scholarly journals Decerebration induced by surgical transection of cerebral ganglion of crayfish

2020 ◽  
Vol 8 (4) ◽  
pp. 1217
Author(s):  
Baltazar Barrera Mera ◽  
Emilio Pérez Ortega ◽  
Rodrigo Banegas Ruiz ◽  
Yuri Jiménez Caprielova ◽  
Francisco Fabián Gómez Mendoza ◽  
...  
Keyword(s):  
Adult Male ◽  
Visual Information ◽  
Cranial Nerves ◽  
Visual Stimuli ◽  
Cerebral Ganglion ◽  
Olfactory Lobe ◽  
Small Incision ◽  
Neuronal Connections ◽  
Defense Reflex ◽  
The Brain

Background: Since the neural structures of the crayfish brain closely resemble their equivalent in the mammals. This can be suggested by observing the similarity that exists in the brain divided by the surgical transection of the crayfish brain in which the protocerebrum remains attached to the first two cranial nerves, findings also described by Frederic Bremer in 1935 in cats with cerebral transection.Methods: Total 11 Adult male crayfish were trained to respond with defense reflex, the animals were placed in water at 0°C, remained without any movement, and subsequently through a small incision of 3 mm in diameter in the medial antero region and dorsal cephalothorax region, a surgical section of the cerebral ganglion was performed. Immediately after surgery, metal microelectrodes were implanted to collect the activity of the photoreceptors and visual fibers.Results: Once the defense reflex begins to recover in previously decerebrated crayfish, it means that it shows signs of reconnection. The isolated protocerebrum with the deutocerebrum olfactory lobe remain alive for several days and the neuronal connections were reestablished, as measured throughout the bilateral defense activity. The defense reflex was observed in all animals and then recovered after surgery.Conclusions: The crayfish is an excellent model to work the visual activity, all coding of visual information was suppressed in de-cerebrated crayfish. The recovery of the neural disconnection is observed from 40 days, where the defence reflex appears again before visual stimuli. 

Difficult Turned Easy: Suggestion Renders a Challenging Visual Task Simple

2020 ◽  
pp. 095679762095485
Author(s):  
Mathieu Landry ◽  
Jason Da Silva Castanheira ◽  
Jérôme Sackur ◽  
Amir Raz
Keyword(s):  
Mental Imagery ◽  
Visual Information ◽  
Perceptual Experience ◽  
Sensory Input ◽  
Moving Objects ◽  
Visual Stimuli ◽  
Perceptual Information ◽  
Hypnotic Suggestion ◽  
Adult Participants ◽  
The Brain

Suggestions can cause some individuals to miss or disregard existing visual stimuli, but can they infuse sensory input with nonexistent information? Although several prominent theories of hypnotic suggestion propose that mental imagery can change our perceptual experience, data to support this stance remain sparse. The present study addressed this lacuna, showing how suggesting the presence of physically absent, yet critical, visual information transforms an otherwise difficult task into an easy one. Here, we show how adult participants who are highly susceptible to hypnotic suggestion successfully hallucinated visual occluders on top of moving objects. Our findings support the idea that, at least in some people, suggestions can add perceptual information to sensory input. This observation adds meaningful weight to theoretical, clinical, and applied aspects of the brain and psychological sciences.

scholarly journals Brain state-dependent modulation of thalamic visual processing by cortico-thalamic feedback

2021 ◽  
Author(s):  
Kimberly Reinhold ◽  
Arbora Resulaj ◽  
Massimo Scanziani
Keyword(s):  
Visual Stimulus ◽  
Visual Processing ◽  
Visual Information ◽  
Early Stage ◽  
Visual Stimuli ◽  
Brain State ◽  
Spatial Features ◽  
State Dependent ◽  
Temporal And Spatial ◽  
The Brain

The behavioral state of a mammal impacts how the brain responds to visual stimuli as early as in the dorsolateral geniculate nucleus of the thalamus (dLGN), the primary relay of visual information to the cortex. A clear example of this is the markedly stronger response of dLGN neurons to higher temporal frequencies of the visual stimulus in alert as compared to quiescent animals. The dLGN receives strong feedback from the visual cortex, yet whether this feedback contributes to these state-dependent responses to visual stimuli is poorly understood. Here we show that in mice, silencing cortico-thalamic feedback abolishes state-dependent differences in the response of dLGN neurons to visual stimuli. This holds true for dLGN responses to both temporal and spatial features of the visual stimulus. These results reveal that the state-dependent shift of the response to visual stimuli in an early stage of visual processing depends on cortico-thalamic feedback.

