Organization and chemical neuroanatomy of the African elephant (Loxodonta africana) hippocampus

Elephants are thought to possess excellent long-term spatial–temporal and social memory, both memory types being at least in part hippocampus dependent. Although the hippocampus has been extensively studied in common laboratory mammalian species and humans, much less is known about comparative hippocampal neuroanatomy, and specifically that of the elephant. Moreover, the data available regarding hippocampal size of the elephant are inconsistent. The aim of the current study was to re-examine hippocampal size and provide a detailed neuroanatomical description of the hippocampus in the African elephant. In order to examine the hippocampal size the perfusion-fixed brains of three wild-caught adult male African elephants, aged 20–30 years, underwent MRI scanning. For the neuroanatomical description brain sections containing the hippocampus were stained for Nissl, myelin, calbindin, calretinin, parvalbumin and doublecortin. This study demonstrates that the elephant hippocampus is not unduly enlarged, nor specifically unusual in its internal morphology. The elephant hippocampus has a volume of 10.84 ± 0.33 cm³ and is slightly larger than the human hippocampus (10.23 cm3). Histological analysis revealed the typical trilaminated architecture of the dentate gyrus (DG) and the cornu ammonis (CA), although the molecular layer of the dentate gyrus appears to have supernumerary sublaminae compared to other mammals. The three main architectonic fields of the cornu ammonis (CA1, CA2, and CA3) could be clearly distinguished. Doublecortin immunostaining revealed the presence of adult neurogenesis in the elephant hippocampus. Thus, the elephant exhibits, for the most part, what might be considered a typically mammalian hippocampus in terms of both size and architectur

Does a Depression Intervention Result in Improved Outcomes for Patients Presenting with Physical Symptoms?

OBJECTIVE: To investigate the effects of exclusively physical presentation of depression on 1) depression management and outcomes under usual care conditions, and 2) the impact of an intervention to improve management and outcomes. DESIGN AND SETTING: Secondary analysis of a depression intervention trial in 12 community-based primary care practices. PARTICIPANTS: Two hundred adults beginning a new treatment episode for depression. MEASUREMENTS: Presenting complaint and physician depression query at index visit; antidepressant use, completion of adequate antidepressant trial, change in depressive symptoms, and physical and emotional role functioning at 6 months. MAIN RESULTS: Sixty-six percent of depressed patients presented exclusively with physical symptoms. Under usual care conditions, psychological presenters were more likely than physical presenters to complete an adequate trial of antidepressant treatment but experienced equivalent improvements in depressive severity and role functioning. In patients presenting exclusively with physical symptoms, the intervention significantly improved physician query (40.8% vs 18.0%;P = .06), receipt of any antidepressant (63.0% vs 20.1%; P = .001), and an adequate antidepressant trial (34.9% vs 5.9%; P = .004), but did not significantly improve depression severity or role functioning. In patients presenting with psychological symptoms, the intervention significantly improved receipt of any antidepressant (79.9% vs 38.0%; P = .01) and an adequate anti(40.8% vs 18.0%;P = .06), receipt of any antidepressant and an adequate antidepressant trial (34.9% vs 5.9%; P = .004), and also improved depression severity and emotional role functioning. CONCLUSIONS: Our results suggest that there is a differential intervention effect by presentation style at the index visit. Thus, current interventions should be targeted at psychological presenters and new approaches should be developed for physical presenters