applications of cog neuroscience on ageing Flashcards
what are the models of brain change
-reorganisation due to decline in function
-reorganisation due to protecting function
what is reorganisation due to decline in function
-dedifferentiation = breakdown of functional specialism
-deficits in inter hemispheric inhibition
what is reorganisation due to protecting function
-advantageous to work together when demand is high and resources low
-compensation = cooperation between regions
which researcher summarises views on compensation and what did they state
Cheryl Grady 2012
-important to pair neuroimaging data with behavioural studies to see context of cognitive capacity
-e.g if RT increases (slower) this suggests decline in function, if RT decreases (faster) this suggests protection of function
what can older people do when compensatory mechanisms cannot maintain performance
early intervention techniques e.g brain training
-e.g sudoku puzzles keep older people neurally and cognitively flexible
-work well to an extent, not sure about LT impacts
-unsure whether it just benefits sudoku performance or enhances other abilities
how can researchers help to promote adaptive neuroplasticity/neural enhancement
-use neurofeedback techniques
-pp presented with representation of brain activity at point in time
-known as real time FMRI
-makes pp aware of their biological responses
-pp can work to alter neural and cog task based performances
where is neurofeedback particularly useful
-in anxiety disorder or phobias
-pp in FMRI scanner, view phobic stim
-see their heightened brain response in real time
-can compare to brain of someone without particular phobia
-patient can work to decreases their response
what are NIBS
non invasive brain stimulation
-directly manipulates way brain is behaving
-way to non invasively infer causation which other methods that use correlations cannot
what is an example of NIBS
transcranial direct current stimulation (tDCS)
-stimulation device
-red cable = anode +
-blue cable = cathode -
-corresponding electrode pads placed on areas of scalp
- 1-2 mA
what sensation might pp experience when going through tDCS
tingling, itching
what are the ancient origins of tDCS
egyptions used electric fish to try and relieve headaches
what does tDCS do
-not capable of evoking action potentials
-makes spontaneous firing of neurons more or less likely to occur
-anodal + stim pushes neurons closer to threshold of spontaneous firing increasing likelihood of action pot by increasing membrane potential
-cathodal - stim pushes neurons further from threshold decreasing likelihood of spontaneous firing and decreasing likelihood of action potential by lowering membrane potential
what is tDCS dependent on
neurotransmitters
-GABA (inhibitory), glutamate (excitatory)
-tDCS changes levels of these
-balance between these neurotransmitters determines increase or decrease in activity
-active stim = change in GABA and glutamate compared to sham
application of neurotransmitters and tDCS
-GABA decreases with ageing
-if we can alter neurotransmission as seen in tDCS, then we could support compensatory mechanisms and maintain brain function and task performance in older adults
buying brain stimulation devices online to do at home
-not safe
-people may push limits and have too much stimulation
-claim online to boost maths performance, athletic performance etc
tDCS and cognitive enhancement research
zimmermann et al 2013: acquisition of complex motor skill was enhanced 24hrs post anodal tDCS
Floel et al 2012: improved object location learning at 1 week follow up after temporoparietal tDCS
evidence for sustained benefits of tDCS
park et al 2014: improved accuracy of verbal WM at 4 week follow up
jones et al 2015: enhanced verbal/visual WM at 1 month follow up
boggio et al 2012: sustained visual WM improvement in mild - moderate alzheimers disease pp
tDCS and neural enhancement study
Meinzer et al 2013
-word generation task, older pp vs sham older vs sham youth
-older pp with anodal tDCS made less errors, similarly to youth group
-anodal tDCS increased semantic word retrieval of pp with cog impairment similar to healthy controls
-reduced overactivity in regions of frontal gyrus in impairment group, and healthy older adults had similar ability to youth
tDCS methodological considerations
-state dependent effects: older adults may benefit more from stimulation during training
-timing or response: older adults may have delayed response to tDCS
-indiv diff: education and baseline performance may predict response to tDCS (learmonth et al 2015)
-stimulation length/intensity: may be need for higher current levels and longer durations for older adults to get round these brain changes (tatti et al 2016)
what is a key strenght of tDSC
can infer causation due to controlling activity and actually have an effect on brain
