hippocampus

Question 1

HM and episodic memory

Answer 1

surgery for epilepsy on both sides of brain (hippocampus, amygdala and surrounding cortex)
severe anterograde amnesia
short term/working memory intact
intact language
able to acquire new motor skills
impaired spatial memory

Question 2

maguire 2000

Answer 2

spatial memory
taxi drivers and their hippocampi- longer they are a texi driver the greter the grey matter density of the hippocampus (posterior not anterior)
lesions to hippocampus disrupt spatial memory

Question 3

morris water maze

Answer 3

a mouse in water will find where a platform is

Question 4

what are place cells?

Answer 4

cells in the hippocamous that tell us about where we are in the environment

Question 5

cortico-hippocampal information flow

Answer 5

primary sensory cortices feed info to the association cortices to the parahippocampal cortex, entorhinal cortex and then hippocampal formation

Question 6

anatomical connections between the hippocamous and cortex

Answer 6

parahippocampal cortex –site of convergence for cortical input
in the hippocampus divergent and convergent connections are involved in formation of associations
outgoing information from the hippocampus is sent back to parahippocampal cortex

Question 7

hippocampal anatomy

Answer 7

dentate gyrus
CA3 which runs into CA1
subicular

Question 8

major excitatory pathways in the hippocampus

Answer 8

dentate gyrus containing granule cells
bundle of axons of the dentate form mossy fibres which travel into the CA3
lateral and medial perferent path fron the entrorinal cortex send axons to the dendrites of the granuale cells
mossy fibres stop at CA2 region
CA3 pyramidal cells dendrites extend and axons project to CA1 and CA2 and form the schaffer collateral commisural which forms synapses on the CA1
CA1 pyramidal cells extend

Question 9

connectivity in the hippocampus: a trisynaptic view

Answer 9

neocortex inputs into entrohinal cortex (2,3,5,6)
entrohinal II and III form perforantpathway to dentate gyrus
dentate gytus to CA2 to CA1/ CA3 via mossy fibre pathway to CA3 schaffer collateral pathway to subiculus and back to V/VI of the entrohinal cortex

Question 10

connectivity in the hippocampus: parallel processing

Answer 10

projects from entrohinal cortex dont follow trisynaptic route and dont go through dentate gyrus (e.g entrohinal cortex to CA2 directly)

Question 11

anatomy of CA (1,2,3,4) pyramidal neurons

Answer 11

CA regions consist of a number of strata:
- stratum oriens
– s. pyramidale
– s. lucidum (CA3 only)
– s. radiatum
– s. lacunosummoleculare

Question 12

anatomy of CA3 pyramidal neurons

Answer 12

pyramidal shaped soma
apical and basal dendritic trees
afferents from entorhinal cortex, dentate gyrus and from other CA3 cells (via associational
commisural fibres)
efferents to CA1, CA2 (via schaffer collaterals), CA3, lateral
septal nucleus (via fimbria)
mossy fibres come in via the s.lucidium

Question 13

place cells

Answer 13

cells in the hippocampus where an individual cell will fire in a sepcific location (essentially 1 cell per spatial location)
specific cells will only fire in certain parts of an animals environment

Question 14

place cells generated by grid cells?

Answer 14

grid cells in entrohinal cortex
places cells in hippocampus
info from entrohinal generated place cells in hippo
may have grid cells where different cells in ento have different kids of grids and it is intergration of these cels which intergarte specific firing in specific parts of the enviro

Question 15

head direction and boundary cells

Answer 15

head direction=subiculum, thalamus and entrohinal cortex
head direction fire based on the direction youre pointing in
boundary cells= extend of the envornment and where it ends