In control owls or prism-adapted owls, which experience small instructive signals, the frequency distributions of pCREB/CREB values obtained for cell nuclei within the external nucleus of the inferior colliculus (ICX) were unimodal. 
To track the origin of SSA, we analyzed responses of neurons in the external nucleus of the inferior colliculus (ICX; the source of auditory input to the OT) to similar sequences of sound bursts.
The combination of ITD and ILD in the subthreshold responses of space-specific neurons in the external nucleus of the inferior colliculus (ICx) is well described by a multiplication of ITD- and ILD-dependent components.
Immunohistochemical protein expression studies of IC showed more serotonin 2B receptor cells in old mice relative to young adult mice, particularly in the external nucleus.
Auditory neurons in the owl's external nucleus of the inferior colliculus (ICX) integrate information across frequency channels to create a map of auditory space.
The first nuclei that belong exclusively to either the forebrain or the tectal pathways are the nucleus ovoidalis (Ov) and the external nucleus of the inferior colliculus (ICx), respectively.
Cells that phase-locked were mainly located in the central nucleus but also occurred in the dorsal cortex and external nucleus. The upper limits in the three divisions were central nucleus, >1,000 Hz; dorsal cortex, 700 Hz; external nucleus, 320 Hz. The mean latencies also varied and were central nucleus, 8.2 +/- 2.8 (SD) ms; dorsal cortex, 17.2 ms; external nucleus, 13.3 ms.
The external nucleus of the inferior colliculus (ICx) receives ascending projections from both auditory and somatosensory nuclei.
The distribution of these cells within the IC was mostly restricted to the external nucleus of the IC (ICX), in which the auditory space map is assembled.
Both long-term deafness and chronic electrical stimulation altered temporal resolution of neurons in the central nucleus (ICC) but not in the external nucleus.
The highest transcript and protein levels were found in the external nucleus of the inferior colliculus and paraolivary nucleus.
In the midbrain auditory localization pathway of the barn owl, a map of auditory space is relayed from the external nucleus of the inferior colliculus (ICX) to the deep and intermediate layers of the optic tectum (OT) and from these layers to the superficial layers.
At birth, the CNTFRalpha immunolabeling was clearly present in somata of the external nucleus of the inferior colliculus but was diffuse throughout brainstem auditory nuclei.
In the external nucleus of the inferior colliculus, in addition to classical auditory neurones, neurones are found which react to the vocalizations of group mates, but not to self-produced vocalizations. The results suggest that the external nucleus of the inferior colliculus and bordering tegmentum are involved in vocalization-dependent auditory gating processes..
To test whether space-specific cells are sensitive to spectral interaural intensity difference cues, pure-tone interaural intensity difference tuning curves were taken at multiple different frequencies for single neurons in the external nucleus of the inferior colliculus.
The barn owl ( Tyto alba) is capable of capturing prey by passive hearing alone, guided by a topographic map of auditory space in the external nucleus of its inferior colliculus.
We could discriminate eight structures that belong to the three subnuclei of the inferior colliculus [ the central nucleus (ICC), the superficial nucleus (ICS), the external nucleus (ICX)] and to the optic tectum.
We studied the development of the projection from the external nucleus of the inferior colliculus (ICX) to the optic tectum (OT) in the barn owl.
In particular, in the external nucleus of the inferior colliculus (ICx), where cells are activated by specific values of ITD, neural activation has been recently observed to be dependent on some measure of the level of cross-correlation between the input auditory signals.
In barn owls, this process takes place in the external nucleus of the inferior colliculus (ICX).
Cortical electrical stimulation facilitated auditory responses of neurons in the external nucleus of the inferior colliculus (ICx) while electrical stimulation in the ICx decreased auditory responses of ICc neurons.
Previously we found that 86% of neurons in the ventral division of the external nucleus of the inferior colliculus (ICXv) were directionally selective for linear FM sweeps and that selectivity was dependent on sweep rate.
The model consists of the neural networks of the central nucleus (ICc) and external nucleus (ICx) of the inferior colliculus.
The parallel pathways that process these cues merge in the external nucleus of the inferior colliculus where the space specific neurons are selective to combinations of ITD and ILD.
When barn owls are raised wearing spectacles that horizontally displace the visual field, the auditory space map in the external nucleus of the inferior colliculus (ICX) shifts according to the optical displacement of the prisms.
