Student Name: Lucy Yarnold Topic: Neuroanatomy
Paper Title: Jeuring, R., Van Driessche, K., Bosseler, L., Devries, C., Vanhaesebrouck, A., Gielen, I., Oevermann, A. and Chiers, K. (2012) 'Intracranial oligodendroglioma with optic nerve infiltration in a Labrador retriever '13, Vlaams Diergeneeskundig Tijdschrift, 81(5), 298-302. [4]
Clinical condition and description of presentation:
A Labrador retriever was presented with complaints of behavioural changes, starting 4 weeks previously. These included frequent urination around the house, hostile or non-existent reaction to the owner’s calls and decreased ability to see. Along with blindness in the left eye, shown by the lack of menace response a reduced mental status was seen on clinical examination. …show more content…
[2] The main function of the thalamus is relaying and integrating information to and from the cerebral cortex using the many nuclei that lie within it. [10] Another vital role of the thalamus is to maintain consciousness of the animal. [11] This would account for the reduced mental status of the Labrador in this case, as the fleshy matter was located here.
The lateral geniculate nuclei (LGN) are ‘olive’ like in shape and are found either side in the posterior thalamus. They receive input via the optic tract, which is the link between the thalamus and the LGN. [12] The input comes from both eyes and projects information to the visual cortex in the occipital lobe. [2]
The medial geniculate nucleus is also found in the thalamus. It is responsible for auditory pathways. It receives auditory signals from both ears and projects them to the primary auditory cortex. Having a tumorous mass around this structure could allow this relay of information to be disrupted and would explain the non-existent or aggressive response of the dog to its owner. …show more content…
[1] The optic nerve is formed by axons of the retinal ganglion cells. [2, 14] These cells contribute to the pupillary light reflex but contribute little to vision [15], showing that they themselves were not damaged in this case as the dog had a pupillary light reflex.
There are 3 types of neurones involved in vision for the conscious perception of light, the second being retinal ganglion cells, the third being within the LGN of the thalamus. [15] The tumour in this case was found in the region of the thalamus, pressure on the LGN could cause an uncompleted pathway for the visual information and therefore the conscious perception of light for the dog could be hindered or absent for this reason. This could be the explanation of blindness in the left eye of this dog.
The fatty mass was infiltrating into the optic nerves and damage to optic nerves produce monocular visual field defects, another possible cause for the clinical presentation.
Paper Title: Jeuring, R., Van Driessche, K., Bosseler, L., Devries, C., Vanhaesebrouck, A., Gielen, I., Oevermann, A. and Chiers, K. (2012) 'Intracranial oligodendroglioma with optic nerve infiltration in a Labrador retriever '13, Vlaams Diergeneeskundig Tijdschrift, 81(5), 298-302. [4]
Clinical condition and description of presentation:
A Labrador retriever was presented with complaints of behavioural changes, starting 4 weeks previously. These included frequent urination around the house, hostile or non-existent reaction to the owner’s calls and decreased ability to see. Along with blindness in the left eye, shown by the lack of menace response a reduced mental status was seen on clinical examination. …show more content…
[2] The main function of the thalamus is relaying and integrating information to and from the cerebral cortex using the many nuclei that lie within it. [10] Another vital role of the thalamus is to maintain consciousness of the animal. [11] This would account for the reduced mental status of the Labrador in this case, as the fleshy matter was located here.
The lateral geniculate nuclei (LGN) are ‘olive’ like in shape and are found either side in the posterior thalamus. They receive input via the optic tract, which is the link between the thalamus and the LGN. [12] The input comes from both eyes and projects information to the visual cortex in the occipital lobe. [2]
The medial geniculate nucleus is also found in the thalamus. It is responsible for auditory pathways. It receives auditory signals from both ears and projects them to the primary auditory cortex. Having a tumorous mass around this structure could allow this relay of information to be disrupted and would explain the non-existent or aggressive response of the dog to its owner. …show more content…
[1] The optic nerve is formed by axons of the retinal ganglion cells. [2, 14] These cells contribute to the pupillary light reflex but contribute little to vision [15], showing that they themselves were not damaged in this case as the dog had a pupillary light reflex.
There are 3 types of neurones involved in vision for the conscious perception of light, the second being retinal ganglion cells, the third being within the LGN of the thalamus. [15] The tumour in this case was found in the region of the thalamus, pressure on the LGN could cause an uncompleted pathway for the visual information and therefore the conscious perception of light for the dog could be hindered or absent for this reason. This could be the explanation of blindness in the left eye of this dog.
The fatty mass was infiltrating into the optic nerves and damage to optic nerves produce monocular visual field defects, another possible cause for the clinical presentation.