Head injury depth as an indicator of causes and mechanisms.

OBJECTIVE: The goal was to measure differences in the causes, mechanisms, acute clinical presentations, injuries, and outcomes of children <36 months of age with varying "greatest depths" of acute cranial injury. METHODS: Children <36 months of age who were hospitalized with acute head trauma were recruited at multiple sites. Clinical and imaging data were collected, and caregivers underwent scripted interviews. Neurodevelopmental evaluations were completed 6 months after injury. Head trauma causes were categorized independently, and subject groups with varying greatest depths of injury were compared. RESULTS: Fifty-four subjects were enrolled at 9 sites. Twenty-seven subjects underwent follow-up neurodevelopmental assessments 6 months after injury. Greatest depth of visible injury was categorized as scalp, skull, or epidural for 20 subjects, subarachnoid or subdural for 13, cortical for 10, and subcortical for 11. Compared with subjects with more-superficial injuries, subjects with subcortical injuries more frequently had been abused (odds ratio [OR]: 35.6; P < .001), more frequently demonstrated inertial injuries (P < .001), more frequently manifested acute respiratory (OR: 43.9; P < .001) and/or circulatory (OR: 60.0; P < .001) compromise, acute encephalopathy (OR: 28.5; P = .003), prolonged impairments of consciousness (OR: 8.4; P = .002), interhemispheric subdural hemorrhage (OR: 10.1; P = .019), and bilateral brain hypoxia, ischemia, or swelling (OR: 241.6; P < .001), and had lower Mental Developmental Index (P = .006) and Gross Motor Quotient (P < .001) scores 6 months after injury. CONCLUSION: For children <3 years of age, head injury depth is a useful indicator of injury causes and mechanisms.

Meadow voles, Microtus pennsylvanicus, have the capacity to recall the "what", "where", and "when" of a single past event.

Some non-human animals may possess the ability to recall the "what", "where", and "when" of a single past event. We tested the hypothesis that male meadow voles possess the capacity to recall the "what", "where", and "when" of a single past event associated with mate selection in two experiments. Briefly, male voles were allowed to explore an apparatus that contained two chambers. One chamber contained a day-20 pregnant female (24 h prepartum). The other chamber contained a sexually mature female that was neither pregnant nor lactating (REF female). Twenty-four hour after the exposure, the males were placed in the same apparatus, which was empty and clean. At this time, the pregnant female would have entered postpartum estrus (PPE), a period of heightened sexual receptivity. Males initially chose and spent significantly more time investigating the chamber that originally housed the pregnant female (now a PPE female) than the chamber that originally housed the REF female. Male voles also explored an apparatus containing a chamber with a PPE female and one chamber containing a REF female. Twenty-four hour later, males were placed into an empty and clean apparatus. The males did not display an initial choice and they spent similar amounts of time investigating the chamber that originally housed the PPE female (now a lactating female) and the chamber that originally housed the REF female. The results of these and additional experiments suggest that male voles may have the capacity to recall the "what", "where", and "when" of a single past event, which may allow males to remember the location of females who would currently be in heightened states of sexual receptivity.