scholarly journals Axon Morphologies and Convergence Patterns of Projections from Different Sensory-Specific Cortices of the Anterior Ectosylvian Sulcus onto Multisensory Neurons in the Cat Superior Colliculus

2009 ◽  
Vol 19 (12) ◽  
pp. 2902-2915 ◽  
Author(s):  
V. Fuentes-Santamaria ◽  
J. C. Alvarado ◽  
J. G. McHaffie ◽  
B. E. Stein
Keyword(s):  
Superior Colliculus ◽  
Anterior Ectosylvian Sulcus ◽  
Cat Superior Colliculus

scholarly journals Neonatal Cortical Ablation Disrupts Multisensory Development in Superior Colliculus

2006 ◽  
Vol 95 (3) ◽  
pp. 1380-1396 ◽  
Author(s):  
Wan Jiang ◽  
Huai Jiang ◽  
Barry E. Stein
Keyword(s):  
Superior Colliculus ◽  
Normal Development ◽  
Receptive Fields ◽  
Early Ontogeny ◽  
Neonatal Brain ◽  
Anterior Ectosylvian Sulcus ◽  
Cortical Ablation ◽  
Cat Superior Colliculus ◽  
Multisensory Processes ◽  
Normal Adults

The ability of cat superior colliculus (SC) neurons to synthesize information from different senses depends on influences from two areas of the cortex: the anterior ectosylvian sulcus (AES) and the rostral lateral suprasylvian sulcus (rLS). Reversibly deactivating the inputs to the SC from either of these areas in normal adults severely compromises this ability and the SC-mediated behaviors that depend on it. In this study, we found that removal of these areas in neonatal animals precluded the normal development of multisensory SC processes. At maturity there was a substantial decrease in the incidence of multisensory neurons, and those multisensory neurons that did develop were highly abnormal. Their cross-modal receptive field register was severely compromised, as was their ability to integrate cross-modal stimuli. Apparently, despite the impressive plasticity of the neonatal brain, it cannot compensate for the early loss of these cortices. Surprisingly, however, neonatal removal of either AES or rLS had comparatively minor consequences on these properties. At maturity multisensory SC neurons were quite common: they developed the characteristic spatial register among their unisensory receptive fields and exhibited normal adult-like multisensory integration. These observations suggest that during early ontogeny, when the multisensory properties of SC neurons are being crafted, AES and rLS may have the ability to compensate for the loss of one another's cortico-collicular influences so that normal multisensory processes can develop in the SC.

Two Cortical Areas Mediate Multisensory Integration in Superior Colliculus Neurons

2001 ◽  
Vol 85 (2) ◽  
pp. 506-522 ◽  
Author(s):  
Wan Jiang ◽  
Mark T. Wallace ◽  
Huai Jiang ◽  
J. William Vaughan ◽  
Barry E. Stein
Keyword(s):  
Superior Colliculus ◽  
Anterior Ectosylvian Sulcus ◽  
Cortical Areas ◽  
Reversible Deactivation ◽  
Response Enhancement ◽  
Multisensory Enhancement ◽  
Superior Colliculus Neurons ◽  
Cat Superior Colliculus ◽  
Single Modality

The majority of multisensory neurons in the cat superior colliculus (SC) are able to synthesize cross-modal cues (e.g., visual and auditory) and thereby produce responses greater than those elicited by the most effective single modality stimulus and, sometimes, greater than those predicted by the arithmetic sum of their modality-specific responses. The present study examined the role of corticotectal inputs from two cortical areas, the anterior ectosylvian sulcus (AES) and the rostral aspect of the lateral suprasylvian sulcus (rLS), in producing these response enhancements. This was accomplished by evaluating the multisensory properties of individual SC neurons during reversible deactivation of these cortices individually and in combination using cryogenic deactivation techniques. Cortical deactivation eliminated the characteristic multisensory response enhancement of nearly all SC neurons but generally had little or no effect on a neuron's modality-specific responses. Thus, the responses of SC neurons to combinations of cross-modal stimuli were now no different from those evoked by one or the other of these stimuli individually. Of the two cortical areas, AES had a much greater impact on SC multisensory integrative processes, with nearly half the SC neurons sampled dependent on it alone. In contrast, only a small number of SC neurons depended solely on rLS. However, most SC neurons exhibited dual dependencies, and their multisensory enhancement was mediated by either synergistic or redundant influences from AES and rLS. Corticotectal synergy was evident when deactivating either cortical area compromised the multisensory enhancement of an SC neuron, whereas corticotectal redundancy was evident when deactivation of both cortical areas was required to produce this effect. The results suggest that, although multisensory SC neurons can be created as a consequence of a variety of converging tectopetal afferents that are derived from a host of subcortical and cortical structures, the ability to synthesize cross-modal inputs, and thereby produce an enhanced multisensory response, requires functional inputs from the AES, the rLS, or both.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

scholarly journals What does a neuron learn from multisensory experience?

