Neuropathology of substance use disorders

Addictions to licit and illicit drugs are chronic relapsing brain disorders that affect circuits that regulate reward, motivation, memory, and decision-making. Drug-induced pathological changes in these brain regions are associated with characteristic enduring behaviors that continue despite adverse biopsychosocial consequences. Repeated exposure to these substances leads to egocentric behaviors that focus on obtaining the drug by any means and on taking the drug under adverse psychosocial and medical conditions. Addiction also includes craving for the substances and, in some cases, involvement in risky behaviors that can cause death. These patterns of behaviors are associated with specific cognitive disturbances and neuroimaging evidence for brain dysfunctions in a diverse population of drug addicts. Postmortem studies have also revealed significant biochemical and/or structural abnormalities in some addicted individuals. The present review provides a summary of the evidence that has accumulated over the past few years to implicate brain dysfunctions in the varied manifestations of drug addiction. We thus review data on cerebrovascular alterations, brain structural abnormalities, and postmortem studies of patients who abuse cannabis, cocaine, amphetamines, heroin, and “bath salts”. We also discuss potential molecular, biochemical, and cellular bases for the varied clinical presentations of these patients. Elucidation of the biological bases of addiction will help to develop better therapeutic approaches to these patient populations.     

Politique et délire

The medico-philosophical study of relations between the physical and moral aspects of man developed during a period marked by major revolutionary movements from the end of the XVIIIth century to the middle of the XIXth century. The authors who published texts on delirious forms recognized as such were often influenced by the dramatic episodes of these revolutions. In Pinel's texts, there are several observations of the insane for who the delusions are directly related to political events both in content as well as in genesis. On the contrary, some of the texts of Esquirol and his students tend to indicate that revolutionary convulsions are themselves the result of a kind of collective folly and that it is participation in these movements that constitutes individual mental insanity. The idea of “to be Napoleon” spreads around during the Monarchie de Juillet following the return of the Emperor's ashes; the popular success of this ceremony had transformed the real person into a myth to which the delirious megalomaniac could identify.     

Cortical inputs innervate calbindin‐immunoreactive interneurons of the rat basolateral amygdaloid complex

The present study was undertaken to shed light on the synaptic organization of the rat basolateral amygdala (BLA). The BLA contains multiple types of GABAergic interneurons that are differentially connected with extrinsic afferents and other BLA cells. Previously, it was reported that parvalbumin immunoreactive (PV⁺) interneurons receive strong excitatory inputs from principal BLA cells but very few cortical inputs, implying a prevalent role in feedback inhibition. However, because prior physiological studies indicate that cortical afferents do trigger feedforward inhibition in principal cells, the present study aimed to determine whether a numerically important subtype of interneurons, expressing calbindin (CB⁺), receives cortical inputs. Rats received injections of the anterograde tracer Phaseolus vulgaris‐leucoagglutinin (PHAL) in the perirhinal cortex or adjacent temporal neocortex. Light and electron microscopic observations of the relations between cortical inputs and BLA neurons were performed in the lateral (LA) and basolateral (BL) nuclei. Irrespective of the injection site (perirhinal or temporal neocortex) and target nucleus (LA or BL), ～90% of cortical axon terminals formed asymmetric synapses with dendritic spines of principal BLA neurons, while 10% contacted the dendritic shafts of presumed interneurons, half of which were CB⁺. Given the previously reported pattern of CB coexpression among GABAergic interneurons of the BLA, these results suggest that a subset of PV‐immunonegative cells that express CB, most likely the somatostatin‐positive interneurons, are important mediators of cortically evoked feedforward inhibition in the BLA. J. Comp. Neurol. 522:1915–1928, 2014. © 2013 Wiley Periodicals, Inc.