Elevated C-reactive protein levels in schizophrenia inpatients is associated with aggressive behavior.

BACKGROUND: An association between inflammation and behavioral domains of mental disorders is of growing interest. Recent studies reported an association between aggression and inflammation. In this study, we investigated the association between aggressive behavior and inflammatory markers in schizophrenia inpatients. METHODS: Adult schizophrenia inpatients without affective symptoms (n=213) were retrospectively identified and categorized according to their C-reactive protein measurement at admission as either elevated (CRP>1 mg/dL; n=57) or normal (CRP<1 mg/dL; n=156). The following indicators of aggression were compared: PANSS excitement component (PANSS-EC), restraints and suicidal behavior during hospitalization. Univariate comparisons between elevated and normal CRP levels were performed and multivariate analysis was conducted to control for relevant covariates. RESULTS: CRP levels significantly correlated with other laboratory markers indicating increased inflammation including leukocyte count and neutrophil to lymphocyte ratio (r=0.387, P<0.0001 and r=0.356, P<0.0001) respectively. Inpatients with elevated C-reactive protein displayed increased aggressive behavior compared to patients with normal CRP levels (<1 mg/dL). This was manifested by higher rates of restraint during hospitalization (χ(2)=5.22, P=0.031) and increased PANSS-EC score (U=5410.5, P=0.012). Elevated CRP levels were not associated with suicidal behavior. Multivariate analysis revealed that higher PANSS-EC score was associated with elevated CRP after controlling for the covariates age, sex, BMI and smoking. CONCLUSION: This study identified a potential biological correlate (inflammation) of a specific behavioral endophenotype (aggression) in schizophrenia inpatients.

Comparative properties of excitatory and inhibitory inter-laminar neocortical axons.

In recent years it has become increasingly clear that variations in voltage-gated channels, as well as highly diverse geometrical properties, shape the way axons conduct action potentials to their terminals. Numerous cell types in the mammalian neocortex form a dense network of connections, and the properties of their axons may have an effect on the processing performed by this network. We studied the conduction properties of local, inter-laminar axons emanating from regular-spiking (RS) pyramidal neurons and Martinotti type inhibitory neurons (MCs) in layer 5 of the mouse barrel neocortex by comparing the patterns of their antidromic activation from layer 1. Both types of axons had similarly slow conduction velocities ( approximately 0.3 m/s), compatible with thin unmyelinated fibers. In addition, in both types of neurons, subthreshold changes of the somatic membrane potential affected the stimulus threshold for evoking an antidromic spike in layer 1, a distance of 600-800 microm. However, the axons differed considerably in their antidromic activation profiles. 1) The antidromic latency in RS neurons was highly consistent while some MCs display considerable activation-latency jitter; 2) RS neurons displayed a steeper increase in excitability to repeated 40 Hz stimulation; 3) RS neurons displayed a sharp, step-like antidromic activation threshold to both somatic voltage and stimulus intensity, while MCs displayed a gradual recruitment pattern. Morphological differences in the branching pattern of the two types of neurons may account for some of these distinctions. These results suggest differences among excitatory and inhibitory neocortical neurons in the computational tasks of their local axons.