Biology and memory Explain how biological factors may affect one cognitive process
What biological factors affect memory? • Brainstorm • Adrenaline and memory http://www.youtube.com/watch?v=JuCMRhT15uQ
Some basics first • Read Crane 76 to 79. • Discuss how neural connections are made. • What is lesioning? Identify a study which involved ‘lesioning’. Comment on any ethical issues. • Review structure of LTM • Why would emotional experiences be remembered longer? • Review Clive Wearing. • Research Kendel- who was he; how did he research memory?
Localization of Function: Memory & the Brain • Memory is the job of the brain • Science is continually exploring the way memory is organized in the brain • But there are still many mysteries about the biological correlates of memory. • Cognitive psychologists and neuroscientists work together to find out about the brain structures involved in memory
Some biological factors in memory • It is not yet possible to have a full picture of the complexity of the biological foundations of memory, but brain research has provided some major insights into the nature of memory. • Kandel’s (2000) research with snails shows that learning, means formation of a memory – that is growing new connections or strengthening existing connections
Eric Kendel is a neuroscientist who won the Nobel Prize in 2000. • He studies learning and memory at a cellular level in the sea snail aplysia, a very simple organism. • He found that STM as well as LTM result in synaptic changes in the neural networks of these sea snails • The snails memory is located in the synapses, and he observed that changes in these synapses are important in memory formation. • Kendel also studied memory functioning in relation to synaptic changes in the brain structure called the hippocampus
Obviously, scientists cannot to this to humans, so researches study people who already have brain damage • Such research suggests that STM and LTM are distinct separate stores of memory (supporting the MSM) • They also suggest that LTM must consist of several stores of memory. • Damage to different parts of the brain affects factual knowledge, or knowledge for example of how to drive a car
The structure of LTM • At the first level, LTM is divided into two systems – the first is explicit, this consists of fact based information that can be consciously retrieved. This type of memory focuses on ‘knowing what’ • Explicit memory is divided into two subsystems – the first is semantic memory, which is a memory for general knowledge - e.g. Mick Jagger is a signer in the Rolling Stones • Episodic memory is the memory of personal experiences and events – e.g. I saw Mick Jagger last year in New York.
The Second unit of LTM is implicit memory, which contains memories which we are not consciously aware of. • Implicit memory contains memories we are not consciously aware of, one of these is procedural memory, which is the non conscious memory for skills, habits and actions – “knowing how”. • Implicit memory also includes emotional memory, which is not fully understood. • It seems that emotional memories are formed via the limbic system and they may persist even when brain damage has destroyed other memories.
Researchers such as Kendel have pointed out the very important role of the hippocampus in the formation of explicit memories • Case studies of people with hippocampal damage have shown that they can no longer form new explicit memories, but apparently they can form new implicit memories • There is evidence that the amygdala plays a role in the storage of implicit emotional memories, perhaps because emotions are used evaluate experience.
Hippocampus • Involved in the processing and storage of memories.
Amygdala • Involved in how we process memory. • More involved in volatile emotions like anger. The emotion of anger has not changed much throughout evolution.
Le Doux found that certain memories based on emotional events are remembered better. • This may be why people suffering from PTSD (Post Traumatic Stress Disorder) have problems forgetting, because emotional memories are quite difficult to get rid of. • Researchers are beginning to find out how the brain regulates emotional expressions, and they have observed that when part of the prefrontal cortex is damaged, emotional memory is very hard to eliminate, and it is difficult to control emotional outbursts.
Some definitions…. • Amnesia can be defined as the ‘inability to learn new information or retrieve information that has already been stored in memory.’ • Neuroscientists distinguish between two key types of amnesia • Anterograde amnesia is the failure to store memories after a trauma • Retrograde amnesia is the failure to recall memories that have been stored before the trauma. • Amnesia can be caused by brain injury or infection. In the case of prolonged misuse of alcohol, a special sort of amnesia called Korsakoff’s syndrome may result.
Clive Wearing: How brain damage affects memory processing • Can you imagine what it would be like if you were caught in the present and unable to remember anything from your past or to learn anything new? • What if you were lost in time, with no sense of the past or future? • This is exactly what happed to Clive Wearing- Oliver Sacks (1997) documented his case (see article)
Clive Wearing suffers from the most extensive amnesia ever seen. • He suffers from both anterograde and retrograde amnesia. • The transcript of his diary gives a heartbreaking insight into what its like to lose ones memory. • MRI scanning of Clive Wearing’s brain shows damage to the hippocampus and some of the frontal regions. • This indicates that retrograde amnesia could be explained as ‘trauma that can disrupt the consolidation of memory’. • The case of Clive Wearing offers insight into the biological foundation of different memory systems. Wearing’s episodic memory and some semantic memory is lost. He cannot transfer new information to long term memory either.
Clive Wearing can still play the piano and conduct the music he knew before his illness. These skills are part of his implicit memory. • The fact that he can do this is evidence of a distributed memory system, since implicit memory is linked to a brain structure other than the hippocampus. • His emotional memory is also intact, which is clearly demonstrated in the affection he constantly shows for his wife • Normally, we do not know the identity of most participants in case studies. Researchers are obliged to keep personal information confidential. However, in the case of Clive Wearing is different because his wife has decided to come forward with his story.
Ethics in case study research • HM and Clive Wearing are famous case studies in cognitive psychology. HM has been studies extensively with all kinds of tests, ever since his operation in 1953. He has even donated his brain to science when he dies. We do not know his identity. Clive Wearings identity is known to us due to his wife's book. 1) discuss why participants in case studies are normally anonymous 2) discuss the ethical considerations in studying an individual with an interesting disorders or brain damage, such as HM and Clive Wearing 3) Crane 79
Animals in memory research • Typically, animals learn to perform a specific task, for example running through a maze – and a memory is formed. • To find out what areas of the brain are involved in such a task, researchers cut away brain tissue and the animal has to run through the maze again. • This procedure, called lesioning, is repeated a number of times until the animal can no longer perform the task – allowing researchers to connect structure with function (Lashley did this type of research)
Focus on the LO • Draw specific conclusions about how biological factors may affect one cognitive process. • Focus on memory. • Refer to localization of function. • Use specific evidence from the casestudy of HM and Clive Wearing. • Look at model answers in revision e-book on review docs page on blog- pages 43-46 • Resource for test