• Motor
• Contralateral finger, hand, and wrist movements (Dorsal) (8643131, 8280976, 9343992, 10841363, 18486490, 18344193, many articles)
• Contralateral lip, tongue, face, and mouth movement (Lateral) (9347937, 15162913, 15734345, 12599281, 11004117, 17560128)
• Swallowing / laryngial movement (10200226, 11568539, 10499047, 17652461, many articles)
• Contralateral lower limb (knee, ankle, foot, toe) movement (Mesial) (17919932, 16859927, 16034570, many articles)
• Motor imagery (8922425, 18425505, 18358742, 17499160, many articles)
• Learning motor sequences (15955490, 15585904, 11244547)
• Volitional breathing control (11252531, 8350282, 10470862, 15311350)
• Control of rhythmic motor tasks (i.e. bicycling) (11104128)
• Inhibition of blinking / voluntary blinking (15882784, 12667852)
• Horizontal saccadic eye movements (9345475, 9749761, 8492144)
• Somatosensory
• Kinesthetic perception of limb movements (14987450, 14505336, 12467600)
• Vibrotactile frequency discrimination (17065253, 10694461)
• Finger proprioception (17911031, 7807222, 15029467)
• Thermal hyperalgesia (contralateral) (8836245)
• Response to touch/observed touch (Left) (18345991)
• Other
• Verbal encoding during a non-semantic process (Right) (11338201)
• Attention to action (posterior) (12091573)
• Topographic memory (motor memory) for visual landmarks (9368932)

According to functional neuroimaging techniques BA4 participates in three different groups of functions: Motor, somatosensory, and “others” (“verbal encoding during a non-semantic process”, “attention to action”, and “motor memory for visual landmarks”). Motor function is the traditional function, and occasionally it has been reported that the primary motor cortex reacts to sensory stimulation. Nonetheless, in these cases the primary motor activation is found in addition to a more extensive pattern of activation, obviously including sensory areas; that is, the BA4 may some times be included in a brain circuitry supporting sensory perception; BA4 activation may reflect in those cases the implicit representation of a potential movement. This implicit representation of movements can also account for “attention to action” and “motor memory”. The participation in “verbal encoding during a non-semantic process” is probably  tangential, considering that it becomes activated (in addition to frontal and temporal networks) only during “successful encoding”, suggesting a certain role in the attentional process (increased muscle tone?)