Chapter 3.1 Flashcards
Biological Psychologists/ Neuroscientists
-study the brain and behaviour
Phrenology
-exploration of the shape, size, and protrusions of the cranium
-super popular in 1820s
-incorrect map of the mind
-pseudoscience; was falsifiable
Original Phrenology Beliefs
-brain is sole organ of the mind
-character traits + intelligence are inherited
-differences between people result from structural brain differences
Disproved Phrenology Beliefs
-it was found that areas they thought corresponded to traits did not lead to deficits
Phrenology Example
Scientists saw bumps or divots in the shape of neural areas as strengths or weaknesses in traits and brain functions
Electrical Stimulation
-investigating brain function by electrically stimulating brain during neurosurgery
-supported that neural communication was electrical
Wilder Penfield
-American-Canadian neurosurgeon
-integral to development and expansion of this technique (electrical stimulation of the brain during surgery)
-“Burnt Toast” video
Lesion Studies
-specific area was damaged to understand the impairment
-done on animal models
Electroencephalograph (EEG)
-recording of the brain’s electrical activity at the surface of the skull
-developed by Hans Berger in 1929
-tells which areas of brain are active during specific tasks
EEG Advantages
-non-invasive
-high temporal resolution
EEG Disadvantges
-doesn’t tell us about individual cell activity
-doesn’t tell us about brain region activation with accuracy or in the deep brain
Computed Tomography (CT) Scans
-scanning technique using multiple x-rays to construct 3D images
CT Scan Advantages
-good for detecting dense tissue
CT Scan Disadvantages
-static image
-do details of activity
Magnetic Resonance Imaging (MRI)
-technique that uses magnetic fields to indirectly visualize brain structure
-detect soft tissue
Advantages of MRI Over CT
-detects soft tissue
-higher spacial resolution
Disadvantages of MRI
-expensive
-static image
-no details regarding activity
Positron Emission Tomography (PET) Scan
-imaging technique that measures consumption of glucose-like molecules
-yields a picture of neural activity in different brain regions
-measures changes in activity in response to stimuli
PET Scan Advantages
-can attach radioactive isotopes to drugs to see where they are used
-shows activity
PET Scan Disadvantages
-invasive
-poor time course (static image)
-poor spatial resolution
Functional MRI (fMRI)
-uses magnetic fields to visualize brain activity
-detects changes in blood oxygenation and flow that occur in response to neural activity
fMRI Advantages
-see activity with good image clarity
fMRI Disadvantages
-sensitive to motion
-spatial resolution is just ok
-expensive
-poor temporal resolution (better than PET/CT)
Spatial Resolution
-ability to tell you which area is active
-ability to differentiate two adjacent structures as being distinct from each other
Temporal Resolution
-ability to tell you exactly when the activation happened
Static Image
-image doesn’t move
Transcranial Magnetic Stimulation (TMS)
-applies strong and quickly changing magnetic fields to the surface of the skull that can either enhance or interrupt brain function
-allows us to see which brain areas are involved in processes
TMS Advantages
-can inhibit neural function
-allows us to infer causation
TMS Disadvantages
-can cause seizures if incorrectly used
-doesn’t work on deep brain, only cortex
Magnetoencephalography (MEG)
-measures brain activity by detecting tiny magnetic fields generated by the brain
MEG Advantages
-excellent temporal resolution
-reasonable spatial resolution
MEG Disadvantages
-not good at detecting deep brain activity
-expensive
-high degree of expertise required
Deep Brain Stimulation (DBS)
-electrodes are implanted within brain to provide stimulation detection to certain areas
-treatment of neuropsychological conditions
-assesses brain activity
DBS Disadvantages
-invasive - requires neurosurgery
-researchers have no control of where electrodes go
-must be implanted for medical purposes
Localization of Function
-certain brain areas are found to be particularly active during a specific psychological task
-caution for claims with limited evidence
Multiple Brain Regions
-multiple areas of the brain contribute to certain functions
-complex functions unlikely to be contained to one area
-depends on the task
-ie. Brocas Area
Brocas Area
-well known role in speech production
-also role in recognition of musical notes
Lateralization
cognitive function that relies more on one side of the brain over the other
Split-brain Surgery
