474
- 1529-2401
publication_status: published
publisher: Society for Neuroscience
quality_controlled: '1'
status: public
title: Signal propagation and logic gating in networks of integrate-and-fire neurons
type: journal_article
user_id: D865714E-FA4E-11E9-B85B-F5C5E5697425
volume: 25
year: '2005'
...
---
_id: '8029'
abstract:
- lang: eng
text: 'Neural network modeling is often concerned with stimulus-driven responses,
but most of the activity in the brain is internally generated. Here, we review
network models of internally generated activity, focusing on three types of network
dynamics: (a) sustained responses to transient stimuli, which provide a model
of working memory; (b) oscillatory network activity; and (c) chaotic activity,
which models complex patterns of background spiking in cortical and other circuits.
We also review propagation of stimulus-driven activity through spontaneously active
networks. Exploring these aspects of neural network dynamics is critical for understanding
how neural circuits produce cognitive function.'
article_processing_charge: No
article_type: review
author:
- first_name: Tim P
full_name: Vogels, Tim P
id: CB6FF8D2-008F-11EA-8E08-2637E6697425
last_name: Vogels
orcid: 0000-0003-3295-6181
- first_name: Kanaka
full_name: Rajan, Kanaka
last_name: Rajan
- first_name: L.F.
full_name: Abbott, L.F.
last_name: Abbott
citation:
ama: Vogels TP, Rajan K, Abbott LF. Neural network dynamics. Annual Review of
Neuroscience. 2005;28(1):357-376. doi:10.1146/annurev.neuro.28.061604.135637
apa: Vogels, T. P., Rajan, K., & Abbott, L. F. (2005). Neural network dynamics.
Annual Review of Neuroscience. Annual Reviews. https://doi.org/10.1146/annurev.neuro.28.061604.135637
chicago: Vogels, Tim P, Kanaka Rajan, and L.F. Abbott. “Neural Network Dynamics.”
Annual Review of Neuroscience. Annual Reviews, 2005. https://doi.org/10.1146/annurev.neuro.28.061604.135637.
ieee: T. P. Vogels, K. Rajan, and L. F. Abbott, “Neural network dynamics,” Annual
Review of Neuroscience, vol. 28, no. 1. Annual Reviews, pp. 357–376, 2005.
ista: Vogels TP, Rajan K, Abbott LF. 2005. Neural network dynamics. Annual Review
of Neuroscience. 28(1), 357–376.
mla: Vogels, Tim P., et al. “Neural Network Dynamics.” Annual Review of Neuroscience,
vol. 28, no. 1, Annual Reviews, 2005, pp. 357–76, doi:10.1146/annurev.neuro.28.061604.135637.
short: T.P. Vogels, K. Rajan, L.F. Abbott, Annual Review of Neuroscience 28 (2005)
357–376.
date_created: 2020-06-25T13:13:11Z
date_published: 2005-07-21T00:00:00Z
date_updated: 2021-01-12T08:16:37Z
day: '21'
doi: 10.1146/annurev.neuro.28.061604.135637
extern: '1'
external_id:
pmid:
- '16022600'
intvolume: ' 28'
issue: '1'
language:
- iso: eng
month: '07'
oa_version: None
page: 357-376
pmid: 1
publication: Annual Review of Neuroscience
publication_identifier:
issn:
- 0147-006X
- 1545-4126
publication_status: published
publisher: Annual Reviews
quality_controlled: '1'
status: public
title: Neural network dynamics
type: journal_article
user_id: D865714E-FA4E-11E9-B85B-F5C5E5697425
volume: 28
year: '2005'
...
---
_id: '9491'
abstract:
- lang: eng
text: Cytosine DNA methylation in vertebrates is widespread, but methylation in
plants is found almost exclusively at transposable elements and repetitive DNA
[1]. Within regions of methylation, methylcytosines are typically found in CG,
CNG, and asymmetric contexts. CG sites are maintained by a plant homolog of mammalian
Dnmt1 acting on hemi-methylated DNA after replication. Methylation of CNG and
asymmetric sites appears to be maintained at each cell cycle by other mechanisms.
We report a new type of DNA methylation in Arabidopsis, dense CG methylation clusters
found at scattered sites throughout the genome. These clusters lack non-CG methylation
and are preferentially found in genes, although they are relatively deficient
toward the 5′ end. CG methylation clusters are present in lines derived from different
accessions and in mutants that eliminate de novo methylation, indicating that
CG methylation clusters are stably maintained at specific sites. Because 5-methylcytosine
is mutagenic, the appearance of CG methylation clusters over evolutionary time
predicts a genome-wide deficiency of CG dinucleotides and an excess of C(A/T)G
trinucleotides within transcribed regions. This is exactly what we find, implying
that CG methylation clusters have contributed profoundly to plant gene evolution.
