Prey-dependent effects of fluprazine hydrochloride on predatory aggression in northern grasshopper mice (Onychomys leucogaster) and rats (Rattus norvegicus)

Treatment with the phenylpiperazine DU 27716 (fluprazine hydrochloride) inhibited the predatory killing of albino mice by northern grasshopper mice (Onychomys leucogaster) and of frogs by rats. This treatment had no effect on cricket predation by grasshopper mice or worm predation by rats. The prey-specific effect of fluprazine did not seem to result from a decreased tendency to attack nor was its effect restricted to prey showing characteristic rodent defensive responses. Rather, the drug seemed to increase fearfulness when the prey exhibited vigorous defensive behavior. It is possible that increased fearfulness induced by treatment with this drug may also contribute to its antioffensive effect during conspecific encounters.     

Semantic ambiguity and the failure of inhibition hypothesis as an explanation for reading errors in deep dyslexia

We report evidence for dissociation between explicit and implicit access to word representations in a deep dyslexic patient (JO). JO read aloud a series of ambiguous (e.g., bank) and unambiguous (e.g., food) words and performed a lexical decision task using these same items. When required to explicitly access the items (i.e., naming), JO showed relative impairment for ambiguous compared with unambiguous words. In contrast, the same stimuli produced an advantage for ambiguous words in lexical decision. The results are discussed within a framework of deep dyslexia that considers errors in production to arise through a failure to inhibit spuriously activated candidate representations.     

Attention and executive functioning profiles in children following perinatal arterial ischemic stroke

Perinatal arterial ischemic stroke (PAIS) is a form of childhood stroke; the majority of those affected experience neurologic sequelae, including motor, language and neurocognitive impairments. This study examines the attention and executive functioning (EF) profiles of children following PAIS, as well as the impact of age and sex. In this single-center cross-sectional study, 40 children aged 3 to 16 years (median age 7.2 years; 58% male) who have suffered a PAIS underwent a comprehensive neuropsychological battery to assess attention and EF. Parents completed behavioral questionnaires regarding real-world functioning. Composite scores were calculated for seven attention and EF domains (Attention, Working Memory, Verbal Retrieval, Inhibitory Control, Flexibility/Shifting, Planning/Organization, and Processing Speed). The results for all measured domains of attention and EF are significantly lower in the participants compared to the normative samples (p < .001), with the exception of Working Memory. However, increasing difficulty with Working Memory is associated with developing age. Older age at time of testing is also associated with a higher incidence of clinically-elevated attention deficit hyperactivity disorder (ADHD) symptoms. Sex is not associated with performance measures or parental report of functioning. The participants demonstrate mild-to-moderate attention and EF impairment compared to the normative population. Clinicians, families, and educators should be informed about the neurocognitive sequelae of PAIS and the need for close developmental surveillance in this population to identify vulnerable children and initiate appropriate therapeutic interventions in a timely fashion.