Tuesday, January 01, 2008

Scholarpedia online neuroscience encyclopedia

I've added a new link to the menu on the right, to Scholarpedia's Encylopedia of Computational Neuroscience. (I learned about this through a blogpost by Mo, at Neurophilosophy, a blog I check every day. Thank you Mo.)

I look forward to more articles going up over there, but for now, this one on grid cells by Edvard Moser pertains to much of the reading/blogging I've been doing since September. I feel that at least part of my job as a human primate social groomer is to read and understand and strive to make more sense of what I do in light of all this lovely information.

Here are a few more that Mo has already preselected:
1. Mirror neurons by Giacomo Rizzolatti
2. Synesthesia by V.S. Ramachandran
3. Neural correlates of consciousness by Chris Koch

Here are a few more I checked out:

1. Synfire chains Definition:
"a feed-forward network of neurons with many layers (or pools). Each neuron in one pool feeds many excitatory connections to neurons in the next pool, and each neuron in the receiving pool is excited by many neurons in the previous pool. When activity in such a cascade of pools is arranged like a volley of spikes propagating synchronously from pool to pool it is called a synfire chain."

2. LTD, or long-term depression Definition:
"Long-term depression (LTD) is a weakening of a synapse after a short series of presynaptic action potentials or asynchronous presynaptic and postsynaptic activity. LTD is distinguished in homosynaptic LTD, heterosynaptic LTD and associative LTD."
(I think this is more along the lines of synaptic inhibition. I'm sure there must have been a good reason to change the name to depression, although I can't imagine what it might have been.)

3. Brain
Seems like it would be something one could slide past, yet it's definitely worth a read.
"Function: The intimate relation of the brain to the sense organs points to the brain’s essential role as an information handling device. Meaningful events to which the animal reacts are but rarely signaled by a single sense organ. More commonly it is a combination of information from different sensory modalities that gives away the aggressor, or the prey, or the sexual partner, or the dangerous cliff etc. Thus the brain is there to make concepts out of sensations, at a higher level of abstraction. It is not only the different senses that contribute to the formation of concepts. Equally important, the monitoring of motor behavior, both in its planning and in its execution, provides crucial information necessary for the correct interpretation of any situation signaled by the senses. All of this requires a brain."

4. Intrinsic plasticity Definition:
"the persistent modification of a neuron’s intrinsic electrical properties by neuronal or synaptic activity. It is mediated by changes in the expression level or biophysical properties of ion channels in the membrane, and can affect such diverse processes as synaptic integration, subthreshold signal propagation, spike generation, spike backpropagation, and meta-plasticity. The function of intrinsic plasticity in behaving animals is uncertain but there is experimental evidence for several distinct roles: as part of the memory engram itself, as a regulator of synaptic plasticity underlying learning and memory, and as a component of homeostatic regulation.
It is important to note that intrinsic plasticity is distinct from synaptic plasticity"

5. High-conductance state

6. Various systems models: Ermentrout-Kopell Canonical Model (aka theta model); XPPAUT; FitzHugh-Nagumo Model; Morris-Lecar Model; Rall model;

7. Cortical memory

8. Synergetics Definition:
"Synergetics deals with material or immaterial systems, composed of, in general, many individual parts (Haken 2004, see also Springer series in Synergetics, about 80 volumes). It focuses its attention on the spontaneous, i.e. self-organized emergence of new qualities which may be structures, processes or functions."

9. Various networks: Hopfield Network; Kohonen network;

10. Neuron

11. Reward, reward signals

12. Stomatogastric ganglion (of crustaceans, sort of a mini-brain)

13. Thalamus Excerpt:
"A consideration of the complexity of thalamic cell and circuit properties puts a lie to the old notion that thalamus represents a simple, machine-like relay of information to cortex. We can now be certain of two major concepts to replace this. The first is that the thalamus represents a last bottleneck of information flow, providing a convenient substrate to influence that flow. This is achieved by the many modulatory pathways that innervate relay cells to influence relay function in numerous ways. One detailed above is the burst/tonic transition in the firing mode of relay cells, but this is just the tip of the iceberg. We need much more information about the many ways thalamic circuitry controls information flow to cortex.
The second point is that the role of thalamus is not limited to getting information to cortex in the first place, which is the role of first order relays, but also continues to function in the higher order cortico-thalamo-cortical pathways, thereby providing an essential, ongoing function for cortical processing. This dramatically alters long-standing views of cortical processing, and we need to know much more about the different roles of cortico-thalamo-cortical versus direct corticocortical pathways in cortical functioning."

14. Binding by Synchrony Excerpt:
"One of the coordinating mechanisms appears to be the synchronization of neuronal activity by phase locking of self-generated network oscillations."

15. Fast Oscillations

16. Blindsight

17. Up and down states

There are about 500 more articles coming along or already written. They are listed alphabetically by author (first names, only up to "L" for some strange reason) here.

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