What is neural plasticity?
When a new memory is formed
What is Acetycholine?
- memory & learning
- muscle movement
- controls REM sleep
What is dopamine?
- Facilitates movement, attention and learning reinforcement
What is serotonin?
- Regulates mood
- controls eating, sleep and pain
What is the role of neurons in memory formation?
Memories are formed through biochemical changes in synapses in response to different neurotransmitters (chemicals)
Neural connections are constantly removed and re-made (neural plasticity)
What is alzheimers disease?
Low levels of acetylcholine due to the progressive destruction of neurons in the brain that cause memory loss
- Amyloid Plaques (proteins that form among axon terminals and interfere with communication between neurons)
- Neurofibrillary Tangles (an abnormal build-up of protein inside neurons)
- Hippocampus shrinks
- Brain Shrinks (atrophy)
What is korasakoffs syndrome?
Levels of serotonin are disrupted by excessive alcohol abuse over time. Affects formation of new memories.
The hippocampus and temporal lobes are unaffected but the frontal lobes deteriorate.
Caused by deficiency in the vitamin thiamine (B1)
Function of neurons
Neurons recieve, transmit & process information
Explain the structure of a neuron
Dendrite's: tree-like extension that receive information from other neurons
Soma: cell body that controls metabolism and maintenance of cell
Axon: nerve fibre which carries information (neural impulse/action potential) away from the cell.
Explain communication between neurons
Within the terminal buttons - synaptic vesicles contain neurotransmitters
Work of Eric Kandel
- Conditioning = extra serotonin released causing new proteins and thus new memories are formed
- new synapses formed and remained
- repeated stimulation of synapses formed new dendrites
What is LTP?
Long Term Potentiation (LTP) refers to:
- repeated stimulation of a particular neural pathway tends to strengthen the likelihood of it firing again
- increased neurotransmitter release
- increased receptor sensitivity
- structural changes in synapses
LTP leads to heightened activation of the receptor of the neurotransmitter glutamate & improved efficiency of the connection between cells
LTP is THEORETICAL (for humans as only tested in animals)
What is glutamate?
- Necessary for changes in synapses that occur with memory formation
What is cortisol?
- Repairs the body
Explain the case of H.M.?
- HM patient with severe temporal lobe epilepsy
- Had an operation to remove portions of both temporal lobes
- Couldn't learn new declarative memories but could learn new procedural memories thus;
Explicit (declarative) & Implicit (procedural) memories are stored in different parts of the brain
Brain structure and memory
Process of consolidation & retrieval of long-term declarative memories
STM & aspects of declarative memory
Working memory, procedural memory, episodic memory
Long-term declarative memories. Regulates emotions
Classically conditioned responses
- Process of consolidation & retrieval of long-term declarative memories
- STM & aspects of declarative memory
- Working memory, procedural memory, episodic memory
- Long-term declarative memories. Regulates emotions
- LTM (procedural)
- Classically conditioned responses
What is the consolidation theory?
- Memory is permanetly stored through processes where there are physical changes to neurons
- Memories strengthen overtime
3 Steps Necessary:
- Physical Neural Change
- No Disruption
- Time - takes approximately 30 mins to set (24 hours/good sleep makes permanent)
Explain memory decline
If memory decline does occur, there are several reasons;
- reduced number of synapses in hippocampus
- reduced insulation of axons of neurons
- changes in the functioning of the pre-frontal cortex
- Working Memory
- Episodic Memory
- Ability to form new memories
- Memory as measured by free recall
No decline in;
- Well learned semantic memories
- procedural memories
- memory as measured by recognition
What is Anterograde Amnesia?
Unable to form new memories but can remember before trauma
What is Retrograde Amnesia?
Unable to remember the past
What is Infantile Amnesia?
Minimal declarative memories from early childhood
List forms of Brain Trauma
- Head Injuries
- Stroke (due to lack of oxygen to the brain)
- Post Traumatic Amnesia
What is the function of the Hippocampus in memory formation?
The hippocampus is a finger-sized curved structure that lies in the interior of each of the temporal lobes and is located close to the amygdala.
Hippocampus cells are special because they are able to reproduce, and therefore, enable new learning to take place and new memories to form.
The hippocampus is important for forming explicit memory and for difficult tasks that draw upon declarative memory.
The function of the Amygdala in memory formation
In each hemisphere, the amygdala is located almost directly behind the temple and beneath the cortex of the temporal lobe. It regulates emotions such as fear and aggression, and plays a more general role in the formation of emotional memory.
- role in the memory of emotions shown on faces
- enhances memorability of an event that is stated as declarative memory
What is dementia?
Dementia is a disorder affecting higher mental functions. It can have various forms and may be caused by disease or brain damage.
e.g. Alzheimer's disease