Neuropsychology 2307 Midterm#1 Flashcards
Human Neuropsychology
- The scientific study of the brain-behavior relationship with an emphasis on humans
- employed by hospitals, rehabs, governm. etc.
Goal of Neuropsychology
- how the nervous system functions lead to the emergnece of experience and behaviour
- functional / anatomical relationship between different brain structures
Clinical Neuropsychology
Brain behaviour studies applied to diagnosis, rehab and long-term prognosis of abnormal brain-behavior relationships
Goal Clinical Neuropsychology
- differential diagnosis of pathology
- assess for dementia and associated conditions
- affect TBI on cognition / behavior
Experimental Psychology
- Assessment of CNS function using testing procedures requiring behavioural responses
- Standardized testing
Valuable Skills to study Neuropsychology
- scientific research
- computer literacy
- applications for testing
neurolinguistics
the neural mechanisms in the brain that control the comprehension, production, and acquisition of language
alexia
loss in the ability to read
agraphia
loss in ability to communicate through writing
la belle indifference
inappropriate lack of concern for the perceptions by others of one’s disability, usually seen in persons with conversion disorder
maximum number of items hold in short term memory
7
conversion disorder
(neurological) symptoms that can’t be explained by a neurological disease or other medical condition.
in vivo Neuroimaging Techniques
- see structure and function of neuronal tissues
- CT, MRI, PET, fMRI, SPECT
- CT can show blood vessels and therefore show if there is an aneurysm or sub-arachnoid hemorrage
- non-invasive / non-destructive
- dTI (e.g. MRI) Tracks flow of water:
Measures direction and get picture of region of brain where water flow signal is large
travels on large tracs, axonal fibres
Tractography
Traces axon bundles through the brain in 3D
Mapping connection amongst brain areas
- Long connections - one lobe to another
- Relatively short connections - one part of lobe to another part same lobe
- Interhemisphereic connections: homotopic points (in “typcial” brain) and heterotopic points (in patients with Agenisis of Corpus Collosum AgCC) - missing part of CC
Connectional methods to link brain and behaviour
Connections to and from neurons or a given region of the brain using tracer substances (maps - non invasive)
MRI, fMRI, Diffusion Tensor Imaging
Correlational Methods
- Make observations of brain activity while an individual performs a behaviour
- Identify pathway and region whose activity correlates wtih the behaviour
Note: need to back up correlational study with causational study
Lesion Method
- Study the effects of brain lesions
- TBI, Stroke, Tumor, Infection, Degenerative disease
- MRI maps out the lesions
Note: lesions can sprawl and include structures that are not involved
Stimulation Method
- Stimulate the brain region or neural circuit and observe effects on cognition and behaviour
- Transcranial magnetic stimulation
- Transcranial direct current stimulation
Risk: can spread beyond target site
Franz Joseph Gall
- Founded phrenology
- Link between mental faculties and specific brain locations
Paul Broca
Broca’s area
Region in frontal lobe (usually left) with functions linked to speech production
Locating Cognitive Functions
Gunshot Wound Neurology / Mental Chronometry
- Gunshot Wound: looked at functional loss associated with damage to that area
- Chronometry: break down human tasks to see stages of information processing during timed task
Brain Metabolism for localization
measure relationship between function and structure by monitoring changes in brain metabolism
Golgi’s Stain
- Used silver nitrate to stain slices of the cerebral cortex to see cellular level in the tissues
- prove nervous system made up of individual cells
Cajal
Used Golgi’s method to show individual neurons
Neuron Doctrine; billions of discrete cells that communicate with each other
Fritsch and Hitzig
Electrically stimulated dog’s brains to identify what is now the area called the primary motor cortex
Galvanometer
- record electrical activity in muscles and nerves
- Heart - ECG
- Eye - electroretinogram
- Brain - electroencephalogram
Challenge: slow to respond
Lee Deforest
Audion
Developed an amplifier to be able to better record small electrical signals
Oscilloscope
Hodgkin and Huxley’s observations of giant axon in squid
shows how signal voltages vary as a funciton of time
Darwin’s Theory of Evolution
Natural Selection
- structural and functional characteristics that allow an organism to reproduce more successfully are passed on to offspring
- characteristics the become more prevalent in species
Molecular Biology
Localize where and understand how the DNA of a genome gives rise to normal and abnormal neural tissues
Intervention in Brain Function
- Behavioral - learning / experience
- Physical - trauma
- Surgical - remove tissue
- Chemical - drugs, alcohol, chemicals
- Electrical - electroshock, TMS
Wilder Penfield
Used electrical stimulation to map the cortical functions of awake epilepsy patients during a craniotomy
“Montreal Procedure”
Ethics of Research on Humans and Animals
Must be humane and worthwhile; need “ethical approval” from the American Psychological Association (e.g.)
