Lecture 14: Cerebral Cortex Flashcards
job of the cerebral cortex
- interpreting sensory information
- perception of sensory information
- active in conscious decisions
- planning, execution, accuracy
Most knowledge of Cortex and Cerebellum activity is due to _______.
study of brain injured individuals
The cerebral cortex demonstrates a characteristic multilayer structure seen in a vertical section. It contains two types of cells which are:____.
pyramidal and stellate
The Molecular layer (I) contains:
axons and dendrites
The External granular layer (II) contains:
small pyramidal and stellate cells
The External Pyramidal layer (III) contains:
mainly pyramidal cells
The Internal granular Layer (IV) contains:
stellate and pyramidal cells
The Granular Layer (V) contains:
large pyramidal cells
The Multiform Layer (VI) contains:
many different neurons that leave the cortex
Most input to the cortex comes from ____.
the thalamus
Thalamus acts as a ____.
relay station.
The thalamus processes information from:
the peripheral afferents, the cerebellum, and the basal ganglia
Thalamic inputs make synaptic connections in which later?
IV- Internal Granular Layer [stellate cells]
Stellate cells then synapse with pyramidal cells
Pyramidal cells receive sensory information from the thalamus and cortex
_______ divided the cerebral cortex into over 50 Areas.
Brodmann
Areas ___ and ____ are of particular importance for control of movements
4 and 6
Area ___ is the Primary Motor Area
4
Area 4 contains what type of cells.
giant output cells, particularly in zone with projections to leg muscles
what kind of map is contained in Area 4?
contains a motor map of the body (somatic organization)
Area 4: Electrical stimulation of certain areas induces___________.
local muscle contractions
Area 4: Active during the execution of _____.
voluntary movements
Damage to Area 4 can cause:
paralysis and spasticity (upper motor neuron syndrome)
Area ___ is the Premotor Area
6
Complex movements originate in ______
Area 6
the _____ is responsible for constructing movements from external cues (example visual cues)
Premotor Cortex
the ____ is responsible for constructing movements from internal motor memory and using bimanual coordination, although recent research has challenged the bimanual coordination.
supplementary motor area
MA: primary motor area responsible for
motor execution
SMA: supplementary motor area responsible for
motor preparation (motor memory)
PMA: premotor area responsible for
interpreting clues or stimuli
parietal areas are responsible for
proprioceptive information, speech, and verbal expression
Inputs to the motor cortex from the spinal cord, the basal ganglia, and the cerebellum are mediated by
the ventrobasal nuclei of the thalamus.
Major projections from other cortical areas include those from the parietal cortex and from certain frontal areas.
Outputs of the motor cortex include projections to
the basal ganglia, the cerebellum (via the pons), the red nucleus, the reticular formation, and the spinal cord.
Corticospinal tracts from the left and right hemispheres change sites at the level of the medulla (at the decussation)
Convergence
stimulating different cortical cells may activate the same group of motor units and result in similar motions
Divergence
stimulating one cortical cell can activate different groups of motor units and move different body parts
The activity of any given cortical neuron affects a number of physical characteristics defining a movement and these effects depend on
the external loading conditions in which the movement proceeds
Any physical characteristic of movement is likely reflected in _______
activation of patterns of distributed populations in cortical cells
