PSYC202 Unit 2 Exam

optogenetics

brain stimulation using light, Deisseroth

process of optogenetics

the gene from a light-sensitive protein in algae is inserted into specific neurons, the proteins will activate/inhibit the neurons, an optical fiber is inserted to shine light

functions of optogenetics

views and controls firings of action potentials, can control behavior and activity in brain cells, not done in humans (invasive)

transcranial magnetic stimulation (TMS)

magnetic stimulation to a portion of the scalp

function of transcranial magnetic stimulation (TMS)

activates or inactivates neurons in a narrow area below the magnet, applies current or magnetic stimuli in a noninvasive way to treat disorders such as depression

temporal lesion

temporary inhibition of brain activity, feeling achieved from TMS

limitations of TMS

difficult to target area, slightly painful/uncomfortable, only for cortex, transient cognitive charges, poor spatial resolution (not specific to brain areas)

spatial resolution

producing high quality images

temporal resolution

producing images quickly

deep brain stimulation (DBS)

electrical stimulation of the brain, neurostimulator transplanted under the skin sends electrical impulses to the brain

uses for deep brain stimulation

only used when medications fail (Parkinson's, depression, OCD)

limitations of deep brain stimulation

highly invasive, requires surgery

electroencephalography (EEG)

sensitive electrodes detect the current generated by millions of active neurons (conducted at the scalp)

uses of electroencephalography

sleep studies and consciousness, epilepsy studies

positives of electroencephalography

non-invasive, high temporal resolution

limitations of electroencephalography

low spatial resolution

magnetoencephalography (MEG)

similar to EEG, measures magnetic fields generated by brain activity

intracranial EEG/electrocortiography (ECOG)

electrodes placed directly on the brain to study the synchronization of brain waves

positives of iEEG/ECOG

good temporal and spatial resolution

limitations of iEEG/ECOG

only used on patients going through brain surgery

MRI

uses strong magnetic fields rather than x-rays to create a structural image of the brain (anatomy)

functional magnetic resonance imaging (fMRI)

measures oxygen content in the blood flowing through each region of the brain and relies on magnetic properties of the atoms

uses of fMRI

used to study brain function, activation/activity in the brain

pros of fMRI

good spatial resolution

limitations of fMRI

poor temporal resolution

resting state fMRI

study of brain connectivity while the person is not performing a specific task

default mode network

regions of the brain that are active when the brain is awake and at rest and attention isn't being directed to external events

maturation

processes in the development of neurons

proliferation

production of new cells, 28 weeks of gestation, stops outside of uterus

overproliferation

overabundance of neurons, leads to megalencephaly (associated w/ autism)

reduced proliferation

lower number of neurons, leads to microencephaly

migration

movement of neurons guided by chemicals, deficit in chemicals leads to decreased brain size and axon growth

contributes to low migration

environmental factors during pregnancy (i.e., influenza, BMI)

differentiation

cell changes into specialized type of neuron, with axons forming first and dendrites forming after migration

myelination

process of myelin formation that continues gradually through adolescence and adulthood

synaptogenesis

neurons form new synapses and discard old ones, slows as one ages

synaptic pruning

removal of unneeded connections; increases in older people/schizophrenics, too little seen in autistic people (hyperactive neurons)

stimulating environment

enhances sprouting of dendrites and axons in many species

physical activity

one of the best ways to maintain intellectual vigor in old age by enhancing both cognitive processes and brain anatomy

prolonged experience

enhances brain's ability to perform same function again, especially starting in childhood

Brain Derived Neurotrophic Factor (BDNF)

formation of new neurons and synapses, serves as neurotransmitter modulator, participates in neuronal plasticity, essential for learning and memory

spinal cord

communicates with the sense organs and muscles; sends sensory information to the brain and receives motor commands

hindbrain

postural support; contains the pons, medulla, and cerebellum

vegetative state

disconnection of hindbrain from the rest of the brain, affects consciousness

midbrain

spontaneous movement, important for operant movements (attacking, getting food); reaction to stimulus, not motivative behavior; superior (vision) and inferior colliculus (hearing)

