Neuro-Final Study

The basil ganglia regulates movement via control of

sequencing, muscle tone, and muscle force

The basil ganglia communicates with motor planning areas of the cerebral cortex via the

thalamus

If we did not have the BG to modulate movement, we would all be

hyperkinetic

The thalamus excretes \________________ influence on the motor cortex.

excitatory.
(think dog on a leash, wants off)

Parkinson's disease\=

lack of dopamine. Poverty of movement.

Huntington's chorea\=

degradation of caudate nucleus and putamen (striatum). Uncontrolled movement.

GABA (gammaaminobutyric acid) function

An inhibitory neurotransmitter

Glutamate function

An excitatory neurotransmitter

Dopamine function

Both excitatory and inhibitory

Afferent information comes from the \________ and the \__________ to the \____________.

from the cerebral cortex and thalamus to the striatum.

Efferent information comes from the \__________ and goes to the \___________ and \___________.

striatum to the globus pallidus and substantia nigra

Does the basil ganglia have direct connection to lower motor neurons?

NO; it influences the motor cortex via the thalamus.

What is the path for direct and indirect pathways

cortex-\> striatum -\> finish in the thalamus

In the direct pathway the thalamus is \__________ and \__________ movement.

excited; facilitates
dopamine has excitatory an effect\=more movement

In the indirect pathway the thalamus is \_________ and \__________ movement.

inhibited; suppresses movement
dopamine has inhibitory an effect\=more movement
double negative

Less dopamine in the direct and indirect pathway results in

decreased facilitation; suppression of movement.

What percentage loss of dopaminergic neurons occurs before onset of physical signs?

60-80% loss

Substantia nigra

Located in the midbrain. Part of the basil ganglia. Involved in motor cortex. Darker then other regions. Dark areas gradually disappear. Areas are grey in patient's with parkinsons disease

Clinical features of Parkinson's disease

tremor and rigidity

Tremors with Parkinsons

pill-rolling tremor; resting tremor (present at rest, diminishes with movement)

Rigidity with Parkinsons

stiffness, cogwheel rigidity (catching). Not rate dependent.

Clinical features of Parkinsons (posture)

stooped posture, problems with balance which can lead to falls.

Clinical features of Parkinsons (movement)

bradykinesia
hypokinesia
akinesia

difficulty initiating movement:
legs freeze up
shuffling gait

Other clinical features of Parkinsons

depression
dementia
sleep disturbances
difficulty smelling
emotionless
dysfunction in prefrontal cortex
dysfunction in other neurotransmitters (acetylcholine)

What is neuroprotective for parkinsons disease

exercise is for both motor and non-motor symptoms.
Brains on exercise use dopamine more efficiently.

Specific effects of exercise on dopamine

1. dopamine stays in the synapse longer.
2. the post-synaptic membrane had more binding sites for dopamine.

The diencephalon is positioned where?

lies between midbrain and cerebrum, surrounded by cerebral hemisphere

Diencephalon is a part of the (AKA)

prosencephalon; forebrain

The diencephalon connects cerebrum with

midbrain

What are the two major parts of the diencephalon?

thalamus (dorsally) and hypothalamus (ventrally)

Thalamus function

relay station for sensory impulses, pain
Connected w/almost all parts of CNS
gathers, combines, and processes afferent information to the cerebral cortex.

thalamus is also important in carrying

detailed information and comparing to previous experiences

The only sensory pathway that does not relay through the thalamus is the

olfactory system

The thalamus connection with the basil ganglia, cerebellum, and frontal lobe functions to

modulate movement

The thalamus connection with the hypothalamus and frontal lobe functions to

influence motivated behavior

The thalamus connection with the reticular formation functions to

alertness and consciousness

What is the function of the hypothalamus

regulates homeostasis; state where conditions are optimal for internal processes to function properly.

Hypothalamus: TAN HATS

thirst and water intake
adenohypophysis and
neurohypophysis (pituitary gland)
hunger and food intake
Autonomic nervous system
temperature
sexual drive and emotional expression

The hypothalamus regulates homeostasis by using

neural, blood, and CSF connections to regulate the body

Name the two ways the hypothalamus maintains homeostasis

connects to the ANS
Release hormones through pituitary gland

growth hormone

stimulates cell growth

Thyrotropic/thyroid-stimulating hormone TSH

Stimulates thyroid gland

Adrenocorticotropic hormone (ACTH)

stimulates adrenal glands

follicle-stimulating hormone (FSH), luteinizing hormone (LH)

stimulation gonads

Luteotropic hormone (LTH) (prolactin)

stimulates milk production and secretion

The epithalamus consists primarily of the

pineal gland

Functions of the pineal gland

regulation of sleep-wake cycle producing melatonin

Subthalamus

most common place for DBS for PWP
modulates movement
connected with basil ganglia

