BIOL122 Lecture Notes - Lecture 9: Prefrontal Cortex, Amyloid Beta, Limbic System
Dementia:
Neurophysiology review:
Types of messages in CNS
1.) Neurotransmitters
- Chemical messengers that transmit information across synapse
2.) Neuromodulators
- Very similar to NT’s, not necessary released at synapses
3.) Neurotrophic factors
- Small proteins that support growth, survival and development of
neurons.
Neurotransmitters: They produce rapid excitatory or inhibitory responses in post
synaptic neurons.
1.) Amino acids:
• Excitatory neurotransmitters include: glutamate, cysteine, etc.
• Glutamate binds to NMDA receptor to allow passage of cations (+)
into the cell. Learning and memory.
• Over excitation- epilepsy, huntingtins disease and chronic pain
• Inhibitory neurotransmitters include: gamma amino nutyric acid
• GABA binds to receptors- influx of CI ions or efflux K+ ions, they
promote relaxation, calming effect.
• May be linked to anxiety and depression,
2.) Monoamines:
• Includes noradrenaline, adrenaline, dopamine, histamine
• Noradrenaline: binds to adrenergic receptors
- Physiology: arousal and mood, blood pressure
- Pathology: High levels: manic phase of bipolar disorder,
depression
• Dopamine: binds to dopaminergic receptors
- Physiology: Motor control, meotion and reward systems, inhibits
prolactin release, vomiting.
- Pathology: Parkinson’s disease (low levels) reward systems
(addiction)
• Serotonin: Binds to serotonin receptors
- Physiology: sleep, wakefulness and mood, feeding appetite,
vomiting
- Pathology: Depression, anxiousness, panic attacks, mental
obsessions, eating disorders, confusion, heavy sweating.
3.) Acetylcholine
• Receptors: cholinergic
- Physiology: arousal, cognition, learning and memory, motor
control
- Pathology: Alzheimer’s disease
Dementia: A broad range of brain diseases characterised by development of
memory impairment and other cognitive deflects with preservation of a normal
level of consciousness. Syndrome of intellectual deterioration, personality
disintegration, confusion and impulse control; enough to interfere with the
persons normal social or working life. Progressive and irreversible loss of higher
mental function, particularly memory.
• Aetiology: Any disorders that permantly damages areas controlling
memory or learning.
- Neurodegenerative diseases
- Vascular diseases
- Space- occupying lesions
- Trauma
- Toxic
Alzheimer’s disease: Impairment of higher intellectual function, with alterations
in mood and behaviour. Progress to disorientation, memory loss and aphasia-
disabled, immobile, mute. Predominantly affects hippocampus, limbic system and
frontal cortex.
• Aetiology: unknown
- Beta- amyloid protein accumulation (plaques on outside of
neuron)
- Neurofibrillary tangles
• Pathogenesis: formation of plaques in learning and memory
regions, then spreading
- Altered processing of amyloid precursor protein
Document Summary
Chemical messengers that transmit information across synapse. Very similar to nt"s, not necessary released at synapses. Small proteins that support growth, survival and development of neurons. Neurotransmitters: they produce rapid excitatory or inhibitory responses in post synaptic neurons. Amino acids: excitatory neurotransmitters include: glutamate, cysteine, etc, glutamate binds to nmda receptor to allow passage of cations (+) into the cell. Learning and memory: over excitation- epilepsy, huntingtins disease and chronic pain. Inhibitory neurotransmitters include: gamma amino nutyric acid: gaba binds to receptors- influx of ci ions or efflux k+ ions, they promote relaxation, calming effect, may be linked to anxiety and depression, Includes noradrenaline, adrenaline, dopamine, histamine: noradrenaline: binds to adrenergic receptors. Pathology: high levels: manic phase of bipolar disorder, depression: dopamine: binds to dopaminergic receptors. Physiology: motor control, meotion and reward systems, inhibits prolactin release, vomiting. Pathology: parkinson"s disease (low levels) reward systems (addiction: serotonin: binds to serotonin receptors. Physiology: sleep, wakefulness and mood, feeding appetite, vomiting.
