Topography of projections to posterior cortical areas from the macaque frontal eye fields

Abstract

Frontal eye field (FEF) projections to posterior cortical areas were mapped by autoradiography of tritiated amino acids (Leu, Pro) in six macaque monkeys. In three monkeys, the large saccade part of the FEF (IFEF) was identified by microstimulation and injected with tracers. In a fourth monkey, the small saccade part of the FEF (sFEF) was identified by microstimulation and injected with tracer. Tracer injections were placed into the sFEF region of two other monkeys using anatomical landmarks. The IFEF and sFEF generally had distinct and largely segregated projections to posterior cortical areas, and the overall pattern of labeling in visual areas with established topology indicates that IFEF neurons preferentially project to areas having large and eccentric receptive fields, whereas sFEF neurons project to areas having smaller, more centrally located fields. The terminal fields from the sFEF were more widespread than those from IFEF. Projections from sFEF terminated in the lateral intraparietal area (LIP), the ventral intraparietal area (VIP), and the parietal part of visual area V3A, in the fundus of the superior temporal visual area (FST), the middle temporal area (MT), the medial superior temporal area (MST), the temporal part of visual area V4, the inferior temporal area (IT), and the temporal-occipital area (TEO) and in occipital visual areas V2, V3, and V4. Projections from IFEF terminated in parietal areas 7a, LIP, and VIP and the medial part of parietal area PE; in temporal areas MST and the superior temporal polysensory area (STP); and in occipital area V2 and posterior cingulate area 23b. Projections from IFEF and sFEF appeared to terminate in different parts of common target areas in MST, LIP, and V2. The topography of IFEF and sFEF projections to LIP suggests that this posterior eye field may also be organized by saccade amplitude. Most terminal labeling from FEF injections was bilaminar to layers I and V/VI, but labeling in area LIP, area MT, the medial part of area PE, and area 23b was columnar-form to all layers.

Remapping for visual stability

“…Extrastriate cortex receives direct projections from FEF that could carry the corollary discharge signal needed to trigger remapping [47,48]. The density of these projections from FEF to extrastriate cortex matches quite well with the proportion of neurons in each area that exhibit remapping [30]. The idea is that corollary discharge signals from these FEF projections could trigger remapping based on local transmission of visual signals within each area and between homologous regions across hemispheres.…”

“…Although specific pathways carrying corollary discharge signals to area LIP have not yet been demonstrated directly, LIP (and extrastriate cortex) could receive corollary discharge signals from FEF. Area LIP and the FEF are known to be strongly interconnected [25][26][27][28][29][30]. It is possible that area LIP receives corollary discharge signals from the SC as well, via the pulvinar [31], a pathway that has not yet been physiologically investigated.…”

The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation

“…Rather, it may be based on distributed proto-object representations. FEF is also reciprocally connected with areas of the ventral (recognition) processing stream with large receptive fields and low spatial resolution, such as area TE [132] ( figure 1).…”

Vestibular Signals in Primate Thalamus: Properties and Origins

“…Some cortical vestibular signals may originate through corticocortical connections Stanton et al, 1995;Lewis and Van Essen, 2000), but ultimately these signals must reach cortex via the thalamus. Among these vestibular cortical regions are portions of the retroinsular cortex [parieto-insular vestibular cortex (PIVC)] (Grüsser et al, 1990a,b), and the neck regions of area 3a of primary somatosensory cortex (3aV) (Fredrickson et al, 1966;Schwarz and Fredrickson, 1971a,b;Odkvist et al, 1974;Büttner and Buettner, 1978;Guldin et al, 1992).…”