The cerebellum is \______% of the brains volume

10

The cerebellum is \________% of the total number of neurons in the brain

50

Parts within Limbic System

telencephalon
diencephalon
midbrain

The limbic system is located at border between

telencephalon and diencephalon

Structures that are part of the limbic system include

mammillary bodies
hippocampal formation
cingulate gyrus
hypothalamus
subcallosal area
olfactory cortex
amygdala
parahippocampal gyrus

Limbic system\= HOME

homeostasis, olfaction, memory, emotion

- olfaction
- regulation of emotions
- memory formation and recollection
- responses of ANS

Limbic system "5 Fs"

Feeding, Fleeing, Fighting, Feeling, Fornicating

hippocampal formation function

short-term memory to long-term memory
long-term storage of memories
Retrieval of memories when needed
involved in spatial orientation

Cingulate gyrus function

helps regulate emotions, behavior, pain

Parahippocampal gyrus function

memory encoding and retrieval

Subcallosal area function

Influence emotional reactions
support learning and memory formation

All hypothalamic nuclei are part of the

limbic system

Mammillary bodies function

play a role in learning and memory
connected to hippocampus
assist in episodic memory

Amygdala function

emotional responses
modulation of memory
attention and decision making
fear
reward and motivation

Orbitofrontal cortex function

decision making
reward learning
affective behavior
emotional reaction
subjective feeling states
personality

Executive and limbic systems work together to coordination human

motivation and behavior.
executive\= deliberate conscious processing
limbic\= rapid unconscious processing

The cerebellum is considered a \___________ structure

motor structure; damage leads to impairments in motor control.

The cerebellum is known as the

little brain

Are motor commands initiated in the cerebellum?

NO

What does the cerebellum do to motor commands?

MODIFIES motor commands of the descending pathways to make movement adaptive and accurate.

The cerebellum sits in the

posterior cranial fossa

Tentorium cerebelli

separates cerebrum from cerebellum
cerebellum from the occipital and temporal lobes.

The cerebellar cortex is folded into \_____ with \______ that are thinner, smaller, and organized in parallel layers.

folia/ ridges

The cerebellum has an external \_______ matter layers and an internal subcortical \__________ layer.

grey; white

Arbor vitae

white matter of the cerebellum
"tree of life"

Name the three lobes of the cerebellum

anterior, posterior, flocculonodular

The posterolateral fissure separates

the posterior lobe from the flocculonodular lobe

Primary fissure of the cerebellum seperates

the anterior lobe from the posterior lobe

Vermis of cerebellum

connects cerebellar hemispheres

corpus cerebelli

Anterior + Posterior lobes

What are the three layers of the cerebellar

innermost layer: granule cell layer
middle layers: purkinje cell layer
Outer layer: molecular layers

The granular layer receives \__________ fibers from the spinal cord and brainstem.

mossy

Granular layer has \________ cells that function to

golgi; limit the input of mossy fibers.
Purkinje cells can limit this inhibitory activity.

The purkinje layer has cell bodies of \____________ and lots of \____________.

purkinje cells; dendrites

What are the only axons that leave the cerebellar cortex?

Purkinje cells

Purkinje fibers receive input from

climbing fibers

The molecular layers of the cerebellum is composed of

axons of the granule cells, dendrites of the purkinje cells, basket and stellate cells.

Function of the vestibulocerebellum flocculodular lobe

eye movement and balance control- maintenance of posture and balance.

The vestibulocerebellum flocculodular lobe receives information from the

semicircular canals and vestibule in the inner ear

Function of the spinocerebellum anterior lobe

posture and monitoring and correcting the motor activity of the limbs/ regulating tone and adjusting movements.

Sensory information comes in from the

muscle spindle, GTO, joint receptors about position

cerebrocerebellum Posterior lobe functions

planning and initiation of movement and motor learning.

The posterior lobe initiates movement from the

cerebral cortex, coordinates fine motor, motor learning (practice makes perfect)

Superior cerebellar peduncle is

efferent (output)

Middle cerebellar peduncle is

afferent (input)

Inferior cerebellar peduncle is

afferent (input)

Motor plan of the cerebellum includes

timing, speed, direction, and precision. Tells which muscle to work and to which degree. Then checks if the plan worked correctly.

Inputs form the cerebellum include

input from motor cortex
proprioceptive from limbs
balance from the inner ear

Damage to the cerebellum is

ipsilateral

Classic signs of cerebellar damage

ataxia
tremor- action tremor
nystagmus
dysarthria
hypotonia

ataxia

inability to perform coordinated movements

Ataxia- dysdiadochokinesia

Cannot perform rapid alternating movements