Pankaj Sah

BIOGRAPHY

ACADEMIC POSITIONS:
• Professor and Head of Synaptic Plasticity
• Deputy Director, Queensland Brain Institute

QUALIFICATIONS:
BSc, MBBS, PhD

RESEARCH INTERESTS:
One project in our group is involved with examining the properties of cells in the input side of the amygdala. We have shown that cells within the lateral and basal nuclei can be divided into two broad categories: pyramidal cells and interneurones. Pyramidal cells form the major type of cell (93%) and are similar to excitatory cells found throughout the cortex. The remaining cells (7%) are interneurons which are inhibitory and form extensive connections with the excitatory cells in the amygdala. Surprisingly we found that the properties of synaptic inputs on to interneurons were quite different from those on to pyramidal cells. These findings indicate that the modulation of inhibitory pathways may be an important control mechanism within the amygdala. We are now examining the properties of these neurons using a combination of electrophysiological and imaging techniques.

Another project is studying the output side of the amygdala – the central nucleus. This structure is divided into two main parts, the medial and lateral. It has recently been shown that cells in the lateral division are inhibitory and make local circuits while cells in the medial division project out of the amygdala. We have been examining the effects of a class of drugs called benzodiazepines (e.g. diazepam or valium). These drugs are widely used as anxiolytics and their role in the amygdala is of great interest. These drugs are thought to work by potentiating the actions of the major inhibitory transmitter in the brain, gamma amino butyric acid (GABA). We have found that the central nucleus also contains a second type of GABA receptor which is inhibited by benzodiazepines. This finding may have therapeutic implications as a potential target for new classes of drugs.

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