This 2016 US human study found:
“A link between existing data on the anatomical and physiological characteristics of striatal regions and psychological functions.
Because we did not limit our metaanalysis to studies that specifically targeted striatal function, our results extend previous knowledge of the involvement of the striatum in reward-related decision-making tasks, and provide a detailed functional map of regional specialization for diverse psychological functions, some of which are sometimes thought of as being the exclusive domain of the PFC [prefrontal cortex].”
The analysis led to dividing the striatum into five segments:
Ventral striatum (VS):
- Stimulus Value
- Terms such as “reward,” “losses,” and “craving”
- The most representative study reported that monetary and social rewards activate overlapping regions within the VS.
- Together with the above finding of a reliable coactivation with OFC [orbitofrontal cortex] and ventromedial PFC, this finding suggests a broad involvement of this area in representing stimulus value and related stimulus-driven motivational states.
Anterior caudate (Ca) Nucleus:
- Incentive Behavior
- Terms such as “grasping,” “reaching,” and “reinforcement”
- The most representative study reported a stronger blood-oxygen level-dependent (BOLD) response in this region during trials in which participants had a chance of winning or losing money in a card guessing game, in comparison to trials where participants merely received feedback about the accuracy of their guess.
- This result suggests a role in evaluating the value of different actions, contrasting with the above role of the VS in evaluating the value of stimuli.
Posterior putamen (Pp):
- Sensorimotor Processes
- Terms such as “foot,” “noxious,” and “taste”
- The most representative study reported activation of this region in response to painful stimulation at the back of the left hand and foot of participants. Anatomically, the most reliable and specific coactivation is with sensorimotor cortices, and the posterior and midinsula and operculum (secondary somatosensory cortex SII) in particular, some parts of which are specifically associated with pain.
- Together, these findings suggest a broad involvement of this area in sensorimotor functions, including aspects of their affective qualities.
Anterior putamen (Pa):
- Social- and Language-Related Functions
- Terms such as “read,” “vocal,” and “empathic”
- The most representative study partially supports a role of this area in social- and language-related functions; it reported a stronger activation of the Pa in experienced singers, but not when novices were singing.
- It is coactivated with frontal areas anterior to the ones coactivated with the Pp, demonstrating topography in frontostriatal associations. These anterior regions have been implicated in language processes.
Posterior caudate (Cp) Nucleus:
- Executive Functions
- Terms such as “causality,” “rehearsal,” and “arithmetic”
- The representative study reported this region to be part of a network that included dorsolateral PFC and ACC, which supported inhibitory control and task set-shifting.
- These results suggest a broad, and previously underappreciated, role for the Cp in cognitive control.
The authors presented comparisons of the above striatal segments with other analyses of striatal zones.
One of the coauthors was the lead researcher of the 2015 Advance science by including emotion in research. The current study similarly used a coactivation view rather than a connectivity paradigm of:
“Inferring striatal function indirectly via psychological functions of connected cortical regions.”
Another of the coauthors was a developer of the system used by the current study and by The function of the dorsal ACC is to monitor pain in survival contexts, and he provided feedback to those authors regarding proper use of the system.
The researchers’ “unbiased, data-driven approach” had to work around the cortical biases evident in many of the 5,809 human imaging studies analyzed. The authors referred to the biases in statements such as:
“The majority of studies investigating these psychological functions report activity preferentially in cortical areas, except for studies investigating reward-related and motor functions.”
The methods and results of research with cortical biases influenced the study’s use of:
“Word frequencies of psychological terms in the full text of studies, rather than a detailed analysis of psychological tasks and statistical contrasts.”
http://www.pnas.org/content/113/7/1907.full “Regional specialization within the human striatum for diverse psychological functions”