After SCI, DH neurons located in Lamina IV-V exhibited increased spine density, redistributed spines, and mature spines compared with control neurons, which was associated with enhancement of EPSCs in computer simulations and hyperexcitable responsiveness to innocuous and noxious peripheral stimuli in unit recordings in vivo. 
Results showed that c-Fos-immunoreactive neurons evoked by HFV were mainly concentrated in Lamina IV-VII of the ipsilateral spinal cord. The number of c-Fos-immunoreactive neurons in Lamina IV and VI-VII were also significantly higher than that in normal rats (P<0.05).
In chronic myositis animals, SFPs induced by GS TTX-r fibres exhibited significant decreases in Lamina IV-VI of Th 12 and L5 as well as in lamina VII of L5. In contrast, SFPs evoked by SU TTX-r afferents showed significant increases in Lamina IV-VI in L1 and in lamina VII in L4.
Some axons reached Lamina IV-V and extended rostrally and caudally in the degenerating dorsal column.
Excitatory cells were located mainly in the central region of Lamina IV and had relatively small somata and restricted dendritic trees.
At every level, there was a relatively strong basal incorporation of GTPgammaS in laminae II-III>Lamina IV-X of spinal grey, even in presence of DPCPX to block endogenous activation by adenosine A1 receptors.
The c-fos immunoreactive neurons are mainly concentrated in Lamina IV of the retrosplenial cortex.
Laminae I and II showed the highest density of immunoreactive fibers for each of the three tachykinins studied, being in general Lamina IV who showed the lowest number of immunoreactive fibers containing substance P, neurokinin A or B.
Velocity of spread along the vertical stimulation axis reached 0.24 m/s in the supragranular layers (layers I to III) and then decreased to 0.09 m/s following layer I activation; stimulation of white matter induced a velocity of spread in layer V of 0.38 m/s, which slowed down to 0.12 m/s when passing the lower border of Lamina IV.
The potency of capsaicin to produce internalization was progressively lower in lamina III (EC(50)=1.9 microM) and Lamina IV (EC(50)=14.5 microM), suggesting that neurokinins released in laminae I-II become diluted as they diffuse to the inner dorsal horn. The correlation was good for laminae I (R(2)=0.82) and III (R(2)=0.78), but it was poor (R(2)=0.35) for Lamina IV because NK1 receptor internalization kept on increasing at high concentrations of capsaicin, whereas substance P release decreased.
When different pontine sites were tested with 20-s pulse trains (50-to 200-microA amplitude, 0.5-ms pulse width, and 50-Hz frequency) during measurement in the dorsal horn (Lamina IV), the largest consistent increases were produced by the locus ceruleus, although effective pontine sites extended 1.5 mm dorsally and ventral from the locus ceruleus.
Further, a special central representation pattern of supraorbital vibrissae was observed in the trigeminal brainstem nuclear complex: (1) Choleratoxin-labelled supraorbital vibrissal primary afferents terminated densely in their appropriate barrelettes in the trigeminal principal sensory nucleus, in the spinal oral subnucleus, in the caudal part of the spinal interpolar subnucleus, and in Lamina IV of the caudal part of the spinal caudal subnucleus.
Whereas most cortical laminae exhibited idiosyncratic increases in zinc histochemical staining with advancing age, Lamina IV barrels were darkly reactive early in life and then lost much of their complement of synaptic zinc during postnatal weeks 2-4. Notably, the influence of experience on development of zinc circuits was most robust during a critical period extending from about P14, when an effect of whisker trimming first could be observed, through P28, after which time chronic deprivation no longer resulted in heightened levels of synaptic zinc in Lamina IV. These findings indicate that sensory input can have a marked influence on development of cortical circuits, including those within Lamina IV, throughout the first postnatal month..
Densely labeled areas were found in Lamina IV, V, VII (intermediolateral nucleus) and X of the spinal cord.
Analysis of CO-stained sections through Lamina IV of S-I in perinatal and adult 5-HT(1B) knockout mice revealed a normal vibrissae-related pattern, indicating that activation of the 5-HT(1B) receptor is not necessary for the normal development of the vibrissae representation in S-I..
In lamina III the labelled perikarya were evenly distributed, while those in Lamina IV accumulated mainly in the lateral part.
However, by adulthood, AChE staining revealed a negative image of the CO staining pattern in Lamina IV.
Ultrastructural analysis in Lamina IV of the spinal cord revealed that BDNF terminals in these central projections establish synaptic contacts.
Thalamorecipient barrel centers in Lamina IV were distinguished by the relative absence of synaptic zinc and were bounded by darkly stained inter-barrel septa. By contrast, neonatal whisker trimming resulted in a marked increase in density of synaptic zinc specifically within the centers of deprived barrels in Lamina IV.
In normal mice, density of synaptic zinc was highest in laminae I, II and V, intermediate in laminae III and VI, and lowest in Lamina IV barrel hollows.
Depletion of cortical serotonin (5-HT) during development results in a decrease in the size of the patches of thalamocortical afferents representing the mystacial vibrissae in Lamina IV of the primary somatosensory cortex (SI).
In situ hybridization experiments revealed the localization of the Y2 messenger RNA signal throughout all cortical regions, with the highest intensity per cell apparent in Lamina IV, with the exception of the striate cortex, which showed an intense labelling primarily in layer VI.
