L1 Flashcards
What’s the difference between neurotransmission and Neuromodulation?
Neurotransmission refers excitatory or inhibitory actions, and serves rapid, precise and point to point communication.
however
Neuromodulation describes slower processes that alter subsequent responsiveness of neurons
How is global modulation achieved?
Hubs, where neurotransmitters are created, are densely connected, allowing for global modulation.
We can dampen or increase arousal all at once… coordinated for global impact on the brain
What are ‘hubs’ ?
Systems deem in the brainstem, sets of neurons that create neurotransmitters and hormones.
They are then released all throughout the CNS.
each system is isolated in terms of the set of neurons that creates each hormone/NT.
What are hormones?
Signalling molecules that are produced by glands and transported through the BLOOD to regulate physiology and behaviour!!!!
How do neurotransmitters and hormones differ?
- NT belong to NS. Hormones belong to Endocrine system.
- transmission of NT is between neurons, hormones travel through blood.
- Target cells of NTs can be specific neurons or other cells, whereas hormones’ targets can be some distance away from endocrine gland.
- NTs work in milliseconds, and hormones can work within seconds or days.
- Hormones directly modulate neurotransmitter levels and function. EG: GABA and Oestrogen receptors are VERY integrated!! Massive co-location!!!
thus, impact of each hormone is very compelx
What is the blood brain barrier?
It prevents many substances from passing between the blood and brain. Protects from infections.
Determines the way hormones afffect the brain
Describe the PNS.
Peripheral Nervous System
Consists of nerves and ganglia outside the brain and spinal cord.
Receives sensory Info about body position, pain and temperature.
Sends messages from brain to control muscles and movement.
Describe the ENS
Enteric Nervous System
“2nd Brain”
100 Million Neurons.
- has it’s own reflexes and senses and can act independently of brain.
- Nearly every NT found in brain is found in gut.
- 95% of serotonin is here.
- Modifies its behaviour according to food that’s passing through, and external stimuli (eg. stress).
- 90% of connections b/w brain and gut go from GUT TO BRAIN (feeds back into our feelings + mental health)
can see that it’s not connected to brain areas that deal with vision and imagery or words. - Plays major role in emotions and stress
- informative to consider what it doesn’t do - consciousness, decision making etc. but.. split second/gut feelings?!
Describe brain-gut interactions.
- Perioheral - Serotonin production in gut may have affects in the brain
- Immune - Intestinal microbiome can prompt production of cytokines to influence neurophysiology
- Bacterial Molecules - Microbes can produce metabolites which can alter activity of cells in blood-brain barrier.
what is the microbiome
trillions of bacteria and other microorganisms that live in the gut
What is sickness behaviour?
A series of temporary behavioural, cognitive and emotional changes due to activation of immune system.
(bi-directional links b/w brain to immune system)
- Fever
- Increased sleep and lethargy
- depressed mood
- impaired concentration
- loss of interest
- hyperalgesia
- anorexia
- decreased social interaction
What causes sickness behaviour?
CYTOKINES!!!!!!!!!!!!!!!!!!! released by the body in response to infection and travel to the brain.
Cytokines are proteins important in cell signalling - they are released by cells and influence behaviour of other cells.
found that if you have cytokines alone, you can get sickness behaviour independent of virus/illness.
Cytokines are too big to pass through BBB so are thought to enter brain indirectly, or trigger cytokine production in the brain.
What are examples of sickness behaviour with a cold, and then with severe illness?
cold - impairments in visual detection, hand-eye coord, and cognitive tasks
severe illness - negative mood, fatigue, memory and attention deficits.
Why do we think sickness behaviour exists? and what are some possible negative outcomes of sickness behaviour?
It is thought that it is a strategy for the body to conserve energy and improve its fight against infection. May also be beneficial for the community, by preventing spread of disease.
However, excessive sickness behaviour may lead to neuropsychiatric syndromes such as fatigue sydromes and MDD.
cytokines can also trigger the stress response, which can lead to changes in immune func.
