Memory formation: evidence for a specific neurochemical system in the amygdala.

beta-Adrenergic antagonists injected into the amygdala complex of rats trained in a passive avoidance task produced time-dependent and dose-dependent decreases in retention of the task. In addition, the effects observed with beta-adrenergic antagonists were both stereospecific and reversed by norepinephrine. The results support a role for an amygdala beta-adrenergic system in memory processes.

Frontal cortex projections to the amygdaloid central nucleus in the rabbit.

Evidence has recently been presented which demonstrates that the amygdaloid central nucleus projects directly upon cardiovascular/autonomic regulatory nuclei of the dorsal medulla and that in the rabbit this nucleus may influence cardiovascular activity during emotional states. The present study is one of a series of investigations designed to provide information on the innervation of the central nucleus in the rabbit and describes the topography and origin of frontal cortex projections to the nucleus based upon retrograde and anterograde axonal transport techniques. Injections of horseradish peroxidase or the fluorescent dyes, Bisbenzimide or Nuclear Yellow, into the central nucleus resulted in abundant numbers of retrogradely labeled neurons in three regions of the frontal cortex: the insular cortex on the lateral surface and areas 25 and 32 on the medial surface of the hemisphere. The majority of labeled neurons in the insular cortex were located in layer V of the dorsal and posterior agranular insular regions, although labeled neurons were observed in layer V of the granular insular cortex as well as in layers II and III of the posterior agranular insular cortex. Labeled neurons in areas 25 and 32 were located throughout all layers and the total number of these neurons was substantially less than that observed in the insular cortex. Autoradiographic experiments in which amino acids were injected into the insular cortex resulted in a dense pattern of transported label within the central nucleus that extended rostrally into the sublenticular substantia innominata and lateral component of the bed nucleus of the stria terminalis. Label was also observed in the cortical, lateral, basolateral and basomedial amygdaloid nuclei. In contrast to the projections from the insular cortex, amino acid injections into areas 25 and 32 resulted in only relatively light labeling within the most rostral region of the central nucleus; otherwise the nucleus was partially encapsulated and virtually devoid of label. These results suggest that the insular cortex possesses the potential to directly influence the central nucleus projection to cardiovascular/autonomic regulatory nuclei of the dorsal medulla and thus, together with the amygdaloid central nucleus, appears to be an important component of a forebrain system involved in cardiovascular/autonomic regulation.

The organization of insular cortex projections to the amygdaloid central nucleus and autonomic regulatory nuclei of the dorsal medulla.

Using the fluorescent dye, double retrograde-labeling tracing technique, separate populations of insular cortex neurons were demonstrated to project to the amygdaloid central nucleus and to autonomic nuclei of the dorsal medulla. Both populations were located in layer V of the agranular and granular insula with neurons projecting to the dorsal medulla demonstrating a more medial distribution. The results yield additional detail on the organization of forebrain areas involved in autonomic regulation.

Trauma systems--state of the art.

Trauma is an inevitable consequence of the lives we lead. There are many approaches to dealing with it but an ideal system, universally applicable, probably does not exist because of the national variations in social, economic, cultural and geographical characteristics. Many countries are beginning to recognise that the 'systems' they have in place for dealing with the burden of trauma are seriously deficient and that this situation cannot be allowed to continue into the new millennium. However, it is highly unlikely that in the near future. governments will suddenly find substantial extra finance for trauma care or the implementation of new systems. Throughout many countries, the individual components of trauma care systems are in place but, for whatever reasons, there is a lack of integration, which results in suboptimal care. The system we all should be aiming for is one of closer communication and greater cooperation. By taking into account community and national needs, available resources, and adapting what is currently in place it should then be possible to create 'a set of things working together as parts of a trauma mechanism'.

Summary of skeletal identification in Tennessee: 1971-1981.

Records of 111 forensic anthropology cases from Tennessee received from September 1971 through September 1981 are analyzed. Thirty percent of the cases in which no identification existed when the skeleton arrived were positively identified and an additional "probable" identification was made in 11%. The skull or skull bones were the most common element recovered followed by femora, mandibles, and innominates, in that order. The sternum was the single major postcranial bone least likely to be recovered. January has been the single busiest month for the discovery of skeletal remains in Tennessee, and there are almost twice as many fire-related discoveries between September and February. In the first half of the decade, from 1971 through 1978, there were 39 cases with 72 cases occurring from 1977 through 1981. This increase is probably because of efforts to educate students at the University of Tennessee as well as lectures to law enforcement and citizens' groups.

ABC of emergency radiology. The ankle.

The os trigonum is a common normal variant of the talus and is due to a separate ossification centre arising from the posterior tubercle. The appearance may resemble an old ununited fracture fragment. However, it is triangular, well corticated, in a classic location, and usually bilateral, which enables it to be distinguished from a fracture. Transverse, sclerotic, linear lines located at the metaphysis of growing long bones are due to short periods of growth arrest and have no clinical importance (fig 5). They may be confused with compression fractures, but again these lines are usually bilateral. Fibrous cortical defects are the most commonly seen benign lesions of long bones and are usually identified incidentally in radiographs taken for another reason. The defect is limited to the cortex, commonly found at the metaphysis, but may be located in the diaphysis as the bone grows. The lesion is well corticated (sclerotic margins) and usually does not produce signs or symptoms.

ABC of emergency radiology. The wrist.

History including detailed mechanism of injury. Meticulous clinical examination. Appropriate radiograph and systematic assessment.