Studies Flashcards
Why is dual binding important (3 examples?)
Traffic lights, post into a red box, names with faces
Previous findings (Para et al., 2016)
Alz sufferers perform the same as healthy adults on single task arrays, but were significantly worse at verbal recall and presentation together (e.g., walk and talk at the same time)
(Para et al., 2017) Previous findings (Della Salla et al., 2002).
Long-term binding in Alz patients is significantly worse (e.g., names and faces)
(Para et al., 2017)
Which gene mutation causes what?
Gene mutation preselenin-1 E280A causes autosomic dominant familial Alz disease, detectable at age 48 (Lopera, 1997)
(Para et al., 2017)
4 AIMS
- Whether binding deficits extend to STM
- Whether the binding deficit extends to visual domain
- Whether this is a feature of ageing (memory declines with age)
- Whether this is a preclinical marker of Alz disease
(Para et al., 2017)
Participant recruitment and inclusion criteria
Recruited from Columbia, underwent genetic screening for gene mutation. Carriers and controls had to have no psychiatric history, and no problems with memory (concluded with a self report and family questionnaire). Aslo had to pass mini mental state examination
(Para et al., 2017)
Neuropsychological test battery
Included tests that assessed associative learning, language, perception, visuospatial, memory, attention ]
(Para et al., 2017)
Test format
Based on a change detection paradigm, 500ms fixation screen, 2000 study display, 900ms fixed retention interval. 50% of tasks where different and 50% were the same
(Para et al., 2017)
What were the test array changes?
Single: Either colour only or shape only change
Binding: Both colour and shape changes
(Para et al., 2017)
How did the controls do? Does this agree with previous research?
The controls performed well on the test battery, and equally across the task. This concurs with previous research that states dual binding is a healthy function of WM (Luck & Vogel, 1997; Brockermole et al, 2008; Wheeler & Triessman, 2002).
(Para et al., 2017)
How did the asymptomatic carriers do? Does this agree with previous research?
They performed as well as the healthy controls on the test battery (except for Recall of the Rey Figure). However, they performed below cut off (like the Alz patients) for Paired Associative Learning Tasks and Dual-binding.
This concurs with previous findings (Fowler et al., 2002) who found that those who performed worse on the Cambridge Neuropsychological Paired Association Test were more likely to develop Sporadic Alz in the following two years.
(Para et al., 2017)
What is the issue with Paired Associative Tasks? Compared to dual-binding?
These tasks are sensitive to the effects of aging, so it is unclear whether aging causes this deficit.
However, dual-binding is not sensitive to aging (Brockermole et al., 2008).
(Para et al., 2017)
What evidence exists that a task is sensitive to aging?
The hippocampus has been linked to associative learning (Mayes, 2007) (and the Paired Associative Learning task) Hippocampal atrophy is linked to aging. This is inter-item learning, intra-item learning (e.g., dual-binding) is linked to other brain regions and connectivity, not damaged by aging (Zimmer et al., 2002). This may explain why dual binding is difficult, because it requires good connectivity.
(Para et al., 2017)
What do the results from this study and other studies suggest? (2)
The type of information (visual / verbal) and the type of retrieval (recall / recognition) does not matter. Alz affects all of STM binding
The gene mutation causes 100% of ALZ cases
(Para et al., 2017)
What is good about the methodology? (4)
No ceiling effects
No floor effects
The differences in memory performance cannot be attributed to individual ability because the tasks were titrated to each person (like Logie et al., 2004; 2007; Parra et al., 2009).
The tests within the test battery are not sensitive to age/SES/academic ability - no semantic difficulty (Brockermole, 2008).
How many people have Alz?
5.8 million people in the US had Alzheimers in 2019. This equates to 1/10 over 65’s
How does light affect rhythms?
Daylight is an exogenous zeitgeber that is processed by the retina. This acts like a pace maker for the hypothalamus, which regulates rhythms such as sleep-wake and temperature. When it is dark, melatonin secretion increased and body temperature drops.
It also regulates hormones and cortisol, which keeps us alert (peak 6am, trough 12am)
Siffre (1975) method and results
Lived in a cave in a glacial cave for 6 months without zeitgebers. simply ate and slept when he felt like it. Found his natural circadian rhythm (sleep-wake) stayed around 24-25 hours, but sometimes ran to 48 hours.
Without the influence of external factors
What has been recorded regarding light and melatonin? (3)
- Blue light in particular (short wavelength) boosts alertness (mimicks the sun’s light wavelength) and suppresses melatonin secretion.
- The Journal of Metabolism documented that artificial light suppressed melaltonin by 85%.
- Queener, 2017 found participants with blue-monitoring light slept better, for 24 minutes longer and fell asleep faster. They also detected a 58% increase in melatonin production (more than over the counter melatonin prescriptions)
However, at night - blue light may not be the only cause of reduced sleep, as phones etc may be mentally and physically stimulating too. (Rice, 2013)
Types of rhythms and examples
Circadian: 24 hour / day (such as sleep-wake cycle)
Ultradian: Less than a day (e.g,. heart beat, digestion)
Infradian: Over a day (menstrual cycle)
Siffres follow up
Examined the study of aging at age 65. Found his body clock ticked more slowly and sleeping patterns changed
Issues with cave study
Case study, cannot generalise, had contact with the outside world
Folkard (1985) Follow up Method
Sent 12 participants to a cave for 30 days without ex zeit, except for a clock which the experimenters controlled. They agreed to go to bed when the clock said 10:45 and awake at 7:45. Overtime, the experiementers eventually sped the clock up so the days were only 22 hours long.
Folkard (1985) Follow up Results
All but one’s cycle adapted. Showing that body clocks can be easily adapted (particularly in a time where the effect of artificial light was thought to be limited).
Campbell & Murphy (1998) Method and results (how was this measured)
Found that shining light onto the back of participants knees (whilst covering their eyes).
They measured nocturnal melatonin secretion and body temperature.
The cycles advanced and altered their circadian rhythm (up to 3 hours).
Blind contradiction to photosensitive findings
Research has reported however, that blind people often experience bouts of insomnia, as they do not receive light through their retina so their cycle runs freely.
however, the rate of breast cancer amongst blind women is lower (Bacal et al., 2006).