LIP comprises the bulk of the lateral wall of the IPS. It’s the caudal half of POa (Blatt et al 1990, Pandya and Seltzer 1982). Based on purely intrinsic anatomical considerations, several authors have suggested a subdivision of LIP into two strips: LIPv closer to the fundus and LIPd closer to the surface (PS80, BAS, LVEa). This division might be supported physiologically (see Saccadic Eye Mvmts below). LIPv seems to be more like the “classic LIP” of Andersen.
Moderate sized contra-lateral visual receptive fields,
10-20deg. There is a good deal of
saccadic activity, attentional modulations, planning, etc. LIP shows memory or delay activity for pending saccades (and other
spatially oriented behaviors). LIP “remaps” activity after an intervening
Topography: There seems to be a very local topography, i.e. as you move along tangential to surface, saccade preferred directions (PDs) change smoothly. Howere there’s only the roughest of global topographies: D-V = Central – Peripheral, A-P = Lower – Upper (Blatt et al 1990). Many repeats, breaks in topography. (Note this is similar to V3, V4; Blatt et al 1990).
LIP is connected to
a whole lot (primarily due to BAS, LVEb):
IPL/STS: MT (ventral only, LVEb; strong forward connection from MT, weak return, BAS), MST, floor of STS (FST), and DP (dorsal pre-lunate), TPO (temporal-parietal-occipital)
dorsal receives lots of projections from all over: SMA, PM, FEF, …
ventral more restrictive: FEF (8a) and Area 46.
Sub-Cortical: SC, pulvinar, etc
rostral-intermediate LIPv <> lateral 8a, medial 46
caudal LIPv <> medial 8a
LIPd <> 46 strongly, 8a weakly
Has stronger connections with FEF (8a) than areas 7a does.