This page can be used to initiate and update various discussions. Please create a new discussion by using a new Heading, for easy separation.

1. From Ramon Huerta: Mushroom Body Pros and Cons

I attach the presentation up to the point I manage to complete it.
Please follow the paper with the machine learning method comparison here
Method comparison

Paper with the simplified model. It also contains connectivities.

2. Odor Space:

C. Kirst

what is odor space ?
single-potato-chip-f4.jpg or potato-b.jpg

main-qimg-449e8895e2e513b143f006b4780de7ae.jpeg or DynamicalTriang.jpg

Odor space in terms of thermo-chemio-physical properties ?

Potato Picture: cf. A. Kulakov talk
Metrics: cf. Chakra Chennubhotla

Do we need odor space at all or is a non-metric set of properties enough ?

Are there any properties in the physical / chemical world that might be exploited for efficient sampling ?

3. Random Sampling / Compressed Sensing in Olfaction

C. Kirst

some references form Vijay's talk:
higher order statistics in vision:

fundamental plan of retina - feature detectors:

lessons from immune system:

odor mixtures:
see also:

cortical aspects:

Some discussion questions:
Random sampling and dynamics ?
How random is the sampling?

Additional interesting references:
compressed sensing and communication:

See also C. Stevens talk.

General questions: What does sparse mean ? Justification for Olfaction (also cf odor space)

4. Dynamics in Olfactory Circuits

Christoph Kirst

What are the characteristic dynamics and time scales in olfactory circuits (ORNs, glomeruli, higher neuronal networks
depending on animal, e.g MCs, piriform cortex) and of odours in the environment and during behaviour ?

Are there any correlations between neuronal circuit dynamics and environmental / behavioural triggered odour statistics ?
E.g. in the timescales of activity rise / persistence / decay, plasticity or feedback dynamics.

How does the olfactory system deal with 'continuous time' stimuli ?

Role of Oscillations ? Just steam of the engine or function ? How do olfactory circuits differ among species with
and without oscillations ?

Why would odour coding use temporal sequence representation rather than a single time point network state?
(e.g Rinberg work on odour encoding by activation of first glomeruli and similar results in talk by Maxim) ?
In case of temporal sequence coding how to deal with continuous inputs in non-sniffing animals ?

Odour is not using the thalamic route to Cortex, is there any analogue of the cortico-thalamic loop and
potential dynamical analogues or differences ?

If the olfactory code is dynamic what is a good representation of an odour, what are distances in 'temporal odour space' ?

How does ORN synchrony propagate in the network upstream ?

This is just a small unsorted unfiltered collection of broad questions that hopefully can trigger some more
detailed discussions. If interest lets have an informal discussion once a week ?

I will update this discussion with interesting papers i come accross and results from discussions.

Some references (feel free to add more relevant and classic ones):


Pattern recognition computation using action potential timing for stimulus representation

Modeling the olfactory bulb and its neural oscillatory processings.

Odor Encoding as an Active Dynamical Process

The Sniff as a Unit of Olfactory Processing

Odour-plume dynamics influence the brain's olfactory code

Adaptive Pattern Classification and Universal Recoding:
II. Feedback, Expectation, Olfaction, Illusions*~hmac=6a3a9ba3d93f78581fea4bd7133157e5b34b7d40f881198ecd7dfdcbbe637e07


Predator-Prey Dynamics: The Role of Olfaction

The Neurobiology of Olfaction.
Temporal Coding in Olfaction

5. Evolution and comparison of olfaction across species

Shyam Srinivasan

Animals have evolved diverse strategies in adapting to their environment. Differences in olfactory systems are evident in terms of anatomy, physiology, and ecology. I came across a few papers (by no means exhaustive) on evolution and comparative studies of olfaction across species which may be of interest. This list does not include much comparative behavior, which would be helpful to link structure and function. Please feel free to update this list.

A review on the comparison of four features of olfactory systems across species:

A paper on the evolution of vertebrate olfactory subsystems (main and vomorenasal) and includes comparisons across fish, reptiles, amphibians, and mammals:

A comparison of olfactory receptors across different clades and some perspectives on receptor evolution:

The number of ORs in elephants and other placental mammals:

Nice review on the neuroethology of insect olfaction:

Conserved features of olfaction across species:

Commonalities and differences between the olfactory systems of vertebrates and insects:

An interesting paper comparing the evolution of diverse sensory systems in species and the trade offs between these senses: