Abstract
Anatomical and functional findings support the contention that there is a distinct posterior parietal cortical area (PPC) in the rat, situated between the rostrally adjacent hindlimb sensorimotor area and the caudally adjacent secondary visual areas. The PPC is distinguished from these areas by receiving thalamic afferents from the lateral dorsal (LD), lateral posterior (LP), and posterior (Po) nuclei, in the absence of input from the ventrobasal complex (VB) or dorsal lateral geniculate (DLG) nuclei. Behavioral studies have demonstrated that PPC is involved in spatial orientation and directed attention. In the present study we used fluorescent retrograde axonal tracers primarily to investigate the cortical connections of PPC, in order to determine the organization of the circuitry by which PPC is likely to participate in these functions, and also to determine how the topography of its thalamic connections differs from that of neighboring cortical areas. The cortical connections of PPC involve the ventrolateral (VLO) and medial (MO) orbital areas, medial agranular cortex (area Fr2), portions of somatic sensory areas Par1 and Par2, secondary visual areas Oc2M and Oc2L, auditory area Tel, and retrosplenial cortex. The secondary visual areas Oc2L and Oc2M have cortical connections which are similar to those of PPC, but are restricted within orbital cortex to area VLO, and within area Fr2 to its caudal portion, and do not involve auditory area Te1. The cortical connections of hindlimb cortex are largely restricted to somatic sensory and motor areas. Retrosplenial cortex, which is medially adjacent to PPC, has cortical connections that are prominent with visual cortex, do not involve somatic sensory or auditory cortex, and include the presubiculum. We conclude that PPC is distinguished by its pattern of cortical connections with the somatic sensory, auditory and visual areas, and with areas Fr2, and VLO/MO, in addition to its exclusive thalamic connectivity with LD, LP and Po. Because recent behavioral studies indicate that PPC, Fr2 and VLO are involved in directed attention and spatial learning, we suggest that the interconnections among these three cortical areas represent a major component of the circuitry for these functions in rats.
Similar content being viewed by others
References
Brody BA, Pribram KA (1978) The role of frontal and parietal cortex in cognitive processing: tests of spatial and sequence functions. Brain 101:607–633
Carvell GE, Simons DJ (1987) Thalamic and corticocortical connections of the second somatic sensory area of the mouse. J Comp Neurol 265:409–427
Cavada C, Goldman-Rakic PS (1989a) Posterior parietal cortex in rhesus monkey. I. Parcellation of areas based on distinctive limbic and sensory corticocortical connections. J Comp Neurol 287:393–421
Cavada C, Goldman-Rakic PS (1989b) Posterior parietal cortex in rhesus monkey: II. Evidence for segregated corticortical networks linking sensory and limbic areas with the frontal lobe. J Comp Neurol 287:422–445
Chandler HC, King V, Corwin JV, Reep RL (1992) Thalamocortical connections of rat posterior parietal cortex. Neurosci Lett 143:237–242
Coleman J, Clerici WJ (1980) Extrastriate projections from thalamus to posterior occipital-temporal cortex in rat. Brain Res 194:205–209
Corwin JV, Kanter S, Watson RT, Heilman KM, Valenstein E, Hashimoto A (1986) Apomorphine has a therapeutic effect on neglect produced by unilateral dorsomedial prefrontal cortex lesions in rats. Exp Neurol 94:683–698
Corwin JV, Fussinger M, Meyer RC, King VR, Reep RL (1994) Bilateral destruction of the ventrolateral orbital cortex produces allocentric but not egocentric spatial deficits in rats. Behav Brain Res 61:79–86
Crowne DP, Richardson CM, Dawson KA (1986) Parietal and frontal eye field neglect in the rat. Behav Brain Res 22:227–231
Crowne DP, Novotny MF, Maier SE, Vitols SR (1992) Effects of unilateral parietal lesions on spatial localization in the rat. Behav Neurosci 106:811–822
DiMattia BV, Kesner RP (1988) Spatial cognitive maps: differential role of parietal cortex and hippocampal formation. Behav Neurosci 102:471–480
Donoghue JP, Kerman KL, Ebner FF (1979) Evidence for two organizational plans within the somatic sensory-motor cortex of the rat. J Comp Neurol 183:647–664
Fabri M, Burton H (1991) Ipsilateral cortical connections of primary somatic sensory cortex in rats. J Comp Neurol 311:405–424
Harting JK, Hall WC, Diamond IT (1972) Evolution of the pulvinar. Brain Behav Evol 6:424–452
Hughes HC (1977) Anatomical and neurobehavioral investigations concerning the thalamo-cortical organization of the rat's visual system. J Comp Neurol 175:311–336
