Neuro Final Flashcards
Ten Intervention Principles
- Use it or lose it
- Use it and improve it
- Specficity of training matters
- Repetition matters
- Intensity matters
- Timing matters
- Salience matters
- Age matters
- Transference
- Interference
Meningitis
Inflammation of the pia-arachnoid
Meningioma
Primary extrinsic tumor of the CNS affecting the venous sinuses
Cerebrospinal fluid is produced by…
the choroid plexus
Papilledema
Optic nerve ensheathed in a continuation of the meninges and subarachnoid space and becomes compressed with increased intracranial pressure
- Optic disk swells and retinal veins engorged
Overt hyrdocephalus
The head enlarges
Occult hydrocephalus
The head size remains normal
Epidural Hematomas
result when a fracture results in a torn menigeal artery and blood escapes into the extradural space
Subdural Hematomas
due to tearing of the superficial cerebral veins
Prognosis of Traumatic Brain Injury (consider)
Depth of impaired responsiveness
Duration of altered consciousness
Duration of post-traumatic amnesia
Loss of pupillary light reflexes
Degree of hypoxia and hypotension
Ischemic Stroke
Due to inadequate blood flow resulting in tissue death
Accounts for 80% of all strokes
Hemorrhagic Stroke
Occurs when there is bleeding into the nervous system
Symptoms of a Transient Ischemic Attack
Numbness, tingling, or weakness in the face, arms, or leg on one side of the body
Difficulty walking
Difficulty talking or understanding what others are saying
Confusion
Difficulty with vision in one or both eyes
Dizziness and loss of coordination
Ischemic Stroke Syndromes: MCA
Infarction of the cortical branches may cause sontralateral sensory loss and weakness of the UMN type, cognitive problems, and contralateral homomynous hemianopsia
Infarcts of the distal stem will affect the UE > LE
Dominant hemisphere … aphasia
Non-dominant hemisphere … prosody or unilateral visuospatial deficits
Ischemic Stroke Syndromes: ACA
Involvement of the cortical branches of one ACA causes UMN weakness and cortical type sensory deficits affecting mostly the contralateral lower extremity and bowel and bladder dysfunction
A bilateral ACA infarction results in cortical sensory-motor syndrome involving both lower extremities. Additionally, a severe behavioral disturbance with wide oscillations of affect and personality
Occlusion of the stem of one ACA proximally with its connection with the anterior communicating artery may cause no symptoms due to collarteral circulation
Ischemic Stroke Syndromes: PCA
Unilateral occlusion of the PCA results in contralateral homomynous hemianopsia
Bilateral PCA infarction results in bilateral homomynous hemianopsia (cortical blindness)
Dominant hemisphere …
- alexia (inability to perceive written words),
- anomia (inability to name objects or to recognize written or spoken names of objects),
- visual agnosia (inability to recognize or interpret objects in the visual field)
When inferomedial temporal lobes infarcted, severe memory problems occur
Lacunar Syndromes
Sensory and/or motor deficits occur without cognitive deficits
Face, leg, and arm typically affected equally as pathways are tightly packed in the internal capsule
Disability from Ischemic Stroke (most severe to least severe)
Large strokes
Presence of edema or hemorrhage
Stroke in more than one territory
Single territory (MCA, ACA, or PCA)
Subarachnoid Hemorrhage
Bleeding into subarachnoid space usually due to ruptured aneurysm
Subdural Hemorrhage
Bleeding into potential space beneath dura, usually due to trauma
Epidural Hemorrhage
Bleeding accumulates outside the dura, usually trauma induced
Arteriovenous Malformations (AVMs)
Tangle of dilated blood vessels that form abnormal communication between the arterial and venous circulation
Life Span
Average age at which an individual would die if able to avoid all disease and accidents
Life Expectancy
Number of years a person may expect to live in the face of disease, injury, and accidents
Dementia
A symptom complex of intellectual, behavioral, and personality deterioration in an otherwise healthy adult that is severe enough to (and must) compromise occupational or social performance
Abnormal Aging
AD:
- 60% of the hippocampal formation neurons are lost
- Additional 30% decline in blood flow with a decrease in glucose consumption
- Additional 10-19% brain weight decreased
- Medial temporal lobe structure degeneration resulting in pronounced memory defecits and emotional changes
- The density of NFTs corelate to the degree of dementia (more than normal aging)
Working Memory
Running commentary mediated by prefrontal cortex
Declarative (Explicit) Memory
Memory for facts and events
Episodic (autobiographical)
Semantic (nonautobiographical)
Hippocampus
Nearby cortical areas
Diencephalon
Procedural (Implicit) Memory
Memory of procedures and skills
Emotional associations
Conditioned reflexes
Striatum
Motor areas of the cortex
Cerebellum
Anygdala
Cerebellum
Psychomotor Epilepsy
Characterized by repeated occurrence of sudden, excessive, and synchronous discharges in large groups of neurons
May result in almost instantaneous disruption of consciousness, disturbances in sensation, convulsive movements, and impaired mental function
Seizure
Positive Signs of Seizure
Exaggeration of normal function
Convulsions
Negative Signs of Seizure
Loss of particular functions
Loss of capacity to form new memories
Limbic System Structures
Cingulate and parahippocampal gyri
Hippocampus
Amygdala
Septal nuclei
Hypothalamus
Orbitofrontal association cortex
Limbic Output End
Septum
Hypothalamus
*Mediates behavioral expression of emotional states
Limbic Input End
Hippocampal formation
Amygdala
Orbitofrontal prefrontal cortex
*Receives highly processed sensory reports from ongoing experience from every sensory modality
What cortices of the prefrontal cortex mediate executive functioning and have a role in altruism?
