Spontaneous spatial navigation circuitry in schizophrenia spectrum disorders

Ketamine as a pharmacological tool for the preclinical study of memory deficit in schizophrenia

Schizophrenia is a serious neuropsychiatric disorder characterized by the presence of positive symptoms (hallucinations, delusions, and disorganization of thought and language), negative symptoms (abulia, alogia, and affective flattening), and cognitive impairment (attention deficit, impaired declarative memory, and deficits in social cognition). Dopaminergic hyperactivity seems to explain the positive symptoms, but it does not completely clarify the appearance of negative and cognitive clinical manifestations. Preclinical data have demonstrated that acute and subchronic treatment with NMDA receptor antagonists such as ketamine (KET) represents a useful model that resembles the schizophrenia symptomatology, including cognitive impairment. This latter has been explained as a hypofunction of NMDA receptors located on the GABA parvalbumin-positive interneurons (near to the cortical pyramidal cells), thus generating an imbalance between the inhibitory and excitatory activity in the corticomesolimbic circuits. The use of behavioral models to explore alterations in different domains of memory is vital to learn more about the neurobiological changes that underlie schizophrenia. Thus, to better understand the neurophysiological mechanisms involved in cognitive impairment related to schizophrenia, the purpose of this review is to analyze the most recent findings regarding the effect of KET administration on these processes.

A geographical exploration of environmental and land use characteristics of suicide in the greater Toronto area

In developed countries, suicide has become one of the leading causes of mortality. With approximately 3500 cases taking place in Canada annually, it is currently the seventh-most common cause of death. A clearer spatial understanding of the suicide landscape in rapidly changing urban environments would especially help mitigate this problem. This study examines suicide rates in Toronto between 2004 and 2011 as to understand the spatial distribution of suicide by means of the importance of metropolitan places. The study uses geocomputation and statistical methods, enabling spatial analysis as tools to further assess the prevalent gender disparities of self-harm, advancing the current findings in the suicide literature. The findings clearly expose that the dichotomy of gender (male and female) produce different spatial patterns of self-harm, and are impacted by landscape characteristics differently. Specifically, the configuration of different land cover types have a much great impact on the female population than male. This spatial-exploratory understanding of not only the geographical distribution of rates, but also an assessment of landscape influence can help to mitigate suicide depending on demographic and spatial-explicit characteristics found through advanced geostatistical and spatial analytical modeling.