TOPIC 3: NEUROSCIENCE AND BEHAVIOUR Flashcards
phrenology
linked physical state and mind, study of bumps on your skull.
reductionism
philosophy that a complex system can be explained by reducing it to its component parts.
myelin sheath
- fatty cells surrounding axon
- increases processing speed of electric current.
- degeneration of myelin sheath can lead to multiple sclerosis
where is the neurone + or - when polarized
positive outside and negative inside
what’s the state when the neuron is polarized
resting potential
action potential
electrochemical process that produces a traveling electrical charge along the axon
depolarization
Na+ channels open briefly, Na+ enters
depolarization
K+ channels open, K+ exits
where does depolarization and repolarization occur
occurs as a wave down the length of the axon terminal button
ion pumps function
restores balance of Na+ and K+ ions
absolute refractory period
time after an action potential during which another action potential cannot begin
synapse
functional connection between neutrons
synaptic cleft
gap between terminal buttons of one neutron and dendrites of another neuron
how are messages given
carried across by neurotransmitters
neurotransmitters
chemical messenger released by traveling charge
excitatory
opens channels allowing inflow of positively charged ions
inhibitory
opens channels allowing outflow of positively charged ions or inflow of negatively charges ions.
when is it increased likelihood of neurone firing?
during excitatory state, decreased likelihood during inhibitory state
threshold
minimum activity needed for action potential to occur
all monoamines
- dopamine
- norepinephrine
- serotonin
all amino acids
- glutamate
- gamma-aminobutyric acid
- endorphins
acetylcholine
(ACh)
-excititory transmitter between motor neurone and muscles; learning and memory
- low levels of ACh associated with Alzheimers disease
- curare is antagonistic towards ACh, and blocks it.
- nicotine ACh receptors activate by nicotine (agonist)
curare
antagonistic : blocks ACh actions on muscles
dopamine
(DA)
- voluntary movements, emotional arousal, learning, memory, pleasure system.
- degeneration is linked to Parkinson’s disease
- high levels implicated in schizophrenia
norepinephrine
(NE)
- alertness and arousal, intense fear and pain, enhances attentions and memory.
serotonin
(5-HT)
- generally inhibitory; controls sleep/wakefulness/arousal; implicated in aggression, mood and pain.
glutamate
(Glu)
- always excitatory; NMD receptor implicated in learning/memory and neural plasticity
gamma-animobutyric acid
always inhibitory; found throughout the brain
endorphins
endogenous (internal) opioids; have analgesic effects, elevate mood.
- hero is exogenous (external) opioid
components of the CNS
brain and spinal cord
components of PNS
somatic and autonomic
what components make up the autonomic
sympathetic and parasympathetic
what parts are ascending tracts connected too
the brain
what parts are descending tracts connect to
the brain ====> muscles
afferent fibre
reflex
interneuron
(spinal cord)
efferent fibre
controls muscle
electrical stimulation of brain
(ESB)
stimulate brain region with electrode and ask patients what they experience
lesions
surgical destruction of tissue, frontal lobotomy severs connection of frontal lobe; reduces seizures.
electroencephalogram
(EEG)
-amplifies evoked potentials produced by large numbers of neurons
intra/extracellular
-recordings: measure activity of a single neuron using micro electrode
CT (computerized tomography)
- multiple X-rays enhanced by computer
- shows structure
PET( positron emission tomography)
- take radioactive form of glucose
- X-rays cause positron to be emitted
- shows metabolic activity
MRI (positron emission tomography)
- magnetic field aligns spinning hydrogen nuclei, found in water molecules I tissue of the body
- resonant radio wave pulse disorients them
- protons emit radio waves open alignment
- shows detailed structure
FMRI (functional MRI)
- hemoglobin (which carried oxygen in the blood) contains an iron atom that has magnetic properties
- strong magnetic fail aligns magnetic molecules
- radio waves pulse disorients them
- upon alignment, protons emit radio waves which can be measured quickly
- shows metabolic activity
pros and cons to brain imaging
PROS:
- can show neural correlates of a function
- applications range from promising (neurodiagnosis)
CONS:
- can ONLY show neural correlates of a function
- to dodgy (neuromarketing, neuropolitics)
- people are more likely to be convinced by:
(evidence. contacting irrelevant information) & ( brain images that are redundant with other evidence)
what is the brain stem made up of
( three components )
- medulla
- pons
- midbrain
what is the brain stem connected to
spinal cord
components of hindbrain
(three components)
- cerebellum
- medulla
- pons
cerebellum
motor coordinations; control of ballistic movements
Medulla
heart rate, respiration
Pons
sleep stages, arousal
Midbrain
- includes relay centres for vision and audition
- reticular formation
reticular formation
reflexes, breathing, pain, sleep & wakefulness.
