Week 2 Flashcards
Neurons
- Basic unit of the nervous system is the neuron
- Use chemical transmission and electrical impulses
- They process, receive and transmit signals
- established networks are faster and more efficient due to myelination
Myelination
White matter that acts as insulation in a neuron
Assists in carrying electrical chare
Neurogenesis
The birth of new neurons through cell division
Death of Neurons
- Don’t appear to have a lifespan
- Die off due to biochemical changes like:
- Too much cortisol (stress)
- Lack of blood flow
- Harmful free radicals that cause degenerative disease
Neural Systems
- Nervous System has two branches
- Peripheral Nervous System -
- Autonomic Nervous System
- Somatic Nervous System
- Central Nervous System - Brain & Spinal Chord
- Peripheral Nervous System -
ANS & SNS communicate information between the CNS and the organs, glands & body.
Autonomic Nervous System
- Has two branches:
- Sympathetic Nervous System
- Parasympathetic Nervous System
- SNS activated in response to threats (fight or flight)
- PNS acts as a balance and supports return to homeostasis (rest & digest)
Vagus Nerve
- Parallel to the PNS
- Dedicated to fine tuning bodily reactions
- Especially used in social situations
Brain Stem
- Fully Functional at birth
- Regulates temperature, heart rate and basic reflexes
- Shaped by genetic history
Cerebral Cortex
- Is Experience Dependent - shaped by countless interactions with the world
- We learn to adapt to the environment using this cortex
- As we for ideas, experiences and mental representations our cortex becomes more and more complex
Lateralisation
- Cerebral Cortex has two halves that seem to have different functions
- Left side processes information using logic - develops around 2 years
- Right side processes information holistically with whole context - fully developed at birth
- Language also processed laterally:
- Right side - communicates broadly and non verbal cues
- Left side - Involved in complex linguistics
Corpus Collosum
- Connects left and right cortex hemispheres to support communication
- Also acts as barrier to block any conflicting information
- Often left & right hemispheres have competing needs
Lobes
- Four Lobes in the Brain
- Frontal - Motor behaviour, language, directed attention
- Parietal - Links senses with motor function, creates sensation of body in space
- Occipital - Visual processing
- Temporal - Auditory processing, receptive language, memory functions
Limbic System
Sits between Brain Stem and Cortex
Involved with learning, memory, motivation and emotion
We focus on hippocampus and amygdala
Amygdala
- Key role in developing neural networks
- Attachment and appraisal and expression of emotions
- Looks at information from thalamus - sight smell, sound, kinaesthetic information
- If threatened transmits to hypothalamus to release stress hormones
- This triggers fight or flight
Neurotransmitters
- Chemical messengers to communicate between neurons
- Dopamine, Serotonin and Norepinephrine regulate cognitive process and emotion
- Too much dopamine leads to depression
- Too much norepinephrine leads to anxiety
- Serotonin functions in arousal and mediates mood
Neuropeptides
Regulate pain, pleasure and behavioural reward
Chemicals include endorphins, oxytocin, vasopressin
Endogenous endorphins serve as analgesic
Also connected to dissociation and self harm behaviour
Cortisol
Stress Hormone produced in adrenal glands
Enhances memory, energy production and helps restore homeostasis after stressful situations
Prolonged stress correlated with memory deficits, poor regulation of homeostasis and reduction in Hippocampus and Amygdala
Neural Plasticity
- Experience sculpts the brain
- Neurons that fire together wire together
- Neurons grow in strength and connectivity to create enduring networks
- Synapses that are not used are eliminated if they become inactive
- Use it or Loose it!!
Synaptogenesis
- Is genetic rapid expansion in synapse formation
- Deals with bombardment of sensory input
Synaptic Pruning
- Reduction in number of synaptic connections
- This enables more, synaptic configurations and more efficient brain function
- This is led by experience; connections not used are pruned
Cortisol Inhibition and Conscious Control
- As cortex develops so do top down circuits in neural network
- These help inhibit reflexes and bring body and emotions to be under cortical control
- This process is central to emotional regulation
Vagus Nerve
- Major part of parasympathetic system
- Controls mood, immune response, digestion and heart rate
- Connects brain to gastrointestinal tract
- Vagus Nerve Stimulation may support treatment of depression, PTSD and inflammatory bowel disease
Bi-Directional Communication
- Communication between brain and gastrointestinal track goes both ways
- Complex system which includes the Vagus Nerve
Vagus Nerve Anatomy
- Longest nerve in the body
- Runs from skull, pharynx, larynx, thorax, heart and intestines’
- Regulates organ functions like digestion, heart rate and respiratory rate
- Also vasomotor activity like reflex actions like coughing, sneezing, swallowing and vomiting
Polyvagal Theory
- Evolution of the Autonomic Nervous System provides parts of the CNS to adapt to behavioural strategies
- Our physiology limits the range of behaviours and psychological experience.