Dynamics and Timing in Birdsong
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Dynamics and Timing in Birdsong Henry D. I. Abarbanel Department of Physics and PowerPoint PPT Presentation


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Dynamics and Timing in Birdsong Henry D. I. Abarbanel Department of Physics and Marine Physical Laboratory (Scripps Institution of Oceanography) Center for Theoretical Biological Physics University of California, San Diego [email protected]

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Dynamics and Timing in Birdsong Henry D. I. Abarbanel Department of Physics and

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Dynamics and timing in birdsong henry d i abarbanel department of physics and

Dynamics and Timing in Birdsong

Henry D. I. Abarbanel

Department of Physics

and

Marine Physical Laboratory (Scripps Institution of Oceanography)

Center for Theoretical Biological Physics

University of California, San Diego

[email protected]

Leif Gibb, Gabriel Mindlin, Misha Rabinovich, Sachin Talathi

Conversations with Michael Brainard, Allison Doupe, David Perkel


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Auditory Feedback

Green:

Pre-motor Pathway

NIf (?)HVcRA

Respiration/Syrinx

Song Production

Red:

Anterior Forebrain Pathway (AFP)

HVcArea DLM

lMANArea X

HVc

Control and Song Maintenance

Songbox

From Brainard and Doupe, 2002


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Tutor sings during sensory period. Bird memorizes template

Bird sings own song; learns memorized song matching template-- sensorimotor period.

Song “matches” template and reaches crystallization

(Brainard and Doupe 2002)


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Auditory Feedback

Deafen Juvenile—song develops “incorrectly”

Lesion lMAN in juvenile---song mismatches template; crystallization occurs early.

Deafen adult—song slowly degrades

Lesion lMAN in adult--song stable

Deafen adult and lesion lMAN—song stable

Lesion HVc or RA—no song produced -------------------------

lMAN (and AFP) important in maintaining song when auditory feedback works—not deaf


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Song is group of motifs—about 1 sec each—composed of groups of syllables—about 100-300 ms.

Zebra Finch bout (song) is about 2-3 motifs

(Hahnloser, Kozhevnikov, and Fee 2002)

When bird sings, HVc-->RA fires sparse bursts of spikes: one burst of 4.5 ± 2 spikes in 6.1 ± 2 ms in each motif. RA neurons fire 13 times more often, suggests one-to-many HVcRA connections

HVc acts as driver of song instructions. RA acts as “junction box” distributing commands to motor processes.


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Auditory Feedback

Time difference in signal from HVcRA and HVcAFPRA is measured to be 50 ±10 ms.

AFP nuclei act as a population

Dynamics of AFP—X, DLM, lMAN is important

Kimpo, Theunissen, Doupe, 2003


Dynamics and timing in birdsong henry d i abarbanel department of physics and

We will discuss three topics:

  • plasticity at HVcRA connections. The alteration of these connections during song learning sets up wiring in song “junction box” (RA).

    This suggests a critical timing of about 40-50 ms.

  • dynamics of AFP and timing of signals from HVcAFPRA: origin of “40 ms”

  • RADLM connection to stabilize synaptic plasticity at HVcRA junction

    We won’t be discussing:

  • connectivity of HVcRA in producing song syllables


Dynamics and timing in birdsong henry d i abarbanel department of physics and

A full theory, which we do not have, would connect HVc sparse bursts with auditory feedback and command signals from brain.

It would trace HVc signals to RA, directly and through AFP, and explain evaluation of produced song through auditory feedback to HVc.

At best we have the beginning of a quantitative picture of the timing issues in the neural part of this loop.


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Motor Instructions Auditory Feedback

Excitation

HVc

Inhibition

AFP

Area X

DLM

RA

lMAN

Motor Signaling


Dynamics and timing in birdsong henry d i abarbanel department of physics and

HVcRA Plasticity


Dynamics and timing in birdsong henry d i abarbanel department of physics and

In adult zebra finch HVc signals arrive at dendritic location with about 1:1 NMDA to AMPA receptors.

In adult zebra finch lMAN signals arrive at RA dendritic locations with 10:1 NMDA to AMPA.

RA projection neurons (PNs) oscillate at 15-30 Hz “at rest”—i.e. no song. When singing begins, global inhibition in RA puts these PNs into small subthreshold variations. These are then driven by high frequency (500-600 Hz) HVc signals

We model “whole” RA with oscillations, etc.

