Presentation on theme: "Navigation-related structural change in the hippocampi of taxi drivers"— Presentation transcript:
1 Navigation-related structural change in the hippocampi of taxi drivers 3FA3- Module 4 Group A5Swiya NathPreeyam RanderiaCatherine LeslieTapiwa MuseweNicholas HawkesTapiwa’s last name?
2 Table of Contents Target Article Background Information Critique Subject SelectionSex BiasCritique MethodsAlternative ResultsConclusionI don’t think we need my name in the TOC
3 Swiya NathTarget ArticleAim : Test adult plasticity Method: Compare taxi driver’s brains to control subjects’ Conclusion: Adult hippocampus is plasticChanged wording a bit.
4 Table of Contents Target Article Background Information Critique Subject SelectionSex BiasCritique MethodsAlternative ResultsConclusionI don’t think we need my name in the TOC
5 Hippocampal size related to foraging behavior Swiya NathHippocampal size related to foraging behaviorFood storing speciesBird species that store food have higher relative hippocampus size
6 Hippocampal plasticity related to season of foraging Swiya NathHippocampal plasticity related to season of foragingRetrievalStoringNumber of large cells in anterior hippocampus increase during AugustNumber of large cells in hippocampus increase during October
7 Table of Contents Target Article Background Information Critique Subject SelectionSex BiasCritique MethodsAlternative ResultsConclusionI don’t think we need my name in the TOC
8 Age Variance Average age = 44 years Range = 32-62 years Preeyam RanderiaAge VarianceAverage age = 44 yearsRange = yearsNot an accurate representation of the wide age groupCan you make the font size of all titles the same as with the text?
9 Training Variance Licensing training lasted = 10 months to 3.5 years Preeyam RanderiaTraining VarianceLicensing training lasted = 10 months to 3.5 yearsAverage time spent before passing the licensing test = 2 yearsAmount of time spent on training can affect spatial developmentSpend = spent (typo)
10 Divide the years of experience into two ranges Preeyam RanderiaExperience VarianceYears of experience ranged = 1.5 years to 42 yearsAverage years of experience = 14.3 yearsToo large a range, leads to inconsistencyDivide the years of experience into two ranges
11 Control Group’s Experience Preeyam RanderiaControl Group’s ExperienceDriving experience of the control group was not calculatedMore driving experience would result in a larger spatial capacity
12 Preeyam RanderiaSelection BiasMRI scans from control group was used to compare hippocampus sizesRecord scans were used thus MRI scans were conducted for some deficit or problemNot representing the general population
13 Socio-Economic Status (SES) Preeyam RanderiaSocio-Economic Status (SES)SES was not identified for drivers or the control groupControl Group: lower SES might take public transportation more often and do not driveDrivers: different SES might depend on the type of area one works inDo examples need to be on slide?
14 Preeyam RanderiaCause and EffectDid not measure or have records of the hippocampus size before the licensing trainingThese individuals became taxi drivers because they were naturally better at spatial memory or vice versa?There is evidence for a correlation but not for a causal relationshipChanged title, ALSO Second point can be said instead of typed?
15 Uncontrolled Variables Preeyam RanderiaUncontrolled VariablesEducation LevelBased on education pursued, the taxi driver might already be used to memorizingSimilar limitation with control group and between the control group and taxi driversDeleted “for example” (I talked to Preeyam about this) and deleted (Cont.)
16 Control Subjects 16 control subjects taken from a group of 50 Catherine LeslieControl Subjects16 control subjects taken from a group of 50Group of 50 came from MRI scan DatabaseNot a random group of peopleIsn’t this a copy of Preeyam’s stuff (slide 10)
17 Table of Contents Target Article Background Information Critique Subject SelectionSex BiasCritique MethodsAlternative ResultsConclusionI don’t think we need my name in the TOC
18 Study cannot be generalized. Catherine LeslieSex DifferencesStudy cannot be generalized.It has been proven that men and women are different in terms of spatial abilityDifferences in spatial functioningDifferences in brain anatomy
19 Spatial Functioning Components of Spatial Function Catherine LeslieSpatial FunctioningComponents of Spatial FunctionSpatial Visualization –Mental rotationSpatial Perception – Water level taskSpatial Memory – Visual features vs. locationSpatial Orientation – Difference in used cues
20 Brain Anatomy Men Women Catherine Leslie Higher % of Working memory and cerebral spinal fluidHigher Amount of grey matter in left hemisphereAsymmetriesHigher % of grey matterNo asymmetriesTapiwa MIGHT be doing this (since its methodology)…haven’t discussed with Cate yet.Sex differences in brain anatomy may be able to explain differences in behaviour.
21 Table of Contents Target Article Background Information Critique Subject SelectionSex BiasCritique MethodsAlternative ResultsConclusionI don’t think we need my name in the TOC
22 Inter-rater Reliability Tapiwa MuseweInter-rater ReliabilityProsConsEliminates rater - rater ambiguityOnly measured by one expertHuman errorsPrecision24 X 32 MeasurementsWould strengthen results if corresponding measurements were found by multiple experts.
23 Restrictive Selection Tapiwa MuseweRestrictive SelectionAll participants were right-handedPrevented age-scale clusterEliminated individual anatomical differences by creating one templateParticipants were all male
24 Test – Retest Reliability Tapiwa MuseweTest – Retest ReliabilityUsed three different approaches to analyse volumetric changes in grey matterMagnetic Resonance Imaging (MRI)Provides detailed images of soft tissues in the brainVoxel-Based Morphology (VBM)Useful for determining neuroanatomical differences between individualsAllows anatomical differences of focal regions of the brain to be analysed rather than volumes of the whole brainPixel countingVolume of hippocampus calculated by logical calculations
25 Table of Contents Target Article Background Information Critique Subject SelectionSex BiasCritique MethodsAlternative ResultsConclusionI don’t think we need my name in the TOC
26 Swiya NathResultsPosterior hippocampus larger for taxi drivers than control subjectsAnterior hippocampus larger for control subjects than taxi driversResults more drastic in left hemisphereAdults show plasticityToo many words…I need help cutting them down.
27 Posterior Hippocampus Swiya NathHIPER ModelAnterior HippocampusPosterior HippocampusSmaller for taxi drivers than control subjectsLarger for taxi drivers than control subjectsEncodingRetrievalAlso say how during ‘Knowledge Test = encoding, driving = retrieval?” “Food storing bird species – larger anterior hippocampus when storing”Question audience: what could have study tested to negate this alternative hypothesis?Do taxi drivers have more experience with spatial memory, or simply retrieval as the HIPER model suggests?
28 Taxi Driver with Bilateral Hippocampal Damage Swiya NathTaxi Driver with Bilateral Hippocampal DamageRetrievalEncodingWell on spatial information (landmarks)Poor in actively navigating novel neighbourhoodsWell on main roadsPoor on detoursWhat could be possible mechanisms that might be an answer to this puzzle?BUT lesion not isolated to posterior hippocampus
29 ConclusionSelection bias = Randomized selection Sex bias = Lacks generalizability Test retest reliability HIPER model = Other memory test