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D N Pandya

Publications and source records attributed to D N Pandya.

At least 73 records · Page 4Linked to original sources
PubMed1983

The distribution of posterior parietal fibers in the corpus callosum of the rhesus monkey.

The distribution of posterior parietal fibers in the corpus callosum of the rhesus monkey was analyzed using autoradiographic techniques. Posterior parietal fibers are located in the posterior half of the body of the corpus callosum. There is some segregation of fibers with respect to their place of origin within the posterior parietal lobe. However, there is also overlap, particularly between fibers coming from the caudal inferior parietal lobule and the medial parietal lobe.

Animals↗
PubMed1982

Intrinsic connections and architectonics of posterior parietal cortex in the rhesus monkey.

By means of autoradiographic and ablation-degeneration techniques, the intrinsic cortical connections of the posterior parietal cortex in the rhesus monkey were traced and correlated with a reappraisal of cerebral architectonics. Two major rostral-to-caudal connectional sequences exist. One begins in the dorsal postcentral gyrus (area 2) and proceeds, through architectonic divisions of the superior parietal lobule (areas PE and PEc), to a cortical region on the medial surface of the parietal lobe (area PGm). This area has architectonic features similar to those of the caudal inferior parietal lobule (area PG). The second sequence begins in the ventral post/central gyrus (area 2) and passes through the rostral inferior parietal lobule (areas PG and PFG) to reach the caudal inferior parietal lobule (area PG). Both the superior parietal lobule and the rostral inferior parietal lobule also send projections to various other zones located in the parietal opercular region, the intraparietal sulcus, and the caudalmost portion of the cingulate sulcus. Areas PGm and PG, on the other hand, project to each other, to the cingulate region, to the caudalmost portion of the superior temporal gyrus, and to the upper bank of the superior temporal sulcus. Finally, a reciprocal sequence of connections, directed from caudal to rostral, links together many of the above-mentioned parietal zones. With regard to the laminar pattern of termination, the rostral-to-caudal connections are primarily distributed in the form of cortical "columns" while the caudal-to-rostral connections are found mainly over the first cortical cell layer.

Animals↗
PubMed1981

Cortical connections of the occipital lobe in the rhesus monkey: interconnections between areas 17, 18, 19 and the superior temporal sulcus.

Using both anterograde and retrograde tracing techniques, the present report investigates the cortical connections of the lateral, median and ventral portions of areas 17 and 18 in the rhesus monkey. All parts of area 17 are found to send topographically organized connections to a strip of prestriate cortex which closely corresponds to area OB of Bonin and Bailey or area 18 of Vogt and Vogt. Striate-recipient area 18, in turn, is topographically connected with an anterior prestriate zone, whose borders coincide with those of area OA or 19. These efferents are topographically organized, with connections from the medial surface of area 18 directed to lateral parts of area 19. In addition, certain parts of area 18, in the annectent gyrus and the inferior occipital sulcus, send 'crossed', dorsoventral connections to ventral and dorsal parts of area 19, respectively. Both areas 17 and 18 project in a topographic fashion to a distinct region in the caudal part of the superior temporal sulcus. Topographically organized reciprocal connections are also found from area 18 to 17, from area 19 to 18, and from the superior temporal sulcus to both areas 17 and 18.

Animals↗
PubMed1981

Efferent connections of the cingulate gyrus in the rhesus monkey.

Efferent cortical connections of the cingulate gyrus are investigated in rhesus monkey using autoradiographic technique. The results indicate that the rostralmost part of the cingulate gyrus (area 32) sends projections to the lateral prefrontal and midorbitofrontal cortex and to the rostral portion of the superior temporal gyrus. In contrast, the other two major subdivisions of the cingulate gyrus, areas 24 and 23, have widespread connections within the cortex. Area 24, for example, projects to the premotor region (areas 6 and 8), the fronto-orbital cortex (area 12), the rostral part of the inferior parietal lobule, the anterior insular cortex, the perirhinal area and the laterobasal nucleus of amygdala. Area 23, likewise, sends its connections to the dorsal prefrontal cortex (areas 9 and 10), the rostral orbital cortex (area 11), the parieto-temporal cortex (posterior part of the inferior parietal lobule and the superior temporal sulcus), the parahippocampal gyrus (areas TH and TF), the retrosplenial region and the presubiculum. It seems that the connections of the rostralmost part of the cingulate gyrus resemble the efferent cortical connectional patterns described for lateral prefrontal and orbito-frontal cortex, whereas the projections of areas 24 and 23 are directed to the neocortical, the paralimbic and the limbic areas.

