ABSTRACT
The afferent projections of the prefrontal cortex(PFC) from the cerebral cortex were studied using WGA-HRP technique in 25 rats. The PFC of the rat re- cieved the afferent projections widely arising from the frontal, parietal,temporal, occipital, cingulate, piriform and retrohippocampal cortex. Furthermore,the dif- ferent organizations of the cortical afferent projections of the medial and lateral part of the PFC were also found. Besides the afferents from the somatic and visceral sensory cortex, the PFC of rat also recives afferents of visual and auditory cortex and it appears to be a multiple sensory convergence area.
ABSTRACT
WGA-HRP was injected into the dorsomedial nucleus of thalamus (DM)by means of microiontophoretical delivery in 19 rats, and into the dorsal division of anterior cingulate cortex (ACd), the prelimbic area (PL), the dorsal agranular insular area (AId) of prefrontal cortex by using microinjective system in 17 rats to observe the efferent projections of the DM.It was found that the DM projected to a large part of the prefrontal cortex including the medial precentral area (PCm), ACd, PL, AId, ventral agranular insular area (AIv), medial orbital area (MO), ventral orbital area (VO), ventrolateral orbital area (VLO), and some topographical organizations were also found. The lateral segment of DM projects to the ACd, PCm, PL, AId, AIv and VLO. The intermediate segment of DM projects to the AId and AIv. The medial segment of DM projects to the AId, PL, IL, AIv, MO and VO. Furthermore, the DM also projects to some subcortical nuclei, such as the reticular nucleus of thalamus (R), the lateral preoptic area (LPO), the lateral hypothalamic area (LHA), the caudoputamen, the nucleus accumbens and the parafascicular nucleus of thalamus. In addition, some reciprocal connections between the DM and the ACd, PCm, PL, IL, AId, R, LPO and LHA were observed.
ABSTRACT
The efferent projections of the rostral ventrolateral medulla(RVL) to the hypothalamic paraventricular nucleus(Pa) and the thoracic cord were studied in the adult cat by using WGA-HRP or fluorescent retrograde tract-tracing method. After injection of WGA-HRP or fluorescent tracer Fast blue(FB) into one side of the Pa, retrogradely labelled cells were found in bilateral RVL, with an ipsilateral predominance. The labelled cells decreased in number from the caudal to the rostral level. After injection of FB into one side of the thoracic cord at T_2-T_3 segments, retrogradely labelled cells in the RVL were observed which increased in number from the caudal to the rostral level and reached the peak at 1.0-1.5mm caudal to the trapezoid body. Most of these cells were distributed in the ipsilateral RVL, and clustered in the region 0.0-1.0mm from the ventral surface of the medulla. After Diamino yellow 2HC1 and FB were injected into the Pa and the thoracic cord respectively, only single labelled cells were detected in the RVL, no double labelled cells were found. The above results suggest that the Pa and the thoracic cord receive separate fiber projections from different cells of the RVL.