Response of Neurons in the Brain Region Locus Coeruleus to Stimuli
Jeff Moehlis
Princeton University
Experimental data shows that neurons in a region of the brain known as
the locus coeruleus (LC) can exhibit two distinct firing patterns which
are strongly correlated with performance on cognitive tasks. In the
phasic mode, associated with good performance, the baseline firing rate
is lower and the neurons show enhanced reponse. In the tonic mode,
associated with poor performance, the average baseline firing rate is
higher and the neurons are less reponsive. From membrane voltage and
ion channel equations, we derive a phase oscillator model for LC neurons.
Average firing probabilities of a pool of neurons in response to stimuli
over many trials are then computed via a probability density formulation.
Using this, we show that: (1) Response is elevated in populations with
lower baseline firing rates; and (2) Response decays due to noise and
distributions of neuron frequencies. These results may account for
much of the experimental response variability.