Brain and Behaviour Flashcards
What is neural pruning?
When you lose synaptic connections in a neural network because you do not use them
What are neural networks?
When neurons connect in a way that allow for the processing and transmission of information
Draganski
To investigate whether “the structure of an adult human brain alters in response to environmental demands.” Participants were split into two groups: ‘jugglers’ and ‘non-jugglers’ and they all had their brains scanned (MRI) at the start of the study. Jugglers had three months to learn a simple juggling pattern and everyone was rescanned when they could sustain the pattern for at least 60 seconds. Jugglers were asked to stop practising their juggling for the next three months and then all ppts’ brains were scanned a third time.
Scan one: no significant differences between the two groups.
Scan two: jugglers “demonstrated a significant … expansion in grey matter” in three areas. The amount of change was closely related to the ppts’ juggling performance: better jugglers showed more change in brain structure.
Scan three: the expansion decreased (but didn’t disappear) after three months without juggling.
No change in grey matter was recorded for the non-jugglers.
Conclusion
The brain can change structurally in response to learning a new skill. Learning to juggle is more about perception and spatial anticipation of moving objects than about motor skills (because of where the greatest changes were detected). Changes in brain structure can be transient (temporary) unless something is practised.
What are the four subheadings under the brain and behaviour?
Techniques to study the brain, neuroplasticity, localisation, neurotransmitters and their effect on behaviour
What studies support localisation?
Maguire, Sharot, Rogers and Kesner
What is localisation?
The view that specific parts of the brain are responsible for specific aspects of behaviour
What is neuroplasticity?
The brain’s ability to change as a result of experience
What studies support Neuroplasticity?
Maguire, Draganski, Rozzenwig Bennett and Diamond
Maguire
-To see if physical changes “could be detected in the healthy human brain associated with extensive experience of spatial navigation.”
-All ppts had their brains scanned using MRI, with the region of interest being the hippocampi, already known to be involved in spatial and navigational memory.
-Maguire compared the average brain scan of the TDs with the average brain scan of the controls, to see if there were any differences and also looked at the size of
the brain between individual TD drivers and the average control with the number of months they had been doing their job.
-The taxi drivers’ (TDs’) anterior hippocampi on both sides were significantly smaller than the controls’, while the TDs’ posterior hippocampi were significantly larger.
-There was a significant positive correlation between time as a taxi driver and the size of the right posterior hippocampus.
What connects Maguire to localisation?
- the posterior hippocampi of taxi drivers is much larger than the anterior hippocampi
- suggests that the posterior hippocampi is used in the storage of spatial navigation and the enterior may be used in the encoding of new environments
- taxi drivers need to use their spatial navigation memory to navigate through london
What studies support the effect of neurotransmitters on behaviour?
Rasch, Gais and Born , Gais and Born, Rogers and Kesner ( might leave out) and Rozenweig, Bennett and Diamond
Rasch Gais and Born
To investigate the claim that high levels of ACh support memory encoding while low levels facilitate consolidation.
Each ppt experienced both conditions (one with ACh antagonists and one with a saline placebo).
Ppts were tested for encoding by learning a list of numbers then doing a recognition task and for consolidation by learning a list of word pairs and being tested on it 10 hours later.
Encoding: Ppts performed significantly worse on this task when they had received the ACh antagonists.’
Consolidation: Ppts performed significantly better on this task when they had received the ACh antagonists.
Conclusion
ACh seems to be excitatory for encoding (encoding requires the formation of new (or more) connections between neurons, which means that neurons need to be firing (the result of excitation).
ACh seems to be inhibitory for consolidation (when present it seems to reduce whatever neurotransmission is necessary for the securing of new memories).
Antagonist = scopolamine
What do Ach antagonists do?
Inhibit cholinergic transmission
What do Ach antagonists do?
Inhibit cholinergic transmission
What do Ach agonists do?
Enhance cholinergic transmission
