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To determine if a moderate traumatic brain injury (TBI) sustained early in life alters the capacity for developmental plasticity, 17-20-day-old rat pups received a lateral fluid percussion and then reared in an enriched environment for 17 days. Compared to sham-injured controls, this moderate TBI prevented the increase in cortical thickness (1.48 vs. 1.68 mm, p < 0.01) as well as the corresponding enhancement in cognitive performance in the Morris Water Maze (39 vs. 25 trials to criterion, p < 0.05). These injured animals exhibited no significant neuronal degeneration and no evidence of neurologic or motor deficits. These findings strongly support the conclusion that a diffuse brain injury is capable of inhibiting both anatomical and cognitive manifestations of experience-dependent developmental plasticity.

Cortical neural prosthetics extract command signals from the brain with the goal to restore function in paralyzed or amputated patients. Continuous control signals can be extracted from the motor cortical areas, whereas neural activity from posterior parietal cortex (PPC) can be used to decode cognitive variables related to the goals of movement. Because typical activities of daily living comprise both continuous control tasks such as reaching, and tasks benefiting from discrete control such as typing on a keyboard, availability of both signals simultaneously would promise significant increases in performance and versatility. Here, we show that PPC can provide 3D hand trajectory information under natural conditions that would be encountered for prosthetic applications, thus allowing simultaneous extraction of continuous and discrete signals without requiring multisite surgical implants. We found that limb movements can be decoded robustly and with high accuracy from a small population of neural units under free gaze in a complex 3D pointto-point reaching task. Both animals' brain-control performance improved rapidly with practice, resulting in faster target acquisition and increasing accuracy. These findings disprove the notion that the motor cortical areas are the only candidate areas for continuous prosthetic command signals and, rather, suggests that PPC can provide equally useful trajectory signals in addition to discrete, cognitive variables. Hybrid use of continuous and discrete signals from PPC may enable a new generation of neural prostheses providing superior performance and additional flexibility in addressing individual patient needs.cognitive neural prosthetic | parietal reach region | area 5 D ifferent cortical areas have been identified as sources for cortical prosthetics to assist subjects with paralysis or amputation (1-13). Motor cortex can provide continuous control of trajectories (3)(4)(5)(11)(12)(13), which is consistent with its normal function of sending commands directly to the movement generating circuits of the spinal cord. More cognitive variables related to reach goals have been extracted from the parietal reach region (PRR) and area 5d in posterior parietal cortex (PPC) (7,14,15). There are several advantages of these cognitive variables for prosthetic applications: (i) decodes of goals are very fast, in the order of 100 ms, and can assist in typing applications (7); (ii) at least two sequential goals can be represented in PRR, and this feature can augment typing and sequential limb movements (16); (iii) goal and trajectory information, when combined, provide better decoding of trajectories than trajectory information alone (17); (iv) bilateral arm movements to a goal are represented and can assist in decoding bimanual behaviors from a single hemisphere (18); and (v) the anterior intraparietal area (AIP) of PPC represents grasp shape, which may reduce the number of cells needed to decode grasping (19).If PPC also encodes trajectories, then its repertoire of uses for prosthetics contr...

The grim prognosis that accompanies a diagnosis of a malignant glioma affects quality of life (QOL) as patients attempt to adapt to overwhelming losses. Caregivers also experience negative changes in QOL as responsibilities grow. This pilot study measured the QOL of patients with malignant gliomas prior to tumor progression and the QOL of their caregivers. It examined negative and positive factors that impacted the QOL while highlighting positive factors often overlooked in brain tumor QOL research. Standardized QOL questionnaires and focus groups were utilized. Patients experienced distress in the domains of physical, psychological, and social QOL but in all four of the QOL domains there were also positive outcomes. Caregiver data demonstrated mostly positive outcomes in the four QOL domains except for loved one's declining health and fear that the loved one would die.