PSYC20006 Lecture Notes - Lecture 1: Time Point, Mental Rotation, Capacitor
2 Jul 2018
School
Department
Course
Professor
PSYC20006 Biological Psychology
1
WEEKS 1 - 5: STATISTICS & IMAGING METHODS
LECTURE 1 – 2 (W1): Transcranial Magnetic Stimulation (TMS)
Introduction to Bio Psych
• Relationship between brain mechanisms & behaviour
• Neurobiological basis of psych function and dysfunction via 2 approaches
o Top-down approach
▪ Describes psychological functions
▪ Explains functions in terms of biological substrates
▪ Uses range of techniques (e.g. TMS, EEG, fMRI, molecular genetic
techniques)
o Bottom-up approach
▪ Description of neurons, neural architecture & transmitters
▪ Links them to explain behaviour and abnormal behaviour
• Quantitative methods to learn
t
-test performance
TMS: What it does
• Non-invasive technique creating virtual cortical lesions
• e.g. Phineas Gage had real legions which informed cognitive science
• Temporary & reversible
• Localised lesions (small scale) could allow for better understanding of specific brain
region function
• Why not real patients
o Not enough patients with circumscribed lesions to study all functions
o Single, specialised area lesions rare
o Recovery & brain plasticity might compensate for lesions over time
TMS: How it works
• Applied externally
• Coil placed on scalp
o Coil produces rapidly changing magnetic field
• Magnetic field induces electrical currents in brain
o Currents depolarise neurons in small, circumscribed area of cortex
o Current causes neurons to fire randomly
▪ Increases level of neural noise
▪ Masks neurons that are firing correctly
• 1870: Fritsch & Hitzig 1st to electrically stimulate animal cortexes
• 1896: D’Arsonval discovered magnetic stimulation of visual cortex can
elicit phosphenes
• 1911: Magnusson & Stevens developed first head coil covering entire head
• 1985: Barker, Jalinous & Freestone developed current TMS technique
o NOT PAINFUL!!
Document Summary
Weeks 1 - 5: statistics & imaging methods. Lecture 1 2 (w1): transcranial magnetic stimulation (tms) Tms: how it works: applied externally, coil placed on scalp, coil produces rapidly changing magnetic field, magnetic field induces electrical currents in brain, currents depolarise neurons in small, circumscribed area of cortex, current causes neurons to fire randomly. Research uses: injection of neural noise: use single-pulse tms to disrupt cognitive processing, single tms pulse to specific region of cortex disrupts cognitive function, powerfully demonstrates causal involvement in the process, testing causality impossible with other neuroimaging techniques. Research uses: probing excitability approach: uses single-pulse tms, particularly for motor system research, test how responsive (excitable) the motor cortex is during a cognitive task. Research uses: probing information transfer with a paired-pulse approach. V1 45ms after v5 stimulation: indicates back-projections from v5 to v1 required for awareness.