Animals↗
PubMed1980

Converging visual and somatic sensory cortical input to the intraparietal sulcus of the rhesus monkey.

A cyto- and myeloarchitectonic study reveals the presence of a distinct cortical zone ("area POa") in the lower bank of the intraparietal sulcus of the rhesus monkey. Using both autoradiographic and silver impregnation techniques, an analysis of cortical connections shows two overlapping projections to this sulcal zone. These come from (1) the middle portion of the preoccipital gyrus (area OA) and (2) the rostral inferior parietal lobule (area PF).

Afferent Pathways↗
PubMed1980

Compound stimulus differentiation behavior in the rhesus monkey following periarcuate ablations.

Anatomical and physiological investigations in cat and monkeys have demonstrated the existence of association areas where evoked and unit responses associated with more than one sensory modality can be recorded. Although it is often assumed that these areas of association cortex form the anatomical substratum for complex cognitive and integrative behavior in higher mammals, there is little experimental evidence in non-human primates to support this viewpoint. This experiment investigated the effects of periarcuate ablations on the ability of the rhesus monkey to perform a compound stimulus (light and tone) versus component stimuli (light or tone) differentiation. Ablation of this well-known polysensory area in the frontal lobe led to large and persistent impairments in performance on this task, while the ability to perform intramodal and intermodal differentiations was spared. Ablations of comparable size in other parts of the frontal lobe had no affect on the performance of these tasks. It was concluded that one function of the periarcuate region may be to synthesize multiple sources of sensory input occurring simultaneously into meaningful elements.

Animals↗
PubMed1979

Laminar origins and terminations of cortical connections of the occipital lobe in the rhesus monkey.

Cortical connections within the occipital lobe (areas 17, 18 and 19) of the rhesus monkey are investigated with the autoradiographic and horseradish peroxidase procedures. Two efferent systems, each with a specific laminar organization, are observed. (1) Rostrally directed connections, from area 17 to 18, area 18 to 19 and area 19 to the inferotemporal region (area TE), originate from neurons in layer IIIc (and, in area 19, from a small complement of neurons in layer Va), and terminate in and around layer IV. (2) In contrast, connections in the reverse direction ('caudally directed' connections), from area TE to 19, area 19 to 18, and area 18 to 17, originate from neurons in layers Vb, VI and, to a lesser extent, IIIa, and terminate mainly in layer I. In addition, the laminar organization of several intrinsic and callosal connections are observed. In trinsic connections within areas 18 and 19 originate from neurons in layers IIIc and, to a lesser extent, Va, and terminate in vertical bands in layers I to IV. Callosal connections from areas 18, 19, and the caudal inferotemporal region originate from neurons mainly in layer IIIc. From areas 18 and 19, these callosal connections terminate in vertical bands in layers I through IV. Thus, different cortical projection systems are characterized by specific laminar distributions of efferent terminations as well as of their neurons of origin.

Animals↗
PubMed1979

Thalamic and cortical afferents differentiate anterior from posterior cingulate cortex in the monkey.

The anterior cingulate cortex receives thalamic afferents mainly from the midline and intralaminar nuclei rather than the anterior thalamic nuclei. In contrast, the posterior cingulate cortex receives afferents primarily from the anterior thalamic nuclei and from extensive cortical areas in the frontal, parietal, and temporal lobes. These contrasting afferents may provide a structural basis for pain-related functions of the anterior cingulate cortex.

