Exam 3 Week 16 ppt 2: Cognition: Basal Nuclei & Cerebellar Contributions

Question 1

What are the cognitive role of the basal ganglia?

Answer 1

• •The basal ganglia function in regulation of motor behavior
• •Parallel pathways (loops) exist for mediating cognitive functions
• •Caudate nucleus plays a central role

We always think of basal ganglia function in regulation of motor behavior but as we learned previously the basal nuclei also function in cognitive functions. Parallel pathways (loops) within the basal nuclei exist for mediating cognitive functions. In this pathway the Caudate nucleus plays a central role

Question 2

which of the basal nuclei plays a central role in the pathways (loops) that mediate cognitive function in parallel to motor functions?

Answer 2

caudate nucleus

Question 3

Describe the basal ganglia lopps:

Answer 3

•Basal Ganglia Loops

• –Dorsolateral prefrontal circuit
  
  • Role in cognition
  • DLPFC –> caudate nucleus –> Gpi/SNpr –> DM of thalamus ->DLPFC

Basal Ganglia cognitive loop involves the following circuit: Dorsolateral prefrontal cortex to the caudate nucleus to the globus pallidus internus and substantia nigra pars reticularis to the mediodorsal nucleus of thalamus and then back to the Dorsolateral prefrontal cortex

Question 4

What are two examples of deases that show cognitive deficits caused by problems with the basal ganglia?

Answer 4

parkinson’s disease

huntington’s disease

Question 5

Explain cognitive deficits related to basal nuclei in Parkinson’s disease:

Answer 5

•Cognitive deficits Occur in early stages of Parkinson’s Disease (PD)

• –Increase with advancing disease
• –Revealed with neuropsychological testing
  
  • §People with PD achieve fewer card-sorting categories on the WCST than matched controls
• –Disassociation of cognitive & motor function as those with worse cognitive performance not those with worse motor performance

Cognitive deficits Occur in early stages of Parkinson’s Disease (PD). These deficits Increase with advancing disease as Revealed with neuropsychological testing. People with Parkinson’s Disease achieve fewer card-sorting categories on the Wisconsin Card Sorting Test than matched controls. There is a Disassociation of cognitive & motor function as those with worse cognitive performance were not those with worse motor performance

Question 6

Explain cognitive deficits related to basal nuclei in Huntington’s disease:

Answer 6

There is a triadf behavioral manifestations in Huntington’s Disease (HD)

1. –Motor symptoms
2. –Cognitive impairments
3. –Memory impairments

• Dementia due to loss of striatal neurons (caudate primarily)
• Co-occurs with depression of prefrontal neuronal function

Question 7

what is the triad of behavior manifestations in Huntington’s Disease?

Answer 7

1. –Motor symptoms
2. –Cognitive impairments
3. –Memory impairments

Question 8

does the cerebellum have any invovlement in cognition?

explain how or why not

Answer 8

•Cognitive and affective role of cerebellum are supported by anatomical, clinical, and neuroimaging data

• Cerebellar neodentate nucleus (ventrolateral part of the dentate nucleus) is only present in humans and is involved in the Closed-loop circuits connecting cerebral association cortex with cerebellar cortex as shown in this diagram

Question 9

what are three cerebellar-cortical closed-loop circuits?

Answer 9

Two formed between the association cortices and the cerebellum

• –Association cortices form the corticoponto-cerebellar mossy fiber input to the cerebellar hemispheres
• –Association cortices via the red nucleus provide climbing fiber input from inferior olivary nucleus

One from the ventrolateral part of the dentate nucleus (neodentate)

Question 10

the association cortices form how many connections to teh cerebellum?

Answer 10

Two

Question 11

describe the two Cerebellar-cortical closed-loop circuits formed between the association cortices and the cerebellum

Answer 11

1. –Association cortices form the corticoponto-cerebellar mossy fiber input to the cerebellar hemispheres
2. –Association cortices via the red nucleus provide climbing fiber input from inferior olivary nucleus

The Association cortices form two connections to the cerebellum

corticoponto-cerebellar mossy fiber input to the cerebellar hemispheres

via the red nucleus provide climbing fiber input from inferior olivary nucleus

Question 12

Describe the Cerebellar-cortical closed-loop circuit that comes form the ventrolateral part of the dentate nucleus (neodentate):

Answer 12

• –Ventrolateral part of dentate nucleus (neodentate) projects via thalamus to DLPFC, PPC and cingulate & parahippocampal (limbic) cortex
• –This loop is thought also to have contributions from Broca’s & Wernicke’s areas

Ventrolateral part of dentate nucleus (neodentate) projects via thalamus to dorsolateral prefrontal cortex, posterior parietal cortex and cingulate & parahippocampal (limbic) cortex

This loop is thought also to have contributions from Broca’s & Wernicke’s areas

Question 13

What are some cognitive deficits that can occur from damage to the cerebellum?

Answer 13

1. –Deficits in executive function
2. –Deficits in visual spatial capacities
3. –Deficits in language production
4. –Flat affect
5. –Disinhibited and inappropriate behavior
6. –Lowering of intellectual function – may be transient

Question 14

what does bilateral posterior lobe lesions to the cerebellum produce?

Answer 14

numerous behaviral deficits

Question 15

what does Damage to anterior lobe of the cerebellum produce?

Answer 15

•Damage to anterior lobe produces minor deficits in executive function and visuo-spatial ability

Question 16

what does Damage to the vermis of the cerebellum produce?

Answer 16

•Damage to the vermis produces major deficits in affect

Question 17

what can happen if cerebellum doesn’t develop properly in infants?

Answer 17

•Lack of proper cerebellar development in premature infants can lead to both motor and cognitive delays

• –25-50% of children born prematurely demonstrate cognitive impairments and learning disabilities
• –Lack of cerebellum development can lead to cerebral problems due to the strong connections between the two structures – this focal deficit due to distant pathology is called diaschisis

Question 18

what is diaschisis?

Answer 18

when damage to one area causes impairment of function in a distant connected area

Question 19

Answer 19