Forebrain
(three components)
- thalamus
- basal ganglia
- hypothalamus
thalamus
relay / processing centre for incoming sensory informational; and regulates arousal
Basal ganglia
control slower, deliberate actions
Hypothalamus
Mediator between brain & endocrine system (glands and hormones); regulates bodily functioning
Limbic system
(three components)
- hippocampus
- amygdala
- nucleus accumbens
hippocampus
important forearming and retrieving memories
amygdala
plays a role in emotion, aggression
nucleus accumbens
involved in reward, pleasure ad addiction
cerebral cortex
- outermost layer of the brain; responsible for higher order functioning
- wrinkles increase surface area (3 components) -Gyrus -sulcus -longitudinal fissure
Gyrus
convolutes ridge between anatomical grooves in the cerebral cortex
Sulcus
small groove in the cortex (vs. fissure which is deeper)
longitudinal Fissure
divides brain into two hemispheres,
how many lobes are the hemispheres dived into
4 four lobes
name the four lobes
- forntal lobe
- parietal lobe
- temporal lobe
- occipital lobe
Frontal lobe
includes motor cortex (move forward)
- assisting in planning, controlling and executive behaviour; emotions control; judgment speech production
Parietal lobe
includes somatosensory cortex (touch a person)
- processing sensory information regarding the location of parts of the body as well as interpreting visual information and processing language
Occipital lobe
includes visual cortex(see an object)
- does vision & spatial processing, colour, motion perception.
contralaterally
opposites side
- motor functions: right side of body is governed by the left side of the brain (& vice-versa)
- vision: object in right visual field first goes to the left occipital lobe (& vice-versa)
which part of the brain connects the two hemispheres
corpus collosum
how can one hemisphere be studied ?
through split brain syndrome
split-brain syndrome
- corpus callous severed surgically, leaving left and right brain hemispheres intact– but mostly separated
- if an image was present to the right visual field, the patient could verbal identify it
- of the image was presented to the left visual field, the patient was unable to verbally name it.
- however, they could select the correct item using their left hand.
Roger Sperry
Studied Split-brain
collection of cell bodies in neutral nervous system
nucleus
collections of body cells in peripheral nervous system
ganglion
alien and syndrome
patient loses conscious control of one hand, which seems to act on its own.
- the domination hemisphere loses conscious control over the ipsilateral hand
- caused when corpus collosum is damaged or severed
ipsilateral
same side
left hand left hemisphere
hemisphere specialization
- in split-brain patients, the two hemispheres of the brain function largely independently; whereas in intact brains, functions are integrated
left and right side of split brain hemispheres
left side: superior for functions like speech, math, and logic
right side: superior for cantons like recognizing faces, handling emotions, and spatial tasks
Neural plasticity
- is experience dependant
- can produce extensive
changes in the cortical regions - can occur during any stages of the lifespan-even adulthood
- ‘brain training’ is billion-dollar industry- but is difficult to help make brains younger
Marian Diamond & colleagues (1964)
Experiment: how do experiences change the cortex of rats.
rats placed in three controlled environments for 30days
- enriched
- standard
- impoverished
- cortex of enriched group increases in thickness compared to standard group
- impoverished groups thickness decreased
Eleanor Maguire & colleagues (2002)
Experiment: ca adult human brains change with experience
- taxi drivers posterior hippocampus were larger compared to control participants
- right posterior hippocampus volume was correlated with ice spent as a taxi driver (problem with this and a following stid followed)
Maguire, Wollett, & Spiers, (2006)
taxi drivers posterior hippocampus were larger then bus drivers
Woollett & Maguire, (2011)
successful trainees had improved memories, and their hippocampi grew over time
conclusions:
• hippocampus is important for processing and storing navigational and spatial information
• may be due to growth of new neurons (neurogenesis), or increased neural connection
conclusion from all of the taxi drivers experiments
- hippocampus is important for processing and storing navigation and spatial information
- may be due to growth of new neurone (neurogenesis), or increases neural connections
neurogenesis
the growth or development of new neurons
Richard Haier & colleagues (2009)
Experiment: how does playing video games affect brain structure
- lil girls played Tetris for 1.5 hours per week for 3 months
- BRAINS WERE ANALYZED USING FMRI
- results: increased efficiency of some cortical area (mostly in frontal lobe)
- different area of the cortex got thicker (indicates grey matter)
what happens when neurotransmitters are not relieved by the other end?? reuptake ??
when neurotransmitters are deactivated by being broken down, or by reuptake which is when they are reabsorbed into axon terminals
( split brain syndrome) If an image was presented to the right visual field
the patient could verbally identify it
( split brain syndrome) If an image was presented to the left visual field
the patient was unable to verbally name it, however, they could select the correct item using their left hand
left hemisphere superior functions
speech, math, and logic
right hemisphere superior functions
recognizing faces, handling emotions, and spatial tasks
what did we learn from Richards Haier’s experiment ??
- increased efficiency of some cortical areas (mostly frontal lobe)
- different area of the cortex got thicker (indicates increased grey area)
Temporal lobe
includes auditory cortex (heara tone)
- handles auditory processing, language comprehension, vision, memory formation; object categorization
