P.B. Cipolloni

Cortical connections of the frontoparietal opercular areas in the Rhesus monkey

The connections of the frontoparietal opercular areas were studied in rhesus monkeys by using antero‐ and retrograde tracer techniques. The rostral opercular cortex including the gustatory and proisocortical motor (ProM) areas is connected with precentral areas 3, 1, and 2 as well as with the rostral portion of the opercular area which resembles the second somatosensory type of cortex (area SII) and the ventral portion of area 6. Its distant connections are with the ventral portion of prefrontal areas 46, 11, 12, and 13 as well as with the rostral insula and cingulate motor area (CMAr). The mid opercular region (areas 1 and 2) is connected with pre‐ and postcentral areas 3, 1, and 2 as well as SII. Additionally, it is connected with the ventral portion of area 6, area 44, area ProM, the gustatory area, and the rostral insula. Its distant connections are with area 4, the ventral portion of area 46, area 7b, and area POa in the intraparietal sulcus (IPS). The rostral parietal opercular region is connected with the postcentral portions of areas 3, 1, and 2; areas 5, 7, and SII; the gustatory area; and the vestibular area. Its other connections are with area 4, area 44, the ventral portion of area 46, area ProM, CMAr, and the supplementary motor area (SMA). The caudal opercular region is connected with the dorsal portion of area 3; areas 2, 5, and 7a; and areas PEa as well as IPd of IPS. It is also connected with area SII, insula, and the superior temporal sulcus. Its distant connections are with area 44; the dorsal portion of area 8 and the ventral portion of area 46; as well as CMAr, SMA, and the supplementary sensory area. This connectivity suggests that the ventral somatosensory areas are involved in sensorimotor activities mainly related to head, neck, and face structures as well as to taste. Additionally, these areas may have a role in frontal (working) and temporal (tactile) memory systems. J. Comp. Neurol. 403:431–458, 1999.

Cytoarchitecture and cortical connections of the posterior cingulate and adjacent somatosensory fields in the rhesus monkey

The cytoarchitecture and connections of the caudal cingulate and medial somatosensory areas were investigated in the rhesus monkey. There is a stepwise laminar differentiation starting from retrosplenial area 30 towards the isocortical regions of the medial parietal cortex. This includes a gradational emphasis on supragranular laminar organization and general reduction of the infragranular neurons as one proceeds from area 30 toward the medial parietal regions, including areas 3, 1, 2, 5, 31, and the supplementary sensory area (SSA). This trend includes a progressive increase in layer IV neurons. Area 23c in the lower bank and transitional somatosensory area (TSA) in the upper bank of the cingulate sulcus appear as nodal points. From area 23c and TSA the architectonic progression can be traced in three directions: one culminates in areas 3a and 3b (core line), the second in areas 1, 2, and 5 (belt line), and the third in areas 31 and SSA (root line). These architectonic gradients are reflected in the connections of these regions. Thus, cingulate areas (30, 23a, and 23b) are connected with area 23c and TSA on the one hand and have widespread connections with parieto‐temporal, frontal, and parahippocampal (limbic) regions on the other. Area 23c has connections with areas 30, 23a and b, and TSA as well as with medial somatosensory areas 3, 1, 2, 5, and SSA. Area 23c also has connections with parietotemporal, frontal, and limbic areas similar to areas 30, 23a, and 23b. Area TSA, like area 23c, has connections with areas 3, 1, 2, 5, and SSA. However, it has only limited connections with the parietotemporal and frontal regions and none with the parahippocampal gyrus. Medial area 3 is mainly connected to medial and dorsal sensory areas 3, 1, 2, 5, and SSA and to areas 4 and 6 as well as to supplementary (M2 or area 6m), rostral cingulate (M3 or areas 24c and d), and caudal cingulate (M4 or areas 23c and d) motor cortices. Thus, in parallel with the architectonic gradient of laminar differentiation, there is also a progressive shift in the pattern of corticocortical connections. Cingulate areas have widespread connections with limbic, parietotemporal, and frontal association areas, whereas parietal area 3 has more restricted connections with adjacent somatosensory and motor cortices. TSA is primarily related to the somatosensory‐motor areas and has limited connections with the parietotemporal and frontal association cortices. J. Comp. Neurol. 469:37–69, 2004.

Confocal light absorption and scattering spectroscopic microscopy monitors organelles in live cells with no exogenous labels

This article reports the development of an optical imaging technique, confocal light absorption and scattering spectroscopic (CLASS) microscopy, capable of noninvasively determining the dimensions and other physical properties of single subcellular organelles. CLASS microscopy combines the principles of light-scattering spectroscopy (LSS) with confocal microscopy. LSS is an optical technique that relates the spectroscopic properties of light elastically scattered by small particles to their size, refractive index, and shape. The multispectral nature of LSS enables it to measure internal cell structures much smaller than the diffraction limit without damaging the cell or requiring exogenous markers, which could affect cell function. Scanning the confocal volume across the sample creates an image. CLASS microscopy approaches the accuracy of electron microscopy but is nondestructive and does not require the contrast agents common to optical microscopy. It provides unique capabilities to study functions of viable cells, which are beyond the capabilities of other techniques.