Afferent Pathways↗
PubMed1978

Afferent cortical connections and architectonics of the superior temporal sulcus and surrounding cortex in the rhesus monkey.

A cyto- and myeloarchitectonic parcellation of the superior temporal sulcus and surrounding cortex in the rhesus monkey has been correlated with the pattern of afferent cortical connections from ipsilateral temporal, parietal and occipital lobes, studied by both silver impregnation and autoradiographic techniques. The results suggest a definite organization of this region. Subdivisions of the superior temporal gyrus are tied together in a precise sequence of connections beginning in primary auditory cortex. The inferotemporal area, which receives input from the lateral peristriate region, can also be divided into architectonic divisions, each of which is related to the others in a specific pattern of connections. Within the superior temporal sulcus several distinct areas exist. In the caudal reaches is found a region that receives input from both primary visual and visual association cortices. This zone is similar to the Clare-Bishop area of the cat. Other superior temporal sulcus zones receive input primarily from one limited area of association cortex. A strip in the upper bank receives input exclusively from the superior temporal gyrus. An area in the rostral lower bank has afferent connections mainly with the inferotemporal area, and a zone in the depth of the superior temporal sulcus receives fibers from a region within the lower bank of the intraparietal sulcus. Two additional zones, in the upper bank of the superior temporal sulcus, however, have multiple sources of cortical input: the peristriate belt, inferior parietal lobule and caudal superior temporal gyrus.

Afferent Pathways↗
PubMed1977

Limbic and sensory connections of the inferior parietal lobule (area PG) in the rhesus monkey: a study with a new method for horseradish peroxidase histochemistry.

The caudal part of the inferior parietal lobule (area PG) was injected with horseradish peroxidase (HRP) in 6 hemispheres of 5 rhesus monkeys. The retrograde transport of HRP resulted in the labeling of neurons in diverse cortical and subcortical areas. In cortex, labeled neurons were noted in prefrontal cortex (areas 8, 45, 46), in the banks of the intraparietal and superior temporal sulci, in medial parietal cortex, in cingulate cortex, in the retrosplenial area, in area TF and the caudal portions of the parahippocampal region. Subcortical sites with labeled neurons included the necleus basalis of the substantia innominata, the claustrum, the pulvinar and intralaminar thalamic nuclei, the pretectal area, the nucleus locus coeruleus and the raphe nuclei. Although many of the labeled neurons were seen in layers IIIc and V, each cortical area had an individual laminar pattern of labeled neurons. In these experiments, a benzidine dihydrochloride (BDHC) method was used which yields a blue reaction-product at sites containing HRP. BDHC affords superior visibility of labeled neurons, and a significant improvement in sensitivity when compared to a diaminobenzidine procedure in matching series of sections. Additional sections were also stained with a method which allows the simultaneous demonstration of HRP (blue) and acetylcholinesterase (reddish-brown). These revealed that virtually all substantia innominata (nucleus basalis) neurons which project to area PG are also rich in the enzyme acetycholinesterase. These afferents of PG may be classified into 'sensory association', 'limbic' and 'reticular' categories. It is argued that this arrangement of afferent imput may afford a convergence of limbic and sensory information in area PG and that this may subserve a significant function in the process of sensory attention.

Acetylcholinesterase↗
PubMed1976

Further observations on corticofrontal connections in the rhesus monkey.