The nucleus centralis of the torus semicircularis receives few 5-HT-, TH-, substance P-, and menkephalin-immunoreactive fibres and terminals, in marked contrast to the external nucleus laminaris of the torus semicircularis, in which 5-HT-, TH-, substance P-, and menkephalin-immunoreactive elements and cell bodies show a laminar distribution.
This electrophysiological study tests the hypothesis that one possible neural pathway for corticofugally inhibited neurons in the central nucleus of the inferior colliculus (ICc) of the big brown bat, Eptesicus fuscus, is mediated through excitatory projections from the auditory cortex (AC) to the external nucleus of the IC (ICx), which then sends inhibitory inputs to the ICc.
The auditory space map in the external nucleus of the inferior colliculus (ICX) of barn owls is highly plastic, especially during early life.
In the midbrain sound localization pathway of the barn owl, a map of auditory space is synthesized in the external nucleus of the inferior colliculus (ICX) and transmitted to the optic tectum.
In the external nucleus (ICX) of the owl's inferior colliculus, ITD curves show multiple peaks when the signal is narrow-band, such as tones.
The two pathways converge in the external nucleus of the inferior colliculus to give rise to neurons that are selective for combinations of the two cues.
We report descending projections from the medial and dorsal divisions of the medial geniculate body to the external nucleus of the ipsilateral inferior colliculus and lower brainstem of the gerbil.
We believe this area to be the ventral extent of the external nucleus of the inferior colliculus (ICXv).
Similar effects were found at the inferior colliculus, mostly at the external nucleus, and at the cortex, mostly at the anterior and less at the secondary auditory cortex but not at the primary auditory cortex.
In the barn owl (Tyto alba), the external nucleus of the inferior colliculus (ICX) contains a map of auditory space that is calibrated by visual experience.
We analyzed the representation of ITD in normal and device-reared owls in two nuclei in the ascending pathway: the external nucleus of the inferior colliculus (ICX), the primary source of ascending auditory input to the tectum, and the lateral shell of the central nucleus of the inferior colliculus (ICCls), the primary source of input to the ICX.
Characteristic differences were seen between the temporal response properties of neurons in the external nucleus (ICX; approximately 16% of the recordings) and neurons in the central nucleus (ICC; approximately 81% of all recordings) of the IC: 1) in all three experimental groups, neurons in the ICX had significantly lower Fmax and longer response latencies than those in the ICC.
The external nucleus of the inferior colliculus (ICX), where a map of auditory space is synthesized, is a major site of plasticity.
The external nucleus of the inferior colliculus in the barn owl contains an auditory map of space that is based on the tuning of neurons for interaural differences in the timing of sound. It has been found that, in an external nucleus that is expressing a learned, abnormal map, the circuitry underlying the normal map still exists but is functionally inactivated by inhibition mediated by gamma-aminobutyric acid type A (GABAA) receptors.
The majority of retrogradely labelled neurons were found in the external nucleus of the inferior colliculus and here predominantly in layer 2. Injections focused onto the medial division of the medial geniculate body additionally labelled magnocellular neurons in layer 3 of the external nucleus and a few neurons in the central nucleus. More ventrally located injections, focused onto the posterior intralaminar and peripeduncular nucleus, almost exclusively labelled neurons in layer 1 of the external nucleus and the dorsal part of the dorsal nucleus.
The external nucleus of the inferior colliculus and medial division of the medial geniculate nucleus were associated more strongly with this pattern for group TL-, which was interpreted as representing the change of the associative value of the tone by the light, mediated through extraauditory influences on these two regions.
The external nucleus of IC (ICx) receives convergent output from a broad range of ICc neurons, which is not tonotopically organized, and projects to several nuclei with major motor connections.
Neural tuning for interaural time difference (ITD) in the optic tectum of the owl is calibrated by experience-dependent plasticity occurring in the external nucleus of the inferior colliculus (ICX).
In addition, we confirmed previously reported projections of the AAr to the basal ganglia, the external nucleus of the inferior colliculus (ICX), the deep layers of the optic tectum, and various brain stem nuclei.
Input projections were observed contralaterally from: all three divisions of cochlear nucleus; intermediate and dorsal nuclei of the lateral lemniscus (LL); and the central nucleus, external nucleus and dorsal cortex of the IC. Input projections were observed ipsilaterally from: the medial and lateral superior olivary nuclei; the superior paraolivary nucleus; the dorsolateral and anterolateral periolivary nuclei; the dorsal and ventral divisions of the ventral nucleus of LL; the dorsal and intermediate nuclei of LL; the central nucleus, external nucleus and dorsal cortex of the IC outside the injection site; and small projections from central gray and the medial geniculate body.