Cytoarchitecture and Cortical Connections of the Anterior Cingulate and Adjacent Somatomotor Fields in the Rhesus Monkey

The cytoarchitecture and cortical connections of the anterior cingulate, medial and dorsal premotor, and precentral region are investigated using the Nissl and NeuN staining methods and the fluorescent retrograde tract tracing technique. There is a gradual stepwise laminar change in the cytoarchitectonic organization from the proisocortical anterior cingulate region, through the lower and upper banks of the cingulate sulcus, to the dorsolateral isocortical premotor and precentral motor regions of the frontal lobe. These changes are characterized by a gradational emphasis on the lower stratum layers (V and VI) in the proisocortical cingulate region to the upper stratum layers (II and III) in the premotor and precentral motor region. This is accompanied by a progressive widening of layers III and VI, a poorly delineated border between layers III and V and a sequential increase in the size of layer V neurons culminating in the presence of giant Betz cells in the precentral motor region. The overall patterns of corticocortical connections paralleled the sequential changes in cytoarchitectonic organization. The proisocortical areas have connections with cingulate motor, supplementary motor, premotor and precentral motor areas on the one hand and have widespread connections with the frontal, parietal, temporal and multimodal association cortex and limbic regions on the other. The dorsal premotor areas have connections with the proisocortical areas including cingulate motor areas and supplementary motor area on the one hand, and premotor and precentral motor cortex on the other. Additionally, this region has significant connections with posterior parietal cortex and limited connections with prefrontal, limbic and multimodal regions. The precentral motor cortex also has connections with the proisocortical areas and premotor areas. Its other connections are limited to the somatosensory regions of the parietal lobe. Since the isocortical motor areas on the dorsal convexity mediate voluntary motor function, their close connectional relationship with the cingulate areas form a pivotal limbic-motor interface that could provide critical sources of cognitive, emotional and motivational influence on complex motor function.

The bilaminar and banded distribution of the callosal terminals in the posterior neocortex of the rat.

After callosal sectioning, the callosal connections of the posterior neocortex of the rat cerebral hemisphere were demonstrated using the Fink-Heimer technique. Serial frozen sections of the whole brains were cut in transverse, horizontal, and tangential planes. In tissue sections, degenerating terminals were concentrated in two distinct laminae within the depth of the cortex. In addition the terminals had a patchy distribution. The degeneration was marked on projection drawings of serially arranged sections, and subsequent reconstruction showed the terminal degeneration to be distributed in bands. Five dorsoventrally oriented bands of terminals were present in areas 39, 41 and 36 collectively, and a rostrocaudal band in area 20. In area 17 terminations were apparently absent except at its borders with areas 18, 18a and 7. The degenerating callosal terminals within these areas produced a circumferential band around area 17. The findings are discussed with respect to the significance of these patterns of corticocortical connections.

The identification of thalamocortical axon terminals in barrels of mouse Sml cortex using immunohistochemistry of anterogradely transported lectin (Phaseolus vulgaris-leucoagglutinin)

The anterograde transport and immunohistochemical demonstration of the lectin, Phaseolus vulgaris-leucoagglutinin (PHA-L) has been used to label thalamocortical axon terminals in barrels of mouse SmI cortex. The reaction product is visible with both the light and electron microscopes so that the distribution of axons and the types of synapses they form can be determined.

Noninvasive sizing of subcellular organelles with light scattering spectroscopy

A long-standing impediment for applications of optical techniques in cellular biology is the inability to characterize subcellular structures whose dimensions are much less than about 1 /spl mu/m. In this paper, we describe a method based on light scattering spectroscopy that can find the size distribution of subcellular organelles as small as 100 nm with an accuracy of 20 nm. We report experiments using aqueous suspensions of subcellular organelles enriched in mitochondria, zymogen granules, and microsomes. From the observed light scattering spectra, we extract size distributions that are in excellent agreement with the results of electron microscopy. Further studies are underway to extract the shapes of organelles in addition to their sizes.

Confocal light absorption and scattering spectroscopic microscopy

We have developed a novel optical method for observing submicrometer intracellular structures in living cells, which is called confocal light absorption and scattering spectroscopic (CLASS) microscopy. It combines confocal microscopy, a well-established high-resolution microscopic technique, with light-scattering spectroscopy. CLASS microscopy requires no exogenous labels and is capable of imaging and continuously monitoring individual viable cells, enabling the observation of cell and organelle functioning at scales of the order of 100 nm.

The termination of callosal fibres in the auditory cortex of the rat. A combined Golgi-electron microscope and degeneration study

SummaryWhen the corpus callosum of the rat is sectioned, the callosal fibres in the cerebral cortex undergo degeneration. In the auditory cortex (area 41) the degenerating axon terminals form asymmetric synapses, and the vast majority of them synapse with dendritic spines. Some others synapse with the shafts of both spiny and smooth dendrites, and a few with the perikarya of non-pyramidal cells. The degenerating axon terminals are contained principally within layer II/III, in which they aggregate in patches. Using a technique in which neurons within the cortex are Golgi-impregnated, then gold-toned and examined in the electron microscope, it has been shown that the dendritic spines of pyramidal neurons with cell bodies in different layers receive the degenerating callosal afferents. The spines arise from the main apical dendritic shafts and their branches, from the dendrites of the apical tufts, and in some cases from the basal dendrites of the pyramidal neurons. The shafts of some pyramidal cell apical dendrites also form asymmetric synapses with callosal afferents. Since we have encountered no spiny non-pyramidal neurons in Golgi preparations of rat auditory cortex, and because other types of non-pyramidal cells have few dendritic spines, it is concluded that practically all of the dendritic spines synapsing with callosal afferents originate from pyramidal neurons.

PROMOTING SAFER HOME ENVIRONMENTS for Persons With Alzheimer's Disease: The Home Safety/Injury Model

This article describes a Home Safety/Injury Model derived from Social Cognitive Theory. The models three components are safety platform, the person with dementia, and risky behaviors. The person with dementia is in the center, located on the safety platform composed of the physical environment and caregiver competence. The interaction between the underlying dementia and indicators of frailty can lead to the person with dementia performing risky behaviors that can overcome the safety platforms resources and lead to an accident or injury, and result in negative consequences. Through education and research, the model guides proactive actions to prevent risky behaviors of individuals with dementia by promoting safer home environments and increased caregiver competence.