Previous experiments from this laboratory demonstrated that intracortical connections in Lamina IV of the rat primary somatosensory cortex (SI) are most dense outside the patches of cytochrome oxidase (CO) staining that correspond to the mystacial vibrissae. This series of experiments was undertaken to determine whether the patterning of either thalamocortical afferents or intracortical projections defines the end of the period over which peripheral damage can alter intracortical projections in Lamina IV of SI.
The adjoining prefrontal areas are distinguishable from area 6 by the presence of a thin internal granular lamina (Lamina IV) and the reduced size of pyramidal cells in lamina V. Laminae are poorly differentiated in the cingulate areas, where a rostral and caudal subdivision can be distinguished on the basis of the absence or presence of Lamina IV. Area 3a is characterized by a thin Lamina IV and is located between frontal agranular and parietal granular (well-defined Lamina IV) fields (3b, 1, 2, 2pri, 5, and 7).
However, recordings from unit clusters in Lamina IV of the primary somatosensory cortex (SI) of these animals revealed the presence of only a very few sites in the forelimb stump representation where responses to hindlimb stimulation could also be recorded. In the present study we tested the possibility that input from the hindlimb was suppressed in Lamina IV of the cortical stump representation via GABAergic inhibitory mechanisms by mapping this cortical region, applying the gamma-aminobutyric acid-A (GABA(A)) and GABA(B) receptor antagonists bicuculline and phaclofen (50 microM each), and then remapping the same sites.
Three types of neuron were studied: nociceptive specific (NS) from lamina I (n = 3), wide dynamic range (WDR) from laminae II-IV (n = 3), and nonnociceptive (NN) from Lamina IV (n = 3).
mu-Receptors are located in lamina III followed by I and II in cingulate, frontal, insular and parietal cortices and Lamina IV in temporal and occiptotemporal cortices.
In the postnatal rats, [ 3H]citalopram binding sites were densely distributed in the lower portion of layer III, Lamina IV, and upper layer V in the primary visual, somatosensory, and auditory cortices.
Particular attention was paid to the emergence of Lamina IV intracortical projections that form a pattern complementary to vibrissae-related thalamocortical afferents. However, in Lamina IV, there was no organization that could be related to the distribution of the vibrissae.
The neuropil in laminae II/III and IV of the mature rabbit visual cortex is subdivided into (a) dendrite bundles consisting of apical dendrites of pyramidal cells and associated axons and glial processes, (b) bundles of myelinated axons ascending vertically from the white matter up to Lamina IV and (c) neuropil between bundles comprising mainly thin unmyelinated axons, small dendrites and associated glial processes. Dendrite bundles are more numerous and more intensively intertwined in lamina II/III than in Lamina IV. After 1 month, in Lamina IV further increase of the neuropil between bundles is less marked, because here the bundles of myelinated axons become visible as an additional compartment. In young adult animals, the volume fractions of dendrite bundles are about 28% in the upper half, 16% in the lower half of lamina II/III and 7% in Lamina IV. The neuropil between bundles comprises about 52% in the upper half, 65% in the lower half of lamina II/III and 62% in Lamina IV. In Lamina IV 14% is occupied by bundles of myelinated axons.
Fenfluramine reduced cortical 5-HT levels to 93.9 +/- 6.0% of normal (P < 0.01) and decreased the average area of vibrissae-related Lamina IV patches by 23.8 +/- 4.4% (P < 0.05).
The Sv of astrocytic processes in Lamina IV but not laminae II/III, V and VI was significantly decreased in the MD group.
HRP injections into Lamina IV of the somatosensory cortex led to retrograde labeling of neurons within one or more barreloids. Following Lamina IV injections the density of labeled neurons tended to be highest in the ventrolateral one-half to two-thirds of VBm.
In Lamina IV, both labelled fibers and cells were restricted for the most part to the septa regions between the barrels. In these laminae, there was no evidence of a pattern of intracortical connections related to the vibrissae representation in overlying Lamina IV..
At days 7-8 virus was detected in laminae IV and Va of the primary somatosensory cortex and Lamina IV of the secondary somatosensory cortex in regions previously shown to receive input from the lower jaw.
These axons descend to Lamina IV, and then turn upward to terminate in laminae III and IV, arborizing primarily rostrocaudally.
The less vulnerable nonpyramidal neuron population in Lamina IV had relatively normal message levels.
In the ipsilateral lamina III, the number of neuropeptide Y-positive nerve terminals markedly increased after axotomy, with a moderate increase in Lamina IV.
From the initially homogenous distribution, two distinct SSTR1 mRNA-positive bands coextensive with laminae V/VI and II/III, respectively, and sparing Lamina IV evolved during the first postnatal week, the grain density of which decreased during further postnatal development.
Receptor immunostaining is relatively intense in upper lamina I and in Lamina IV, where patches of intense receptor staining are interleaved with narrow zones of moderate immunoreactivity. Tangential sections through Lamina IV reveal that each large cortical barrel encompasses several patches of intense receptor staining that are aligned with the corners or edges of individual barrels; interbarrel septa are moderately of intense cytochrome oxidase (CO) histochemical staining. The density of GABAA receptors is reduced in Lamina IV following complete loss of peripheral afferent input.
Some labeled fibers entered the dorsal horn from medial to terminate in Lamina IV.