After multiple injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the SC, the heaviest concentrations of labelled cells were found in the nucleus of the brachium (BIN) and external nucleus of the inferior colliculus, with much weaker labelling in the nucleus sagulum, dorsal, intermediate and ventral nuclei of the lateral lemniscus, paralemniscal regions, and periolivary nuclei.
Neurons in the external nucleus of the inferior colliculus (ICx) resolve the ambiguity by gathering ITD information across many frequencies, thereby suppressing false responses (side peaks, SP) relative to the true ITD (the main peak, MP) in a response versus ITD curve.
No afferent input was provided to the N.Ov from the external nucleus of the inferior colliculus or the optic tectum.
The map of auditory space in the external nucleus of the inferior colliculus (ICX) of the barn owl is calibrated by visual experience during development.
The ICc lacks direct motor outputs but sends a major projection to the external nucleus of IC (ICx), which does project to the sensorimotor integration nuclei within the AGS neuronal network.
In spontaneously active neurons in the external nucleus of the inferior colliculus of the barn owl, a stimulus-driven discharge was followed by a quiescent period lasting tens of milliseconds before the spontaneous activity resumed.
Efferent projections were observed ipsilaterally in: medial and ventral divisions of the medial geniculate body (MGB); middle layers of the superior colliculus; central gray; and external nucleus (E), dorsal cortex (DC) and central nucleus of IC.
In the rats which were injected unilaterally with tetramethylrhodamine-dextran amine (TMR-DA) and Fluoro-Gold (FG) respectively into the posterolateral ventral thalamic nucleus and the external nucleus of IC, a number of neuronal cell bodies labeled retrogradely with both TMR-DA and FG were found throughout DCN contralateral to the injections.
Brain sections from such rats showed dense labeling in both the dorsal cortex and external nucleus of the inferior colliculus.
The divisions of the inferior colliculus could be distinguished on the basis of GluR1-4 immunoreactivity, with high levels of GluR4 and moderate levels of GluR1 in the external nucleus.
The external nucleus of the inferior colliculus (ICx), an auditory center that projects massively to the tectum, is the main site of plasticity; however, it is unclear by what mechanisms the alignment between the auditory map in the ICx and the visual map in the tectum is established and maintained.
In auditory structures retrograde labeling was found mainly in the external nucleus of the inferior colliculus and in the nucleus of the brachium of the inferior colliculus.
The external nucleus of IC (ICx) is a suggested site of convergence of the auditory output onto the sensorimotor integration network components for AGS in the brainstem.
In the guinea-pig two subcortical structures have been shown to contain representations of auditory space, the deep layers of the superior colliculus (SC) and the external nucleus of the inferior colliculus (ICX).
The output of this cross-correlation is displayed as neural activity across the auditory space map in the external nucleus of the owl's inferior colliculus.
The external nucleus of the owl's inferior colliculus (ICx) contains a retina-like map of space composed of "space-specific" auditory neurons that have spatially limited receptive fields.
In the present investigation, we show that the amplitudes of all peaks in the click-evoked response from the external nucleus of the inferior colliculus decrease during a 30 min exposure to a tone (104 dB sound pressure level (SPL) at 4 kHz and 8 kHz). After tone exposure, the amplitudes of two of the peaks of the response from the external nucleus of the inferior colliculus that reflect the input from more caudal structures slowly returned to baseline levels, whereas the amplitudes of the two peaks reflecting neuronal activity in the inferior colliculus increased above baseline levels and remained at the increased levels for at least 90 min following exposure to the tone. We also show that exposure to a 4 kHz tone at 104 dB SPL causes changes in the neuronal processing of tonebursts in the form of changes in the temporal integration function for one of the peaks of the response from the external nucleus of the inferior colliculus that originates in the inferior colliculus.
Alignment of auditory and visual receptive fields in the optic tectum of the barn owl (Tyto alba) is maintained through experience-dependent modification of auditory responses in the external nucleus of the inferior colliculus (ICX), which provides auditory input to the tectum.
Cholecystokinin-like immunoreactive (CCK-LI) neurons are observed in the pericentral nucleus, the external nucleus and the dorsomedial part of the central nucleus of the cat's inferior colliculus.
Recordings were made in the output fibers of nucleus laminaris (NL), the anterior division of the ventral lateral lemniscal nucleus (VLVa), the core of the central nucleus of the inferior colliculus (ICcC), the lateral shell of the central nucleus of the inferior colliculus (ICcLS), and the external nucleus of the inferior colliculus (ICx).
