There exists such a large spectrum of research directions and possibilities when it comes to discovering new secrets about the brain. One of the leading areas of todays focus lies in the hippocampus. Still very little is understood with what all the hippocampus performs and how it does so. We seem to have a general idea of the many functions maintained by the hippocampus, but the how and why of each mechanism within the workings of the hippocampus is very much a mystery and remain distant from our vision. Current research is trying to shed some light on many of them questions while in the process bringing up new possibilities and new questions. We could not even come close to describing all the areas of research out there today, but perhaps we can touch upon some of the leading and most exciting areas in the field.
Learning and Memory
Some research has been done on investigating the neuronal basis of learning and memory. This research focuses on how cells change and adapt to provide for us the basis or remembering and storing retrievable information. There are many different experiences and situations that play a role in manipulating change in cellular function. How do certain changes, whether they occur in early life or in adult life, alter the function of memory storage and retrieval? There are potentially an infinite number of ways for neurons to change in function, yet for the majority of us memory processes stay intact and fully functional.
Research being done by scientists at the MRC C0-Operative on Neural Plasticity, learning and Memory are testing the hypothesis that LTP, a lasting alteration of cell communication strength between neurons and the basis for learning, by examining the learning-induced plasticity and sensory experience-dependent plasticity. The research includes the behavioral training of rats to perform tasks and electrophysiological techniques to assess synaptic malleability. By doing so they hope to reach a better understanding of not only the different brain regions that add to learning and the mechanisms behind each regions function, but also the hope is to understand the communication and networking between regions that produce the fully functional mechanism. A clearer understanding could reap huge benefits and potentially lead towards understanding the mechanisms behind Alzheimer’s disease and possible treatment and therapies to the disease.
Other researchers at MIT are taking a close look at how sensory experiences affect the brain through modification of the synapses between neurons. Based upon the Hebbian principle, synaptic strength between neurons are strengthened or weakened depending on the association made between the neurons. These researchers are looking at exactly how synapses in the cortex are altered by each experience. There seem to be certain areas in the brain that have selectivity towards specific types of signal inputs. By manipulating and viewing these certain regions, detectable changes in the synaptic interaction can be noted within hours. These experience dependent shifts in selectivity and function are the best representation of memory formation and storage.
Along the same lines with Alzheimer’s research, there has been done a lot of work done to take a look at the different proteins and peptides and how they affect long term potentiation and Long Term Depression by the different functions they serve in intra and intercellular communication.
An interesting project is underway that attempts to look at the very cellular mechanism in opiate addiction. The research is looking at how mechanisms as small as a single neuron and even a single ion channel affect the system and function of certain memory processes. The study is being done by genetically mutating rats, manipulating opiate intake and taking recordings from brain slices in the hopes of generating and understanding opioid desensitization and the cellular potentiation process involved.
For the behaviorists out there, or anyone interested in the biological aspects of fear, recent work done by scientists at UCLA have investigated cellular and molecular mechanisms in the learned acquisition and extinction of Pavlovian fear conditioning. The paper states that fear responses are necessary protections taken from environmental threats, but the paper says is not necessarily adaptive. An organism does not forget their fear or any learned processes, it must be reconditioned through extinction processes. Using previous studies done showing how rats and the use of a CS, such as a tone and its pairing/nonparing with an aversive US, they continue with the idea that extinction is simply a learned inhibition of the expression of a certain learned behavior that can spontaneously return with only one cue. This shows that the memory remains over time. The scientists hope to understand more of this process looking at the cellular and molecular aspects of the procedure. The paper states that previous studies implicate the amygdala as an important structure involved, however the hope is to learn what neurotransmitters and second messenger systems play a role in the extinction of fear processes. It is hypothesized that that some of the cellular and molecular mechanisms involved with LTP should be similar and even share processes with inhibitory learning. The relationship between should provide key insights into the functioning of these types of learning and the regions they exist. The experiment designed hoped to uncover these relationships. One finding was that, unlike most forms of learning, extinction is efficient with temporal training rather than spaced training, also they found that length of exposure was a major factor in extinction learning. The total amount of extinction acquired was shown to be the net outcome of these two opposing processes. Future work will be looking more of the neuropharmacoligcal aspects of the process by injecting chemical agents directly into the amygdala and prefrontal cortex to look at the narcotics effects on the system. Eventually brain slices will be taken to view what cellular changes occurred in the extinction processes. The end goal is to obtain a better understanding of the process in order to find better treatments of different anxiety disorders and psychotherapy practices.