We suggest that CG methylation clusters silence cryptic promoters that arise sporadically
within transcription units.
article_processing_charge: No
article_type: original
author:
- first_name: Robert K.
full_name: Tran, Robert K.
last_name: Tran
- first_name: Jorja G.
full_name: Henikoff, Jorja G.
last_name: Henikoff
- first_name: Daniel
full_name: Zilberman, Daniel
id: 6973db13-dd5f-11ea-814e-b3e5455e9ed1
last_name: Zilberman
orcid: 0000-0002-0123-8649
- first_name: Renata F.
full_name: Ditt, Renata F.
last_name: Ditt
- first_name: Steven E.
full_name: Jacobsen, Steven E.
last_name: Jacobsen
- first_name: Steven
full_name: Henikoff, Steven
last_name: Henikoff
citation:
ama: Tran RK, Henikoff JG, Zilberman D, Ditt RF, Jacobsen SE, Henikoff S. DNA methylation
profiling identifies CG methylation clusters in Arabidopsis genes. Current
Biology. 2005;15(2):154-159. doi:10.1016/j.cub.2005.01.008
apa: Tran, R. K., Henikoff, J. G., Zilberman, D., Ditt, R. F., Jacobsen, S. E.,
& Henikoff, S. (2005). DNA methylation profiling identifies CG methylation
clusters in Arabidopsis genes. Current Biology. Elsevier. https://doi.org/10.1016/j.cub.2005.01.008
chicago: Tran, Robert K., Jorja G. Henikoff, Daniel Zilberman, Renata F. Ditt, Steven
E. Jacobsen, and Steven Henikoff. “DNA Methylation Profiling Identifies CG Methylation
Clusters in Arabidopsis Genes.” Current Biology. Elsevier, 2005. https://doi.org/10.1016/j.cub.2005.01.008.
ieee: R. K. Tran, J. G. Henikoff, D. Zilberman, R. F. Ditt, S. E. Jacobsen, and
S. Henikoff, “DNA methylation profiling identifies CG methylation clusters in
Arabidopsis genes,” Current Biology, vol. 15, no. 2. Elsevier, pp. 154–159,
2005.
ista: Tran RK, Henikoff JG, Zilberman D, Ditt RF, Jacobsen SE, Henikoff S. 2005.
DNA methylation profiling identifies CG methylation clusters in Arabidopsis genes.
Current Biology. 15(2), 154–159.
mla: Tran, Robert K., et al. “DNA Methylation Profiling Identifies CG Methylation
Clusters in Arabidopsis Genes.” Current Biology, vol. 15, no. 2, Elsevier,
2005, pp. 154–59, doi:10.1016/j.cub.2005.01.008.
short: R.K. Tran, J.G. Henikoff, D. Zilberman, R.F. Ditt, S.E. Jacobsen, S. Henikoff,
Current Biology 15 (2005) 154–159.
date_created: 2021-06-07T10:24:30Z
date_published: 2005-01-26T00:00:00Z
date_updated: 2021-12-14T09:12:26Z
day: '26'
department:
- _id: DaZi
doi: 10.1016/j.cub.2005.01.008
extern: '1'
external_id:
pmid:
- '15668172 '
intvolume: ' 15'
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1016/j.cub.2005.01.008
month: '01'
oa: 1
oa_version: Published Version
page: 154-159
pmid: 1
publication: Current Biology
publication_identifier:
eissn:
- 1879-0445
issn:
- 0960-9822
publication_status: published
publisher: Elsevier
quality_controlled: '1'
scopus_import: '1'
status: public
title: DNA methylation profiling identifies CG methylation clusters in Arabidopsis
genes
type: journal_article
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
volume: 15
year: '2005'
...