Lamina IV had one of the highest numerical densities (67.6 x 10(3) neurons/mm3) and contributed nearly 27% of the total neuron number in AI. The numerical density of PV+ nonpyramidal cells was also greatest within Lamina IV (7.1 x 10(3)/mm3) where they formed 10.4% of the neuronal population. PV+ nonpyramidal cells in Lamina IV and lamina III were predominantly large basket-type cells with bitufted dendritic domains and tangentially oriented local axonal plexuses.
Nissl staining of the C8 segment showed that in the aged rat the dorsal horn was more oblique and narrow, the central canal was enlarged, the cellular density was reduced, and the neurons of the intermediolateral and ventral horns and of Lamina IV were smaller.
Five 3b TPNs were identified in lamina II, 19 in lamina III, 7 in Lamina IV, 7 in lamina V, and 1 in lamina VI.
This neural path arises primarily from neurons in the ipsilateral lamina V and, to a much lesser extent, from Lamina IV in the cervical area and, to a far smaller degree, from the thoracic and lumbar dorsal horn.
An increase in GAD67 immunoreactivity was observed in the cerebral cortex ipsilateral to the ischemic insult, most prominent in Lamina IV, 3 to 14 days after MCAO.
However, 8 out of 13 somatostatin-immunoreactive neurones located deeper in the dorsal horn (ventral lamina III and Lamina IV) showed glycine-like immunoreactivity, and 6 of these were also GABA-immunoreactive.
On the other hand, the collaterals of the other half of the periodontium afferent fibers terminated mainly in Lamina IV at the rostral level of Vc, and rostrally these terminal areas shifted to the most medial part of Vi.
The receptors are very dense in Lamina IV of both the primary visual and somatosensory cortices and, like 5-HT immunoreactive axons within the somatosensory cortex, form patches matching the distribution of the mystacial vibrissae. In adult animals, the density of these receptors in Lamina IV and the supragranular layers of the visual and somatosensory cortices is reduced relative to that in the surrounding cortex.
Low levels of binding (not significantly above background) were detected with [ 3H]SCH39166 in Lamina IV of the cortex and in choroid plexus; areas which had significant [ 3H]SCH23390 binding and are known to have a high density of 5-HT (5-HT2 and 5-HT1c respectively) receptors..
Physiologically characterized STT cells, one located in lamina V and two located in lateral Lamina IV, were intracellularly injected with horseradish peroxidase (HRP).
For these studies three Lamina IV or V STT cells in the lumbar spinal cords of three monkeys (Macaca fascicularis) were identified electrophysiologically and characterized.
Lamina IV showed the strongest center receptive field response probability magnitude (spikes/stimulus) and the shortest modal latency of evoked responses. In Lamina IV, in contrast to laminae II/III and V, response probability magnitude from center receptive field vibrissae was not significantly depressed whilst modal latency of the evoked response was significantly reduced..
Highest densities of binding sites were present in the hippocampus (CA1 to CA3 pyramidal cell layers and the granule cells of the dentate gyrus), the cerebral cortex (Lamina IV), the dorsal raphe nucleus and the interpeduncular nucleus.
Our interpretation is that there may be an extension of fine primary afferent fibers into lamina III and possibly Lamina IV following peripheral axotomy.
A distinct paucity of binding was apparent in Lamina IV of the cerebral cortex and in the choroid plexus, two areas thought to have D1 receptors.
These cells had dendrites which were oriented along the rostrocaudal axis and occupied lamina III, with some extension into Lamina IV and the ventral half of lamina II.
The cases were divided into three sets: in seven optimal cases the injections were restricted to lamina I; in ten nominal cases the injections involved laminae I-II or laminae I-III and occasionally Lamina IV; and in eight mixed cases laminae I-V were injected.
An analysis of the laminar distribution of the callosal cells revealed a significant increase in the percentage of callosal cells in Lamina IV in ME, DR, and TTX animals.
Ipsi and contralaterally projecting SPNs in laminae I, VII and VIII and the lateral spinal nucleus, which are known to give rise to long sensory pathways, were generated simultaneously throughout their neurogenic period (E12-E14), while ipsilaterally projecting SPNs in Lamina IV and the nucleus dorsalis, which give rise to short sensory pathways, completed neurogenesis one day later (E15).
Stimulation of a single facial vibrissa in rats receiving [ 14C]2-deoxyglucose leads to increased local cerebral glucose utilization in the corresponding contralateral barrel of Lamina IV of the first somatosensory cortex (SmI).
Whereas in the cervical spinal cord of pigeons Lamina IV and medial lamina V neurons are at the origin of postsynaptic pathways to the dorsal column nuclei, lumbar Lamina IV neurons do not project substantially beyond the cervical enlargement.
In normal rats GAD immunoreactive neurons and puncta are present in all laminae, with dense patches of GAD immunoreactive puncta centered on the barrels in Lamina IV.
At the concentration of ligand used (1 nM), there was a noticeable paucity of labeling in Lamina IV of the cerebral cortex and in the choroid plexus, regions of high 5HT2 and 5HT1C receptor binding, respectively.
Lamina IV is in microphthalmic mice significantly thinner than in normal animals. The reduction of the thickness of Lamina IV maybe caused by a reduced projection from the lateral geniculate nucleus..
The highest densities were localized to the median eminence-arcuate nucleus complex, hippocampal formation, Lamina IV of the cerebral cortex, lateral septum, neostriatum and cerebellum.
The small, sparsely spined neurons are not only in Lamina IV - like in other species - but they can also be found in laminae II to IV.
Cerebral cortical changes were characterized by a band-like intraparenchymal accumulation of Gaucher cells in Lamina IV with an accompanying astrogliosis.