2015 ◽  
Vol 113 (3) ◽  
pp. 883-889 ◽  
Author(s):  
Jinghong Xu ◽  
Liping Yu ◽  
Terrence R. Stanford ◽  
Benjamin A. Rowland ◽  
Barry E. Stein
Keyword(s):  
Superior Colliculus ◽  
Early Life ◽  
Life Experience ◽  
Sensory Experience ◽  
Rearing Environment ◽  
Early Life Experience ◽  
Environmental Events ◽  
Cat Superior Colliculus ◽  
Maturational Process ◽  
Multisensory Experience

The brain's ability to integrate information from different senses is acquired only after extensive sensory experience. However, whether early life experience instantiates a general integrative capacity in multisensory neurons or one limited to the particular cross-modal stimulus combinations to which one has been exposed is not known. By selectively restricting either visual-nonvisual or auditory-nonauditory experience during the first few months of life, the present study found that trisensory neurons in cat superior colliculus (as well as their bisensory counterparts) became adapted to the cross-modal stimulus combinations specific to each rearing environment. Thus, even at maturity, trisensory neurons did not integrate all cross-modal stimulus combinations to which they were capable of responding, but only those that had been linked via experience to constitute a coherent spatiotemporal event. This selective maturational process determines which environmental events will become the most effective targets for superior colliculus-mediated shifts of attention and orientation.

Corticotectal and corticothalamic efferent projections of SIV somatosensory cortex in cat

1983 ◽  
Vol 50 (4) ◽  
pp. 896-909 ◽  
Author(s):  
B. E. Stein ◽  
R. F. Spencer ◽  
S. B. Edwards
Keyword(s):  
Superior Colliculus ◽  
Somatosensory Cortex ◽  
Species Difference ◽  
Pyramidal Cells ◽  
Thalamic Nuclei ◽  
Anterior Ectosylvian Sulcus ◽  
Ventrobasal Complex ◽  
Posterior Group ◽  
Corticothalamic Projection ◽  
Efferent Projections

Substantial corticotectal (and corticothalamic) projections from the cortex of the anterior ectosylvian sulcus (AES) were demonstrated in the cat using the axonal transport methods of autoradiography and horseradish peroxidase. The corticotectal projection arises nearly exclusively from medium-large pyramidal cells in lamina V. One of the densest projecting areas of the AES is the rostral aspect of its superior bank, where a fourth somatotopic representation (SIV) has recently been demonstrated. It terminates in the intermediate and deep laminae of the superior colliculus, where somatic cells are located. The pathway is bilateral but much heavier ipsilaterally than contralaterally. In contrast to the substantial corticotectal projection from SIV and adjacent tissue, there was no unequivocal evidence for a corticotectal projection from traditional somatosensory cortex SI-SIII. This finding, that somatosensory projections to the cat superior colliculus arise from an area outside of SI-SIII, was unexpected on the basis of what is known about visual corticotectal projections. However, it is consistent with the patterns of other cortical projections that terminate in the intermediate and deep laminae of this structure and with the absence of demonstrable corticotectal influences from SI to SIII in this animal. These data are in contrast to demonstrations by other investigators that there is a corticotectal projection from SI cortex in rodents. Apparently there is a fundamental species difference in the organization of descending somatosensory pathways. A corticothalamic projection of the AES was also observed. This descending projection appeared to form a shell of labeled cells and fibers around the ventrobasal complex, but unequivocal terminal labeling within the ventrobasal complex could not be demonstrated. Dense terminal labeling was apparent in the posterior group of thalamic nuclei (PO) where thalamocortical afferents to the AES originate.

Glutamate-like immunoreactivity in the cat superior colliculus and visual cortex: Further evidence that glutamate is the neurotransmitter of the corticocollicular pathway

1997 ◽  
Vol 14 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Chang-Jin Jeon ◽  
Michael K. Hartman ◽  
R. Ranney Mize
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Optical Density ◽  
Retrograde Tracing ◽  
Biochemical Studies ◽  
Deep Layers ◽  
Dense Band ◽  
Cat Superior Colliculus ◽  
Made In ◽  
In Cells

AbstractBiochemical studies provide evidence that the pathway from visual cortex to the superior colliculus (SC) utilizes glutamate as a neurotransmitter. In the present study, we have used immunocytochemistry, visual cortex lesions, and retrograde tracing to show directly by anatomical methods that glutamate or a closely related analog is contained in corticocollicular neurons and terminals. A monoclonal antibody directed against gamma-L-glutamyl-L-glutamate (gamma glu glu) was used to localize glutamate-like immunoreactivity in both the superior colliculus (SC) and visual cortex (VC). Unilateral lesions of areas 17–18 were made in four cats to determine if gamma glu glu labeling was reduced in SC by this lesion. WGA-HRP was injected into the SC of 10 additional cats in order to determine if corticocollicular neurons were also labeled by the gamma glu glu antibody. A distinctive dense band of gamma glu glu immunoreactivity was found within the deep superficial gray and upper optic layers of SC where many corticotectal axons are known to terminate. Both fibers and cells were labeled within the band. Immunoreactivity was also found in cells and fibers throughout the deep layers of SC. Measures of total immunoreactivity (i.e. optical density) in the dense band were made in sections from the SC both ipsilateral to and contralateral to the lesions of areas 17–18. A consistent reduction in optical density was found in both the neuropil and in cells within the dense band of the SC ipsilateral to the lesion. A large percentage of all corticocollicular neurons that were retrogradely labeled by WGA-HRP also contained gamma glu glu. These results provide further evidence that the corticocollicular pathway in mammals is glutamatergic. The results also suggest that visual cortex ablation alters synthesis or storage of glutamate within postsynaptic SC neurons, presumably as a result of partial deafferentation.

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