Transcript Parieto-prefrontal pathway

Group 3
Kindra Akridge
Antoinette Sellers
Hanna Stolarczyk
Tawni Voyles
Parieto-prefrontal pathway
The subregions of the occipito-parietal circuit that give rise to this
pathway (LIP, VIP, MT, MST) are strongly involved in the initiation and
control of eye movements and are crucial for spatial working memory.
The parieto-prefrontal pathway provides the input to the
prefrontal cortex that is necessary for top-down executive
control of visuospatial processing
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Helps maintain maps of space and body position (V6A,
MIP, VIP, LIP, VIP, MT and MST)
Subregions maintain visual coordinates relative to body part
location
Necessary for visually guided action
Study in monkeys showed that LIP and MIP receive input
about position of arms, eyes, and head and possibly support
visual reconfiguration during movement
These regions have been found in monkeys and humans to
be involved in reaching and grasping for objects.
Damage to parieto-premotor pathway can lead to problems
in reaching and grasping
 cIPL
is specialized in processing distant space and
less involved with the guiding of bodily actions
 Some cIPL neurons encode object centered
reference frames
 These neurons are sensitive to the speed of optic
flow
 Both of these abilities are essential for navigation
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Links the cIPL with the MTL
both directly and indirectly
The MTL includes the
hippocampus
One set directly moves from
the cytoartchitectonic zone
between the sucivulum and
CA1 then to the pre and
para subicular subdicisions
of the hippocampus then to
the post hippocampal areas
These same sources and
targets are also connected
indirectly using serially
connected limibic areas: the
PCC and RSC
(thought) Why is the hippocampus connected into the
parieto-medial temporal pathway?
•Much of the processing done by the parieto-medial temporal pathway is
focused on navigation and relating ourselves to our environment.
•The hippocampus creates cognitive maps, which reduce the cognitive
load required for navigation, as well as allow us to acquire, code, decode,
store, and recall information about the relative locations and attributes of
phenomena in our spatial environment.
•When navigating through a new environment, as the parieto-medialtemporal pathway perceives the new spatial information, the hippocampus
is most likely creating memories about this environment to form a new
cognitive map.
•Already existing cognitive maps allow us to navigate through familiar
environments more efficiently.
•Speculation: It makes sense that the hippocampus and the parieto-medial
temporal pathway are connected via many both direct and indirect
projections – this large number of connections between these areas allow
the two to integrate their information to form the best cognitive map
possible.
 Consistent
fMRI signals (“rise and falls” in
activity) within the occipito-parietal system
and within the parieto-medial pathway (PCC,
RSC, IPL) show cells working as a unit
 Findings support the complex extent in which
the visuospatial processing system functions
 A complex processing system calls for a
complex variety of pathways (as is discussed
within the dorsal stream and its
pathways/circuits