Kesner RP, Farnsworth G, DiMattia BV (1989) Double dissociation of egocentric and allocentric space following prefrontal and parietal cortex lesions in the rat. Behav Neurosci 103:956–961
King V, Corwin JV (1990) Neglect following unilateral ablation of the caudal but not the rostral portion of medial agranular cortex of the rat and the therapeutic effect of apomorphine. Behav Brain Res 37:169–184
King V, Corwin JV (1992) Spatial deficits and hemispheric asymmetries in the rat following unilateral and bilateral lesions of posterior parietal or medial agranular cortex. Behav Brain Res 143:237–242
King V, Corwin JV (1993) Comparison of hemiinattention produced by unilateral lesions of posterior parietal cortex or medial agranular prefrontal cortex in rats: neglect, extinction, and the role of stimulus distance. Behav Brain Res 54:117–131
King V, Corwin JV, Reep RL (1989) Production and characterization of neglect in rats with unilateral lesions of ventrolateral orbital cortex. Exp Neurol 105:287–299
Kolb B (1990) Posterior parietal and temporal association cortex. In: Kolb B, Tees RC (eds) The cerebral cortex of the rat. MIT Press, Cambridge, pp 459–471
Kolb B, Walkey J (1987) Behavioral and anatomical studies of the posterior parietal cortex in the rat. Behav Brain Res 23:127–145
Koralek KA, Olavarria J, Killackey HP (1990) Areal and laminar organization of corticocortical projections in the rat somatosensory cortex. J Comp Neurol 299:133–150
Krieg WJS (1946) Connections of the cerebral cortex. I. Albino rat. A. Topography of the cortical areas. J Comp Neurol 84:221–275
Li X-G, Florence SL, Kaas JH (1990) Areal distributions of cortical neurons projecting to different levels of the caudal brain stem and spinal cord in rats. Somatosens Mot Res 7:315–335
Miller MW, Vogt BA (1984) Direct connections of rat visual cortex with sensory, motor, and association cortices. J Comp Neurol 226:184–202
Olavarria J (1979) A horseradish peroxidase study of the projections from the latero-posterior nucleus to three lateral peristriate areas in the rat. Brain Res 173:137–141
Paxinos G, Watson C (1986) The rat brain in stereotaxic coordinates, 2nd edn. Academic, Sydney
Perry VH (1980) A tectocortical visual pathway in the rat. Neuroscience 5:915–927
Peters A (1985) The visual cortex of the rat. Cereb Cortex 3:19–80
Pohl W (1973) Dissociation of spatial discrimination deficits following frontal and parietal lesions in monkeys. J Comp Physiol Psychol 82:227–239
Reep RL, Corwin JV, Hashimoto A, Watson RT (1987) Efferent connections of the rostral portion of medial agranular cortex in rats. Brain Res Bull 19:203–221
Reep RL, Goodwin GS, Corwin JV (1990) Topographic organization in the corticocortical connections of medial agranular cortex in rats. J Comp Neurol 294:262–280
Ribak CE, Peters A (1975) An autoradiographic study of the projections from the lateral geniculate body of the rat. Brain Res 92:341–368
Sanderson KJ, Dreher B, Gayer N (1991) Prosencephalic connections of striate and extrastriate areas of rat visual cortex. Exp Brain Res 85:324–334
Schmahmann JD, Pandya DN (1990) Anatomical investigation of projections from thalamus to posterior parietal cortex in the rhesus monkey: a WGA-HRP and fluorescent tracer study. J Comp Neurol 295:299–326
Selemon LD, Goldman-Rakic PS (1988) Common cortical and subcortical targets of the dorsolateral prefrontal and posterior parietal cortices in the rhesus monkey: evidence for a distributed neural network subserving spatially guided behavior. J Neurosci 8:4049–4068
Sukekawa K (1988) Interconnections of the visual cortex with the frontal cortex in the rat. J Hirnforsch 29:83–93
Torrealba F, Olavarria J, Carrasco MA (1984) Cortical connections of the anteromedial extrastriate visual cortex in the rat. Exp Brain Res 56:543–549
Van Groen T, Wyss MJ (1992) Connections of the retrosplenial dysgranular cortex in the rat. J Comp Neurol 315:200–216
Vogt BA, Miller MW (1983) Cortical connections between rat cingulate cortex and visual, motor, and postsubicular cortices. J Comp Neurol 216:192–210
Zilles K (1985) The cortex of the rat: a stereotaxic atlas. Springer, Berlin Heidelberg New York
Zilles K, Wree A (1985) Cortex: areal and laminar structure. In: Paxinos G (eds) The rat nervous system: forebrain and midbrain, vol 1. Academic, Sydney, pp 375–415
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Reep, R.L., Chandler, H.C., King, V. et al. Rat posterior parietal cortex: topography of corticocortical and thalamic connections. Exp Brain Res 100, 67–84 (1994). https://doi.org/10.1007/BF00227280
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00227280