Stark and Perkel, 1999


Dynamics and timing in birdsong henry d i abarbanel department of physics and

From lMAN

From HVc

RAPN

RAPN

RA

RAIN

To DLMIN

Excitation

At “rest” (no song) RA PN

oscillates at 15-30 Hz; RA IN is silent

Inhibition


Dynamics and timing in birdsong henry d i abarbanel department of physics and

We present bursts of NHVc spikes with fixed interspike intervals (ISIs) to RA neurons and ΔT later present NlMAN spikes. We determine VRA(t) from HH equations. Then using a calcium flux equation we determine from which, using a phenomenological connection between elevation over equilibrium intracellular Ca, we determine Δg for AMPA receptors.

NHVc

ΔT

NlMAN

Time

The idea, following the observations of Yang, Tang, and Zucker, 1999 is that long term changes in Δg, LTP and LTD, can be induced by postsynaptic Ca changes alone. The mechanisms leading from Ca elevation to changes in Δg are not fully known.


Dynamics and timing in birdsong henry d i abarbanel department of physics and

From HVc or lMAN

Presynaptic Membrane

Vpre(t) action potential leads to release of neurotransmitter--glutamate

Mg2+

Postsynaptic Membrane

NMDA Receptor

AMPA Receptor

RA Neuron PN

Voltage Gated Calcium Channel

[Ca2+](t) = Ca(t)

Vpost(t)


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Phenomenological Connection between Ca elevation and Δg


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Spike Timing Induction Protocol

Time

Action potential arrives at presynaptic terminal

Action potential induced in postsynaptic neuron


Dynamics and timing in birdsong henry d i abarbanel department of physics and

We present bursts of NHVc spikes with fixed interspike intervals (ISIs) to RA neurons and ΔT later present NlMAN spikes. Using a simple voltage equation for RA membrane voltage, we determine VRA(t). Then using a calcium flux equation we determine from which, using a phenomenological connection between elevation over equilibrium intracellular Ca, we determine Δg for AMPA receptors.

NHVc

ΔT

NlMAN

Time


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Lesion lMAN ΔgRA=0

Crystallization of song ΔgRA=0

Stable??


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Dynamics of the Anterior Forebrain Pathway


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Auditory Feedback

AFP:

HVc

XDLMlMANX

RA


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Motor Instructions Auditory Feedback

HVc

Excitation

AFP

Inhibition

Area X

DLM

RA

lMAN

Motor Signaling


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Signal from HVc activates SN which inhibits AF allowing DLM to fire.

With no input SN cells are at rest;

AF cells fire periodically at 15-30 Hz.


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Timing for signals to traverse the AFP depends on distribution of inhibition and excitation. In a coarse grained sense, the ratio RIE = gI/gE determines time delay


Dynamics and timing in birdsong henry d i abarbanel department of physics and

RIE = 4

Burst of spikes arrives from HVc at X at t = 4000 ms


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Burst of spikes arrives from HVc at X at t = 4000 ms


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Motor Instructions Auditory Feedback

Now connect in RADLM link

HVc

Area X

DLM

RA

lMAN

Motor Signaling


Dynamics and timing in birdsong henry d i abarbanel department of physics and

With RADLM connection in we present N = 1,2 , … bursts from HVc to RA and to Area X. Each burst is 5 spikes with ISI = 2 ms.

Before spiking we have the HVcRA AMPA strength set at the initial condition gRA(0), then we compute gRA(1) = gRA(0)+ΔgRA(0), gRA(2) = gRA(1)+ΔgRA(1), .…, gRA(N) = gRA(N-1)+ΔgRA(N-1) .

This is a nonlinear map gRA(N)  gRA(N+1). The results for large N depend on RIE and gRA(0), as ever with such maps.


Dynamics and timing in birdsong henry d i abarbanel department of physics and

Auditory Feedback

Can we change AFP time delay with neuromodulators??

Can we block GABA or decrease inhibition in AFP? or excitation?

Dopamine is known to modulate excitation in Area X.

Tests of properties of RA—DLM connection.

Plasticity not yet found at HVcRA PNs !!!

Where is tutor template?

How does auditory feedback work?

What are the dynamics of HVc? WLC???


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