Dorsolateral Cortex
Orbital Cortex
Propositional language depends exclusively on:
structures of the cerebral hemispheres
(think Broca’s and Wenikie’s)
Deficits in speech may follow injury to:
Cerebrum
Brainstem
Cerebellum
PNS structures
Prosody
…you should be thinking non-dominant hemisphere right now ;-)
Where might I look, if so inclined, for the structures that produce prosody?
Right inferior frontal gyrus
*Think motor aprosodia
Where might I look, if the mood hits just right, for the regions involed in comprehending prosody?
Right posterior temporoparietal
*Think sensory aprosodia
Neocortical substrates of Language
- Association fortex of the dominant hemisphere
- Perisylvian language zone includes Broca’s and Wenicke’s areas
- Superior longitudinal fasciculus
Broca’s Aphasia
Comprehension is intact
Few words and difficulty with language production
*Damage to the posterior part of the inferior frontal gyrus and surrounding cerebrum
Wernicke’s Aphasia
Fluent, error-filled production
Deficit in language comprehension
*Results from damage to the posterior part of the superior temporal gyrus and surrounding cerebrm
Aphasic Disconnection Syndrome: Conduction Aphasia
Damage to the superior longitudinal fasciculus
Aphasic Disconnection Syndrome: Transcortical Motor Aphasia
Damage in the watershed area between ACA and MCA
Aphasic Disconnection Syndrome: Transcortical Sensory Aphasia
Damage in the watershed area between ACA and MCA-PCA
Cortical Contributions to Cognition
Unimodal Association Cortex
(Specific Modality)
Multimodal Association Cortex
(Cross-Modal Integration)
- Lateral Association Cortex+ Posterior Association Cortex+ Anterior Association Cortex
- Basomedal (Limbic) Association Cortex
Posterior Association Areas
Spatial Cognition
- Unilateral hemispatial neglect most prominent deficit with damage
Facial Recognition
- Damage = prosopagnosia
Anterior Association Areas
Neural substrates for:
- planning
- insight
- empathy
- altruism
- abstract reasoning
- self-awareness
- governing of emotion
Basomedial (Limbic) Association Cortex
Roles in:
- focused problem solving
- error recognition
- anticipation
- emotional processing
- performance evaluation & optimization
Includes the anterior cingulate cortex (ACC)
Cognitive Functions of the Basal Ganglia
Dorsolateral Prefrontal Circuit
- COGNITION
- DLPFC … Caudate Nucleus … Gpi/SNpr … DM of the Thalamus
Limbic Circuit
- MOTIVATION
- Cingulate gyrus … Striatum … DM of the Thalamus … Limbic Structures
Lateral Orbitofrontal Circuit
- COMBINATION
Cognitive Functions of the Cerebellum
Closed-loop circuits connecting association cortex of the cerebrum with the cerebellar cortex
Neodentate only present in humans
Frontal: Primary Motor Cortex (M1)
Central gyrus with distorted homunculus
Corticomotoneuronal projections to LMNs in the spinal cord
BA 4
Frontal: Premotor Cortex
Includes:
- The lateral premotor area
- The supplementary motor area
BA 6
Parietal: Posterior Parietal Cortex (PPC)
Involved in the regulation of goal-directed movement, particularly of the upper extremity
Provides sensory guidance, knowledge about body orientation and about the physical properties of the object during reach and grasp
BAs 5 and 7
Limbic: Cingulate Motor Areas (CMAs)
Mediate emotion and drive-realted behavior
Note: cingulospinal projections, which terminate in the intermediate gray, influence LMNs via interneurons
Five Connections of the Cortical Motor Areas
M1 receives projections from:
- Primary Somatosensory Cortex
- Posterior Parietal Cortex (PPC)
- Cingulate Motor Areas (CMAs)
- Supplementary Motor Area
- Dorsolateral Prefrontal Cortex (DLPFC)
Two Subcortical Projections
M1 and the Premotor Cortices are reciprocally connected with:
- The Cerebellum
- The Basal Ganglia
Perceptual Action System (PAS)
Purposeful movement does not occur in isolation from the sensory perceptual exerpience of the environment
Haptic Sensing
Exploration of an object by the hand
The integration of cutaneous and proprioceptive info inot motor commands
Important note:
Power grip is mediated by non-CM projections (outside of M1)
What coordinates movements of the eyes and head via the tectospinal tract?
