Neuronal oscillation Flashcards
(27 cards)
Describe feed forward excitation [2]
- presynaptic excitatory neurones relay info to post synaptic excitatory neurones
- allow info to propagate through the CNS
Describe feed forward inhibition [3]
- presynaptic excitatory neurones excite post-synaptic inhibitory neurone
- thus inhibiting next neurone in circuit
- act as a brake to limit spread of excitation
Define convergence
- one post-synaptic neurone receives and integrates info from multiple presynaptic partners
Define the term divergence
one-presynaptic neurone distributes info to multiple post-synaptic partners
Describe lateral inhibition [2]
- presynaptic excitatory neurone excites post synaptic inhibitory neurones
- which then inhibit neighbouring excitatory neurone
Describe the two way recurrent inhibition can occur [6]
- presynaptic excitatory neurone excites post-synaptic neurone
- which then excites inhibitory neurone that inhibits the first neurone
- prevent runaway excitation
- presynaptic excitatory neurone excites post synaptic neurone
-which provides additional excavation on first neurone - mechanism for amplifying to a signal
Describe disinhibition [2]
- presynaptic inhibitory neurone inhibits ost synaptic inhibitory neurone
- release downstream excitatory neurone from inhibition
Describe the term oscillation
something that occurs repeatedly at regular rhythm
What causes neuronal oscillations [4]
- synchronous brain activity
- excitatory and inhibitory neurones connect together
- they will be active together
- give rise to waves of electrical activity
What is ECoG? [2]
- electrodes placed on brain surface
- measures brain activity with high spatial resolution
Identify a way ECoG has been used in a clinical setting [2]
- in epilepsy
- used to identify the origin of seizures
Define the term amplitude
magnitude of oscillation
Define the term period
time (T) to complete one full oscillation (up and down)
Define the term frequency
number of complete oscillations in one second
Define the term phase [3]
- Angle representing a portion of oscillation period
- wave is sine, which can be divided into 360 degrees
- e.g. 90 degrees = 1/4 period
- Label diagram
see diagram
Describe Delta waves
- 0.1-4 Hz
- sleep
Describe theta ocsillations [5]
- 4-7 Hz
- creative thinking/ emotional arousal
- linked to spacial and performance cognitive tasks
- prominent in medial temporal lobes (hippocampus, EC)
- ad multimodal association cortices (PFC. Parietal cortices)
Describe alpha oscillations
- 8-12 oscillations
- restfulness
Describe beta oscillations
12-30 HZ
concentration
Describe gamma. oscillation [3]
- 30-120 Hz
- problem solving/cognition
- seen in most brain areas
Describe slow wave-ripple oscillations [4]
- brief VHF oscillations (120-150Hz)
- seen in nREM sleep
- seen simultaneously in hippocampal structures
- important in memory consolidation
Describe a study that showed PFC and hippocampus oscillations coordinate for spatial working memory [5]
- rats sent down route with choice of two paths
- in one trial rat forced to take turn towards goal arm
- in other rat had choice which path to take to reach goal arm
- EEG taken
- oscillations in HPC and PFC had matched sequences during choice trials but not in forced trials
What does the spike timing tell us about how HPC and PFC coordinate [3]
- spike timing in the PC slightly receded that of PFC
- thought that HPC leads to pFC
- enabling animal to problem solve
