Systems Level CNS Artchitecture

Question 1

Central nervous system

Answer 1

Brain
Spinal cord

Question 2

Peripheral nervous system

Answer 2

Division located outside the skull and spine

Question 3

Somatic nervous system

Answer 3

Interacts with the external environment

Question 4

Autonomic nervous system

Answer 4

Regulates the body’s internal environment

Question 5

The spinal cord of CNS

Answer 5

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

Question 6

Brain compromises hierarchy of functional systems providing increasingly sophisticated actions

Answer 6

The subdivisions map onto the hierarchy

Question 7

Hindbrain- medulla

Answer 7

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

Question 8

Hindbrain- Pons (bridge)

Answer 8

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

Question 9

Hindbrain- Cerebellum

Answer 9

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

Question 10

Midbrain

Answer 10

Contains the tegmentum and tectum

Question 11

Tectum- visual/spatial and auditory frequency maps

Answer 11

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

Question 12

Midbrain- tegmentum

Answer 12

Made up of

Periaqueductal gray
Red nucleus
Substantia nigra

Question 13

The Periaqueductal gray

Answer 13

Role in defensive behaviour

Role in pain ascending and descending signals

Role in reproduction

Question 14

Red nucleus

Answer 14

Target of the cortex and cerebellum, projects to spinal cord

Role in pre- cortical motor control (especially arms and legs)

Question 15

Substantia nigra – part of basal ganglia

Answer 15

Substantia nigra pars compacta
(Dopamine cells) – basal ganglia Input
Parkinson’s disease

Substantia nigra pars reticulata –
basal ganglia output

Question 16

Diencephalon- forebrain

Answer 16

Made up of thalamus and hypothalamus

Question 17

Thalamus- relay structure

Answer 17

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

Question 18

Hypothalamus

Answer 18

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

Question 19

Forebrain- cerebral cortex

Answer 19

Subcortical (under the cortex) made up of:

Basal Ganglia
Limbic system

Question 20

Basal ganglia

Answer 20

Group of structures

Loop organisation

These structures throughout to be involved in motor function since involvement in movement disorders

Question 21

Limbic system

Answer 21

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

Question 22

What is the limibic system made up of

Answer 22

Amygdala

Hippocampus

Fornix

Cingulate gyrus

Septum

Mammillary body

Question 23

Amygdala

Answer 23

Involved in associating sensory
stimuli with emotional impact

Question 24

Hippocampus

Answer 24

Involved in laying down memory (long term)
Involved in spatial memory

Question 25

Cingulate gyrus

Answer 25

(Limbic cortex)
Linking behavioural outcomes to motivation and autonomic control – atrophied in schizophrenia (wasted away)

Question 26

Mammillary body

Answer 26

Breast shaped Important for the formation of recollective memory – amnesia

Question 27

Septum

Answer 27

Involved in defense and aggression

Question 28

Fornix

Answer 28

C-shaped bundle of fibers
Carries signals from the hippocam-pus to the mammillary bodies and septal nucleus

Question 29

Forebrain- cerebral cortex

Answer 29

Gray matter- 6 layers- cell bodies

White matter: fibres/axons

Biggest part of the brain in primates

Question 30

Cerebral cortex- frontal lobe

Answer 30

Contain the precentral gyrus from which motor instructions (particularly for fine motor control) that are sent to muscles controlling hands and feet.

Primary motor cortex: contains many of the cells giving origin to the descending motor pathways - it is involved in the initiation of voluntary movements.

Premotor and supplementary motor areas: higher level motor plans and initiation of voluntary movements

Involved in judgmental roles and emotional modulation
Working memory: short term information rather than long term factual
Control of behaviour that depends upon context or setting

Prefrontal cortex generating sophisticated behavioural options that are mindful consequences

Question 31

Cerebral cortex- parietal lobe

Answer 31

Contains the postcentral gyrus which receives sensation from the rest of the body

(Primary somatosensory cortex)
This maintains representations of the body’s and of the head’s position in space
Permits complicated spatio-temporal predictions – e.g. catching something when you are moving

Question 32

Cerbral cortex- temporal lobe

Answer 32

Contains the primary auditory cortex

Inferotenporal cortex reignites faces and objects

Plays important roles in integrating sensory information from various parts of the body

Interface between cortex and limbic system – association of affect/emotion with things

Question 33

Cerebral cortex- occipital lobe

Answer 33

Dorsal stream
Vision for movement
Where [is it in relation to us – path towards motor areas]

Ventral stream
Vision for identification
Path towards temporal/limbic areas