The superior colliculus
Where do motor programs for saccades reside?
In the reticular formation
Gait is a function resulting from the integrated control of:
Cortical Areas
Cerebellum
Basal Ganglia
Spinal Cord
Ideational Apraxia
Inability to organize single actions into a sequence for intended purpose
Ideomotor Apraxia
Inability to translate the idea of the action into an appropriate motor program
Kinetic Apraxia
Loss of hand and finger dexterity not due to paresis, ataxia, or sensory loss
Oral Apraxia
Inability to execute facial movements on command
Where are the neural networks subserving praxis?
In the left (dominant) hemisphere near those serving language … aphasia
Motivation, the decision to act, and learning
M1
M2
M3
M4
Planning
M1
M2
Basal Ganglia
Cerebellum
Thalamus
Execution
M1
Efferent copy to cerebellum
Automatization
Cortical and subcortical areas of:
The Basal Ganglia
Cerebellum
Three layers of the Cerebellum
Molecular
Purkinje
Granular
Mossy Fibers originate from:
vestibular nuclei
spinal cord
cerebral cortex
Climbing fibers originate from:
contralateral inferior olivary nucleus
The net effect of Purkinje neurons is:
Inhibitory
Archicerebellum
(Inputs and Outputs)
Inputs:
- Flocculonodular lobe and deep parts of the vermis
- Vestibular afferents project to here influencing the distribution of tone in limbs, trunk, neck, and extraocular eye muscles
- Retina projects indirectly to here through climbing fibers of the inferior olivary nucleus
Outputs:
- To the brainstem influencing extraocular motor neurons via the MLF and to influence body and limb tone
- To the reticular formation to influence descending fibers of the reticulospinal tracts
Paleocerebellum
Intermediate zone and most of the vermis
Role as comparator between intended movement and patterns of peripheral receptor discharge
Neocerebellum
Lateral hemispheres … ponto/cerebro … motor planning and learning
Role in the governance of voluntary movement and motor learning
Does not receive projections from peripheral receptors as afferent projections to this area originate in the motor and association cortices of the cerebrum via corticopontocerebellar projections
Projects to the dentate nuclei by way of the superior cerebellar peduncle (contralateral red nucleus and contralateral ventrolateral nucleus)
*Think deficits in timing of agonist and antagonist muscle contractions
Five Tracts of the Paleocerebellum
Dorsal Spinocerebellar Tract
Cuneocerebellar Tract
Ventral Spinocerebellar Tract
Rostral Spinocerebellar Tract
Trigeminocerebellar Projections
With Cerebellar Damage
Unilateral lesions produce ipsilateral deficits
Medulloblastoma
Symptoms of listlessness, vomiting, headaches, and falling
Most common lesion of the archicerebellum
Disinhibition
VA/VL are tonically inhibited by output nuclei of the basal ganglia
In order for the thalamus to excite the cortex, it must phasically disinhibit the motor nuclei of the thalamus
Which pathway facilitates initiation of movement by disinhibiting the VA/VL?
Direct Pathway
Which pathway increases inhibition thus failing to facilitate movement?
Indirect pathway
Four Cardinal Signs of PD:
Tremor
Bradykinesia
Rigidity
Postural Instability
Brain Disease in HD
Gross atrophy of the stiatum (caudate and putamen)
Overall loss of GABAergic neurons and reduction of inhibition in the basal ganglia circuitry
Loss of Excitation of the subthalamic nucleus of the indirect pathway to the basal ganglia output nuclei
Hemiballismus
Caused by a discrete lesion of the subthalamic nucleus contralateral to the symptoms
*Think about underactivity of the indirect pathway
*Also think about a vascular disorder of the penetrating branch of the posterior cerebral artery (PCA)