These investigations examined SP-containing neurons located in the ventral half of Lamina IV and the lateral aspects of laminae V, VII, and IX, in lumbar spinal levels 1,2.
Labelled boutons were found bilaterally from Lamina IV to IX as well as in lamina X.
A significant number of cervical nucleus proprius neurons (Lamina IV) descends to the lumbar enlargement.
The projections to Lamina IV were organized in a similar manner as in lamina III, even though the projections showed a higher degree of overlap than in lamina III.
Plaque distributions differed; in the normal aged, plaques concentrated in Lamina IV; in the demented they were more evenly spread throughout the laminae.
A portion of labelled neurons in Lamina IV and on the ventromedial aspect of the lateral motor column in the ventral horn disclosed both PV- and CaBP-immunoreactivity.
Both cells have extensive axon terminal fields within trigeminal nucleus interpolaris as well as Lamina IV and V of trigeminal nucleus caudalis.
Though laminae I-V of the dorsomedial region of the medullary and cervical dorsal horns all exhibited contralateral endings of the mental and mylohyoid nerves, most such endings were found in laminae IIi-III, followed by Lamina IV, which suggests their involvement in the reception of mechanical stimuli and in the sensory motor reflexes of the orofacial region.
TB-labeled neurons projecting to the dorsal medulla were concentrated in Lamina IV and the medial parts of laminae V and VI (probably representing postsynaptic dorsal column--PSDC--neurons), but were also present in lamina I, the LSN, the lateral dorsal horn, and in laminae VII and VIII.
The primary negative component (N30) had an amplitude maximum in Lamina IV in both areas. Current source-density analysis (CSD) in connection with amplitude depth profiles indicated that the surface-negative component N30 is generated mainly by the synaptic excitatory inputs in Lamina IV.
In all 12 areas, bundling of apical dendrites is found both in Lamina IV and II/III. Differences in bundle structure are found to be more pronounced amongst bundles in Lamina IV than in lamina II/III.
These experiments show that substance P-positive axon terminals may originate from both small dorsal root ganglion neurons and from spinodorsal column nuclei neurons in Lamina IV.
CST termination is primarily located in Lamina IV and extends into lamina V and VI.
In C rats, lamination of enzyme activity was evident from 10 days by a band of higher activity in Lamina IV. Lamination of M-GPDH activity became less pronounced with increasing age, whereas distinct bands of high SDH activity in Lamina IV and VI remained also in adult rats. A band of higher enzyme activity in Lamina IV was present from 10 days, but it was markedly less distinct in the PD rats compared to the C rats between 15 and 25 days.
The mean increment in lCMRglc was 42% in Lamina IV of barrel-field cortex and 49% in ventrobasal thalamus.
However, the lamination was different from species to species, with high densities predominating in Lamina IV in rat, mouse and guinea-pig cortex, in lamina II and VI in cat and monkey cortex and in lamina V in human cortex.
Lamina IV showed staining associated with medium-sized and large cell bodies.
Beyond their clinical implications, these results offer an unique view of the timing and sequence of cortical visual processing in the alert monkey, including the somewhat surprising findings of an extremely short-latency response in Lamina IVA, a contra- over ipsilateral latency advantage throughout Lamina IV, and the lack of a consistent flash-evoked response in the major cortical recipient of the magnocellular system, Lamina IVCa.
Some such cells, lying in Lamina IV, were similar to spinocervical tract cells and may have projected to both lateral cervical and dorsal column nuclei.
The commonest type (C), centred on Lamina IV, had dendritic trees greatly extended rostrocaudally and restricted mediolaterally in the lateral dorsal horn, the extension and restriction diminishing for more medial cells.
With the exception of the striate cortex, in the neocortex, a tri-laminar pattern was seen consisting of a high density across laminae I-III, a layer of low density corresponding to the region of Lamina IV, and a band of moderate density across laminae V and VI, except for [ 3H]AMPA where the middle zone of low density was usually wider.
Combined injections of fluorescent retrograde tracers into the lateral thalamus and parabrachial area resulted in double labeling of projection neurons in lamina I, Lamina IV VIII and the lateral spinal nucleus of the cervical and lumbar enlargements.
In addition there is a general increase in synaptic densities and numbers as one proceeds from lamina I to Lamina IV.
SP neurons were found dorsal to the central canal (CC) and in Lamina IV throughout the cord. In addition, two dense plexuses of SP fibers were noticed in Lamina IV.
Very high densities were observed in Lamina IV of the neocortex (with higher densities in the occipital than in the frontal pole), the substantia innominata and molecular layer of the dentate gyrus. With both approaches, a preferential enrichment in omega 1 sites was observed in Lamina IV of sensorimotor cortical regions and in the extrapyramidal motor system (globus pallidus, ventral thalamic complex, subthalamic nucleus, substantia nigra and cerebellum).
With small injections of the fluorescent dye Fast blue into parts of the DCN it could be shown that aside from a primary afferent projection a well-developed postsynaptic dorsal column system exists only for the wing and that it takes its origin in the neurons of the Lamina IV of the spinal dorsal horn..
In the cerebral cortex, H1-receptors are present in all areas and layers with a higher density in Lamina IV.
Manual or mechanically controlled brush stroking of a single vibrissa (typically C3) was used in order to evoke neural activity and increase glucose utilization in a single cortical barrel in Lamina IV and in adjacent supra- and infragranular layers in register with the single cortical barrel labeling in Lamina IV.