---
_id: '9514'
abstract:
- lang: eng
text: "Background:\r\nDNA methylation occurs at preferred sites in eukaryotes. In
Arabidopsis, DNA cytosine methylation is maintained by three subfamilies of methyltransferases
with distinct substrate specificities and different modes of action. Targeting
of cytosine methylation at selected loci has been found to sometimes involve histone
H3 methylation and small interfering (si)RNAs. However, the relationship between
different cytosine methylation pathways and their preferred targets is not known.\r\nResults:\r\nWe
used a microarray-based profiling method to explore the involvement of Arabidopsis
CMT3 and DRM DNA methyltransferases, a histone H3 lysine-9 methyltransferase (KYP)
and an Argonaute-related siRNA silencing component (AGO4) in methylating target
loci. We found that KYP targets are also CMT3 targets, suggesting that histone
methylation maintains CNG methylation genome-wide. CMT3 and KYP targets show similar
proximal distributions that correspond to the overall distribution of transposable
elements of all types, whereas DRM targets are distributed more distally along
the chromosome. We find an inverse relationship between element size and loss
of methylation in ago4 and drm mutants.\r\nConclusion:\r\nWe conclude that the
targets of both DNA methylation and histone H3K9 methylation pathways are transposable
elements genome-wide, irrespective of element type and position. Our findings
also suggest that RNA-directed DNA methylation is required to silence isolated
elements that may be too small to be maintained in a silent state by a chromatin-based
mechanism alone. Thus, parallel pathways would be needed to maintain silencing
of transposable elements."
article_number: R90
article_processing_charge: No
article_type: original
author:
- first_name: Robert K.
full_name: Tran, Robert K.
last_name: Tran
- first_name: Daniel
full_name: Zilberman, Daniel
id: 6973db13-dd5f-11ea-814e-b3e5455e9ed1
last_name: Zilberman
orcid: 0000-0002-0123-8649
- first_name: Cecilia
full_name: de Bustos, Cecilia
last_name: de Bustos
- first_name: Renata F.
full_name: Ditt, Renata F.
last_name: Ditt
- first_name: Jorja G.
full_name: Henikoff, Jorja G.
last_name: Henikoff
- first_name: Anders M.
full_name: Lindroth, Anders M.
last_name: Lindroth
- first_name: Jeffrey
full_name: Delrow, Jeffrey
last_name: Delrow
- first_name: Tom
full_name: Boyle, Tom
last_name: Boyle
- first_name: Samson
full_name: Kwong, Samson
last_name: Kwong
- first_name: Terri D.
full_name: Bryson, Terri D.
last_name: Bryson
- first_name: Steven E.
full_name: Jacobsen, Steven E.
last_name: Jacobsen
- first_name: Steven
full_name: Henikoff, Steven
last_name: Henikoff
citation:
ama: Tran RK, Zilberman D, de Bustos C, et al. Chromatin and siRNA pathways cooperate
to maintain DNA methylation of small transposable elements in Arabidopsis. Genome
Biology. 2005;6(11). doi:10.1186/gb-2005-6-11-r90
apa: Tran, R. K., Zilberman, D., de Bustos, C., Ditt, R. F., Henikoff, J. G., Lindroth,
A. M., … Henikoff, S. (2005). Chromatin and siRNA pathways cooperate to maintain
DNA methylation of small transposable elements in Arabidopsis. Genome Biology.
Springer Nature. https://doi.org/10.1186/gb-2005-6-11-r90
chicago: Tran, Robert K., Daniel Zilberman, Cecilia de Bustos, Renata F. Ditt, Jorja
G. Henikoff, Anders M. Lindroth, Jeffrey Delrow, et al. “Chromatin and SiRNA Pathways
Cooperate to Maintain DNA Methylation of Small Transposable Elements in Arabidopsis.”
Genome Biology. Springer Nature, 2005. https://doi.org/10.1186/gb-2005-6-11-r90.
ieee: R. K. Tran et al., “Chromatin and siRNA pathways cooperate to maintain
DNA methylation of small transposable elements in Arabidopsis,” Genome Biology,
vol. 6, no. 11. Springer Nature, 2005.
ista: Tran RK, Zilberman D, de Bustos C, Ditt RF, Henikoff JG, Lindroth AM, Delrow
J, Boyle T, Kwong S, Bryson TD, Jacobsen SE, Henikoff S. 2005. Chromatin and siRNA
pathways cooperate to maintain DNA methylation of small transposable elements
in Arabidopsis. Genome Biology. 6(11), R90.
mla: Tran, Robert K., et al. “Chromatin and SiRNA Pathways Cooperate to Maintain
DNA Methylation of Small Transposable Elements in Arabidopsis.” Genome Biology,
vol. 6, no. 11, R90, Springer Nature, 2005, doi:10.1186/gb-2005-6-11-r90.
short: R.K. Tran, D. Zilberman, C. de Bustos, R.F. Ditt, J.G. Henikoff, A.M. Lindroth,
J. Delrow, T. Boyle, S. Kwong, T.D. Bryson, S.E. Jacobsen, S. Henikoff, Genome
Biology 6 (2005).
date_created: 2021-06-07T13:12:41Z
date_published: 2005-10-19T00:00:00Z
date_updated: 2021-12-14T09:09:41Z
day: '19'
department:
- _id: DaZi
doi: 10.1186/gb-2005-6-11-r90
extern: '1'
external_id:
pmid:
- '16277745'
intvolume: ' 6'
issue: '11'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1186/gb-2005-6-11-r90
month: '10'
oa: 1
oa_version: Published Version
pmid: 1
publication: Genome Biology
publication_identifier:
eissn:
- 1465-6906
issn:
- 1474-760X
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Chromatin and siRNA pathways cooperate to maintain DNA methylation of small
transposable elements in Arabidopsis
type: journal_article
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
volume: 6
year: '2005'
...
