[Verse 1] Out on the lateral strip of area six, Premotor cortex does its sorting tricks, Split like a river into two separate streams, Dorsal up top, ventral down where the hand dreams, PMd eyes the reach, charts the arm's whole glide, PMv shapes the grip, fingers folding inside, Not one single blob, no, it's cleverly zoned, Two roommates sharing a single home [Chorus] Premotor plans before you ever start, Reading the cue, then playing its part, Straight line down to M1, straight line to the cord, This is the brain's own storyboard, Dorsal and ventral, a two-chambered choice, Listen for the cue, it's got no voice, Remember it plans, it isn't the doer, Premotor's the sketch before the mover [Verse 2] It's not shy either, sends fibers of its own, Straight to the spinal cord, bypassing the throne Of M1 alone, it's got its own direct line, Planning and acting, both at the same time, Show it a color, show it a light, It picks the response, decides left or right, Arbitrary rules, like "green means press," Premotor's the broker that settles the guess [Verse 3] Now picture a waiting room, call it the antechamber, A quiet hallway where intentions amble, That's the delay task, cue comes, then you pause, Neurons keep firing for the "go" because They're holding the plan like a held breath, suspended, Not yet released, the movement unended, Watch the firing climb before the cue drops, Premotor's rehearsing before the clock stops [Verse 4] Damage this region, something strange occurs, Reaching and grasping, nothing really blurs, Basic movement still runs clean and fine, But hand them a rule and they can't read the sign, "Blue card means lift," the logic goes dim, Arbitrary mapping slips away from him, So premotor's not strength, it's choice under cue, Lose it, and the menu's unreadable to you [Bridge] Now shift your gaze toward the middle crease, That's SMA, the self-starting piece, Medial for the urge that wells up inside, Lateral premotor rides the outside tide, One waits for a whisper, a light, or a bell, One just decides, with no outside spell, Medial versus lateral, the classic divide, Keep that split sitting close by your side [Chorus] Premotor plans before you ever start, Reading the cue, then playing its part, Straight line down to M1, straight line to the cord, This is the brain's own storyboard, Dorsal and ventral, a two-chambered choice, Listen for the cue, it's got no voice, Remember it plans, it isn't the doer, Premotor's the sketch before the mover [Outro] Lateral six, waiting on the sign, Dorsal, ventral, drawing out the line, Cue comes knocking, premotor answers true, Sketching the movement before it's due
← M1 as a Dynamical System | Dorsal Premotor: Choosing What to Do →