These areas include Lamina IV of the parietal cortex, substantia innominata, anterior amygdaloid nucleus, substantia nigra, zona incerta, and molecular layer of the cerebellum.
Stimulation of rat facial vibrissae increases glucose utilization in the corresponding barrels (Lamina IV) and associated columns in laminae I-VIa of the contralateral first somatosensory (SmI) cortex as assessed autoradiographically by the uptake of [ 14C]2-deoxy-glucose (2-DG).
Type I collaterals divide into well defined medial and lateral collateral branches which arborize mainly in lamina III with a few branches to Lamina IV.
Large spiny stellate cells were not only seen in Lamina IV but also quite frequently in laminae II and III.
At 0.5 and 1.5 mg/kg, depression by pentobarbital was positively correlated with the depth of the recording site in the spinal cord (laminae IV-VI), i.e., neurons in deeper laminae (V-VI) were attenuated, while neurons in Lamina IV were unaffected.
Neurons with somata located more ventrally (deep Lamina IV and V) were also postsynaptic to large (greater than 2 microns) electron lucent profiles which formed multiple synapses with the labelled cells.
R(-)- or S(+)-baclofen were injected into Lamina IV-V of the sensorimotor cortex of the rat.
Spinal neurons projecting to the facial nucleus, located in the lateral portion of lamina V from the C1 to C4 segments, had long dendrites extending into Lamina IV. Dorsal root fibers were distributed mainly to Lamina IV at the C1 and C2 segments. These findings indicated the possibility of direct connections between the primary afferent fibers and spinal neurons projecting to the facial nucleus in Lamina IV of the upper cervical cords.
Similar levels of binding for both ligands were found in brain regions enriched in BZD1 receptors, e.g., substantia nigra pars reticulata, inferior colliculus, cerebellum, and cerebral cortex Lamina IV.
The density of glycine-labeled neurons in Lamina IV, however, was significantly less than the number observed in lamina III even though lamina III was farther away from the injection site which was at the boundary between laminae V-VI.
The terminal arborizations of the HFAs had a distinctive morphology identical to the flame-shaped arbors described in earlier Golgi studies and included synaptic boutons extending from inner lamina II to Lamina IV. The morphologies of the RA and SA terminal arborizations were similar to each other, but the former tended to be concentrated in Lamina IV with branches in III and V, whereas the latter tended to V with few branches more superficial than Lamina IV. While there are similarities between the morphology of the central terminals of cutaneous low-threshold mechanoreceptors in the rat and those previously described in the cat (for example, the longitudinally continuous arrangement of the mediolaterally restricted flame-shaped HFA arborizations and the discontinuous RA arborizations arising from a dorsally located axon), there are also some major differences: the large number of HFA arbors extending to lamina IIi and to Lamina IV rather than being restricted to lamina III, the deeper location of the RA arbors (in laminae IV and V rather than lamina III),(ABSTRACT TRUNCATED AT 400 WORDS).
Autoradiography showed that the receptor subpopulation labelled with [ 125I]204-090, which we named SS1, was preferentially localized in layers V and VI, whereas the subpopulation having low affinity for somatostatin octapeptides (named SS2), measured with somatostatin-28 radioligand, was concentrated in the superficial cortical layers (I-IV) and particularly enriched in parts of Lamina IV..
Cortical regions involving the representation of the neck musculature were shown to project principally ipsilaterally to Lamina IV of the SC as well as to the anterior pretectal nucleus.(ABSTRACT TRUNCATED AT 400 WORDS).
Dorsal horn neurons situated more than about 0.25 mm medial of the lateral edge (at the level of Lamina IV) of the dorsal horn lost their light touch receptive fields, and did not acquire new light touch RFs on the proximal part of the hind limb for as long as 49 days after nerve transection.
An extracellular recording of excitatory amino acid-induced activity of a dorsal horn Lamina IV cell is shown.
Labeled cells in Lamina IV of the dorsal horn were only observed when injections spread dorsally, into the dorsal column nuclei, and are thus not considered to be at the origin of the spinosolitary tract.
A different laminar distribution was seen in the visual cortex, where a low receptor density was observed in Lamina IV but higher density in laminae II and VI.
The only apparent difference between rhizotomy and capsaicin treatment occurred in Lamina IV, where rhizotomy produced a greater reduction than capsaicin. The greater reduction in Lamina IV after rhizotomy would suggest that GABAB sites may be present on large-diameter afferent fibres that terminate in this region as well as on smaller-diameter C and A delta fibres..
In addition to primary afferent fibers many ipsilaterally located Lamina IV neurons of cervical segments project to the dorsal columns, indicating a substantial postsynaptic dorsal column pathway in birds.
Lamina IV cells had mechanical thresholds comparable to those of the primary afferents, significantly lower than the thresholds of cells of laminae III or VI. The receptive fields (RF) of the Lamina IV cells were significantly larger than those of the primary afferent fibers or of the lamina VI cells.
Within visual cortical areas 17 and 18 of adult brains, the density of beta 1 and beta 2 adrenergic receptors was highest in laminae I-III, lowest in Lamina IV, and intermediate in laminae V-VI.
After birth a network of fine vessels, presumable precursors of capillaries, increased, particularly vascular layer 3 (neuronal Lamina IV and Va).
