psyc 375 chapter 7

neuropsychology

study of the relationship between brain function and behaviour with emphasis on humans

ways to observe brain structure

chemical and genetic lesions

noninvasive imaging

molecular genetics

isomers

molecules that have the same chemical formula but differ in bonding pattern

where in the brain is affected in parkinson’s disease like symptoms

Mpp+ killed dopaminergeric neurons within the substantial nigra

what does the removal of adrenal glands result in (experiment)

eliminates cortisol/corticosterone which leads to the deathy of neurons in denate gyrus

where is the denate gyrus located

hippocampus

conclusion of ADX experiment

denate gyrus neurons are necessary for contextual learning, exercise/enrichment can produce neurons in denate gyrus

morris swimming tasks components

• rats are good swimmers but like to get out of water

• opaque water

• tests spatial memory

place-learning task set up

platform hidden in pool, rat placed in various positions each time, use of room cues, long breaks in between

what does the place learning test

long term memory (hippocampus), distal external cues

matching to place task set up

new location of each platform each test day, short break in between, rat placed in random places

what does the matching to place task test

working memory (short term memory)

landmark learning task set up

uses local cues more than room cues, platform is signalled by the local cue

skilled reaching task experiment

vertal slot seperating rat and food, rat is trained to reach through the slot, tests fine motor skills

whole animal manipulations examples

diet, exercise, stress, social enviroment

manipulating specific brain regions examples

brain lesions, stimulation/inhibitiong with drugs, electrical, genetics

stereotaxic apparatus use

head held in fixed position to target a specific part of the brain for precise positioning

result of injury to frontal lobe

personality changes, more irritable, mean, lack of impulse control

stimulation

cerebrum gets operated on, and electrically stimulated while patient is awake

brain mapping

map of human body on the m1 and s1

deep brain stimulation (DBS)

electrodes implanted in the brain stimulate a targeted area with a low voltage electrical current to facilitate behaviour

where is the brain does parkinson disease affect

basal ganglia

transcranial magnetic stimulation (TMS)

non invasive procedure in which a magnetic coil is placed over the skull to stimulate the underlying brain

haloperidol

hypokinetic, reduced DAergic neuron function

amphetamine

hyperkinetic, increases DA activity

knock outs

loss of function, gene deletion

knock ins

gain of function, gene activation or insertion

how does CRISPR- Cas9 work

1. guide RNA recognizes where modification is to be made on DNA

2. binds with Ca9 protein

3. Ca9 targets specific cleavage

4. either knock out due to error prone repair or knock in

CRISPR-Cas9 technique

bacterial defense mechanism for fending off viruses, all purpose tool for cutting DNA, can be used for gene inactivation and insertions, or to repair mutated gene

everything abt electrical strategy to manipulate neural activity in vivo

injecting current

pros: high temporal

cons: affects all surrounding cells

everything abt physical strategy to manipulate neural activity in vivo

cool probe inserted

cons: low temporal precision

affects all cells surrounding

everything abt pharmacological strategy to manipulate neural activity in vivo

cannula adds drug to stimulate neuron

pros: cell type specific

cons: low temporal precision

everything abt genetic strategy to manipulate neural activity in vivo

knock in/out

pros: cell type specific

cons: no temporal precision

irreversible

everything abt optogenetics strategy to manipulate neural activity in vivo

transgenic technique that combines genetics and light to control targeted cells, diff wavelengths control specific light sensitive ion channels or pumps

pros: high temporal

reversible

targets specific cell types

Channelrhodopsin-2

(ChR2) an opsin that responds to blue light, increases Na+ into cell and K+ out via channel, depolarizes the cell, increases firing rate

Halorhodopsin

(NpHR) an opsin that responds to green-yellow light, increases Cl- into cell via pump, hyperpolarizes the cell, decreases firing rate

extracellular recording, electrophysiology

• possible to record from groups of neuron

• high temporal resolution and high spatial

• can be done in live animals

• yields much less information

intracellular recording, electrophysiology

• recording of a single neuron’s electrical activity

• high temporal and spatial resolution

• harmful to cells

• confined to cells in vitro

Electroencephalography (EEG)

• records graded potentials from thousands of cells

• measured by electrodes on scalp

• simple, non invasive

features of the brain’s electrical activity

• EEG changes as behaviour changes

• an EEG recorded from the cortex displays an array of patterns

• the electrical activity of a living brain is never silent even when asleep or comatose

event-related potentials (ERP)

• complex EEG waveforms produced in response to a discrete stimulus

• needs to clean up electrical noise

• P is positive N is negative, can be flipped

• Pro: high temproal resolutiion, non incasive

• Con: low spatial resolution, limited tissue depth

static anatomical imaging techniques

CT and MRI

Functional/dyamic anatomical imaging techiques

fMRI and PET

computed tomography (CT)

narrow x-ray beams are passed through the brain at different time/angles, creates 3D image of brain

light colour=high density areas

pro: high spatial resolution

con: radiation, cost

Magnetic resonance imaging (MRI)

passes a magnetic field through the brain followed by radio wave then measues the radiation emitted from hydrogen atoms

more water/hydrogen=darker

functional magnetic resonance imaging (fMRI)

when brain activity increases so does oxygen due to increases blood flow which leads to overcompensation

o2 poor blood more magnetic, leads to distortion of magnetic field, reducing signal of protons surrounding, less MRI signal

pros: spatial resolution

cons: cost, expertise