Why I’m here

Rhythm.  What is in rhythm?  And why does it help us to distill information?

In childhood I learned that it is easier to learn information when it is accompanied by some sort of rhythm, or pattern, of delivery.  Then a while ago I went deaf in one ear, and I became vastly more aware of this.  Particularly in scenarios where communication is important.

How does a brain encode and uses rhythmic/patterned auditory information, and why need that information be rhythmic/patterned?  To approach these questions, I’m working at two broad endeavours: one at the level of the neuronal network, and one behavioral.

The Network: encoding rhythm

In the network realm, my animal is the zebra finch: a songbird who learns to produce a highly stereotyped ‘motif’ of four to seven ‘syllables’.  The motif, once learned, becomes ~ invariant over the bird’s lifetime.

Collections of neuronal nuclei (the ‘song system’) have been identified as instrumental in producing this motif.   In particular: specific excitatory neurons that project from nucleus HVC to RA enact a series of bursts that are tightly locked to the motif (look up richard hahnloser and michale fee).  Meanwhile, inhibition has been identified as an organizer of this activity (michael long).

This scheme smells of a central pattern generator (CPG) at work within – and perhaps distributed throughout – the song system.  To date, detailed work on CPGs is confined to the tiniest of circuits – on the order of ten neurons (eve marder).  I’d like to get at how Nature scales it.  What does a CPG – and the pattern it drives – look like on a scale of a million neurons, as opposed to ten?

Link to Behavior

Meanwhile: why sing in the first place?

Collaborators at Penn have built an aviary (marc schmidt), in which both audio and video will be recorded continually throughout mating season.  Here, the species is: cowbirds.  These birds form pair bonds, and yet they do not raise their young.

Motivated by this riddle, we seek to identify the pairwise interactions that lead to success of a flock – where we define ‘success’ in terms of the rate of fertile egg production.  This plan is in its infancy; I am working on applying an Ising/Potts modeling scheme – to identify the pairwise interactions that correlate with egg production.

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