In both areas the dendritic pattern of lamina II/III is characterized by vertical bundles reminiscent of the pattern in Lamina IV/V. They consist mainly of apical dendrites from lamina II/III pyramidal cells and receive branches from dendrite bundles in Lamina IV/V, i.e., branches from apical dendrites arising from lamina V pyramidal cells. Besides these features in common, the lamina II/III bundles in the visual cortex on the one hand and in the motor cortex on the other differ with regards to the size and shape of individual bundles as well as to the extent of connections with bundles in Lamina IV/V..
Thus, quazepam and halazepam preferentially bind to benzodiazepine type-1 receptors in Lamina IV of the cerebral cortex, the zona incerta, substantia nigra and the cerebellum..
In adults, the A1 adenosine receptors were found in all lamina except for Lamina IV, and in particularly high concentration within laminas I-III.
L-STT cells were located mostly in Lamina IV, whereas most LM-STT cells were found in lamina V.
MUA in the 20-60 msec range shows phasic increases throughout Lamina IV, which are maximum in amplitude within Lamina IVA. A subsequent component, P65, coincident with a decrease in MUA to below the spontaneous level co-located with a Lamina IVCb current source, probably arises from intracortically generated inhibitory activity within IVCb.
The striking capillary density of Lamina IV overlaps the stria Gennarii and, like it, is limited to area 17.
Neurons in each lamina of the nucleus have dendritic arbors which ramify extensively within adjacent laminae, except cells in lamina IIIb, which have relatively few dendrites that cross into the cell-free zone and Lamina IV..
Moreover, [ 3H]ketanserin (serotonin type-2) binding is significantly decreased in Lamina IV of the anterior and middle cortex on the lesioned vs control side. This suggests that at least a certain proportion of serotonin type-2 receptor binding sites are located on cholinergic terminals in Lamina IV of the rat cortex.
Cell bodies were frequently observed in Lamina IV.
In normal mice, beta-1-receptors predominate in striatum, cortical layers I to III, hippocampal regio superior and some thalamic nuclei; they are moderately concentrated in cortical layers V and VI and poorly represented in Lamina IV.(ABSTRACT TRUNCATED AT 400 WORDS).
Noxious stimuli also excite a system with contralateral topographical projection, high synaptic security and termination in Lamina IV. Pronounced inhibition of cells in Lamina IV and more superficial layers is induced by activity in low threshold afferents.
However, the increase in galactocerebroside resulted entirely from increases in the lower lamina of somatosensory cortex (Lamina IV and below), suggesting on-going myelination of afferent and efferent axons.
Neurons located in either lamina I or Lamina IV were recorded. Most Lamina IV neurons had short-latency responses to electrical stimulation of a cutaneous nerve and were activated by stimulation of sensitive mechanoreceptors.
Precise localization showed that large fibers project to deeper, medially located areas of the dorsal horn (near Lamina IV) whereas smaller fibers project primarily to more laterally located superficial layers.
Each nucleus received only ipsilateral afferents with most of the labeled cells forming a band which covered the mediolateral extent of the dorsal horn in an area that resembled Lamina IV in the cat.
staining occurred in Lamina IV, with alternating rows of dark and lightly reactive puffs superimposed in exact register.
Contrast sensitivity and orientation selectivity were measured for neurons in Lamina IV of macaque striate cortex. The assignment of each recording site to a subdivision of Lamina IV was made by histological reconstruction of each electrode penetration from sections reacted for cytochrome oxidase and stained for Nissl substance. Both of the upper subdivisions of Lamina IV (IVa and IVb) contain a mixture of neurons with high and low contrast sensitivities. There were orientation selective neurons within all subdivisions of Lamina IV, even in IVc, whereas non-oriented neurons were found only in those subdivisions that receive a direct parvocellular geniculate input (IVa and IVc beta)..
Lamina IV was restricted to the dorsal horn and did not extend through the midline..
In semithin sections cut tangentially with respect to the surface of the cerebral cortex and with a side length of at most a few mm, it is extremely difficult to be certain which lamina has been sectioned, for instance lamina III or upper Lamina IV. The relation between these three zones and the cytoarchitectonic pattern is as follows: Zone A corresponds to the cytoarchitectonic lamina I; zone B comprises lamina II/III, Lamina IV and the upper half of lamina V; zone C corresponds to the lower half of lamina V and all of lamina VI.
Lamina IV stellate cells and lamina V pyramidal cells were studied in Golgi material of visual cortex of rabbits ranging in age from 10 days to adult.
(3) The sizes of labelled boutons decreased significantly and linearly with depth from Lamina IV to VI.
[ 3H]beta-endorphin labeled some clusters as well as the subcallosal streak in the striatum, the nucleus accumbens, Lamina IV of the cortex, medial regions of the thalamus, hippocampus, inferior colliculus, dorsal raphe, median raphe and pontine nuclei.
Counts have been made of the number of cells in individual laminae of the cortex in area 17 of the macaque monkey and cat, and degenerating terminals of geniculo-cortical axons have been studied with the electron-microscope in laminae IVab and IVc of the cortex of area 17 and Lamina IV of area 18 of the visual cortex of the cat. In Lamina IVab of area 17 of the cat the axon terminals of Y-type geniculo-cortical fibres make many more synapses per bouton than those of X-type fibres ending in Lamina IVc. The geniculo-cortical axons ending in Lamina IV of area 18 also make more multisynaptic boutons than those in Lamina IVc of area 17.