diencephalon

motivations, contains hypothalamus and pituitary gland

hypothalamus

motivated behaviors (sleep, sex) and thermoregulation

pituitary gland

hormonal control

basal ganglia

self-maintenance, helps with learning simple sequences of movements; allows for animals to learn w/o cortex and makes behaviors more biologically adaptive

cortex

intention, pro-activity and skilled movements/sequences; allows extension of usefulness of learned behaviors to new situations, problem solving

middle cortical layers (layer IV)

input zone of sensory analysis, large in sensory areas, smaller in motor areas

cortical layers V and VI

output zone, send axons to other cortical and brain areas, large in motor areas

superficial layers (II and III)

receive inputs from other cortical areas and integrates them with inputs from layer IV

cortical columns/modules

interactions and functions, with most interactions between neurons taking place vertically; higher in sensory regions and lower in motor regions

vision receptors

specialize in energy from light

audition receptors

specialize in pressure changes in air

touch receptors

specialize in pressure changes in skin

smell and taste receptors

specialize in chemicals

transduction

receptors transform energy to a different type of energy, often electrical

retina

neural tissue that receives light

fovea

small area specialized for acute, detailed vision

periphery

better sensitivity to dim light

retina receptors

cones and rods

cones

mostly in fovea, better with detail

rods

mostly in periphery, better at night

geniculostriate pathway

eye -> lateral geniculate nucleus -> striate cortex -> other visual cortical areas; pattern, color, and motion recognition

visual form agnosia

inability to recognize objects

tectopulvinar pathway

eye -> superior colliculus -> pulvinar -> other visual cortical areas; spatial location of objects, unconscious

visual ataxia

inability to recognize where objects are at

V1 of occipital lobe

striate cortex

V2 of occipital lobe

functionally heterogenous area (so is V1)

V4 of occipital lobe

important for color vision

V5 of occipital lobe (middle temporal)

perceives objects in motion

ventral stream

from V1 -> temporal cortex, determines an object's identity; the "what" pathway

dorsal stream

from V1 -> parietal cortex, determines an object's location and how to interact with an object in regards to stimulus; the "where" or "how" pathway

fusiform face area (FFA)

ventral stream region for face analysis

extrastriate body area (EBA)

ventral stream region for body analysis

superior temporal locus (STS)

ventral stream region for biological motion (body movement analysis)

parahippocampal place area (PPA)

ventral stream region for scenes (indoor/outdoor places, landmarks)

parietal reach region

dorsal stream region for visually guided reach

hemianopia/hemianopsia

blindness in half of visual field due to damage in left of right V1

blindsight/cortical blindness

responding to stimuli that one can't consciously see

cortical colorblindness

damage of V4 area, also impacts imagery and memory

visual agnosia

inability to recognize visual information

apperceptive

inability to develop a percept of the structure of an object, can't copy it

simultagnosia

issues perceiving more than one object at a time; often due to damage in different areas or Balint's syndrome

associative agnosia

inability to recognize an object despite its apparent perception (can copy but can't recognize)

prosopagnosia

difficulty recognizing familiar faces due to bilateral damage of fusiform area

alexia

word blindness, damage of left fusiform area affects word recognition

auditory receptors

hair cells in the cochlea that move with vibrations to open K+ channels

release of neurotransmitters

caused by electrical signal from K+ ions flowing into hair cells

auditory pathway

cochlea -> medulla -> inferior colliculus (midbrain) -> medial geniculate nucleus of Thalamus -> auditory cortex (A1)

tonotopic map

in the primary auditory cortex (A1), cells in this area have a preferred tone; left -> low frequencies right -> high frequencies

‘what’ auditory pathway

primary auditory cortex (A1) -> anterior (inferior) temporal sulcus, object recognition

‘where’ auditory pathway

primary auditory cortex (A1) -> posterior temporal cortex and parietal cortex, object localization

superior temporal gyrus and inferior temporal gyrus -> superior temporal sulcus

polymodal pathway, probably underlies stimulus categorization

superior temporal gyrus

auditory ventral stream

middle temporal gyrus

auditory and visual processes

inferior temporal gyrus

visual ventral stream (w/ fusiform gyrus)

insula

gray matter near STG