Brain Basis of Blindsight

2020 ◽  
Author(s):  
Holly Bridge
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Visual Information ◽  
Diffusion Imaging ◽  
Visual Stimuli ◽  
Cortical Blindness ◽  
Functional Brain Imaging ◽  
Rehabilitation Programs ◽  
The World ◽  
The Brain

The sensation of vision arises from the detection of photons of light at the eye, but in order to produce the percept of the world, extensive regions of the brain are required to process the visual information. The majority of information entering the brain via the optic nerve from the eye projects via the lateral geniculate nucleus (LGN) of the thalamus to the primary visual cortex, the largest visual area, having been reorganized such that one side of the brain represents one side of the world. Damage to the primary visual cortex in one hemisphere therefore leads to a loss of conscious vision on the opposite side of the world, known as hemianopia. Despite this cortical blindness, many patients are still able to detect visual stimuli that are presented in the blind region if forced to guess whether a stimulus is present or absent. This is known as “blindsight.” For patients to gain any information (conscious or unconscious) about the visual world, the input from the eye must be processed by the brain. Indeed, there is considerable evidence from functional brain imaging that several visual areas continue to respond to visual stimuli presented within the blind region, even when the patient is unaware of the stimulus. Furthermore, the use of diffusion imaging allows the microstructure of white matter pathways within the visual system to be examined to see whether they are damaged or intact. By comparing patients who have hemianopia with and without blindsight it is possible to determine the pathways that are linked to blindsight function. Through understanding the brain areas and pathways that underlie blindsight in humans and non-human primates, the aim is to use modern neuroscience to guide rehabilitation programs for use after stroke.

The plated bayonet: a new instrument to facilitate surgery for intra-axial neoplasms of the spinal cord and brain stem

1993 ◽  
Vol 78 (3) ◽  
pp. 505-507 ◽  
Author(s):  
Fred J. Epstein ◽  
Memet Ozek
Keyword(s):  
Spinal Cord ◽  
Brain Stem ◽  
Cranial Nerves ◽  
Neoplastic Tissue ◽  
Content Type ◽  
Small Incision ◽  
New Instrument ◽  
The Brain ◽  
Fine Print

✓ A new instrument for use in surgically treating intra-axial neoplasms of the spinal cord and brain stem is described. The plated bayonet allows neoplastic tissue in the spinal cord to be separated from functioning neural elements without perforating the adjacent spinal cord. In addition, the plated bayonet facilitates exposure through the very small incision necessary to remove tumors of the brain stem without damaging cranial nerves or other vital structures.

scholarly journals Effects of auditory reliability and ambiguous visual stimuli on auditory spatial discrimination

2020 ◽  
Author(s):  
Madeline S. Cappelloni ◽  
Sabyasachi Shivkumar ◽  
Ralf M. Haefner ◽  
Ross K. Maddox
Keyword(s):  
Causal Inference ◽  
Correct Response ◽  
Visual Information ◽  
Discrimination Task ◽  
Sensory Modality ◽  
Visual Stimuli ◽  
Sensory Information ◽  
Spatial Discrimination ◽  
Auditory Information ◽  
The Brain

ABSTRACTThe brain combines information from multiple sensory modalities to interpret the environment. Multisensory integration is often modeled by ideal Bayesian causal inference, a model proposing that perceptual decisions arise from a statistical weighting of information from each sensory modality based on its reliability and relevance to the observer’s task. However, ideal Bayesian causal inference fails to describe human behavior in a simultaneous auditory spatial discrimination task in which spatially aligned visual stimuli improve performance despite providing no information about the correct response. This work tests the hypothesis that humans weight auditory and visual information in this task based on their relative reliabilities, even though the visual stimuli are task-uninformative, carrying no information about the correct response, and should be given zero weight. Listeners perform an auditory spatial discrimination task with relative reliabilities modulated by the stimulus durations. By comparing conditions in which task-uninformative visual stimuli are spatially aligned with auditory stimuli or centrally located (control condition), listeners are shown to have a larger multisensory effect when their auditory thresholds are worse. Even in cases in which visual stimuli are not task-informative, the brain combines sensory information that is scene-relevant, especially when the task is difficult due to unreliable auditory information.

scholarly journals Cross-Modal Effect of Presenting Visual and Force Feedback That Create the Illusion of Stair-Climbing