Additional projections arrive from the thalamic reticular nucleus, external nucleus of the inferior colliculus, and pericollicular tegmentum.
Bipolar recordings from the external nucleus of the inferior colliculus showed that L-baclofen caused a reduction in the amplitude of three or four distinct peaks in this response. D-Baclofen had no detectable effect on the response from the cochlear nucleus, and had only a slight effect on one component of the response from the external nucleus of the inferior colliculus.
Finally, the use of knife cuts through the midbrain indicated that the ICCN sends an important projection to the external nucleus and that this projection plays a vital role in the propagation of seizure activity from the site of seizure initiation in the ICCN.
A topographic representation of the auditory azimuth has been described in the external nucleus of the inferior colliculus (ICX) of the guinea-pig [ 3].
The evaluation of the spontaneous activity of 471 units from the external nucleus of the IC revealed that salicylate induces an increase of the spontaneous activity and the emergence of a bursting type of activity longer than 4 spikes.
Dynamic changes in ITD tuning similar to those recorded in the optic tectum also occurred in the external nucleus of the inferior colliculus (ICX), which provides the major source of ascending auditory input to the tectum.
Onset units were the predominant unit found in the external nucleus, whereas sustained units were found almost exclusively in the central nucleus.
The pharmacology of auditory responses in the inferior colliculus (IC) of the barn owl was investigated by iontophoresis of excitatory amino acid receptor antagonists into two different functional subdivisions of the IC, the external nucleus (ICx) and the lateral shell of the central nucleus (lateral shell), both of which carry out important computations in the processing of auditory spatial information.
Extrathalamic regions receiving input included the pontine gray, external nucleus of the inferior colliculus, pericollicular tegmentum, nucleus of the brachium of the inferior colliculus, and pretectum.
In the cases with intercollicular lesions, HRP-labeled axons were observed to arise from neurons in both the external nucleus and dorsal cortex of the IC, but not the central nucleus, and they entered the deep layers of the superior colliculus. These results indicate that the projection from the central nucleus to the external nucleus of the IC is important for the propagation of seizure activity in GEPR-9s.
It is known that some neurons in the external nucleus of the inferior colliculus (ICX) receive both auditory and somatosensory input.
In the inferior colliculus a moderately active external nucleus could be distinguished from a more intensely stained central and superficial nucleus.
Units were recorded in the external nucleus of the inferior colliculus (ICx), which is a major source of auditory input to the optic tectum.
The external nucleus of the inferior colliculus was also found to contain significantly greater numbers of GAD67 cRNA labeled neurons whereas in the frontal cortex, a region of the brain that is not required for audiogenic seizure activity in GEPR-9s, there were no significant differences in hybridization between GEPR-9s and SD rats.
The map appears in its final form in the external nucleus of the inferior colliculus (ICx) and is projected from there to the optic tectum (OT).
The possibility that the external nucleus of the inferior colliculus (ICX) of the pigmented guinea-pig contains a map of auditory space has been investigated.
A variable number of degenerating synaptic boutons were observed bilaterally in the IC-external nucleus and in the intercollicular area. The greatest number of degenerating terminals was encountered in the rostral portions of the IC-external nucleus and in the intercollicular area contralateral to the DCN lesion. In the caudal portion of the contralateral IC-external nucleus the number of degenerating boutons greatly diminished and the latter showed a patchy distribution. Ipsilateral to the DCN lesion the number of degenerating terminals was low, and a more substantial number was found only in the rostroventral portion of the IC-external nucleus and in the intercollicular area.
Labeled cells were more common in the caudal half of the central nucleus, and in the external nucleus and dorsal cortex.
These areas include zona incerta, nucleus of the posterior commissure, anterior and posterior pretectal nuclei, nucleus of the optic tract, superior colliculus, cuneiform nucleus, subcuneiform area, substantia nigra pars reticulata and pars lateralis, periparabigeminal area, external nucleus of the inferior colliculus, the area ventral to the external nucleus of the inferior colliculus, mesencephalic reticular formation, dorsal and ventral nuclei of the lateral lemniscus, and the perihypoglossal nucleus.
The responses with noise stimulation are similar to the responses with tonal stimulation in all but the hierarchically highest nucleus, the external nucleus of the inferior colliculus.
