Systems Level CNS Artchitecture Flashcards
Central nervous system
Brain
Spinal cord
Peripheral nervous system
Division located outside the skull and spine
Somatic nervous system
Interacts with the external environment
Autonomic nervous system
Regulates the body’s internal environment
The spinal cord of CNS
Dorsal root sends signals to CNS (afferent)
This is sensory
At back
Ventral root receives signals from the CNS (efferent)
This is motor
At front
Brain compromises hierarchy of functional systems providing increasingly sophisticated actions
The subdivisions map onto the hierarchy
Hindbrain- medulla
Contains tracts carrying signals between the rest of the brain and the body
Contain caudal part of the reticular formation (‘little net)
-low level sensorimotor control such as balance
Involved in a variety of vital functions
Sleep waking up
Motor plant- movement, maintenance of muscle tone Various cardiac, circulatory, respiratory, excretory reflexes
Hindbrain- Pons (bridge)
Relay from cortex and midbrain to the cerebellum
Contains millions of neuronal fibres
Pontine reticular formation (pattern generators) e.g. for walking don’t have to think where to/how to place feet
Hindbrain- Cerebellum
Smaller than the brain but contains as many neurons as all the rest of the CNS
“Motor errors” between intended movement and actual movement – cerebellum adjusts synaptic weights to eliminate error
Online correction can take place during the movement : motor learning.
Thought exclusive for motor coordin-ation – recently implicated in cognitive and affective/emotional function
Decides how you do something
Midbrain
Contains the tegmentum and tectum
Tectum- visual/spatial and auditory frequency maps
The superior Colliculus o the tectum is sensitive to sensory change- orienting/ defensive movements
The inferior colliculus of the tectum is similar but for auditory events
Midbrain- tegmentum
Made up of
Periaqueductal gray
Red nucleus
Substantia nigra
The Periaqueductal gray
Role in defensive behaviour
Role in pain ascending and descending signals
Role in reproduction
Red nucleus
Target of the cortex and cerebellum, projects to spinal cord
Role in pre- cortical motor control (especially arms and legs)
Substantia nigra – part of basal ganglia
Substantia nigra pars compacta
(Dopamine cells) – basal ganglia Input
Parkinson’s disease
Substantia nigra pars reticulata –
basal ganglia output
Diencephalon- forebrain
Made up of thalamus and hypothalamus
Thalamus- relay structure
Specific nuclei: relay to cortex/limbic system for all sensations (but smell…)
Non-specific nuclei : Role in regulating state of sleep and wakefulness and levels of arousal
Important relays from basal ganglia and cerebellum back to cortex
Hypothalamus
Regulates the pituitary gland which regulates hormonal secretion: interface between brain and hormones
Role in hormonal control of motivated behavior
including hunger, thirst, temperature, pain, pleasure and sex
Forebrain- cerebral cortex
Subcortical (under the cortex) made up of:
Basal Ganglia Limbic system
Basal ganglia
Group of structures
Loop organisation
These structures throughout to be involved in motor function since involvement in movement disorders
Limbic system
Group of structures
These structures involved in emotion, motivation and emotional association with memory
The limbic system influences the formation of memory by integrating emotional states with stored memories of physical sensations
What is the limibic system made up of
Amygdala
Hippocampus
Fornix
Cingulate gyrus
Septum
Mammillary body
Amygdala
Involved in associating sensory
stimuli with emotional impact
Hippocampus
Involved in laying down memory (long term)
Involved in spatial memory