2021 ◽  
Vol 11 (7) ◽  
pp. 2987
Author(s):  
Takumi Okumura ◽  
Yuichi Kurita
Keyword(s):  
Visual Information ◽  
Force Feedback ◽  
Activity Level ◽  
Experimental Results ◽  
Stair Climbing ◽  
Mirror Therapy ◽  
Visual Condition ◽  
Stroke Patients ◽  
Head Mount Display ◽  
The Brain

Image therapy, which creates illusions with a mirror and a head mount display, assists movement relearning in stroke patients. Mirror therapy presents the movement of the unaffected limb in a mirror, creating the illusion of movement of the affected limb. As the visual information of images cannot create a fully immersive experience, we propose a cross-modal strategy that supplements the image with sensual information. By interacting with the stimuli received from multiple sensory organs, the brain complements missing senses, and the patient experiences a different sense of motion. Our system generates the sense of stair-climbing in a subject walking on a level floor. The force sensation is presented by a pneumatic gel muscle (PGM). Based on motion analysis in a human lower-limb model and the characteristics of the force exerted by the PGM, we set the appropriate air pressure of the PGM. The effectiveness of the proposed system was evaluated by surface electromyography and a questionnaire. The experimental results showed that by synchronizing the force sensation with visual information, we could match the motor and perceived sensations at the muscle-activity level, enhancing the sense of stair-climbing. The experimental results showed that the visual condition significantly improved the illusion intensity during stair-climbing.

scholarly journals Bio-Inspired Modality Fusion for Active Speaker Detection

2021 ◽  
Vol 11 (8) ◽  
pp. 3397
Author(s):  
Gustavo Assunção ◽  
Nuno Gonçalves ◽  
Paulo Menezes
Keyword(s):  
Superior Colliculus ◽  
Visual Information ◽  
Human Beings ◽  
Validation Process ◽  
Detection Approach ◽  
Wide Range ◽  
Speaker Detection ◽  
The One ◽  
The Brain ◽  
Fusion Ability

Human beings have developed fantastic abilities to integrate information from various sensory sources exploring their inherent complementarity. Perceptual capabilities are therefore heightened, enabling, for instance, the well-known "cocktail party" and McGurk effects, i.e., speech disambiguation from a panoply of sound signals. This fusion ability is also key in refining the perception of sound source location, as in distinguishing whose voice is being heard in a group conversation. Furthermore, neuroscience has successfully identified the superior colliculus region in the brain as the one responsible for this modality fusion, with a handful of biological models having been proposed to approach its underlying neurophysiological process. Deriving inspiration from one of these models, this paper presents a methodology for effectively fusing correlated auditory and visual information for active speaker detection. Such an ability can have a wide range of applications, from teleconferencing systems to social robotics. The detection approach initially routes auditory and visual information through two specialized neural network structures. The resulting embeddings are fused via a novel layer based on the superior colliculus, whose topological structure emulates spatial neuron cross-mapping of unimodal perceptual fields. The validation process employed two publicly available datasets, with achieved results confirming and greatly surpassing initial expectations.

Preservation of cranial nerves during removal of the brain for an enhanced student experience in neuroanatomy classes

2013 ◽  
Vol 27 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Jennifer Long ◽  
David J.H. Roberts ◽  
James D. Pickering
Keyword(s):  
Cranial Nerves ◽  
Student Experience ◽  
The Brain

Facial Ganglia - Anatomy, Symptomatology of Lesions and Biological Relevance

2021 ◽  
Vol 53 ◽  
pp. 41-50
Author(s):  
Ilya Lebedev ◽  
Alexander Bragin ◽  
Yulia Boldyreva ◽  
Artem Borsukov ◽  
Alexander Tersenov ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Facial Pain ◽  
Multidisciplinary Approach ◽  
Human Life ◽  
Cranial Nerves ◽  
Living Organism ◽  
Sympathetic Ganglia ◽  
Historical Background ◽  
Brain And Spinal Cord ◽  
The Brain

The article summarizes information about the head ganglia (the sympathetic ganglia and in the sensory cranial nerves). Gives а brief historical background on the history issue and relevance of the topic. Characterized by each node with its topography and lesion clinic. The described process of treatment, and prospects for new therapies. Raised the issue of the significance of the defeat ganglia, namely, the suffering of the sick and forced treatment costs (due to the complex differential diagnosis). In a biological sense, pain first appears in chordates and during evolution, as well as transformations of the brain and spinal cord, it acquires new types, localization and significance for the performance of a living organism. And facial pain, being a nosology with a multidisciplinary approach in diagnosis and treatment, demonstrates both its complexity and importance in human life.

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