African Neuroscience: Social Responsibility and a New Sense of Community.

Africa is home to a longstanding tradition of scientific enquiry dating back to the Pharaohs. In the last century, Africa's universities were instrumental in nation building and in training expertise in many fields of scientific endeavor, including neuroscience. In 1988 IBRO, committed to neuroscience development in Africa, organized a workshop at the University of Nairobi to bring African neuroscientists together to discuss advancement of the discipline on the continent. That meeting eventually led to the launch of the Society of Neuroscientists of Africa. Since then, IBRO has continued its support for African neuroscience through several initiatives including organization of a series of high-level schools in Africa that have kept the continent's educators and researchers abreast of the latest advances and technological tools in the discipline. The rapid development of new neuroscience methodologies for the treatment and enhancement of brain function, including brain stimulation, pharmaceutical treatment of psychiatric disorders, and stem cell transplants to treat neurodegenerative diseases create research environments in which Africa's rich genetic diversity and its medicinal plant resources can play an important role. The continued support of IBRO to African neuroscience over the past 35 years has contributed effectively to laying the groundwork for a new sense of community that Africa's educators need to develop further through cooperation in defining curricula and joint research projects.

Dopaminergic control of the globus pallidus through activation of D2 receptors and its impact on the electrical activity of subthalamic nucleus and substantia nigra reticulata neurons.

The globus pallidus (GP) receives dopaminergic afferents from the pars compacta of substantia nigra and several studies suggested that dopamine exerts its action in the GP through presynaptic D2 receptors (D2Rs). However, the impact of dopamine in GP on the pallido-subthalamic and pallido-nigral neurotransmission is not known. Here, we investigated the role of dopamine, through activation of D2Rs, in the modulation of GP neuronal activity and its impact on the electrical activity of subthalamic nucleus (STN) and substantia nigra reticulata (SNr) neurons. Extracellular recordings combined with local intracerebral microinjection of drugs were done in male Sprague-Dawley rats under urethane anesthesia. We showed that dopamine, when injected locally, increased the firing rate of the majority of neurons in the GP. This increase of the firing rate was mimicked by quinpirole, a D2R agonist, and prevented by sulpiride, a D2R antagonist. In parallel, the injection of dopamine, as well as quinpirole, in the GP reduced the firing rate of majority of STN and SNr neurons. However, neither dopamine nor quinpirole changed the tonic discharge pattern of GP, STN and SNr neurons. Our results are the first to demonstrate that dopamine through activation of D2Rs located in the GP plays an important role in the modulation of GP-STN and GP-SNr neurotransmission and consequently controls STN and SNr neuronal firing. Moreover, we provide evidence that dopamine modulate the firing rate but not the pattern of GP neurons, which in turn control the firing rate, but not the pattern of STN and SNr neurons.