Dear All,
The CEU Department of Cognitive Science and the Center for Cognitive Computation (CCC)
invites you to the upcoming event of the Budapest Computational Neuroscience
Forum<https://ccc.ceu.edu/budapest-computational-neuroscience-forum>um>.
* Room change: please note that this event has been moved to N15. room 101. Quantum. *
Speaker: Nikola Milićević, Pennsylvania State University
Title: Sensory systems and combinatorial neural codes
Abstract: Neural activity in sensory areas of the brain is shaped both by the stimulus and
by the internal neural dynamics. When the stimulus space is known we can compute receptive
fields of neurons. Receptive fields of individual neurons are convex in a number of brain
regions (such as the hippocampus, and the visual cortex). The combinatorial neural code
are the subsets of co-active neurons for some input to the neural network. Not any
combinatorial code is compatible with convex receptive fields. This raises a natural
question: how do recurrent networks produce convex codes? Towards this end, we study a
recurrent neural network with the Dale’s law architecture.
We describe the combinatorics of equilibria and steady states of neurons in
threshold-linear networks that satisfy Dale's law. The combinatorial code of a Dale
network is characterized in terms of two conditions: (i) a condition on the network
connectivity graph, and (ii) a spectral condition on the synaptic matrix. In the weak
synaptic coupling regime, the combinatorial code depends only on the connectivity graph,
and not on the synaptic strengths. Moreover, we prove that the combinatorial code of a
weakly coupled network is a sublattice, and we provide a learning rule for encoding a
sublattice in a weakly coupled excitatory network. Surprisingly, we find that the
architecture of a Dale network “enforces” convex code output, in both strong and weak
coupling regimes. Finally, we introduce a method inspired by game theory for inferring
receptive fields, when the stimulus space is unknown or at least no consensus has been
reached as in the case of olfactory systems.
Time: 17:00, Wednesday, 22 May, 2024.
Location: CEU Budapest (1051 Budapest, Nádor u. 15.) N15. room 101. Quantum.
Zoom: Meeting ID: 924 6832
6063<https://ceu-edu.zoom.us/j/92468326063?pwd=ZTgxYmk4WUFQaXZvbFZGNUhaTFNwZz09>
Passcode: 764846
Should you have any inquiries about the series, please contact Mihály
Bányai<mailto:mihaly.s.banyai@gmail.com>.
Please, be informed that video/photo recording might take place at the event and the
edited version of the video material might be published to communicate or promote
CEU's activities. Please, find our Privacy Notice
here<https://www.ceu.edu/privacy>cy>.
Best regards,
Ildikó Varga
Department Coordinator (Budapest)
Department of Cognitive Science
[cid:ed116b04-865c-443d-9fa3-24a4e655f690]
H-1051 Budapest
Nádor u. 15. FT room 404.
tel: +36-1 327-3000 2941
http://www.ceu.edu<http://www.ceu.edu/>
http://cognitivescience.ceu.edu<http://cognitivescience.ceu.edu/>
________________________________
From: Ildiko Zsoka Varga
Sent: Thursday, May 16, 2024 10:03 AM
To: 'talks(a)cogsci.ceu.edu (talks(a)cogsci.ceu.edu)' <talks(a)cogsci.ceu.edu>
Subject: Budapest Computational Neuroscience Forum, 22 May 5 PM, Nikola Milićević
Dear All,
The CEU Department of Cognitive Science and the Center for Cognitive Computation (CCC)
invites you to the upcoming event of the Budapest Computational Neuroscience
Forum<https://ccc.ceu.edu/budapest-computational-neuroscience-forum>um>.
Speaker: Nikola Milićević, Pennsylvania State University
Title: Sensory systems and combinatorial neural codes
Abstract: Neural activity in sensory areas of the brain is shaped both by the stimulus and
by the internal neural dynamics. When the stimulus space is known we can compute receptive
fields of neurons. Receptive fields of individual neurons are convex in a number of brain
regions (such as the hippocampus, and the visual cortex). The combinatorial neural code
are the subsets of co-active neurons for some input to the neural network. Not any
combinatorial code is compatible with convex receptive fields. This raises a natural
question: how do recurrent networks produce convex codes? Towards this end, we study a
recurrent neural network with the Dale’s law architecture.
We describe the combinatorics of equilibria and steady states of neurons in
threshold-linear networks that satisfy Dale's law. The combinatorial code of a Dale
network is characterized in terms of two conditions: (i) a condition on the network
connectivity graph, and (ii) a spectral condition on the synaptic matrix. In the weak
synaptic coupling regime, the combinatorial code depends only on the connectivity graph,
and not on the synaptic strengths. Moreover, we prove that the combinatorial code of a
weakly coupled network is a sublattice, and we provide a learning rule for encoding a
sublattice in a weakly coupled excitatory network. Surprisingly, we find that the
architecture of a Dale network “enforces” convex code output, in both strong and weak
coupling regimes. Finally, we introduce a method inspired by game theory for inferring
receptive fields, when the stimulus space is unknown or at least no consensus has been
reached as in the case of olfactory systems.
Time: 17:00, Wednesday, 22 May, 2024.
Location: CEU Budapest (1051 Budapest, Nádor u. 15.) N13. room 118*.
*Anyone not affiliated with CEU wishing to attend in-person must RSVP to vargai(a)ceu.edu
get access to the lecture hall.
Zoom: Meeting ID: 924 6832
6063<https://ceu-edu.zoom.us/j/92468326063?pwd=ZTgxYmk4WUFQaXZvbFZGNUhaTFNwZz09>
Passcode: 764846
Should you have any inquiries about the series, please contact Mihály
Bányai<mailto:mihaly.s.banyai@gmail.com>.
Please, be informed that video/photo recording might take place at the event and the
edited version of the video material might be published to communicate or promote
CEU's activities. Please, find our Privacy Notice
here<https://www.ceu.edu/privacy>cy>.
Best regards,
Ildikó Varga
Department Coordinator (Budapest)
Department of Cognitive Science
[cid:504c9e33-b62b-49d0-8ebc-c0cd5b5a6437]
H-1051 Budapest
Nádor u. 15. FT room 404.
tel: +36-1 327-3000 2941
http://www.ceu.edu<http://www.ceu.edu/>
http://cognitivescience.ceu.edu<http://cognitivescience.ceu.edu/>
______________________________________________
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