---
_id: '843'
abstract:
- lang: eng
text: The impact of an amino acid replacement on the organism's fitness can vary
from lethal to selectively neutral and even, in rare cases, beneficial. Substantial
data are available on either pathogenic or acceptable replacements. However, the
whole distribution of coefficients of selection against individual replacements
is not known for any organism. To ascertain this distribution for human proteins,
we combined data on pathogenic missense mutations, on human non-synonymous SNPs
and on human-chimpanzee divergence of orthologous proteins. Fractions of amino
acid replacements which reduce fitness by >10-2, 10-2-10-4, 10-4-10-5 and <10-5
are 25, 49, 14 and 12%, respectively. On average, the strength of selection against
a replacement is substantially higher when chemically dissimilar amino acids are
involved, and the Grantham's index of a replacement explains 35% of variance in
the average logarithm of selection coefficients associated with different replacements.
Still, the impact of a replacement depends on its context within the protein more
than on its own nature. Reciprocal replacements are often associated with rather
different selection coefficients, in particular, replacements of non-polar amino
acids with polar ones are typically much more deleterious than replacements in
the opposite direction. However, differences between evolutionary fluxes of reciprocal
replacements are only weakly correlated with the differences between the corresponding
selection coefficients.
author:
- first_name: Lev
full_name: Yampolsky, Lev Y
last_name: Yampolsky
- first_name: Fyodor
full_name: Fyodor Kondrashov
id: 44FDEF62-F248-11E8-B48F-1D18A9856A87
last_name: Kondrashov
orcid: 0000-0001-8243-4694
- first_name: Alexey
full_name: Kondrashov, Alexey S
last_name: Kondrashov
citation:
ama: Yampolsky L, Kondrashov F, Kondrashov A. Distribution of the strength of selection
against amino acid replacements in human proteins. Human Molecular Genetics.
2005;14(21):3191-3201. doi:10.1093/hmg/ddi350
apa: Yampolsky, L., Kondrashov, F., & Kondrashov, A. (2005). Distribution of
the strength of selection against amino acid replacements in human proteins. Human
Molecular Genetics. Oxford University Press. https://doi.org/10.1093/hmg/ddi350
chicago: Yampolsky, Lev, Fyodor Kondrashov, and Alexey Kondrashov. “Distribution
of the Strength of Selection against Amino Acid Replacements in Human Proteins.”
Human Molecular Genetics. Oxford University Press, 2005. https://doi.org/10.1093/hmg/ddi350.
ieee: L. Yampolsky, F. Kondrashov, and A. Kondrashov, “Distribution of the strength
of selection against amino acid replacements in human proteins,” Human Molecular
Genetics, vol. 14, no. 21. Oxford University Press, pp. 3191–3201, 2005.
ista: Yampolsky L, Kondrashov F, Kondrashov A. 2005. Distribution of the strength
of selection against amino acid replacements in human proteins. Human Molecular
Genetics. 14(21), 3191–3201.
mla: Yampolsky, Lev, et al. “Distribution of the Strength of Selection against Amino
Acid Replacements in Human Proteins.” Human Molecular Genetics, vol. 14,
no. 21, Oxford University Press, 2005, pp. 3191–201, doi:10.1093/hmg/ddi350.
short: L. Yampolsky, F. Kondrashov, A. Kondrashov, Human Molecular Genetics 14 (2005)
3191–3201.
date_created: 2018-12-11T11:48:48Z
date_published: 2005-11-01T00:00:00Z
date_updated: 2021-01-12T08:19:13Z
day: '01'
doi: 10.1093/hmg/ddi350
extern: 1
intvolume: ' 14'
issue: '21'
month: '11'
page: 3191 - 3201
publication: Human Molecular Genetics
publication_status: published
publisher: Oxford University Press
publist_id: '6807'
quality_controlled: 0
status: public
title: Distribution of the strength of selection against amino acid replacements in
human proteins
type: journal_article
volume: 14
year: '2005'
...