A Maynooth researcher is studying structures in the brain as a way of understanding how memory and learning work, writes Dick Ahlstrom
Memory and the ability to learn are fundamental activities of the brain, but these processes remain full of mystery. A researcher at NUI Maynooth is hoping to shed light on the subject by studying the physiology of how memory works.
Dr Sean Commins, a lecturer in the department of psychology at Maynooth, was recently awarded a three-year Health Research Board grant to study the neurophysiologal and neuroanatomical properties of the regions of the brain associated with memory and learning. His work focuses on several key components of the brain, including the hippocampus, which sits at its base; the subiculum, the major output structure of the hippocampus; and the cortex, the thinking part of the brain.
The hippocampus is an important structure known to be critically involved in memory formation, says Commins. Information is stored in the hippocampus for a short time before being transferred to a more permanent store in the cortex.
"Certainly the hippocampus is involved in certain types of memory," says Commins. It is known to be linked to spatial memory and also to "declarative memory", or the retention of factual information.
The subiculum channels information away from the hippocampus and is considered an important area in the initial process of consolidation of long-term memory.
"We believe that information is stored in the hippocampus for a short time and must then be consolidated when it moves from the hippocampus," says Commins.
Currently, there is little or no anatomical information about how information is passed from the subiculum to the cortex and its structures, explains Commins. It is unclear what route it follows and whether any pathways are topographically organised.
The connections between structures are made by "projections", axons or nerve fibres that link cells. The first part of the new study will look at the neuroanatomy of the projections from the subiculum to the cortex. Intense study of the subicular projections should provide answers to the nature of information processing through brain regions involved in learning and memory.
The next step is to investigate what takes place during the consolidation of memories. "There have to be some sort of changes for the consolidation to take place, and this is the second part of the project," Commins states.
This part of the work will involve examining the electrophysiological properties of the projections that link hippocampus to cortex. Theories of learning and memory suggest that the connections between the hippocampus and the cortex undergo use- dependent changes in the synapses. A synapse is the junction across which a nerve impulse passes as it travels from the end of an axon to the next nerve cell.
The changes are permanent, enabling a memory to be retained. The nature of such changes are embodied in a process called "long-term potentiation". The project will examine whether the projections linking brain structures show signs of synaptic changes. Both parts of the project will rely on studies of rat brains and how they retain memories.
The study has practical relevance because the hippocampus is affected in diseases such as Alzheimer's and epilepsy. "The hippocampus is one of the primary areas destroyed in Alzheimer's," says Commins, while epilepsy is initially localised in the hippocampus.