We investigated the neural basis of sound localization in symmetrical and asymmetrical species, to deduce how ear asymmetry might have evolved from the ancestral condition, by comparing the response properties of neurons in the external nucleus of the inferior colliculus (ICx) of the symmetrical burrowing owl and asymmetrical long-eared owl with previous findings in the symmetrical great horned owl and asymmetrical barn owl.
Within the external nucleus of its inferior colliculus are auditory neurones, called 'space-specific neurones', that have spatial receptive fields.
The central nucleus of the inferior colliculus contains a larger number of fusiform and stellate GABAergic neurons and a dense plexus of immunoreactive terminals, whereas the external nucleus contains slightly fewer immunoreactive cells and terminals.
The representation of contralateral space in the lateral shell is ultimately conveyed to the external nucleus of the inferior colliculus where it contributes the horizontal axis to a two-dimensional map of space..
The projection from the lateral shell to the ipsilateral external nucleus forms a map of contralateral space in the external nucleus..
Injections of WGA-HRP into the superior colliculus gave terminal label in the cuneiform nucleus and also in surrounding structures which included central grey, the midbrain tegmentum bordering the parabigeminal nucleus, and the external nucleus of the inferior colliculus.
Individual space-specific neurons of the external nucleus, which receive inputs from a wide range of frequency channels (Knudsen and Konishi, 1978), are selective for a unique ITD.
By means of the modified Co-GOD method, CRFI cells were detected in almost all the subdivisions of the IC, including the dorsomedial part of the central nucleus, the ventrolateral part of the central nucleus, the pericentral nucleus and the external nucleus.
The mean number of discharges for the sample population of units of the central nucleus (ICC) and the external nucleus (ICX) were also inversely proportional to stimulus rate.
Regions dominated by 60 kHz EI responses are also found in the lateral extremity of the IC, probably within the external nucleus.
The anterograde transport of HRP revealed that following injections into the central nucleus, the axonal terminals are arranged in a fixed, ipsi- and contralateral banding pattern across the central, pericentral and external nucleus irrespective of the location of the injection.
In contrast, the dorsal cortex and external nucleus of the inferior colliculus project to each division of the MG and to several additional nuclei in adjacent areas of the posterior thalamus.
The positions of retrogradely labeled cells in the external nucleus of the inferior colliculus (ICX) were the same as those observed in control birds (Knudsen, E.
Anterograde labelling was seen mainly contralateral to the injection site: in the external nucleus of the inferior colliculus, the intercollicular zone, the brachium of the inferior colliculus, the lateral reticular nucleus of the thalamus and in the thalamic ventroposterior complex.
In animals with lesions, the lateral part of the deep grey layers of the superior colliculus, the intercollicular area and the rostromedial portion of the external nucleus of the inferior colliculus were destroyed. Injections made in the area of the lateral cervical nucleus and in the cuneate and gracile nuclei labelled fibres and "terminal-like" fields in the external nucleus of the inferior colliculus, the intercollicular area, the deep grey layers of the superior colliculus and in the mesencephalic lateral tegmentum. After injections in the posterior nucleus and ventroposterior complex of the thalamus, retrogradely labelled cells were found in the lateral tegmentum, the intercollicular area and the external nucleus of the inferior colliculus.
Stimulation sites within the dorsal mesencephalon effective in antidromically activating M and MD neurons were in the caudal ventrolateral superior colliculus, the intercollicular area, and external nucleus of the inferior colliculus. This input is probably responsible for providing some of the somatosensory input to the deeper layers of the superior colliculus, the external nucleus of the inferior colliculus, and the intercollicular area, regions known to have neurons responding to somatosensory stimuli..
The cells giving rise to commissural axons form an array tilted dorsally from caudal to rostral that spreads mediolaterally through the central nucleus into the external nucleus of the IC, but largely excludes the dorsomedial sector at posterior levels.
The recording sites of most units were identified histologically with the aid of microlesions and were related to the major subdivisions of the inferior colliculus: the central nucleus (ICC), the lateral part of the external nucleus (ICX), and the rostroventral process (R-ICX).
A smaller number of labelled cells was observed in the ipsilateral external nucleus of the inferior colliculus and a few labelled cells were distributed in the dorsomedial part of the inferior colliculus ipsilaterally.
The external nucleus of the inferior colliculus (IX) receives the heaviest projection from both the gracile and cuneate nuclei.
Injections of HRP into the medial division (MGM) produced labeled cells scattered throughout the external nucleus of the inferior colliculus and the ventral part of ICC.
