Can sex influence the neurocognition of language? Evidence from Parkinson's disease.

Parkinson's disease (PD), which involves basal ganglia degeneration, affects language as well as motor function. However, which aspects of language are impaired in PD and under what circumstances remains unclear. We examined whether lexical and grammatical aspects of language are differentially affected in PD, and whether this dissociation is moderated by sex as well as the degree of basal ganglia degeneration. Our predictions were based on the declarative/procedural model of language. The model posits that grammatical composition, including in regular inflection, depends importantly on left basal ganglia procedural memory circuits, whereas irregular and other lexicalized forms are memorized in declarative memory. Since females tend to show declarative memory advantages as compared to males, the model further posits that females should tend to rely on this system for regulars, which can be stored as lexicalized chunks. We tested non-demented male and female PD patients and healthy control participants on the intensively studied paradigm of English regular and irregular past-tense production. Mixed-effects regression revealed PD deficits only at regular inflection, only in male patients. The degree of left basal ganglia degeneration, as reflected by right-side hypokinesia, predicted only regular inflection, and only in male patients. Left-side hypokinesia did not show this pattern. Past-tense frequency effects suggested that the female patients retrieved regular as well as irregular past-tense forms from declarative memory, whereas the males retrieved only irregulars. Sensitivity analyses showed that the pattern of findings was robust. The results, which are consistent with the declarative/procedural model, suggest a grammatical deficit in PD due to left basal ganglia degeneration, with a relative sparing of lexical retrieval. Female patients appear to compensate for this deficit by relying on chunks stored in declarative memory. More generally, the study elucidates the neurocognition of inflectional morphology and provides evidence that sex can influence how language is computed in the mind and brain.

Successful Treatment of War Zone Traumatic Lower Extremity Wound With Exposed Tendons Using an Autologous Homologous Skin Construct.

Extremity injuries are common in contemporary combat and have become more prevalent as fatality rates have dropped to historic lows. Traumatic extremity wounds, especially those sustained in theater, often present with exposed structures such as tendon, bone, and joint, preventing the use of split-thickness skin grafts (STSG) for coverage. Traditional reconstructive options for these complex wounds include skin substitute with delayed STSG, local flaps, debridement of tendons, pedicled distant flaps (such as cross-leg flap), free tissue transfer, and amputation. STSG, whether on top of skin substitutes or after tendon debridement, can result in contracture and functional limitations in the extremities. Flap reconstructions require prolonged procedures, hospital stays, and periods of immobility. As an alternative to traditional reconstructive options, an autologous homologous skin construct (AHSC) uses a small full-thickness elliptical skin harvest from the patient, which is sent to a biomedical manufacturing facility, processed into AHSC, and can be returned and applied to a wound bed as soon as 48 hours after harvest and used up to 14 days after harvest. We present in this case report the treatment of a 42 cm2 complex dorsolateral ankle wound with exposed tendons in an active duty soldier following a rollover motor vehicle accident sustained in theater. After application of AHSC, the soldier's wound closed in nine weeks with pliable, sensate skin. The patient retained function without contractures limiting ankle motion or adhesions limiting tendon gliding. The successful treatment of this complex war zone injury with AHSC has allowed the soldier to quickly participate in unrestricted physical therapy and is on a trajectory for near-term return to active duty.

Wake-related activity of tuberomammillary neurons in rats.

Histaminergic neurons of the tuberomammillary nucleus (TMN) are hypothesized to promote wakefulness, but little is known about the activity of these cells during spontaneous behavior. We measured histaminergic neuron activity in the dorsomedial, ventrolateral, and caudal TMN at four different times using Fos and adenosine deaminase immunohistochemistry and recordings of sleep/wake behavior. Because circadian factors could influence neuronal activity, we then assessed TMN neuron activity in predominantly sleeping or awake animals, all killed at the same time of day. In both experiments, Fos expression in histaminergic neurons of all three TMN subnuclei was higher during periods of wakefulness. These results demonstrate that histaminergic neurons throughout the TMN are wake-active, and this activity is largely independent of the time of day.