The Motor System. Lesion in the Brain. Flashcards
Will lesions to the spinal cord or brain affect only 1 neurological pathway?
It is quite likely that they will affect more than 1 pathway.
What dictates the clinical signs that are associated with a neurological lesion?
The exact location of the lesion.
What areas of the body will be affected by a lesion in the brain or spinal cord?
The areas of the body that are downstream or caudal to the lesion.
What part of the brain is affected by seizures?
Only present the forebrain is affected.
What is the first thing to do when dealing with a lesion of the nervous system?
Finding out where the lesion is.
How can we discover the location of a lesion in the brain or spinal cord?
By observing the clinical signs.
What should we do once we have worked out the location of a neurological lesion in the spinal cord?
We want to find out which neurological tracts run through that particular area of the spinal cord.
Where can neurological lesions occur in the brain?
The forebrain.
The brainstem.
The cerebellum.
How will lesions in the cerebellum affect the body?
They affect coordination.
This results in differences between what the body wants the limbs to do and they actually do.
What kind of movements are characteristic of damage to the cerebellum?
Uncoordinated movements.
What parts of the body are affected by lesions in the brainstem?
All of the body as all incoming senses must go through the brainstem.
Will lesions to the brainstem affect motor neurons?
Yes, as they pass through the brain stem.
What kind of movements will we get if there is a lesion in the brainstem?
Uncoordinated movements (ataxia).
What nerves will not be affected by a lesion in the brainstem?
Cranial nerves 1 (smell) and 2 (vision).
Will a lesion in the brainstem affect the cranial nerves?
It affects all cranial nerves except CN 1 and CN2.
How can we pinpoint the location of a lesion in the brainstem?
By performing checks on the cranial nerves.
Lesions to what part of the brain are most likely to affect behaviour and memory?
The forebrain.
What are the 2 parts of the forebrain?
The cerebrum and the diencephalon.
What 5 areas of the cortex will be affected by lesions to the forebrain?
The somatosensory cortex.
The visual cortex.
The auditory cortex.
The olfactory cortex.
The motor cortex/pyramidal system.
What are the 3 major areas of the brainstem?
The mesencephalon.
The metencephalon.
The myelencephalon.
What is generally processed in the forebrain?
Mental status and behaviour.
What is the mental status in animals that have suffered a forebrain lesion?
They tend to be very depressed and they can sometimes be in a stupor or coma.
What is a common behaviour in animals that have suffered a forebrain lesion?
Pacing, other common behaviours are circling, or memory loss.
Seizures only occur in what part of the brain?
The forebrain.
Will postural responses be affected if there is a lesion in the forebrain?
Yes, as the pyramidal system runs through the forebrain.
Will the animals gait be normal if there is a lesion in the forebrain?
Yes.
Will the animals be able to perform normal fine motor movements if there is a lesion in the forebrain?
No, as the movements for postural responses and for fine motor movement are controlled in the forebrain.
Will the animal lose the ability to feel touches or pain if there is a lesion in the forebrain?
It may also lose the ability to feel pain or touch.
What cranial nerves will be affected by a lesion in the forebrain?
Cranial nerves 1 and 2 (smell and vision).
At what point of the brain will the pyramidal system and conscious proprioceptive system both cross over?
In the medulla.
Will the menace response be normal if there is a lesion to the cranial nerves of the forebrain?
No, it will be absent.
How will the animal behave if it has a forebrain lesion?
Compulsive behaviour.
There may also be a loss of appetite/thirst if the hypothalamus is is affected.
Will the PLR response be normal if there is a lesion to the cranial nerves of the forebrain?
No.
Why will lesions in the brainstem affect an animals mental status?
As the incoming information has to travel to the forebrain via the brainstem.
Will all incoming information to the brain travel through the brain stem?
Yes.
What is the mental status of an animal with a brainstem lesion?
Serious depression and often a coma or stupor.
What is a stupor?
Serious depression where only very strong stimulation can bring the animal round.
Will an animals depression be worse for lesions in the forebrain or the brain stem?
The depression tends to be worse for brainstem lesions brainstem than forebrain lesions as no information is getting through.
Will there be behavioural changes associated with lesions in the brainstem?
No, as behaviour is governed by the forebrain.
Will lesions in the brainstem affect gait?
Yes.
Why will lesions in the brainstem affect gait?
As the extra pyramidal system originates in the brainstem.
How do lesions of the brainstem affect the muscles of the body?
They tend to be very tense and there will be problems ranging from spasticity to paralysis.
Will lesions in the brainstem affect upper or lower motor neurons?
Mainly upper motor neurons.
Will there be postural responses associated with lesions in the brainstem?
Whenever gait is affected the postural responses will also be affected.
Will the damage to postural responses following a lesion to the brainstem be ipsilateral or contralateral?
They tend to affect ipsi-lateral responses more than contra-lateral responses.
What cranial nerves are located in the midbrain?
Cranial nerves 3 and 4.
What cranial nerves are located in the pons?
Cranial nerve 5.
What part of the brain governs coordination?
The cerebellum.
What senses arise from the cerebellum?
Proprioceptive senses.
Extrapyramidal/pyramidal senses.
Will lesions in the cerebellum affect gait?
Yes, but there will be no muscle weakness/paralysis.
What movements are affected if there is a lesion in the cerebellum?
Large ranges of movements.
Will the be a menace response in animals with lesions in the cerebellum?
No.
Are there changes in mental status or behaviour with lesions in the cerebellum?
No.
What kind of ataxia will we see with lesions in the cerebellum?
Proprioceptive ataxia and the animal will have a severe loss of coordination.
What cranial nerves are affected by lesions in the cerebellum?
Cranial nerves 2 and 7.
Will there be postural response deficits if there is a lesion in the cerebellum?
Yes.
