We previously showed that feedback connections from MT play a role in figure/ground segmentation. Figure/ground coding has been described at the V1 level late part of neuronal responses to visual stimuli, and it suggested these modulations depend on connections. In present work we tested whether actually takes time for this information be fed back lower order areas. analyzed extracellular 169 V1, V2, V3 neurons recorded two anesthetized macaque monkeys. was inactivated by cooling. studied...

We describe a very adaptable reversible inactivation technique for the behavioral or electrophysiological analysis of neural circuits. The cryoloop device can be permanently implanted topically applied in an acute preparation to apply cold discrete surface regions central nervous system (e.g. cerebral cortex midbrain). consists custom shaped, stainless steel, hypodermic tubing and cooling is effected by passing chilled methanol through lumen tubing. Cryoloop temperature monitored...

Feedback connections are prevalent throughout the cerebral cortex, yet their function remains poorly understood. Previous studies in anesthetized monkeys found that inactivating feedback from extrastriate visual cortex produced effects striate were relatively weak, generally suppressive, largest for stimuli confined to receptive field center, and detectable only at low stimulus contrast. We studied influence of corticocortical alert using cortical cooling reversibly inactivate areas 2 (V2) 3...

It is well known that early disruption of sensory input from one modality can induce crossmodal reorganization a deprived cortical area, resulting in compensatory abilities the remaining senses. Compensatory effects, however, occur selected regions and it not whether such phenomena have any relation to original function reorganized area. In cortex hearing cats, auditory field anterior ectosylvian sulcus (FAES) largely responsive acoustic stimulation its unilateral deactivation results...

Congenital sensory deprivation can lead to reorganization of the deprived cortical regions by another system. Such cross-modal may either compete with or complement “original“ inputs area after restoration and thus be adverse beneficial for restoration. In congenital deafness, a previous inactivation study documented that supranormal visual behavior was mediated higher-order auditory fields in congenitally deaf cats (CDCs). However, both responsiveness “deaf” interactions between reorganized...

Following sensory deprivation, areas and networks in the brain may adapt reorganize to compensate for loss of input. These adaptations are manifestations compensatory crossmodal plasticity, which has been documented both human animal models deafness–including domestic cat. Although there abundant examples structural plasticity deaf felines from retrograde tracer-based studies, is a lack diffusion-based knowledge involving this model compared current breadth research. The purpose study was...

In response to sensory deprivation, the brain adapts efficiently navigate a modified perceptual environment through process referred as compensatory crossmodal plasticity, allowing remaining senses repurpose deprived regions and networks. A mechanism that has been proposed contribute this plasticity involves adaptations within subcortical nuclei trigger cascading effects throughout brain. The current study uses 7T MRI investigate effect of perinatal deafness on volumes structures in felines,...

We examined the ability of mature cats to accurately orient to, and approach, an acoustic stimulus during unilateral reversible cooling deactivation primary auditory cortex (AI) or 1 18 other cerebral loci. After attending a central visual stimulus, learned 100-ms broad-band, white-noise emitted from speaker 12 peripheral sites (at 15° intervals) positioned along horizontal plane. Twenty-eight had two six cryoloops implanted over multiple Within cortex, AI, posterior field (PAF) anterior...

Microsaccades aid vision by helping to strategically sample visual scenes. Despite the importance of these small eye movements, no cortical area has ever been implicated in their generation. Here, we used unilateral and bilateral reversible inactivation frontal fields (FEF) identify a drive for microsaccades. Unexpectedly, FEF altered microsaccade metrics kinematics. Such also impaired deployment following peripheral cue onset, regardless side or configuration. Our results demonstrate that...

The purpose of the present study was to compare visual orienting behavior in adult cat during (1) unilateral and bilateral cooling deactivation posterior-middle suprasylvian (pMS) sulcal cortex, (2) superior colliculus. As expected, either pMS cortex or colliculus resulted a profound neglect contracooled hemifield. addition homotopic region opposite hemisphere largely reversed this deficit restored into previously neglected These results show that are essential for normal detection targets,...

In the primary visual cortex, neurons with similar response preferences are grouped into domains forming continuous maps of stimulus orientation and direction movement. These properties widely believed to result from combination ascending lateral interactions in system. We have tested this view by examining influence deactivating feedback signals descending visuoparietal cortex on emergence these representations cat area 18. thermally deactivated dominant motion-processing region used...

Although the contributions of primary auditory cortex (AI) to sound localization have been extensively studied in a large number mammals, little is known nonprimary localization. Therefore purpose this study was examine both and all recognized regions acoustically responsive during bilateral unilateral reversible deactivation. The cats learned make an orienting response (head movement approach) 100-ms broad-band noise stimulus emitted from central speaker or one 12 peripheral sites (located...

ABSTRACT Cat auditory cortex is known to undergo cross‐modal reorganization following deafness, such that behavioral advantages in visual motion detection are abolished when a specific region of deaf cortex, the dorsal zone (DZ), deactivated. The purpose present investigation was examine connectional adaptations might subserve this plasticity. We deposited biotinylated dextran amine (BDA; 3,000 MW), retrograde tracer, unilaterally into posterior portion suprasylvian fringe, corresponding...

Cross-modal reorganization following the loss of input from a sensory modality can recruit sensory-deprived cortical areas to process information remaining senses. Specifically, in early-deaf cats, anterior auditory field (AAF) is unresponsive stimuli but be activated by somatosensory and visual stimuli. Similarly, AAF neurons respond tactile adult-deafened animals. To examine anatomical changes that may underlie this functional adaptation early or late deafness, afferent projections were...