Retrograde Amnesia
- backward-acting
- loss of memory for events or information learned BEFORE the amnesia-inducing lesion
- Mild in H.M.
Anterograde Amnesia
- forward-acting
- loss of memory for events or information learned AFTER the amnesia-inducing lesion
- Severe in H.M.
Which lobes are involved in memory
medial temporal lobes
Medial Temporal Lobe Amnesia
- the ability to learn facts but don’t remember doing it so
- may have trouble imagining future events
-Difficulty forming explicit long term memory but have the ability to retain implicit memory
Cerebral Ischemia can result in…
medial temporal lobe amnesia
damage to hippicamopus can result in
amnesia
Korsakoff’s Syndrome causes
- thiamine deficiency
- mediodorsal nucleus damage
- located in diencephalon
symptoms of korsakoff syndrome
- anterograde amnesia
- retrograde amnesia, severe memory loss
- Confabulation - invented memories which are then taken as true due to gaps in memory sometimes associated with blackouts
A distinct symptom to korsakoff syndrom
- Confabulations
- invented memories which are then taken as true
- due to gaps in memory sometimes associated with blackouts
symptoms of Alzheimer’s Disease
- Anterograde deficits
- Retrograde deficits
- STM
- Implicit memory – problems with implicit verbal and perceptual info, but usual not implicit sensorimotor
the brain on alzheimer’s and causes
- Decreased acetylcholine due to basal forebrain degeneration
- Diffuse brain damage that includes medial temporal lobe and prefrontal cortex
Concussion
temporary disturbance in consciousness produced by non-penetrating head injury
Posttraumatic Amnesia (PTA)
– amnesia following a non-penetrating blow to the head
- coma and confusion following a coma
- retrograde amnesia – can’t remember events leading up to blow
- anterograde amnesia – can’t remember events during confusion
- Return to normal
Memory Consolidation – Hebb’s Theory
Consolidation is a neurological process that involves gradually converting information from short-term memory into long-term memory.
Eventual neural activity will induce structural changes in the synapses -> stable LTM
The fact that people with concussions show retrograde amnesia suggest….
memory consolidation is strongly affected
time of Consolidation of a memory test takes between
10 min and 1 hour but can also continue a long time after learning
what is an engram
change in the brain that stores a memory
Standard consolidation theory
memories are temporarily stored in the hippocampus until they can be transferred to a more stable cortical system
Multiple trace theory
- Hippocampus stores memories permanently
- Each time memory is recalled, new engram is established and linked to original engram
- Thus, the more a memory is recalled, the more resistant it becomes to disruption
- essentially, hipp is strengthening memory
What is the Reconsolidation Hypothesis?
- Each time a memory is retrieved from long term memory, it is temporarily held in short term memory
- Memory in short term memory is capable to post-traumatic amnesia until it is brought together
Evidence for Reconsolidation Hypothesis
Anisomycin – a protein synthesis inhibitor
- anisomycin in injected in amygdala
- causes forget what they were conditioned ….as if they never learned it to begin with
part of brain associated with object recognition
rhinal cortex….especially perirhinal cortex
The effects the amygdala and hippocampus had on object recognition
NONE
Hippocampus plays a key role in memory for
spacial location
