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The Brain and Behaviour
Transcript of The Brain and Behaviour
Are Mental Abnormalities Caused by Genetic or Environmental Factors?
Why study brain function?
Three major subdivisions
Nature Vs. Nurture
‘a disorder in children who, despite conventional classroom experience, fail to attain the language skills of reading, writing and spelling commensurate with their intellectual abilities’
Struggle with skill automatisation,
time estimation, balance, and
demonstrate classic cerebellar
signs of dystonia
Located above the Midbrain
Between both cerebral hemispheres
Highly confusing world
No single symptom
Andreason et al. (1994)
47 'healthy' males and 39 schizophrenic males
Decrease in thalamus size
Cause and Effect
Schizophrenia cause decrease
Thalamus size cause schizophrenia
May have to screen capture the ref. it won't let me paste it in, it wither has to be all italics or all normal :/
Twin Studies (Gottesman and Shields, 1972)
Concordance rate of schizophrenia
DZ twins: 9%
MZ twins: 42%
Concordance not 100%
Muscular movement,learning & memory
Timing and coordination of movement
(Howes et al., 2004)
More than genetic
Drug use and social adversity
Trigger is needed
Eliminate environmental factors
10 times more likely
Not just genetic or environmental
Cause and effect
Interaction of both?
Developmental dyslexia: the cerebellar deficit hypothesis
Roderick I. Nicolson, Angela J. Fawcett
and Paul Dean (2001)
Subjects learned a sequence of eight button presses by trial and error using a four-key response board
Dyslexic subjects show less activity in the cerebellum than control subjects
Cause and effect
Contradictory theories and research
Impairment in the representation, storage and/or retrieval of speech sounds
Ramus et al. (2003): little evidence for motor impairments having a cerebellar origin
Supports phonological deficit theory
Phonological Deficit Theory
Samuelson and Lundberg (2003): 17- 26 percent of the variance in reading skills were accounted for by environmental factors.
But... phonological deficits are the core component in defining dyslexia.
Nature versus Nurture
Cause and effec
Andreasen, N. C., Arndt, S., Swayze II, V., Cizadlo, T., Flaum, M., O’Leary, D., Ehrhardt, J. C.,
Yuh, W, T, C., (1994). Thalamic Abnormalities in Schizophrenia Visualized Through Magnetic Resonance Image Averaging. Science. 266, 294-298
Firestone, J., Smith-Weller, T., Franklin, G., Swanson, P., Longstreth, W., & Checkoway, H.
(2005). Pesticides and Risk of Parkinson Disease. Archives Of Neurology, 62(1), 91. doi:10.1001/archneur.62.1.91
Golbe, & Lawrence,. (1998). Parkinson's disease: nature meets nurture. The Lancet, 352
(9137), 1328-1329. doi:10.1016/s0140-6736(05)60741-6
Heston, L, L., (1966) Psychiatric Disorders in Foster Home Reared Children of Schizophrenic
Mothers. The British Journal of Psychiatry. 112, 819-825.
Howes, D. O., McDonald, C., Cannon, M., Arseneault, L., Boydell, J., Murray, R. M. (2004).
Pathways to schizophrenia: the impact of environmental factors. The International Journal of Neuropsychopharmacology, 7, S7-S13
Nicolson, R., Fawcett, A., & Dean, P. (2001). Developmental dyslexia: the cerebellar deficit
hypothesis. Trends in Neurosciences, 24(9), 508-11.
Puschmann, A. Genetics of Parkinson's. Epda.eu.com. Retrieved 26 November 2014, from
Ramus, F., Rosen, S., Dakin, S. C., Day, B. L., Castellote, J. M., White, S., & Frith, U. (2003).
Theories of developmental dyslexia: insights from a multiple case study of dyslexic adults. Brain, 126(4), 841–865.
Samuelsson, S., & Lundberg, I. (2003). The impact of environmental factors on components of
reading and dyslexia. Annals of Dyslexia, 53(1), 201–217.
Schnabel, j. (2014). Does Parkinson’s Disease Start Outside the Brain?. Dana.org. Retrieved
26 November 2014, from https://www.dana.org/News/Details.aspx?id=43093
Sohmiya, M., Tanaka, M., Aihara, Y., & Okamoto, K. (2004). Structural changes in the
midbrain with aging and Parkinson’s disease: an MRI study. Neurobiology Of Aging, 25(4), 449-453. doi:10.1016/s0197-4580(03)00125-8
Thalamus Location [Online Image]. Retrieved November 19 from http://imgarcade.com/1/
Visanji, N., Brooks, P., Hazrati, L., & Lang, A. (2013). The prion hypothesis in Parkinson's disease: Braak to the future. Acta Neuropathol Commun, 1(1), 2. doi:10.1186/2051-5960-1-2
- Contains clusters of neurones: sensory (relay centres for visual and auditory) and motor (eye movement)
- Reticular formation=sentry
- Ascending part: alerts
- Descending part: admits or blocks out sensory input
- Severe damage = permanent coma (Pendlebury, 2007)
= less dopamine
Aging (Sohmiya et al., 2004):
–59 subjects with PD and 140 age- and gender-matched normal subjects
–used T2-weighted MR imaging
–different amounts of substantia nigra of subjects in the 70 years old or less group
Parkinson's Disease (PD) – What is it?
Parkinson's Disease (PD) - Why?
Genes, in the brain?
–Dominant and recessive
Outside the brain? (
Schnabel, 2010; Visanji et al., 2013)
–Earliest symptoms: constipation and other gastrointestinal problems
–Protein clusters could be toxic and kill cells
Pesticides and Herbicides
(Lawrence & Golbe, 1998)
- 'Virtually every case-control study [...] has shown that pesticide or herbide exposure [...] increases Parkinson's disease'
That's not true (Firestone et al, 2005)
- Associations are weak