However, when the animals were sacrificed by decapitation, the concentrations varied among the layers with the highest being detected in the internal granular layer (Lamina IV) followed by the external granular (II), external pyramidal (III) and internal pyramidal layers (V).
Lamina IV did not appear to have a peak density at 70 days of age, but there was a gradual decline after this age in the synaptic density toward adulthood, as for other laminae. Lamina IV was the least affected. Much of the changes in the development of synapses involved asymmetric axo-spinous synapses, with a small reduction in the number of symmetric synapses chiefly in Lamina IV..
One system appears to be specific with topographical distribution and activates cells mainly in Lamina IV in a restricted region of the coronal gyrus.
In a small region of the coronal gyrus, cells in Lamina IV were responding at stimulation of contralateral tooth pulp afferents with short latency, steeply rising EPSPs, and one or two action potentials followed by an IPSP.
In the cat, DCPS neurons were concentrated in a band centered in Lamina IV that swept down through laminae V-VI along the medial border of the dorsal horn.
Axonal profiles with rounded synaptic vesicles (R) constitute about one-fourth of the total synaptic population in Lamina IV and gradually increase in number to comprise more than a third of the synaptic population in lamina VI. Conversely, profiles with flattened vesicles (F) make up two-thirds of the synaptic population in Lamina IV and slightly more than half in lamina VI.
A second type of degeneration, electron-lucent degeneration, is seen in laminae V and VI, and only occasionally in Lamina IV.
Laminar analysis showed that the region with initial positivity in the response to stimulation of the tooth pulp coincided with an intracortical negative focal potential of maximum amplitude mainly in Lamina IV. It is postulated that the projection system underlying the initially positive cortical responses has a topographically arranged cortical projection terminating mainly in Lamina IV.
In both these cortical areas, the principal site of geniculocortical termination was in Lamina IV with some diminished input spreading into laminae II-III and a light termination in layer I overlying the Lamina IV termination. The lateral posterior nucleus (LPN) was similarly demonstrated to project to both striate and occipital cortices, the projection terminating principally in Lamina IV of occipital cortex, lamina V of striate cortex, and layer I over a large, continuous area of the posterior pole of the cortex.
However, long-ranging projections were observed that were more extensive than predicted from the somatotopy of dorsal horn cells: these long-ranging projections may reflect the presence of normally ineffective synapses (synapses that do not cause postsynaptic discharge during receptive-field mapping of dorsal horn cells,) or a misconception of dorsal horn cell somatotopy in S2 and caudal segments, or the existence of a functionally separate cell group in ventral Lamina IV and lamina V of these segments.
Three types of nonpyramidal cells were observed in Lamina IV and the lower part of lamina III: (1) large, multipolar cells with radiate, spine-free dendrites and stout axons which arborized locally, (2) spiny multipolar cells with vertically aligned dendrites and ascending axons which arborized in lamina II and III via long horizontal collaterals, and (3) spine-free bipolar cells with vertical dendrites and axons which arborized in a narrow vertical column adjacent to the dendrites.
Injections into the nucleus ventralis posterior of the thalamus resulted in labeling of neurons in lamina I (subnucleus zonalis), the deeper part of Lamina IV (the subnucleus magnocellularis) of the nucleus caudalis and in lamina V (the lateral extension of the nucleus medullae oblongatae centralis) on the contralateral side. Injections into the known projection areas of the cerebellar cortex labeled mainly ipsilaterally the trigeminocerebellar neurons in a restricted ventrolateral area of Lamina IV of the nucleus caudalis at its rostral level and in lamina V. They were located in laminae I and III, the deeper part of Lamina IV of the nucleus caudalis and in lamina V.
Lamina IV neurons were concentrated along laminar edges, while those in laminae V and VI were distributed more homogeneously.
Of the 218 units examined, 133 were located in Lamina IV and 85 in lamina V.
Electrical stimulation of SI produced SC unit responses at the same depths as did peripheral tactile stimulation, in SC laminae IV and VI; mapping of corticotectal projections was performed only in Lamina IV.
The termination of geniculocortical fibres within the different subdivisions of Lamina IV in area 17 of the visual cortex of the monkey has been studied quantitatively with the electron microscope. In Lamina IVC alpha the axon terminals of fibres coming from the magnocellular layers of the lateral geniculate nucleus (LGN) make significantly more synapses per bouton than those of fibres arising from the parvocellular layers and terminating in laminae IVA and IVC beta. In all parts of area 17 examined there was a clear difference in the relative proportions of multisynaptic geniculocortical boutons between the alpha and beta divisions of Lamina IVC. Calculations have shown that a single cell in the magnocellular laminae of the LGN may make about 6 times as many synaptic contacts within Lamina IV of the visual cortex than one in the parvocellular laminae. It has also been estimated that there are at least 500 million geniculocortical boutons, or 1200 million synapses, in Lamina IVC alpha and 100 million boutons, 1200 million synapses, in Lamina IVC beta for one hemisphere, giving an approximate total number of 1500 million boutons and 2400 million synapses..
All Lamina IV neurons are medium or large sized "antenna-like neurons' whose dorsally oriented, cone-shaped dendritic domaine may have a height of 1000 micrometers.
Neurons with broad tuning curves tended to be restricted to Lamina IV and its environs, being concentrated in the deep part of lamina II-III and the upper part of Lamina IV ab.
