The Cerebellum Flashcards
The Cerebrum
Diencephalpn
Cerebral Hemispheres
Diencephalon
Thalamus
Hypothalamus
Epithalamus
Subthalamus
Thalamic Injury
- May interrupt ascending pathways, severely compromising or eliminating contralateral sensation
- Usually proprioception is most effected.
- A thalamic pain syndrome may ensue, producing severe contralateral pain that may occur with or without provoking external stimuli.
( have to determine if it is Thalamic or Musculoskeletal origin) Pain is not a typical Post Stroke symptom unless it is a thalamic stroke origin. Delayed Musculoskeletal pain can occur post stroke and be relieved with treatment!)
Cerebrum
Cerebral Hemispheres + Diencephalon
Cerebral Hemispheres
- —-Cortical Areas
- —-Subcortical Areas
Subcortical Structures: Basal Ganglia
Caudate Putamen Globus Pallidus--- -----Internus and externus Subthalamic Nucleus Substantia Nigra
Globus pallidus + Putamen = Lentiform Nucleus
Caudate + Putamen = Striatum
Basal Ganglia Functions
- Vital for normal motor function
- Executive function
- –Goal Directed Behavior - Sustained attention
- Ability to change behavior as task requirements change
- Motivation
Subcortical Structures
Subcortical White Matter ---Projection, commissural and association fibers -----Corona Radiata -----Internal Capsule Basal Ganglia (Deep Cerebral Nuclei)
Subcortical Structures: Subcortical White Matter
- Projection, commissural, and association fibers
- Corona Radiata
- Internal Capsule
Types of White Matter FIbers
Projection
Commissural
Association
Projection Fibers
extend into and out of the cerebrum
Thalamocortical
Corticospinal
Commissural Fibers
connect homologous areas
Corpus callosum
Anterior white commissure
Association Fibers
connect cortical areas within one hemisphere
Short association fibers
Superior longitudinal fasciculus
Inferior longitudinal fasciculus
Internal capsule Review
Anterior Limb
lateral to head of caudate
frontopontine fibers
fibers interconnecting thalamic and cortical limbic areas
Genu
most medial portion and “knee bend” of IC
cortical fibers to cranial nerve motor nuclei and reticular formation
Posterior Limb
between thalamus and lenticular nucleus
corticopontine fibers
corticospinal fibers
thalamocortical projections
somatosensory, auditory, visual, and motor information to cerebral cortex
Subcortical White Matter Lesions
+Occlusion or hemorrhage of arteries supplying the internal capsule is common.
+Because the internal capsule is composed of many projection axons, even a small lesion can have severe consequences.
—-Catastrophic hemiplegia with somatosensory loss, auditory and/or visual impairments
15
Cerebral Cortex
Vast collection of cell bodies, axons, and dendrites
6 cortical layers
Primary cells:
Pyramidal – output cells; apical dendrite to cortex surface, several basal dendrites, and one axon
Fusiform – output cells, primarily to the thalamus
Stellate – interneurons
Looking at the Axon
Axon Hillux free of organelles
Basal Dendrites stay primarily
with in the paramaters of the cortex
Layers of the Cerebral Cortex
I Molecular layer; ainly axons and dendrites; contains few cells
II External granular layer; many small pyramidal and stellate cells
III External Pyramidal layer; pyramidal cells
IV Internal granular layer; mainly stellate cells
V Internal pyramidal layer; predominately pyramidal cells, with stellate and other interneurons
VI Multiform layer, primarily fusiform cells
Primary Sensory Cortex
simple sensory discrimination (intensity and quality)
Secondary Sensory Cortex
Recognition or sensations
Association Cortex
Goals selection
Interpretation of sensation
Emotions, memory processing
Motor planning areas
Movement, composition, sequencing
Primary motor cortex
Cortical motor output
Cerebral Cortex
Mapping=Brodmann’s Areas
Issues of Cerebral Dominace
Primary Sensory Areas
Somatosensory 3, 1, 2,
significant number of paramydal cells that can originate here
Discriminates shape, texture, or size of objects
Injury to 3,1,2
Depends on which part of somatosensory hommunculus cortex affected (look at picture)
Lateral Hemisphere _Middle cerebral
Medial Hemisphere-lateral cerebral artery
A stroke that affects the entire side of the body
Has to be internal
Corona Radiata
Auditory 41
Conscious discrimination of loudness and pitch of sounds
Visual 17
Distinguishes intensity of light, shape, size and location of objects
Vestibular 40
Discriminates among head positions and head movements
Sensory Association Areas
Somatosensory= 5,7
—–sterognosis and memory of the tactile and spatial environment
Sensory Association Areas
Auditory=22,42
Classification of sounds
Sensory Association Areas
Visual = 18,19,20,21
Analysis of motion, color, control of visual fixations
Secondary Sensory Areas
Agnosia
The inability to recognize objects when using a specific sense, even thought discriminative ability with that sense is intact.
Forms of Agnosia
astereognosis
visual agnosia
auditory agnosia
Astereognosis
The inability to identify objects by touch and manipulation, despite intact discriminative somatosensation.
Person with astereognosis would be able to describe an object being palpated but not recognize the object by touching and manipulating it.
Auditory Agnosia
Destruction of the secondary auditory cortex spares the ability to perceive sound but deprives the person of recognition of sounds.
- Lesion is left association auditory cortex.
- –Person is unable to understand speech (speech sounds like a foreign language) - Lesion is right association auditory cortex
- —-Person unable to interpret environmental sounds (no meaning attached to sound)
Visual Agnosia
- The inability to visually recognize objects, despite having intact vision
- Person with visual agnosia can describe the shape and size of objects using vision but cannot identify the objects visually.