Compensation of Postural Control by Squirrel Monkeys Following Dorsal Column Lesions

Forelimb performance by squirrel monkeys (Saimiri sciureus) before and after dorsal column lesions.

“…Similarly, the squirrel monkey, which readily jumps 10 m to land with perfect body alignment on a bobbing branch 1 cm in diameter (Du Mond, 1968), might find jumping .5 m to a large, flat, rotating turntable relatively easy even after dorsal column lesions. This was apparently the case (Beck, 1973).…”

“…The dorsal column medial lemniscal system may have evolved to serve distal limb apparatus rather than the axial sensorimotor structures (Dreyer, Schneider, Metz, & Whitsel, 1974;Noback & Shriver, 1966, 1969. However, squirrel monkeys with lesions of the dorsal columns do not slip and stumble when jumping to a rotating platform (Beck, 1973) as do cats with dorsal column lesions (Melzack & Bridges, 1971). The evolutionary specialization of the motor system of carnivores has been in the direction of terrestrial quadrupedal locomotion.…”

Dual Dorsal Columns: A Review

“…The same behavioral tests do not necessarily produce similar effects in different species following dorsal column lesions. Cervical, dorsal column lesions in cats cause the cat to stumble and fall when jumping to a moving turntable (Melzack and Bridges, 1971) but have no observable effect on squirrel monkeys with similar lesions (Beck, 1973). Nor do operated squirrel monkeys exhibit forelimb ataxia when reaching into extrapersonal space (Beck, in press), as do macaques (Gilman and Denny- Brown, 1966).…”