Brain Injury And Memory Loss
Memory is the process of drawing past experiences to use this information in the present (Sternberg, 1999) Unknowingly or knowingly, it plays a massive role in our life. Firstly, lets shed some light on the parietal lobe (PL) located in the back of the mind, also known as the primary sensory area, because its prime role is to manage our five senses. Moreover helps us interpret visual information and process language and mathematics. Previously, it was found that the Bilateral parietal lobe (BPL) damage affects the visual working memory (WM) in a way that the patient does not suffer total memory retrieval deficits, rather selective deficits that were observed only in old/new recognition tasks. In light of these findings, we could infer particular interpretations. The post parietal cortex (PPC) may have a purpose related to old/new recognition tasks.
A possible reason why there must exist recall/recognition detachment must be due to the use of definite maintenance strategies (planning, scheduling ). However, these findings could not be generalized since the patients were older and could be going through growing illness or brain restructuring post-injury. A recent study aimed to test whether the previous findings would apply to a healthy average population if transcranial direct current stimulation (tDCS) applied to the right inferior parietal cortex. A procedure by which low current is applied to the scalp and used to check structure-function relationships. The results revealed that cathodal stimulation led to WM impairment on recognition tasks and that previous results were due to the odd age group or brain restructuring post-injury. One problem this particular study faced was limited spatial specificity. Past lesion studies signify that the superior parietal cortex is vital for the executive rearrangement of information in the WM. While the prefrontal cortex has been known for decades as the de facto ‘seat’ of executive function, documented neurological patient results indicate the PPC’s prominent role in the mental manipulation of knowledge in WM. A recent study stressed on the fact that the left angular gyrus (AG), a region in the PL responsible for attention, memory retrieval, and spatial cognition, plays a crucial role in familiarity and subjectively perceived memory confidence as well. In addition to this, lesions in the BPL interfere with the episodic memory (EM) or recalling intricate details of autobiographical events. Therefore, Patients display lower confidence in recollection.
Similarly, the temporal lobe (TL), otherwise known as the primary auditory cortex, located just behind the ears, contributes to the EM as well. Patients who have undergone temporal lobectomy (a procedure involving the removal of parts of the brain where seizures are recurrent) performed both short term and long term memory tasks (STM and LTM). The results indicate active involvement of the medial temporal lobe (MTL) in object- location binding, STM, and LTM. Furthermore, the MTL framework serves both EM and possible episodic thinking. The hippocampus is a small curved structure in the MTL, which is responsible for the emergence of new memories and emotions. Heur and Bachevalier (2011) used monkeys as their subject and induced them with bilateral hippocampal lesions and tested them on tasks. Results indicated a selective deficit in the self-ordered WM task. Heur and bachevalier (2013) evaluated the performance of the same monkeys and discovered that deficiencies could lead to abnormalities in prefrontal hippocampal interactions. However, inducing innocent neonatal monkeys with hippocampal lesions goes against the ethical guidelines. Human hippocampal atrophy patients obtained similar results. They faced impairment in WM tasks as well but only on blocks of trials with intermediate memory load.