Neural Pathways to
Long term memory
Presented by: Gerald Lai, Scott Nisbitt, Ed Fong, Phat Ha

What is procedural memory?

Procedural memory is memory storage of skills and procedures. This type of memory has also been referred to as “tacit knowledge” or “implicit knowledge”. Procedural memory is involved in tasks such as remembering how to play handball or how to ride a bike. This is “know how” memory, it often can only be expressed by performing the specific skill and people have problems verbalizing what they are doing and why. Procedural memory is therefore very important in human motor performance.

What physical pathway of the brain is procedural memory associated with?

Procedural memory has been broken down into three separate groups; conditioned reflexes, emotional associations, and skills and habits. Each of these memories are associated to probable anatomical structures in the brain. Memories and learning of conditioned reflexes such as pulling your hand away from a hot fire is related to the cerebellum. On the other hand, emotional associations such as knowing when to be afraid or mad in a particular situation are related to the amygdala.

The context of this course (kin 356) is most interested in the skills and habits of  motor learning.  Unfortunately the anatomy that is associated with skills and habits is speculative.  However, it is most commonly thought that the striatum, cerebellum and motor areas of the cortex (neocortex) are the responsible areas.

What evidence is there of procedural memory?

Most of the evidence of a separate procedural long-term memory area in the brain is through studies involving patients with Korsakoff’s psychosis or amnestic confabulatory syndrome.  These people have damage to mammillary bodies (hippocampus, diencephalons), which are related to the other area of long-term memory called declarative memory.  First, Corkin (1968) studied this type of amnesic (HM) and found that he was able to learn a mirror tracing task, rotary pursuit, and bimanual tracking task. HM had to be told the instructions on how to perform each task all of the time because he had no recollection of doing the task before.  Cermak, Lewis, Butters, and Goodglass (1973) found similar results when Korsakoff patients were able to learn a pursuit rotor task (procedural task) just as well as a normal control group, but were unable to learn a finger maze task (declarative task) as well as the control group.  Cohen, Eichenbaum, Decedo and Corkin (1985) also found that Korsakoff patients were able to learn a different procedural task (Tower of Hanoi puzzle) just as well as a normal control group.

There are a number of studies that reinforce the differences between declarative and procedural memory through Korsakoff patients.  However, no research was found that involves patients that have an intact declarative memory but no procedural memory.  For this reason the  neural pathways associated with procedural memory are only speculative and do not have any hard evidence.