Discuss the interaction between cognition and physiology in terms of behavior
•Introduction: cognition, physiology, relation
•Amnesia: retrograde, anterograde
•Memory: multi-store, division, *amnesic patients, ways of distinguishing types of memory (KC, spiers maguire and burgess, vargha and khadem)
•Conclusion: cognition, physiology
Cognition, as defined by Neisser, is all the processes by which the brain transforms, reduces, elaborates, stores, retrieves, and uses information. Physiology refers to the structures of the human body and brain. The relationship between cognition and physiology is bi-directional, meaning that cognition can effect physiology and vice versa. Every cognitive aspect can be localized to a specific structure in the brain. This close interaction can have an effect on behavior. This essay will study ‘memory’ as the cognition, and ‘amnesia’ as the behavior.
Amnesia, simply put, is a loss of memory. There are two types of amnesia: retrograde, where information acquired before the onset of amnesia is forgotten, but new memories can be made, and anterograde, where information acquired after the onset of amnesia is forgotten, making the patient unable to form new memories.
Memory is defined by ‘Baddeley’ as an active system which receives information from the senses, organizes and alters it, and stores it away, and then retrieves the information from storage. A model called the ‘multi-store model’ by Atkinson and Shiffrin states that there are 2 stores of memory: short term (STM), and long term (LTM). Information is received by the sensory unit, and then sent to the STM. after this information is rehearsed, it is sent to the LTM. The researchers describe these 2 stores as ‘unitary stores’, which differ in terms of capacity, duration, and encoding. The fact that the stores are ‘unitary’ was refuted by later studies.
Later studies of memory prove that the LTM can be divided into 2: explicit, and implicit. Explicit refers to the memories that one can declare, and implicit refers to the memories that are more underlying, like the memories of how to ride a bike. These two stores and further divided. Explicit memory contains episodic (events) and semantic (facts). implicit contains procedural (skills) and emotional (emotions). For amnesic patients, the problem lies mostly with explicit memory.
There are three main ways to study the differences between the types of memories. The first is the study of anterograde amnesic patients. For example, the study done by Spiers, Maguire and Burgess. They studied 147 cases of anterograde amnesia with damage to the hippocampus. psychological testing proved that all cases had impaired episodic memory and limitedly impaired semantic. This shows that the hippocampus is responsible for episodic memory. To make the conclusion more reliable, another study was done by Vargha and Khadem, with 3 anterograde amnesic patients, and found the same results, except that the semantic memory was completely intact. They found that semantic memory was localized to the cortices underlying the hippocampus.
Another way of studying the differences between the two is by studying retrograde amnesic patients. a retrograde amnesic patient known as KC was studied to find that the damage to his hippocampus impaired his episodic memory, but his semantic memory was still intact. The study of amnesic patients is done in psychology to study the relations between the physiology and cognition, because the damage to the brain can be seen easily, and it’s effects on cognition can also be studied.
The third way of distinguishing would be the use of neuro-imaging. Studies using neuro-imaging have concluded that emotional memory relates to the amygdala in the brain, and procedural locates at the striatum and cerebellum.
Moving on to a specific study, one was done on a man known as HM. At the age of 9, HM started having uncontrollable epileptic seizures that couldn’t be controlled by medication at the time. At the age of 27, the doctors removed his medial temporal lobe, to control his seizures. The surgery was successful, but after the surgery, HM suffered anterograde and partial retrograde amnesia.
He had a loss of episodic memory, and a limited impairment with semantic and emotional. The medial temporal lobe contained the hippocampus, and some of the cortices underlying it, as well as part of the amygdala. The doctor, John Harlow concluded that the specific types of memory located to the specific structures in the brain that were removed. This method of research, the case study, was ethical because they kept his identity from the media and referred to him as HM.
One of the worst recorded cases of amnesia was that of Clive Wearing. He was a pianist and a conductor, and he developed ‘herpes encephalitis’, a brain infection that affected his temporal lobe. He was left with both retrograde and anterograde amnesia. His episodic memory was impaired as well as part of him emotional memory. His procedural memory stayed intact, he could still remember how to play the piano. His name was released into the media only because his wife allowed the researchers to do so, which abides by the ethical consideration of taking consent from one’s caretaker in case of not being able to take consent from the participant himself.
The studies showed both the causes and effects of the behavior: amnesia. Since the studies were case studies, they were unique in nature, which gave the researchers a way of understanding the distinction between the types of memories. A disadvantage is that case studies cannot be replicated. The studies, being completely of reality, had high ecological validity.
To conclude, in terms of amnesia, it is evident that damage to a specific brain structure can have an effect of the cognitive aspects, which overall has an effect on behavior.