Hippocampal memory chapter 30
Learning and memory British man with severe short-term memory problems from
Learning: the process by which new information is acquired by hippocampal damage caused by herpes infection (the man with
the nervous system and gives rise to changes in behaviour. Which the 30-sec memory). Hippocampal damage is selective for
is necessary for survival. declarative memories but leaves procedural memories intact.
Memory: encoding, storage and retrieval of learnt information.
Anterograde amnesia: inability to form new memories fMRI studies & human hippocampal function
Retrograde amnesia: inability to recall prior events and memories • Navigation accuracy in the virtual town correlates with
activation of the right hippocampus
• London taxi drivers have to pass a navigational memory test
called ‘The Knowledge’ to memorise pre-set routes in the city.
Taxi drivers also had an increase in hippocampal volume.
Types of memory
Declarative memory: storage and retrieval of information that is
available to our consciousness and can largely be expressed by
language.
Nondeclarative memory: often called ‘procedural memory’ that is
often not available to consciousness and covers many memory
processes which are non-verbalised. This type of memory cannot Disease-damaged hippocampus & dementia
be explained in words. Alzheimer’s starts in the hippocampus/memory regions.
In animals, a type of declarative memory tested in the lab could
be spatial (“where”) or even an episodic-like recollection (“what/
where/when”).
Lesion studies in rodents
Neuronal activation during spatial navigation in rodents.
Morris Water Maze: Rodent must learn to find the submerged
platform to get out of the water and stop swimming. The animal
uses external cues in the room to learn and later remember
where the platform is. In vivo recordings of the rodent
hippocampus record neuronal spiking activity from different
Hippocampus and memory neurons in the hippocampus during a behavioural task.
There were a lot of clinical case studies done on lesions/
hippocampal damage, such as:
• fMRI navigation experiments
• Hippocampal disease & memory function
• Lesion studies in rodents
• Neuronal activation during spatial navigation
Lesion studies into memories
Patient H.M. had surgery for epilepsy in 1953 where most of his
medial temporal lobes were bilaterally removed. He suffered The rodent hippocampus contains place cells. Place cells are cells
severe anterograde amnesia and could not make new long-term in the hippocampus that fire action potentials when the animal is
memories. in a certain spot.
There are also other cells, such as grid cells, head direction cells,
and border cells.
Patient K.C. Horizontal plane MRI section showing damage to
hippocampal and parahippocampal brain regions. Procedural
learning and memory are intact. Anterograde and retrograde
episodic memory (what/where/when) is severely impaired.
However, retrograde ‘semantic’ memory (general knowledge) is
still intact.
Learning and memory British man with severe short-term memory problems from
Learning: the process by which new information is acquired by hippocampal damage caused by herpes infection (the man with
the nervous system and gives rise to changes in behaviour. Which the 30-sec memory). Hippocampal damage is selective for
is necessary for survival. declarative memories but leaves procedural memories intact.
Memory: encoding, storage and retrieval of learnt information.
Anterograde amnesia: inability to form new memories fMRI studies & human hippocampal function
Retrograde amnesia: inability to recall prior events and memories • Navigation accuracy in the virtual town correlates with
activation of the right hippocampus
• London taxi drivers have to pass a navigational memory test
called ‘The Knowledge’ to memorise pre-set routes in the city.
Taxi drivers also had an increase in hippocampal volume.
Types of memory
Declarative memory: storage and retrieval of information that is
available to our consciousness and can largely be expressed by
language.
Nondeclarative memory: often called ‘procedural memory’ that is
often not available to consciousness and covers many memory
processes which are non-verbalised. This type of memory cannot Disease-damaged hippocampus & dementia
be explained in words. Alzheimer’s starts in the hippocampus/memory regions.
In animals, a type of declarative memory tested in the lab could
be spatial (“where”) or even an episodic-like recollection (“what/
where/when”).
Lesion studies in rodents
Neuronal activation during spatial navigation in rodents.
Morris Water Maze: Rodent must learn to find the submerged
platform to get out of the water and stop swimming. The animal
uses external cues in the room to learn and later remember
where the platform is. In vivo recordings of the rodent
hippocampus record neuronal spiking activity from different
Hippocampus and memory neurons in the hippocampus during a behavioural task.
There were a lot of clinical case studies done on lesions/
hippocampal damage, such as:
• fMRI navigation experiments
• Hippocampal disease & memory function
• Lesion studies in rodents
• Neuronal activation during spatial navigation
Lesion studies into memories
Patient H.M. had surgery for epilepsy in 1953 where most of his
medial temporal lobes were bilaterally removed. He suffered The rodent hippocampus contains place cells. Place cells are cells
severe anterograde amnesia and could not make new long-term in the hippocampus that fire action potentials when the animal is
memories. in a certain spot.
There are also other cells, such as grid cells, head direction cells,
and border cells.
Patient K.C. Horizontal plane MRI section showing damage to
hippocampal and parahippocampal brain regions. Procedural
learning and memory are intact. Anterograde and retrograde
episodic memory (what/where/when) is severely impaired.
However, retrograde ‘semantic’ memory (general knowledge) is
still intact.
