systems level CNS architecture Flashcards
vertebrate brain evolution
- Size and proportions of various parts of our brain is very different to ancestors
- Preservation of brain architecture (function) tells us that the major survival issues for us as a species are not that different to our ancestor species
where is the peripheral nervous system located
outside the skull and spine
what is the peripheral nervous system divided into?
somatic nervous system (external environment)
autonomic nervous system (regulates the body’s internal environment)
describe the dorsal root of the spinal cord
afferent
affected by world
sensory
describe the ventral root of the spinal cord
efferent
having an effect on the world
motor
what can the forebrain be divided into
telencephalon
diencephalon
what is another name for the midbrain
mesencephalon
what can the hindbrain be divided into
metencephalon
myelencephalon
describe the medulla (myelencephalon) and its functions
- contains tracts that carry signals between the rest of the brain and the body
- Low level sensorimotor control – e.g. balance
- Involved in: sleep, movement, maintenance of muscle tone, cardiac, circulatory and excretory reflexes
describe the pons and it’s functions
- Relay from cortex and midbrain to the cerebellum
- Contains millions of neural fibres
- Pontine reticular formation (pattern generators e.g. walking)
describe the cerebellum and its functions
- Smaller than brain but contains as many neurons as rest of the CNS
- Motor error between intended movement and actual movement – adjusts synaptic weights to eliminate error
- Online correction can take place during the movement: motor learning
- Thought exclusive for motor coordination – recently implicated cognitive and affective/emotional function
what is the role of the tectum
visual/spatial and auditory functions
what can the tectum be divided into
superior colliculus - sensitive to sensory change, orienting/defensive movements
inferior Colliculus - similar but for auditory events
name the structures within the Tegmentum
Periaqueductal grey
red nucleus
substantia nigra
what does the Periaqueductal grey do?
- Role In defensive behaviour
- Role in pain (ascending and descending signals)
- Role in reproduction
what does the red nucleus do?
- Target of cortex and cerebellum, projects to spinal cord
* Role in pre-cortical motor control (especially in arms and legs)
what does the substantia nigra do?
- Substantia nigra pars compacta (dopamine cells) – basal ganglia output… Parkinson’s disease
- Substantia nigra pars reticulata – basal ganglia output
what makes up the diencephalon
thalamus
hypothalamus
describe the thalamus and its functions
- Specific nuclei: relay signals 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
describe the hypothalamus and its role
- Regulates the pituitary gland which regulates hormonal secretion: interface between brain and hormones
- Role in hormonal control of motivated behaviour including hunger, thirst, temperature, pain, pleasure and sex
name the subcortical telencephalon structures
- Basal Ganglia
* Limbic system
what are the basal ganglia?
- Group of structures
- Loop organisation
- Thought to be involved in motor function since involved in movement disorders
what makes up the limbic system
• Amygdala, hippocampus, fornix, cingulate gyrus, septum and mammillary body
what is the limbic system involved in?
- Involved in emotion, motivation and emotional association with memory
- Limbic system influences the formation of memory by integrating emotional states with stored memories of physical sensations
what is the role of the Amygdala
involved in associating sensory stimuli with emotional impact
what is the role of the mammillary bodies
importance for the formation of recollective memory – amnesia
what is the role of the hippocampus
involved in long term and special memory
what is the septum involved with
defence and aggression
what is the role of the cingulate gyrus
linking behavioural outcomes to motivation and autonomic control – atrophied in schizophrenia
what is the role of the fornix
carries signals from the hippocampus to the mammillary bodies and septal nucleus
role of the 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.
role of prefrontal cortex
generating sophisticated behavioural options that are mindful of consequences
role of the primary somatosensory cortex
Maintains representations of the body’s and of the head’s position in space and permits complicated spatio-temporal predictions – e.g. catching something when you are moving
roles of temporal lobe
- Contains primary auditory cortex
- Inferotemporal cortex recognises 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
describe the dorsal stream of occipital lobe
Vision for movement, where [is it in relation to us – note path towards motor areas]
describe the ventral stream of occipital lobe
Vision for identification, what [does it mean to us – note path towards temporal/limbic areas]
what are brain functions
emergent properties of signal processing in neural networks
