Lecture 1 Flashcards
What is the Triune brain:
- Thinking brain
- Emotional brain
- Survival brain
Neocortex Limbic System Basic/primitive/reptilian brain
Who was Kim Peek?
- Nickname: “Kim-puter”
- non-autistic savant
- born with malformed cerebellum and
absent corpus callosum
- Inpiration for “Rain Man”
- Encyclopedic knowledge of history, literature, classical music, U.S. Zip codes, travel routes
- Outgoing/sociable, issues w coordination, abstract and conceptual thinking
History of Neuropsychology:
- Cardiocentric hypothesis
- Aristotle
- Hippocrates
- Since 1990 - present
- Cardiocentric Hypothesis: heart was responsible for behaviour. Broken heart/heart representing love=remnants of hypothesis
- Aritstotle: thought brain was a radiator to cool body’s blood
- Hippocrates: Brain is the most powerful organ; everything takes orders from brain
- 1990 - present: more knowledge of brain acquired since all time previous (imaging)
Patients with Epilepsy were the 1st to be experimented on while awake leading to these 2 discoveries:
- the brain itself has no somatosensory receptors
- does not feel pain
important b/c:
- showed localization of function (related to epilepsy)
- could remove source of seizure leaving most of cortex intact
- could operate on patients while awake to refine procedures and conduct brain mapping
Cytoarchitecture
Involves grouping regions of the brain together in terms of their neuron types. neurons of a similar size and shape tend to be grouped together. Discovered by Brodmann (1909) who numbered these regions. This numbering system is crazy but still used.
Lobotomy
Based on the idea that the prefrontal cortex was related to neurosis and aggressive behavior Tracts between the felinist and frontal lobe were severed About 50,000 performed in the U.S. Best 1/3 have patience sorry improvements, and about 30% of people with these conditions tend to improve without treatment anyway. Sallie Ellen Lonesco was the first person to undergo ice pick lobotomy
Where did idea come from that we only use 10% of our
Experiments where animals could perform basic functions even when they had damage to 90% of their brains Not transferable to humans Every part of the brain is doing something important
Name three types of brain imaging
Structural, electrophysiological, functional
Explain CT scan
Computed tomography (Greek:slice) scanning: Reasons a series of x-rays taken from many directions Typically used for brain injuries This is a computer program to perform numerical integration calculation (radon transform) to estimate how much x-ray beam is absorbed in each volume of brain (attenuation of each voxel)
Basic definition of MRI, 1 pro 1 con
Magnetic resonance imaging Uses magnetic fields and radio waves for high-quality 2D and 3D images Pro: no radiation Con: some get claustrophobic
Electrophysiological methods
Record electrical activity of the brain Measures electrical activity of neurons, and, in particular, action potential activity (EEG)
EEG: electroencephalogram
Non-invasive Electrodes placed along scalp measures voltage fluctuations resulting from ionic current within the neurons Records spontaneous electrical activity over period of time
What is EEG used to diagnose?
Epilepsy, sleep disorders, coma, encephalopathies, and brain death Used to be afirst line method of diagnosing: tumors, stroke and other focal brain disorders, but it has decreased with Advent of high-resolution anatomical imaging techniques like MRI and CT
Functional neuroimaging What is PET
Measures metabolic processes in the brain: Fluctuations of metabolism of glucose and oxygen flow of blood to different parts of the brain is measured indirectly, which is also believed to be correlated to function Was most preferred method of functional imaging before fmri
What is the oxygenation hypothesis (FMRI)
Changes in oxygen usage during cognitive or behavioral activity can be associated with regional neurons as being directly related to cognitive or behavioral tasks being attended to E.g. motor neurons-related to movement, can see on imaging
How does fmri work?
Relies on oxygenated and deoxygenated hemoglobin to see changes of blood flow associated with neural activity can reveal brain structures and processes associated with perception, thought and action
Technical and methodological limitations of imaging
Human brain is composed of about 100 billion neurons; forming an intricate and dynamic Network Individual variation-every brain is different, how do we make an “average”picture of the brain We rely on case studies (unique to person, generally abnormal) or averages of many brains
5 types of research methods relied upon
The scientific method
Quasi-experimental research
Animal studies
Cognitive testingf
Case studies
Quasi-experimental research
Participant is not randomly assigned, it may be unethical or impractical to manipulate independent variable directly (can’t give frontal lobe lesions) Because they are not around amli assigned, there may be confounding variables, other differences between conditions Half observation, half meddling with the IV
Limitations of animal studies
Not a natural setting Not necessarily generalizable across species Limited in studying cognitive skills Different complexities of CNS Uniquely human behavior (language or memory systems) Differences in brain areas Consciousness is difficult to study in humans, let alone animals Ethics
Limitations of a neuropsychological exam (cognitive testing) (3 things)
Tester May deviate from standard delivery Comorbid disorders may confound results Language/lack of cultural sensitivity (may never draw as kids)
story/importance of Phineas Gage
Tamping explosives to make new railway, Tamping iron shot through face and out top of head. Contributed to early theories of localization, and localized aspects of personality in the frontal lobes
Define memory, and 3 types
- The ability to consciously recall events or facts
(also the structures and processes invovled in storage and retrieval)
Sensory, short term, long term
Long-term memory is divided into:
- explicit/declarative = “knowing what”
- facts and events, memories that can be consciously recalled (declared).
- implicit/procedural memory, e.g., tying shoes, riding bicycle, also evidenced by subconscious priming
Who was HM?
Name, disorder, when studied
Henry Gustav Molaison (Patient HM)
Childhood epilepsy progressively more severe
Studied from age 27-82 (death)
The experimental surgery of HM
(surgery name and brain areas)
- bilateral medial temporal lobe resection (lobectomy)
- removing some of temp. lobe (both sides)
- incl. parts of hippocampus & amygdala
3 effects of HM’s surgery
- no more seizures
- severe amnesia - remembered childhood but not events a few years leading up to surgery (up to 11 yrs before)
- anterograde amnesia: no ability to form new memories “like waking from a dream…every day is alone in itself” (50 1st dates)
- working memory and procedural memory were intact, but could not commit new events to his explicit memory. According to some, he was impaired in his ability to form new semantic knowledge
- Hippo removed, so long-term memory affected
- before HM, they didn’t think memory was localized
Agnosia
Is specific deficit in the ability to perceive objects
Hemiplegia
Paralysis of one side of the body
Aphasia
An impairment of language, affecting the production or comprehension of speech and the ability to read or write. Aphasia is always due to injury to the brain-most commonly from a stroke, but also from head trauma, brain tumors, or infections
Mnemonic for efferent and afferent
Afferent=arriving Efferent=exiting
Interhemispheric vs intrahemispheric
Interhemispheric-interactions between the two cerebral hemispheres Intrahemispheric-interactions within one cerebral hemisphere
