Nervous System 7 - Memory and the Hippocampus Flashcards
What are the two types of memory?
Declarative/Explicit and Nondeclarative/Implicit
What is Declarative memory concerned with?
Facts and events
What kind of recall does Declarative memory require?
Conscious recall
What is the capacity of Declarative memory?
Unlimited
What is Nondeclarative memory concerned with?
Skills and behavior
What kind of recall is found in Nondeclarative memory?
Automatic recall that does not need conscious recollection
What are the characteristics of Short-term memory?
- Seconds to minutes
- Limited in capacity
- Needs continual rehearsal
What are the Characteristics of Long-Term memory?
- Days to years
- Large capacity
- Does not require rehearsal once info is stored in LTM
What parts of the brain are involved in Declarative memory?
Hippocampus and Diencephalon
What parts of the brain are involved in Nondeclarative memory?
Striatum, Cerebellum, Amygdala (emotional memory)
What is Consolidation?
The process of storing new information into the long term memory
Where is Long Term storage for Declarative memory found?
A variety of sites
•e.g. Wernicke’s area, temporal cortex
Where is Long term storage for Nondeclarative memory found?
- Cerebellum
- Basal Ganglia
- Premotor cortex
- Other sites related to motor behavior
What is Short term storage for Declarative memory?
Hippocampus and related structures
What is Short term storage for Nondeclarative memory?
Sites unknown but presumably across the cortex
What is stored in Wernicke’s area?
The meaning of words
What is stored in the Temporal cortex?
Memories of objects and faces
What information does the Hippocampus handle?
- Processing spatial infor
- Navigation
- Info that doesn’t have a clear spatial component
What converges in the hippocampal region?
Widespread projection from the association neocortex’s
Where does the hippocampus send the information it receives from the association neocortexes?
Back to the same neocortical areas
What are the two types of Amnesia?
Retrograde Amnesia
Anterograde Amnesia
What is Retrograde Amnesia?
Memory loss for events occurring prior to trauma but very old memories remain intacts
What is Anterograde Amnesia?
The inability to form new memories
What is the relation between the structures of the brain that encode explicit and implicit memory?
Brain structures that underlie explicit and implicit memory are different
Which side of the hippocampus is activated for Spacial Learning?
The right side
Which side of the hippocampus activated for Verbal memory-word recall?
Left hippocampus
What are the variety of tests used to probe hippocampal function?
- Imaging studies in humans
- Various mazes
- Place cell recordings
What are Place cells?
Cells that fire action potentials when an animal is in one location but not another
Which neurons can act as place cells?
Hippocampal neurons can act as place cells but they are not exclusive to the hippocampus
What are place cells important for?
Navigation
What is the Hippocampus critical for?
Making associations between events occuring in close temporal succession to each other
What are the two types of genetically engineered mice?
Knockout and Transgenic mice
What occurs in Knockout?
A gene encoding a particular protein is completely knocked out so that the protein is missing from the brain
What occurs in transgenic mice?
A gene that you introduce encodes a modified form of the protein that your interested in
What does a Transgenic construct contain?
- A specific promoter (Pspec)
- A gene of interest
- A Polyadenylyl sequence (pA)
What does the Promoter do?
Drive expression of the gene of interest
What is the promoter for the alpha-subunit of CaMK2 often used for?
It is used to restrict expression of the transgene (modified protein) to brain cells
What is interesting about Knock-ins?
The endogenous protein is still present but we are introducing a modified form of the protein that co-exists with the endogenous one
What are the steps in creating a Transgenic mouse that expresses the mutant form of CaMK2?
- A promoter is found that restricts expression of tTA protein to brain cells
- Another mouse containing tetO promoter that is only activated with tTA is attached to a mutant form of CaMKII is created
- The mice are bred together and now contain a mutant form of CaMKII protein and the protein that activates the promoter tetO, tTA
How can transcription of the mutant CaMKII be stopped?
Doxycycline can be ingested by the mice and bind to tTA which is supposed to bind to the tetO, the promoter of CaMKII
How were mice affected by having the mutant form of CaMKII?
They display Long Term Depression rather than LTP. They express CaMkII that is hyperactive and have impaired spatial learning skills
What is Angelman’s syndrome characterized by?
Severe mental impairment and epileptic seizures
What is thought to be the trigger for Angelman’s syndrome?
Dysfunction of CaMKII
What is the Goldilocks Phenomenon?
The idea that too much or too little of something is not good
What is Dementia characterized by?
A syndrome characterized by amnesia and intellectual dysfunctions
What is the most common form of Dementia?
Alzheimer’s disease
What are the symptoms of Alzheimer’s Disease?
- Memory loss: inability to form short term memories
* Failure of language skills, visual spatial orientation and judgment
What are some of the Pathological changes in the brain tissue of Alzheimer’s patients?
- Accumulation of neurofibrillary tangles in neurons
- Extracellular accumulation of plaques containing a protein, amyloid
- Widespread loss of neurons
What are the possible causes of AD?
- Genetics mutations of genes encoding: amyloid precursor protein (APP), Presenilin 1 and 2
- Inheritance of gene for apolipoprotein-E increases risk of developing AD
What are the consequences of Presenilin 1 and 2?
Increase levels of toxic form of A-beta peptide (AB42)
Which part of the brain is the most hard hit is AD?
The Temporal lobe
