2: The Lesioned Brain Flashcards
how does TMS work?
a means of disrupting normal brain activity by introducing neural noise – ‘virtual lesion’, the current created a change in the electrical charges of someone’s brain, causing changes in behaviour
what are the 4 advantages of TMS?
- interference/virtual lesion technique.
- transient and reversible
- control location of stimulation
- establishes a causal link of different brain areas and a behavioural task
define: transient
temporary
which hemisphere if the brain used to be associated with language?
left - people are now though of to be predominately bilateral
what area if the brain is associated with speech?
Wernicke’s area
how do people perform at word-matching tasks when their dominant vs non-dominant speech hemisphere is stimulated (TMS)
left dominant were a lot slower if you stimulate the left side of the brain and the right sides were faster (& vice versa for right stimulation)
Improved RT for opposite stimulation: this could be because stimulating the weaker area inhibits the interference it may bring
what are the 3 types of TES?
Transcranial direct current stimulation - tDCS
Transcranial alternating current stimulation -tACS
Transcranial random noise stimulation - tRNS
how does TES work?
TES uses low-level (1-2 mA) currents applied via scalp electrodes to specific brain regions.
what effect can tDCS have on the brain?
When applied in sessions of repeated stimulation, tDCS can lead to changes in neuronal excitability that outlast the stimulation itself.
which conditions is TES used in treatment for?
migraines, dementia, stroke, Parkinson’s disease, neglect, depression, schizophrenia, OCD, eating disorders
what are the 3 types of tDCS?
Anodal
Cathodal
Sham (CONTROL)
what is the function of anodal tDCS
facilitation effects
Inhibits GABA (an inhibitory neurotransmitter) = excited response
what is the function of cathodal tDCS?
inhibition effects
Omhibits glutamate (and excitatory neurotransmitter) = inhibitory response
what is the function of sham tDCS?
control
how does lucid dreaming relate to consciousness?
A lucid dream can be thought of as an overlap between two states of consciousness, the one that exists in normal dreaming, and the one during wakefulness, which involves higher levels of awareness and control. In lucid dreaming, we transfer elements of waking consciousness into the dream
how is lucid dreaming reflected in EEGs?
When people have lucid dreams, they show gamma waves in the frontal cortex, an activity pattern that is linked to consciousness but is nearly absent during sleep and normal dreaming
how does tACS work?
tACS applies gentle electrical currents to the brain to entrain it and synchronise brain rhythms to use this route, this can train the brain to be better at tasks if they tap into the correct pathway in the brain
what is phase-locking?
the firing of neurons preferentially at a certain phase of an amplitude-modulated stimulus
how does tACS influence sleep experience?
Increased lucid dreaming
The EEG data showed that the brain’s gamma activity increased during stimulation with 40 Hz, and to a lesser degree during stimulation with 25 Hz
Insight is the awareness that one is currently dreaming improved
Dissociation is taking a third-person perspective within the dream improved
Control is control over the dream plot improved
which 2 brain measuring techniques can be combined to enhance cognitive performance?
TMS and tES