[Verse 1] In the retina where vision starts its dance Photoreceptors catch each ray of light No spikes here, just graded potentials' stance Analog whispers in the fading night Bipolar cells and horizontal too Signal with voltage that flows smooth and clean Short distance chatter, continuous and true The eye's front stage sets up the visual scene [Chorus] From the ganglion forward, spikes take the wheel All-or-none messages down the neural line Action potentials make the long haul real Digital pulses in a spike train design Glutamate excites, GABA holds it back Chemical bridges where the neurons meet Neuromodulators change the neural track Global state signals make the circuit complete [Verse 2] Once ganglion cells fire their electric song Action potentials race through axon wire No more graded signals rolling along Just binary bursts of neural fire Chemical synapses bridge the gap between Spikes trigger vesicles to dump their load Neurotransmitters cross the space unseen Messages jumping down the neural road [Chorus] From the ganglion forward, spikes take the wheel All-or-none messages down the neural line Action potentials make the long haul real Digital pulses in a spike train design Glutamate excites, GABA holds it back Chemical bridges where the neurons meet Neuromodulators change the neural track Global state signals make the circuit complete [Verse 3] Glutamate's the workhorse pushing things ahead Cortico-cortical highways run on this fuel AMPA receptors carry signals widespread NMDA detects coincidence like a jewel Plasticity and sustained activity flow Through NMDA's coincidence detection gate Learning and memory begin to grow When timing and voltage properly relate [Verse 4] Visual cortex layers process what we see Layer four receives the thalamic drive Pyramidal cells in two and three Send feedback signals to keep loops alive Layer five projects to distant brain parts While layer six controls the thalamic gate Each cortical column plays its neural parts In the grand design of visual fate [Bridge] GABA interneurons keep the balance tight Normalization and gain control their game Surround suppression sharpens up the sight Gamma rhythms pulse with inhibitory flame PV interneurons set the gamma pace While ACh and noradrenaline set the gain Arousal and attention find their place Context switches how the circuits train [Chorus] From the ganglion forward, spikes take the wheel All-or-none messages down the neural line Action potentials make the long haul real Digital pulses in a spike train design Glutamate excites, GABA holds it back Chemical bridges where the neurons meet Neuromodulators change the neural track Global state signals make the circuit complete [Outro] From graded potentials to the spike train's beat Chemical transmission makes it all complete Excitation, inhibition, modulation's art Neural symphonies of the visual part
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