The frontal lobe connections of the post-Rolandic sensory association areas are investigated; Our results indicate that the caudal portion of the superior temporal gyrus (area 22), the lateral peristriate belt (area 18,19), and the superior parietal lobule and the rostralmost portion of the inferior parietal lobule (areas 5 and 7), all project to periarcuate cortex, while the middle portion of area 22, caudal infero-temporal cortex (area 20), and the middle portion of the lower bank of the intraparietal sulcus, all have connections predominantly to prearcurate cortexmin contrast, rostral area 22 and the rostral inferotemporal cortex (area 21) project primarily to the orbital surface, and the middle portion of area 7 projects to the mid-principal sulcus. Those regions that project to periarcuate cortex are termed first association areas (AA1, VA1, SA1), those that project primarily to prearcuate cortex are designated second association areas (AA2, VA2, SA2), while those that project mainly to the orbital surface or the mid-principal sulcus are called third association areas (AA3, VA3, SA3). It was also found that the caudalmost portion of area 7 has a distinct projection pattern, connecting with the dorsal prearcuate cortex--areas 8B and 46. Additionally, it was observed that the connections from the association area of different sensory modalities appear to overlap in specific areas of frontal cortex. Projections from the first association areas seem to coverage in the periarcuate zone (bimodal overlap is noted between VA1 and AA1 in the arcuate concavity, and SA1 and VA1 dorsal to the arcuate sulcus), while those from the second association areas overlap in the ventral prearcuate cortex (area 46), where both bimodal and trimodal overlap is observed.

Animals↗
PubMed1975

Some connections of the entorhinal (area 28) and perirhinal (area 35) cortices of the rhesus monkey. I. Temporal lobe afferents.

In this investigation the efferent projections from ventral temporal neocortical and limbic cortical areas to the entorhinal and perirhinal cortices have been investigated in the rhesus monkey using silver impregnation methods. It was observed that virtually all ventral temporal neocortical areas contribute some afferents to the transitional zones of periallocortex (perirhinal and prorhinal cortices) forming the walls of the rhinal sulcus. These areas in turn project medially to the entorhinal cortex and hippocampus. Additional direct sources of afferent input to the entorhinal cortex were found to originate in Brodmann's areas 51, 49 and 27, and Bonin and Bailey's areas TF and TH. These connections have been characterized as final relays in multisynaptic cortico-cortical pathways linking the entorhinal cortex and, ultimately, hippocampus to the association areas of the frontal, parietal, temporal, and occipital lobes.

Animals↗
PubMed1975

Some connections of the entorhinal (area 28) and perirhinal (area 35) cortices of the rhesus monkey. II. Frontal lobe afferents.

In this investigation, the efferent cortico-cortical projections of the orbitofrontal cortex in the rhesus monkey have been investigated using silver impregnation methods. Projections from this area were observed to terminate in the rostral portions of the temporal lobe (areas TA, TE and TG) and cingulate gyrus (area 24), the insular cortex, and some dorsolateral prefrontal areas. Although these connections characterized all areas, with the exception of Walker's area 14 and Bonin and Bailey's area FL, the caudal levels of the orbitofrontal area were found to give rise to an additional projection which terminated in the entorhinal cortex and the transitional cortices bordering the rhinal sulcus. The source of this projection correlated closely with an area labeled FF by Bonin and Bailey. This connection may provide a much more direct means for the frontal lobe to influence the hippocampus than those involving the cingulate gyrus.

Amygdala↗
PubMed1975

Some connections of the entorhinal (area 28) and perirhinal (area 35) cortices of the rhesus monkey. III. Efferent connections.

In this investigation the efferent projections of the entorhinal and prorhinal cortices relative to their sites of termination in the hippocampus and fascia dentata were investigated in the rhesus monkey using experimental silver impregnation methods. Contrary to the often cited observations of Lorente de No, all entorhinal areas, including the laterally lying prorhinal cortex, were found to give rise to the perforant pathway, and furthermore, each cytoarchitectonically defined subarea was found to contribute a unique component. These perforant pathway components terminate in distinct regions of the dendritic zones of the fascia dentata granule cell and the hippocampal pyramidal cell. A previously undescribed projection to the prosubiculum and hippocampus has been found to originate from the prorhinal cortex which forms the medial wall of the rhinal sulcus along the lateral-most portion of the entorhinal cortex in the rhesus monkey. These results, in conjunction with our previous observations regarding differential afferents to the entorhinal cortex, indicate that specific afferent and efferent connections characterize each cytoarchitectonically definable subareas of this periallocortical region. Additionally, they indicate that the perforant pathway might be conceptualized as the final link in a multisynaptic series of connections instrumental in providing the hippocampus with potential modality specific and multimodal input.

Animals↗