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Jeniffer Jeykumar, F1000Research, discusses memory and highlights a few articles published on F1000Research looking into the processes involved and what we can do to improve our working memory.

Memory is something which we all rely on, often without thinking much about the specifics, and how we’re able to store, process and retrieve information on a daily basis. There are many forms of memory, which can broadly be categorized into either short or long term – one form of long-term memory is associative memory. This type of memory helps us learn and remember the connections between objects and the environment using our five basic senses.

The information from the senses comes together to help you process this data into something as simple as recognizing an orange, for example. As Jin-Hui Wang et al.’s paper explains ‘..an orange is detected by the olfactory system for aromatic odour, the visual system for shape and colour..’.  This review looks in detail at the processes likely to be involved in associative memory, although quite a few mechanisms still remain unknown.

From what is known, it is likely that synaptic and neuronal plasticity is involved. The ability of neurons to fire action potentials at a lower threshold, combined with firing at a higher frequency, allows the associative memory cells to encode signals from different groups of cells. This converges the signals from the sensory cortices to help us understand what something is. Other areas of the brain are also involved, especially the regions relating to emotion and behavior.

This is apparent when we remember a past event and can recall how we felt at the time. These secondary cells form synapses with the primary associative cells within the sensory cortices. This allows signals from both cells to be activated together to form an association.

Research into this area needs to expand especially as one potential link could be to Schizophrenia. Dr Wang goes onto briefly discuss that if the associative memory cells are over-activated this could lead to hallucinations, which is a common symptom seen in patients with Schizophrenia.

Regions linking working memory and Schizophrenia

Some researchers such as Dr Chatterjee and colleagues at the University of Delhi have already started to investigate a similar connection. They used machine learning, which uses algorithms to analyse data, combined with fMRI to identify regions within the brain that are responsible for impaired working memory in people with Schizophrenia and those without.

In the dataset the authors used, the participants were given a task which used their working memory, as this is another type of memory that is largely known to be impaired in schizophrenic patients. Working memory, in contrast to associative memory, is a short-term memory store that we use every day when carrying out tasks such as reading and mathematics.

The participants were shown a series of digits to remember, and then had to identify whether the proceeding digits were in the former set. The cerebellum, amygdala, the insula, the Heschl and the vermian were among the various regions that were shown to be affected within people with Schizophrenia compared to healthy individuals. These areas are known to be involved in working memory and within schizophrenia they are known as areas responsible for worsening working memory.

Improving working memory

Working memory is also studied through other methods for example Fiona Pugin et al’s article on whether working memory can be improved. Their study involved training male students using visuospatial tasks and auditory tasks over the course of three weeks. During the visuospatial task, the participants had to indicate when a blue square was in the same position as it was shown to be at the beginning of the task on the computer screen. The auditory task was similar, however instead of a blue square, spoken letters were used.  

The cognitive performance of these students increased not only in the short term but also a few months later when they were tested again. This leads to potential benefits in your everyday life such as remembering where you parked your car.

This study and others which have focused on improving other forms of memory, such as associative memory, can be used to look into the potential benefits this can have within patients with Schizophrenia. This in turn could help us grow our understanding of these disorders and give us further options to help manage them.