Signals in the Neuron
Signals within neurons are mainly electrical
Signals between neurons are mostly chemical
Biological Information Processing
- Within cells: specialization of cellular organelles
- Between cells: specialization of cell groups
- Among multicellular organisms: society, civilization
Eukaryokes
Plant and animal cells
Selectively permeable plasma membrane
Different ionic concentrations of cytosol and ECM or interstitium
Transduction
Ability to sense the environment through muscles, glands and neurons and create electrical signals which convert to the release of neurotransmitters to respond to the information
Iinformation Processing from Within the Neuron
Done through the Dendrites, Soma and Axon
3 Main types of Neurons
Sensory, Motor, Interneuron
3 Ways Eukaryotes transfer ions across plasma membrane
- Diffusion: ions and molecules move from area of higher to lower concentration
- Facilitated Diffusion: Proteins embed in plasma membrane and are “gated” by ligands, mechanical force or voltage
- Active Transport: proteins use ATP to pump the ions through the plasma membrane (sodium/potassium pumps) - every cell has one
Active Transport
- ATP pumps ion through the membrane
- Each cycle pumps 2 + potassium ions in and 3 + sodium ions out so net charge is negative voltage across membrane
- 100’s and millions of these pumps along membrane
- -50 to -70 mv inside cell (resting potential)
Interstitium / Extra cellular Matrix
- Cells float in this
- It is outside the cell
- Help coordinate how the cells all relate to each other
Neuron-Astrocyte Cooperation
- Astrocytes can make, store and relese glycogen
- When Glucose molecule oxydizes it makes ATP
- ATP proveds the energy for the neuron
- Neurons use 3x as much ATP as other eukaryotes
Transmembranal Potential
- Voltage difference across the cell membrane
- typically about -70mV
- Neurons change the voltage difference to be able to signal by adding or subracting ions
- (Change the ionic permeability of the plasma membrane)
Depolarization
Depolarization:
- change the ionic concentration to a “less negative number” - i.e. more towards zero
- as it heads towards zero it is likely to produce an Action Potential and be an Excitatory Post Synaptic Potential (EPSP)
Hyperpolarization
Concentration across post synaptic membrane to a more negative number (further away from zero)
- inhibits Action Potentials
Action Potential
- Spikes of electrical signals along axons that starts at the axon hillock and can contiue over a long distance
- It is how neurons send messages; in the resting state not information is being sent, not communicating
- Less subject to degradation
- All or none ballistic process and stays same (same shape, same amplitude); only the rate of production changes
Graded Potential
- Can be either excitatory or inhibatory
- Signal amplitude is proportional to the stimulus intensity
- Used mostly for grey matter or for signals that do not have to travel a long distance
- Are more subject to degradation
- Message will become distorted if long axon
Synaptic Transmission
- changes the electrical properties of the receiving neuron (post-synaptic potential PSP)
- changes the permeability of the Post. Syn. Membr.
- bind to receptors that are gated
Integration of Signals
- Receiving neuron integrates received signals in dendritic tree (from all arbors)
- If IPSP and EPSP add to 0 then no net result
- Has to exceed the “threshold of excitation” to force open enough voltage gated channels to depolarize a membrane (usually about -55mV)
Channels
- Voltage gated channels change the membrane potential
- Voltage gated sodium channels open first
- Potassium channels open next to allow potassium out
- Returns to resting
- Voltage gated calcium channels are activated by signals along the membrane; once the channels are activated they cause the NT’s to migrate to the pre-synaptic membrane
Signals Between Neurons
- Signals are chemical, chemicals called neurotransmitters
Neurotransmitters
- chemical synthesized in transmitting neuron
- able to bind to receptors on receiving neuron
- able to decompose in synaptic cleft (enzymatic)
- able to bind to receptors on presynaptic membrane, causing the NT release
- NT’s can also bind with autoreceptors in the pre-synaptic membrane (to shut off the dumping of NT’s into the cleft) - usually G protein receptors
Rate Law
Only way Action Potentials can be used for signalling is to vary the number produced over time (because all same shape and size)
Action Potential Rate
number of action potentials produced per period unit time
“Spike” - single Action Potential