Lawrence York PhD

Lawrence York


Publications:
2009
  A computational model of latency based stimulus selection
York, LC & van Rossum, MCW 2009, 'A computational model of latency based stimulus selection' BMC Neuroscience, vol 10, no. 1, pp. 1-1. DOI: 10.1186/1471-2202-10-S1-P307
General Information
Organisations: School of Informatics.
Authors: York, Lawrence C. & van Rossum, Mark CW.
Number of pages: 1
Pages: 1-1
Publication Date: Sep 2009
Publication Information
Category: Article
Journal: BMC Neuroscience
Volume: 10
Issue number: 1
ISSN: 1471-2202
Original Language: English
DOIs: 10.1186/1471-2202-10-S1-P307
  Recurrent networks with short term synaptic depression
York, L & van Rossum, M 2009, 'Recurrent networks with short term synaptic depression' Journal of Computational Neuroscience, vol 27, no. 3, pp. 607-620. DOI: 10.1007/s10827-009-0172-4
Cortical circuitry shows an abundance of recurrent connections. A widely used model that relies on recurrence is the ring attractor network, which has been used to describe phenomena as diverse as working memory, visual processing and head direction cells. Commonly, the synapses in these models are static. Here, we examine the behaviour of ring attractor networks when the recurrent connections are subject to short term synaptic depression, as observed in many brain regions. We find that in the presence of a uniform background current, the network activity can be in either of three states: a stationary attractor state, a uniform state, or a rotating attractor state. The rotation speed can be adjusted over a large range by changing the background current, opening the possibility to use the network as a variable frequency oscillator or pattern generator. Finally, using simulations we extend the network to two-dimensional fields and find a rich range of possible behaviours.
General Information
Organisations: Institute for Adaptive and Neural Computation .
Authors: York, Lawrence & van Rossum, Mark.
Keywords: (Short term synaptic depression , Ring attractor network , Propagating activity, , , . )
Number of pages: 14
Pages: 607-620
Publication Date: Dec 2009
Publication Information
Category: Article
Journal: Journal of Computational Neuroscience
Volume: 27
Issue number: 3
ISSN: 0929-5313
Original Language: English
DOIs: 10.1007/s10827-009-0172-4
2007
  Contrast dependent response latency in a spiking neural network
York, LC, Oram, M & van Rossum, MCW 2007, 'Contrast dependent response latency in a spiking neural network' 30th European Conference on Visual Perception, Arezzo, Italy, 27/08/07 - 31/08/07, .
The onset latency of single neuron responses in the visual system depends strongly on stimulus contrast. While in V1 latency increases are tens of ms, in higher visual areas (IT) the latency can increase 200 ms at the lowest contrast (Oram et al, 2002 Philosophical Transactions of the Royal Society B: Biological Sciences 357 987 - 1001). We present a layered neural network model of noisy integrate-and-fire neurons. Crucially, the model has strong recurrent connectivity and synapses with short-term synaptic depression. With these realistic ingredients, the model reproduces the contrast-dependent latencies. The model furthermore predicts a strong dependence of the spiking statistics on the contrast and time after stimulus onset. We analysed the response statistics predicted by the model and compared them to the data. The study shows that recurrence and short-term synaptic depression are important to explain dynamics and statistics of visually evoked responses in higher visual areas.
General Information
Organisations: Institute for Adaptive and Neural Computation .
Authors: York, Lawrence C., Oram, Mike & van Rossum, Mark C. W..
Publication Date: 2007
Publication Information
Category: Poster
Original Language: English
2006
  Probabilistic Independent Component Analysis of fMRI Data
York, LC, Marjoram, DKS, Johnstone, E, Lawrie, S & Moorhead, B 2006, 'Probabilistic Independent Component Analysis of fMRI Data'.
General Information
Organisations: Centre for Clinical Brain Sciences.
Authors: York, Lawrence C., Marjoram, Dominic K. S., Johnstone, Eve, Lawrie, Stephen & Moorhead, Bill.
Publication Date: 2006
Publication Information
Category: Poster
Original Language: English

Projects:
Modelling contrast-dependent latency dynamics of STS neuro responses in a spiking neural network (PhD)