Proefschrift_Holstein

Chapter 2

Box 2.2 | Dopamine Neuroimaging tools (e.g. functional MRI (fMRI); box 2.4 and TMS; box 2.5 ) provide valuable insight in the brain regions involved in the execution of tasks or in the connectivity between regions. Although fMRI BOLD might correlate with changes in dopamine (Knutson and Gibbs, 2007) and TMS can induce changes in dopamine release in the striatum (Strafella et al., 2003), these methods alone do not provide direct evidence for the involvement of any given neurotransmitter system. Ideally then, to assess the involvement of dopamine in the anticipation of reward, one would want to administer a drug that manipulates the dopamine system.

B

C

Sulpiride

Bromocriptine (high dose)

dopamine post-synaptic dopamine D1 receptor post-synaptic dopamine D2 receptor

pre-synaptic dopamine D2 receptor

dopamine transporter (DAT)

blocking bromocriptine - induced e ects e.g. no longer enhanced exible behavior

more inhibition of the cortex e.g. enhanced exible behavior

A

E

D

Bromocriptine (low dose)

Methylphenidate

VTA/SN

Axon terminal of a dopamine neuron

PFC

Glutamatergic neuron

less inhibition of the cortex e.g. favoring stable representations

more inhibition of the cortex e.g. enhanced exible behavior

Post-synaptic: Striatal MSN neuron

is gure was inspired by: Marieke van der Schaaf (2014) Dopaminergic modulation of reward and punishment learning (PhD thesis)

36