Abstract # 37:

Scheduled for Saturday, September 17, 2011 02:00 PM-02:20 PM: Session 9 (Meeting Room 410) Oral Presentation


J. H. Kaas1,2
1Psychology Department, Vanderbilt University, PMB 407817, 2301 Vanderbilt Place, Nashville, TN 37240-7817, USA, 2Vanderbilt University

In prosimian galagos, New World owl monkeys (Otolemur garnetti) and squirrel monkeys (Aotus nancymaae), and Old World macaques (Macaca), electrical stimulation with half-second trains of electrical pulses was used to identify zones in posterior parietal cortex where reaching, grasping, defensive, or other complex movements were evoked. Injections of tracers into these zones labeled other nodes in the neural networks for these zones, indicating that each zone in posterior parietal cortex projects to functionally matched zones in premotor and motor cortex, while receiving a different pattern of visual, somatosensory, and thalamic inputs. The presence of these functionally distinct networks in members of three major branches of primate evolution suggests that the networks were present in early primates, and likely are characteristic of most or all primates, including humans. As posterior parietal cortex is a proportionately small portion of cortex in most mammals, including close relatives of primates, posterior parietal cortex appears to have an expanded role in initiating and controlling several classes of useful behaviors in primates. The fixed relative position of the functional zones in posterior parietal cortex across studied primates suggests that they emerged in brain development largely independent of individual differences in postnatal experience.