Block 4 Flashcards
What doe the hippocampal formation do?
Memory consolidations
What does the fornix connect in the limbic system?
Hippocampal formation to mammillary bodies, anterior thalamic nucleus and septal area
Where do the trigeminal nerve fibers pass?
Through the middle cerebellar peduncle
What does the internal auditory canal carry?
Facial & Vestibulocochlear nerves!
What do the pyramids of the medulla contain?
Ipsilateral corticospinal neurons
What does the PICA supply?
Posterior Inferior Cerebellar Artery - Cerebellum & lateral medulla
What does the posterior cerebral artery supply? What artery does it branch off of?
- Occipital lobes, Temporal lobes and midbrain
- Basilar artery
What is the pineal gland a part of? What does it produce?
Epithalamus - produces melatonin
Where does the superior colliculus receive afferents from?
Lateral geniculate body (visual system) -
Superior colliculus is located in the tectum.
Where does the inferior colliculus receive afferents from?
Lateral lemniscus (auditory system) - Located in the tectum
Where are the cerebellar tonsils?
Located near the base of the cerebellum, adjacent to the foramen magnum.
What do the superior cerebellar peduncles contain?
Efferent neurons from deep cerebellar nuclei to the red nucleus via the VA/VL thalamic nuclei - afferent ventral spinocerebellar tract
What does the anterior commissure connect within the brain?
Temporal lobes
What does the posterior limb of the internal capsule contain?
Optic and auditory radiations
What does the stroop test do?
It tests attention. You have to say the color of the word rather than the word. In people with parietal damage, they cannot do this.
What can damage to the posterior parietal cortex cause?
- Spatial neglect (nondominant hemisphere)
- Motor apraxias (dominant hemisphere)
What is the main function of the parietal association cortex on the non dominant side?
- Attention
- Visuospatial localization: Searching or reaching for an object
- Spatial relationships: binding the elements of a visual scene together into a single image
What is the main function of the parietal association cortex on the dominant side (side specialized for language)?
- Skilled movements
- Right-left orientation
What is spatial neglect and when does it usually occur?
Failure to acknowledge half of the world
-Sensory systems intact
Occurs in about half of right-hemisphere strokes
-Damage to posterior parietal cortex
What is ideomotor apraxia and what can cause it?
Involves gestures or use of tools in daily life
- not being able to mime these as a patient may indicate damage
- Caused by damage to the posterior parietal cortex
Where are the cells involved in recognition?
Inferior temporal cortex
What is an agnosia?
Inability to recognize or identify objects even though sensory systems are working normally
What is one thing you forgot damage to the prefrontal cortex causes?
Perseveration (repetition of a behavior)
Inability to use information to guide behavior (cognitive inflexibility)
Where is attention localized?
Parietal Association Cortex
What does the Wisconsin Card Sorting Test check on?
Perseveration (reputation of a behavior)
What happens to the cortex/myelination as brain matures?
More development of myelination & pathways (axons), More organization and “pruning” of tracts.
- Gray matter becomes thicker over time (until age 5) and then gets thinner over the rest of your life (more mature state - ‘pruned’ connections)
- Last areas to mature are often the first to degenerate
What creates nociceptive pain?
Complex, peripheral or central reorganization of pathways -> no need for stimulus to perceive pain – may lead to chronic pain syndromes
What is referred pain?
Activation of nociceptors in viscera –> perceived as a somatosensory stimulation
Where do the FEF project (frontal eye fields)?
FEF -> PPRF (paramedian pontine reticular formation-horizontal gaze center) -> abduction of one eye and adduction of other (saccade)
What happens with injury to the FEFs?
- Loss of voluntary saccades to contralateral side
- Deviation of eyes to side of lesion
- Loss of ability to move gaze away from a stimulus
What do neurons in M1 (primary motor cortex) encode?
- Force
- Direction
- Extent
- Velocity
What inputs come into the primary cortex?
- Proprioceptive info: dorsal column nuclei & VP thalamus
- Tactile information from hands
- Other areas of cortex
- Cerebellum & Basal Ganglia (via thalamus)
What is the FUNCTIONAL organization of the premotor cortex?
Dorsal - reaching
Ventral -grasping, cognitive control
What is the function of the premotor cortex?
- Higher level of motor coordination than M1
- More complex, multi-joint motions
- Often stereotyped action, e.g. bringing hand to mouth and opening mouth
- More externally drive than M1 - turns sensory cues into motor actions
What are the more interesting functions of the premotor cortex?
- Preparation for movement
- Mirror neurons - same neurons stimulated when we watch someone else do an action as when we do it ourselves
- Behavioral context - neurons have a different response whether we’re reaching for a full or empty cup (context for emotions of others)
What can premotor cortex lesions cause?
- Problems responding to stimuli (ex: stand up when light turns on)
- Planning appropriate movements based on circumstances (ex: going around screen to get food)
- Learn new sensory-motor actions
- Steer arm accurately (pure motor effects)
What does stimulation of the supplementary motor area cause?
- Motion in multiple joints (fewer joint movements than premotor, but more than M1)
- Postural changes
What is the main function of the supplementary motor area (SMA)?
Internal generation of movement
Activity linked to:
1. Learning sequences of movements
2. Performing sequences of learned movements
3. Mental rehearsal
–As tasks become proficient, M1 assumes control (and activity in SMA dec.!)
What happens with damage to the supplementary motor area?
- Reduction in volitional (internally driven) movements
- Loss of suppression of motor programs triggered by visual stimuli
- -Ex: alien hand syndrome: contralateral semi-purposeful movements out of patients control (picking up brush)
- -Utilization behavior - use of objects in an inappropriate setting (excessive response to external stimuli - using demo tooth brush) - Neglect of affected limb
What is the primary motor cortex involved in?
Tied to the movement itself (active during visual cue and prior training)
What is the supplementary motor cortex involved in?
Not active to external stimuli - active during prior training/internal stimuli (no activity during visual cue)
What is the premotor area involved in?
-Responds to external stimuli
-Doesn’t respond to plan (internal)
-Some activity during visual due, no activity during prior training
“going through the premotor motions”
