Bio SAQs

Technique used to study the brain P1

• magnetic resonance imaging

• a type of neuroimaging used to investigate the relationship between brain structure and behavior

• specifically, structural imaging - deals w structure of the brain and the diagnosis of large-scale intracranial diseases + other injuries

• produces 3D images of the brain’s structure by measuring the hydrogen nuclei present (which are abundant in water and fat and present in varying amounts in different brain tissues) through a strong magnetic field and radio waves

• when the magnetic field excites these atoms, each tissue type takes a unique amount of time to return to a normal state, allowing the scanner to distinguish between them

• the resulting images can show a single slice of the brain from any angle or be combined to create a 3d model of the brain

• analysis thorugh pixel-counting (calculate area of brain structures) and voxel-based morphometry (to measure density of grey matter)

Technique/localization of function, research method P2

Maguire (2000)

Aim: to examine whether structural changes could be detected in the brains of taxi drivers, who have extensive experience with spacial navigation.

Sample: 16 right-hand male London taxi drivers, average of 2 years taxi-driving experience, average age of 44 + control group of 50 non-taxi drivers

Procedure:

• MRIs used to show relationship between brain scans and length of time drivers were licensed for

• VBM was used to measure the grey matter density by identifying differences in density in different parts of the brain

• pixel-counting used to calculate hippocampal area - researchers were not aware whether they were looking at a taxi-drivers scan or not

Results:

• taxi drivers, on average, had a greater posterior hippocampal volume compared to non-taxi drivers with a lower anterior hippocampal volume

• volume of posterior hippocampi positively correlated with the amount of time spent as a taxi driver

Conclusion: hippocampus had changed in response to environmental demands (the need to use spatial memory), as observed on MRI scans

Technique P3

• used MRI to show brain scans and length of time drivers were licensed for

• scans indicated structural differences between control group and taxi group

• because the environment of the drivers demanded regular use of their spatial memory, their posterior hippocampus had developed more neural connections

• therefore, grey matter appeared on the scans, which was analyzed using VBM

• directly evident in scans as the volume of this region was determined, using pixel counting, to be larger compared to the posterior hippocampus of the control group.

• anterior hippocampus was found to be smaller in taxi: suggests a redistribution of grey matter in the hippocampus depending on the demands placed on different memory functions

Localization of function P1

• proposes that a specific part of the brain is responsible for a certain brain function and behavior

• one example is the anterior and posterior hippocampus

• focuses on the transfer of STM to LTM

• is involved in spatial navigation and memory

• memory encoding (spatial and non-spatial) is often associated with the anterior hippocampus

• memory retrieval is associated with the posterior hippocampus

Localization of function P3

• researchers studied localization of function in spatial memory

• both posterior and anterior hippocampi played significant roles in the creation of a large spatial memory for taxi drivers, enabling them to create maps of the city in their head and easily use this info to drive wherever they need to go

• posterior hippocampus was significant in creating spatial memory and navigation → sig. larger than non-taxi drivers → suggesting it is often involved in situations where previously-learned memories are used

• anterior hippocampus could be more involved in the encoding of new spatial memories

• maguire provides empirical evidence of the localization of function (specifically, spatial memory processed in ph)

• localization of function → different areas of hippocampus are responsible for different aspects of spatial memory

Research method p1

quasi experiment

• type of experiment where participants are grouped based on a shared characteristic (e.g. race, gender, age)

• no random allocation

• do not show causation, can imply a casual relationship between iv and dv

• researcher is unable to manipulate iv (cannot randomly assign people to a culture, for example)

Research method p3

• naturally grouped based on shared characteristic - taxi driver

• no random allocaiton

• IV - taxi-driving experience

• DV - change in hippocampal structure

Ethics p1

undue stress or harm

• potential psychological or physical risks that an experiment may pose on its participants

• can be because of deception or nature of procedure

• any stress that would be greater to a participant than in everyday life

• no changes to the patients mental health and physical health during or after experiment

• no lasting effects

Ethics p3 (same as in cog - maybe talk a bit about fmri being stressful for claustrophobic people etc)

• asked to recall triggering, emotionally distressing, traumatic memories of terrorist attack

• use of emotionally charged cues and memory recall of a truamatic event → psychological stress

• no reported lasting effect, so likely that RtW was present

• stress induced would not be considered excessive for someone who had already processed the event over time

• might’ve caused undue harm