Lecture 3: Exploring the brain Flashcards
What does the brain generally do?
Sensing -> processing -> effect/response
or
input -> computation -> output
What are the two divisions of the nervous system?
Central nervous system - Computation of the input
Peripheral nerve system - Produces a response and senses
Describe the peripheral nervous system?
Separated into autonomic nervous system (internal environment detecting) and somatic nervous system (external environment detecting)
Describe how the somatic nervous system works
Communicates with the central nervous system through sensory (external to central) and motor (central to external) neurons. skin and muscles.
sensory neuron (receptor) -> dorsal root ganglion/dorsal root -> synapse in spinal cord.
Spinal cord is made up of grey matter (cell bodies/synapses) and white matter (axons of neurones)
each nerve in the dorsal root ganglion innervate a specific strip of skin.
What are the two pathways within the spinal cord?
The sensory pathways (mostly) & Motor pathways
Describe dermatomes and an exmaple of a disease which shows this
nerves in each dorsal root ganglion innervate a specific strip of skin.
shingles - affect a singular dorsal root ganglion
Describe the autonomic nervous system
Communciates internal environment to central nervous system and vice versa through sensory and motor/effector neurons. Internal organs, etc.
Made up of parasympathetic (fight or flight) and sympathetic (rest and digest).
Describe the sympathetic and parasympathetic nervous systems
- Sympathetic - fight or flight e.g. chain of sympathetic ganglia dilates pupils, increases heart rate, solar plexus causes secretion of adrenaline and noradrenaline,glycogen converted to glucose, dilated brochi, inhibition of bladder contraction, etc.
- Parasympathetic - rest and digest e.g. vagus nerve slows heartbeat, constricts bronchi, stimulates release of bile, etc. Medulla oblongata stimulates flow of saliva.
Define the forebrain and hindbrain areas of the brain
Forebrain is made up of cerebral cortex (hypothalamus and thalamus) and subcortical regions. It contains grey (cell bodies and synapses) and white matter (connections)like the spinal cord and envelops the whole forebrain.
Hindbrain is made up of:
- Brainstem: medulla
- Pons
- Midbrain
- cerebellum
What is decussation and what carries this out
The brainstem carries out the crossing over of information toand from left and right sides of the brain i.e. signal on left affects right side of body, etc.
How does the forebrain work:
- Information from the spinal cord or brainstem usually synapses first in the thalamus (information hub).
- Information is then sent on to the cerebral cortex and other areas.
- Descending information often loops back through the thalamus and back to other brain areas as it is processed. It is not unidirectional.
somatosensory -> cognition/emotion -> motor regions
How does the hindbrain work
Brainstem carries information to the brain from spinal cord. Carries out decussation (cross information) + have neurons that produce neurotransmitters like dopamine, acetylcholine, serotonin and norepinephrine.
Define the lobes of the cereral cortex
- Frontal lobe
- Temporal
- Parietal
- Occipital
How many layers of cells does the cerebral cortex have and what is this called?
6 layers called cellular architecture, whithin motor and sensory cortex:
layers 1,2,3: integrative functions
layers 4: sensory input (afferent)
layers 5&6: output to other parts of brain (efferent)
there are many different functions for each of these layers.
each number of each function area relate to Brodmann’s areas.
What’s the function of the basal ganglia
Information about planning actions loops through the basal ganglia before reaching the premotor and motor cortical areas.
Function of hippocampus
Integrates information from across the cortex to store and activate memories.
Describe corpus callosum
Whiter matter tract that connects the two cerebral hemispheres
Function of the hipothalamus
Regulates lots of homeostatic processes like feeding and drinking. Can regulate hormone release and thereby behaviour via its connections with the pituitary gland.
Whta is the function of the cerebellum?
Involved in learning unconscious motor skills like riding a bike. It brings sensory and motor information together to guide learning.