Procedure that involves severing the corpus callosum to reduce the spread of epileptic seizures
Neuron
-nerve cell specialized for communication
-the brain has ~100 billion neurons
Cell Body (Soma)
-central region of the neuron
-manufactures cell components
-contains the nucleus (protein manufacture)
Dendrites
-portion of neuron that receives signals
-branchlike extensions
Axon
-portion of the neuron that sends signals
Axon Terminal
-knoblike structure at the far end
-releases synaptic vesicles
Synaptic Vesicle
-spherical sac containing neurotransmitters
Neurotransmitter
-chemical messenger specialized for communication from neuron to neuron
Information within a cell
-electrical communication
Information between cells
-chemical communication (synapse)
Synapse
-space between two connecting neurons through which messages are transmitted chemically
Synaptic Cleft
-gap in which NTs are released from the axon terminal
Glial Cells
-cell in nervous system that plays a role in the formation of myelin and the BBB
-responds to injury, removes debris, enhances learning and memory
Myelin Sheath
-glial cells wrapped around axons that act as insulators of the neurons signal
Astrocytes
-responsible for the BBB
-embryo development
-thought, memory, immune system
Oligodendrocytes
-promotes new connections among nerve cells
-aid in healing
-produces myelin sheath
Resting Potential
-electrical change difference (-60 to -70 mV)
-when neuron is not being stimulated or inhibited
Threshold
-membrane potential necessary to trigger an action potential
-all-or-none law
Action Potential
-electrical impulse that travels down the axon
-triggers the release of NTs
Absolute Refractory Period
-time during which another action potential is impossible
-limits maximal firing rate
Graded Potentials
-postsynaptic potentials that can be excitatory or inhibitory depending on +/- charge flow across membrane
Relative Refractory Period
-interval of time when a second action potential can be initiated
-will require a greater stimulus than before
All or None Law
-cell depolarizes or it does not
-stronger signals ≠ stronger action potentials
-stronger signals = more action potentials
Excitatory Postsynaptic Potential (EPSP)
-graded potential in a dendrite that is caused by excitatory synaptic transmission
Inhibitory Postsynaptic Potential (IPSP)
-graded potential in a dendrite that is caused by inhibitory synaptic transmission
Receptor Site
location that uniquely recognizes a NT
Reuptake
-recycling of NTs by presynaptic axon terminals
Neurotransmitter Synthesis
-occurs in presynaptic terminals
-enzymes transported to cytoplasm
Neurotransmitter Storage
-stored in synaptic vesicles in presynaptic axons
Excitatory NTs
-excite the nervous system
-increase activity
Inhibitory NTs
-inhibit nervous system
-decrease activity
Glutamate
-main excitatory NT
-sensory and learning
-alcohol and sensory enhancers
GABA
-main inhibitory NT
-alcohol and anti-anxiety
Norepinephrine
-both excitatory and inhibitory
-cortical arousal
-amphetamine and methamphetamine
Acetlycholine
-cortical arousal
-attention
-memory
-muscle contraction
-nicotine, botox, memory enhancers
Dopamine
-motor function
-pleasure
-Leva dopa (Parkinsons), antipsychotics
Serotonin
-mood regulation
-aggression
-sleep-wake cycles
-temperature
-anti-depressants
Endorphins
-pain killer
-codeine, morphine, heroin
Anandamide
-pain killer
-appetite increase
-THC
Psychoactive Drugs
-impact the nervous system
Agonist
-drug enhances activity at the receptor site
-either binds to receptor or blocks reuptake
Antagonist
-drug reduces activity at the receptor site
-binds to receptor site and blocks NTs
Neural Plasticity
-ability of neurons in the nervous system to change over time
-change in structure or function
Plasticity over development
-brain doesn’t fully mature until early adulthood
-brain changes even in later years
-4 parts:
Growth
-of dendrites and axons in the nervous system
Synaptogenesis
-formation of new synapses
Pruning
-death of certain neurons
-retraction of axons to remove connections that aren’t useful
Myelination
-insulation of axons with a myelin sheath
Neural Plasticity and Learning
-brains change as we learn
-creation of new synapses
-potentiation
-structural plasticity
Potentiation
-increased connection and communication among neurons
-strengthening of existing connections
Structural Plasticity
-change in the shape of neurons
Neural Plasticity following Injury and Degeneration
-neural connections can take the place of others
Neurogenesis
-creation of new neurons in the adult brain
Stem Cells
-a cell having the capacity to differentiate into more specialized cells
-used to repair and replace
