the hippocampus and the striatum

anterograde amnesia

inhability to form memories for events that happened after brain damage

retrograde amnesia

loss of memory for events that occured before the brain damage

semantic memories

memories of factual information

episodic memories

memories of personal events that occured in a particular place, with a a particular sequence of events over time

generally include much more contextual detail, however in most cases detail will fade and we remember only the gist of it

a loss of place cells and time cells may disrupt the memory formation

imagining future

imagining a future event calls for using your memory of similar experiences and modifying them

people with amnesia are just as impaired at imagining the future as they are at describing the past

explicit memory

deliberate recall of information that one recognizes as a memory

also known as declarative memory

implicit memory

an influence of experience on behaviour, even if you do not recognize the influence

procedural memory

the development of motor skills and habits

a form of implicit memory

declarative memory

memories that are directly accessible to conscious recollection.

delayed matching-to-sample task

an animal sees an object (the sample) and after a delay, gets a choice between two objects from which it must choose the one that matches the sample

shows how the hippocampus contributes to declarative and episodic memory

delayed nonmatching-to-sample task

the animals must choose the object that is different from the saple

strongly impaired performance from hippocampal damage

hippocampus and context

hypothesis that the hippocampus relates to memory through context

when people succesfully retrieve an epuisodic memory, activity in and around the hippocampus synchronizes with activity in several parts of the cortex, consistent with the idea that the hippocampus is providing the connections that are necessary for recall

memories with contextual detail depends on the hippocampus, but older less detailed memories depend mainly on the cereberal cortex

spatial memory

navigation without other stimuli to help you

special type of memory, depending on the hippocampus and surrounding areas

growth of the adult hippocampus in response to spatial learning experiences

place cells

hippocampal neurons turned to particular spatial locations, responding best when an animal is in a a particular place and looking in a particular direction

time cells

many place cells also function as time cells that respond at a particular point in a sequence of time

grid cells

cells active at certain locations seperated form one another in a hexagonal grid

differnent cells respond to differnt sets of locations at different levels within the entorhinal cortex, but always in a hexagon

at each deeper level, the area covered by a given cell doubles in size.

the striatum

the caudate nucleus and putamen together, within the basal ganglia

involved in the gradual learning of habits or learning what probably will or wont happen under certain circumstances

speed of learning

hippocampus can learn in a single trial

striatum learns gradually over many trials

type of behaviour

hippocampus has flexible responses

striatum has habits

feedback type

hippocampus sometimes connects information over a delay

striatum generally requires prompt feedback

explicit vs impicit

hippocampus = explicit learning

striatum = implicit learning

effects of damage

damage in the hippocampus results in impaired declarative memory, especially episodic memory

damage in the striatum results in impaired learning of skills and habits

semanttic dementia

related to damage in the anterior temporal cortex

loss of semantic memory

the anterior temporal cortex stores some semantic information and serves as a hub for communicating with other brain areas to bring together a full concept

hippocampus vs striatum

the hippocampus is important for rapid storage of an event, while the striatum is important for gradually developing habits and for seeing complex patterns that may not be evident on a single trial

in some cases learning depends at first on the hippocampus and after much practise becomes dependent on the striatum