For example, only dopaminergic sites were found in the glomerular layer of the olfactory bulb; only serotonergic sites were found in Lamina IV of the neocortex, and a high concentration of unique spiperone sites was found in parts of the hippocampus..
These experiments demonstrated that the tectum receives axons from pyramidal cells in layer V of the ipsilateral sensorimotor cortex, contralateral Lamina IV of all levels of the spinal cord, the contralateral dorsal column nuclei, lateral cervical nucleus, internal basilar nucleus, and nucleus of the spinal trigeminal tract.
These areas included Lamina IV of the cerebral cortex, nucleus tractus diagonalis, some thalamic nuclei, the zona incerta and the dorsal lateral geniculate body..
The termination region of rapidly adapting afferents was limited almost exclusively to lamina III, with only slight extension into Lamina IV.
Morphine-like (mu) receptors, labeled by 125I-labeled [ D-Ala-2MePhe4Met(O)5-ol]enkephalin, are concentrated selectively in Lamina IV of the cerebral cortex, certain thalamic nuclei, and the periaqueductal grey, while delta receptors, labeled by 125I-labeled [ D-Ala2-D-Leu5]enkephalin, are more diffused, having high densities in cerebral cortex, corpus striatum, amygdala, and olfactory tubercle.
About 25% are in lamina III, 60% in Lamina IV and 10% in lamina V.
The collaterals coursed cranially on a direct path through the dorsal horn to Lamina IV or V before branching. Occasionally, less extensive arborizations were seen more dorsally in Lamina IV and V.
At the cortical level, Lamina IV in area 17 of normal cats was stained darkly as a continuous band.
At posterior medullary levels projections also exist to laminae IV, V, and VI of the spinal nucleus of V (although those to Lamina IV are circumscribed), to the deep layers and lateral margin of the cuneate nucleus, and to the inferior olive.
Ascending spinal afferents to the dorsal column nuclei originate mainly from the ipsilateral dorsal horn, particularly from its medial part at upper cervical levels and from a band of gray, throughout the cord, largely corresponding to Lamina IV and adjacent laminae.
For all of the cortical areas examined except area 17, Lamina IV is the principal 'receptive' layer for associational fibers, while layers III and II, as well as V and VI within the same column, receive progressively less input.
4th It is possible to differentiate between pyramidal cells and stellate cells of Lamina IV.
The group of cells rich in cytoplasm is related to pyramidal cells, multiangular cells and stellate cells of Lamina IV.
It is concluded that these data that anatomic specification of convergence occurs in the LCN with respect to receptor connectivity, and that this specification originates in Lamina IV of the dorsal horn.
SCT cells were found predominantly, if not exclusively, within Lamina IV, with some extension into medial lamina V. No apparent mediolateral or dorsoventral density gradient was observed within Lamina IV; cells of all sizes were labeled.
There was a loss of normal activity in Lamina IV within the focus and in somatosensory and occipital cortex far behind the focus. Increased metabolic activity was found in a small area in contralateral homotopic cortex, in lamina Vb with columns extending above this from Lamina IV to the surface.
After appropriate lesions, rubral axons and their synaptic terminals were found in electron micrographs of Lamina IV, V and VI as well as within the dorsal extreme of lamina VII.
They descended through laminae I-III of the dorsal horn into the deeper parts of Lamina IV or into lamina V, before turning and ascending back into superficial Lamina IV and lamina III where they branched profusely to give rise to their terminal arborizations. Terminal boutons, most commonly of the ;en passant' type, were numerous in lamina III, but were also seen in the dorsal part of Lamina IV and in ventral lamina II.
Many neurons in Lamina IV had dense, bushy dendritic fields. Lamina V contained, in addition to bushy cells similar in appearance to those of Lamina IV, increasing numbers of neurons with radiating dendritic fields.
These neurons are mainly located in Lamina IV and medially in more ventral laminae of the dorsal horn on the side ipsilateral to the medullary injection.
Most of the units were located in Lamina IV of the dorsal horn and had their receptive fields in the ipsilateral foot.
Twenty cells, driven only by non-noxious cutaneous stimulation and mainly located in Lamina IV, were not affected by the administration of algogenic substances.
Cells projecting to the dorsal medulla are mainly localized in Lamina IV and, more ventrally, along the medial border of the dorsal horn in the brachial and lumbosacral cord. From cases in which bilateral HRP injections were preceded by spinal tractotomy, it appears that the axons of at least the majority of labelled cells in Lamina IV ascend in the ipsilateral dorsal quadrant of the spinal cord. Labelled cells in these cases are found almost exclusively in the medial part of lamina VI at upper cervical levels and, at brachial and lumbosacral levels, throughout Lamina IV and medially in lamina V on the side of the cord ipsilateral to the injection.
They, however, had no effect on cells in Lamina IV.
The same areas contained labelled cells after injections in the ventroposterior thalamic region, but in such experiments labelled cells were also present in the Lamina IV-V region of the spinal cord, in the gracile and main cuneate nuclei and in the external cuneate nucleus.
A specialized type of spinal cord cell has its cell body in Lamina IV and has a small low threshold cutaneous receptive field which is remarkable for its abrupt edge.
A method is described to study the modification in the activity of the Lamina IV and V cells of the dorsal horn under the intra-arterial administration of bradykinin into the hind limb of the spinal cat.2. The modifications induced by intra-arterial injection of bradykinin preferentially affected the lamina V cells (77% of the units) and produced few changes in the Lamina IV cells (16% of the units showed variations).3.
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