In the external nucleus labeled cells tended to be distributed in the middle to rostral regions, but they were few in number in the caudal part.
The major source of auditory input to the optic tectum is the ipsilateral external nucleus of the inferior colliculus (ICX), which is known to contain a map of auditory space also.
In hamster only two putatively auditory structures showed labeled cells, the external nucleus of inferior colliculus and nucleus of the brachium of the inferior colliculus, whereas in cat additional cells are reported in the dorsal cochlear nucleus, trapezoid and superior olivary nuclei, and nucleus of the lateral lemniscus.
After injections of horseradish peroxidase into the central tegmental field of the midbrain reticular formation and centrum medianum of the thalamus in the cat, labelled neurons were found in the nucleus of solitary tract, cuneate and gracile nuclei, spinal nuclei of trigeminal nerve, external nucleus and brachium nucleus of inferior colliculus, nuclei of the lemniscus lateralis in the area pretectalis, nucleus of the posterior commissure and stratum intermediale of the superior colliculus and in reticular structures of medulla and pons.
First, potential sources of auditory afferents were limited mainly to the external nucleus of the inferior colliculus, the nucleus sagulum, and the dorsomedial periolivary cell group.
Within IC, labeling is dense in the ventrolateral part of the central nucleus (CNv) and moderate in the external nucleus (EN).
Parallel single unit and retrograde tracing experiments were carried out in the anesthetized cat to elucidate the representation of the auditory and somatosensory systems in the external nucleus of the inferior colliculus (ICX).
Other projections replicated in several animals included the zona incerta and nearby sectors of the substantia nigra; three distinct mesencephalic arrangements within the deep layers of the superior colliculus, the external nucleus of the inferior colliculus, and the intercollicular nucleus; the anterior pretectal nucleus; dorsal sectors of the inferior olivary complex and the ipsilateral cerebellar cortex.
It is noteworthy that the external nucleus of IC (EN) projects to the superior colliculus, part of the pretectum, and the anterior extremity of MGB ipsilaterally, in addition to the ventral and medial divisions of MGB.
Some brainstem and neocortical neurons projecting to the external nucleus of the inferior colliculus were identified by retrograde axonal transport of horseradish peroxidase (HRP). Subsequently, tiny injections of HRP were delivered electrophoretically to various parts of the external nucleus using micropipettes. In general, sites in the external nucleus which were identified by their responsiveness to stimulation of the body were not responsive to click stimuli. After small electrophoretic injections of HRP absolutely restricted to the external nucleus, HRP-filled neurons were found bilaterally in the nucleus gracilis, nucleus Bischoff, (the midline and tail representation of the dorsal column nuclei), nucleus cuneatus, and nucleus trigeminalis, subnucleus caudalis. In sum, small somatic-activated loci of the external nucleus receive bilateral, topographically convergent projections from hindbrain somatosensory structures and from the SMII cortex..
Units recorded in the external nucleus of the inferior colliculus displayed spontaneous rates which were similar to those of central nucleus units, and were affected by variation in stimulus intensity in the same fashion.
The inferior colliculus of the possum consists of a central nucleus - a darkly stained, densely packed group of cells - flanked laterally by an external nucleus with a lower density of paler cells. Tonotopic organization was demonstrated by discretelytuned elements in the central nucleus, but was not observed in the external nucleus.
The discharges of 129 units were studied in the external nucleus of the inferior colliculus of 11 anesthetised and paralyzed cats. The results indicate that both auditory and somatosensory information is contained in the discharges of units in the external nucleus of the inferior colliculus.
Other ipsilateral targets of the deep tectal layers are the cuneiform nucleus and the external nucleus of the inferior colliculus.
In addition to its classical connection with VPLm, nucleus cuneatus projected to the following contralateral brainstem or thalamic nuclei: medial and dorsal accessory olives, external nucleus of the inferior colliculus, ventrolateral part of the superior colliculus, nucleus ruber, medial geniculate nucleus pars magnocellularis, suprageniculatus, medial and lateral divisions of the posterior thalamic nuclear group, zona incerta, and Fields of Forel.
The intercollicular terminal zone covers the entirety of the external nucleus of the inferior colliculus and the intercollicular nucleus of Mehler, spilling over into adjacent parts of the central gray and deep layers of the superior colliculus. These materials showed that the dendritic spread of neurons in the external nucleus of the inferior colliculus and the intercollicular nucleus, taken together, covers the entirety of the intercollicular terminal zone.
including the external nucleus (lateral cortex) also had no effect on echo-location.4.
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