Superior frontal gyrus


The superior frontal gyrus also marginal gyrus, makes up about one third of the frontal lobe of the human brain. It is bounded laterally by the superior frontal sulcus.
The superior frontal gyrus is one of the frontal gyri.

Function

Self-awareness

In fMRI experiments, Goldberg et al. have found evidence that the superior frontal gyrus is involved in self-awareness, in coordination with the action of the sensory system.

Laughter

In 1998, neurosurgeon Itzhak Fried described a 16-year-old female patient who laughed when her SFG was stimulated with electric current during treatment for epilepsy. Electrical stimulation was applied to the cortical surface of AK's left frontal lobe while an attempt was made to locate the focus of her epileptic seizures.
Fried identified a 2 cm by 2 cm area on the left SFG where stimulation produced laughter consistently. AK reported that the laughter was accompanied by a sensation of merriment or mirth. AK gave a different explanation for the laughter each time, attributing it to an external stimulus. Thus, laughter was attributed to the picture she was asked to name, or to the sentence she was asked to read, or to persons present in the room.
Increasing the level of stimulation current increased the duration and intensity of laughter.
For example, at low currents only a smile was present, while at higher currents a louder, contagious laughter was induced. The laughter was also accompanied by the stopping of all activities involving speech or hand movements.

Additional images