prefrontal cortex – Page 8 – The Miller Lab @ MIT

13

Sep 2013

Dynamic Construction of a Coherent Attentional State in a Prefrontal Cell Population

Miller Lab

Neuroscience

John Duncan and colleagues examined dynamic allocation of attention in the prefrontal cortex. A behaviorally relevant target and non-target were simultaneously presented in both visual hemifields. At first, activity in each hemifield was dominated by the stimulus in the contralateral field but then all activity became dominated by the target alone. The speed and degree of attentional reallocation depend on relative attentional weights; more experience with a target led to faster and greater allocation to the target. Because neurons rapidly shifted their representation from an irrelevant to relevant stimulus in the opposite hemifield, these results are consistent with adaptive coding models of neural representation.
Kadohisa et al (2013) Dynamic Construction of a Coherent Attentional State in a Prefrontal Cell Population

Further reading on adaptive coding:
Miller, E.K. and Cohen, J.D. (2001) An integrative theory of prefrontal cortex function. Annual Review of Neuroscience, 24:167-202. View PDF »

Duncan, J. and Miller, E.K. (2013) Adaptive neural coding in frontal and parietal cortex. In: Stuss, D.T. and Knight, R.T. (Eds). Principles of Frontal Lobe Function: Second Edition.

Rigotti, M., Barak, O., Warden, M.R., Wang, X., Daw, N.D., Miller, E.K., & Fusi, S. “The importance of mixed selectivity in complex cognitive tasks”. Nature, 497, 585-590, 2013 doi:10.1038/nature12160. View PDF
4

Sep 2013

Prefrontal neurons transmit signals to parietal neurons that reflect executive control of cognition

Miller Lab

Neuroscience

Matt Chafee and colleagues used multiple-electrode recording in the prefrontal and parietal cortices to examine the temporal dynamics of their neural activity during a categorization task. They decoded category signals from patterns of simultaneously recorded in small bins and asked whether the resulting information time series in one area could predict the other. This showed that “executive” top-down signals flow from the prefrontal to parietal cortex.
4

Sep 2013

Time Course of Shape and Category Selectivity Revealed by EEG Rapid Adaptation

Miller Lab

Neuroscience

Max Riesenhuber and colleagues used EEG to examine the time course of shape and category signals in the human brain. Neural adaptation for category changes was seen in frontal cortex and then subsequently in temporal cortex. This supports the hypothesis that shape categories are formed by shape signals from temporal cortex that converge and form explicit category representations in frontal cortex. A late category signal in temporal cortex is consistent with category signals feeding back from frontal to temporal cortex.
28

Aug 2013

Involvement of the Globus Pallidus in Behavioral Goal Determination and Action Specification

Miller Lab

Neuroscience

Arimura et al compared neural responses in the globus pallidus (GP), prefrontal cortex (PFC) and premotor cortex (PMC) during a task in which a visual cue instructed a goal and then another cue instructed which action to perform. The GP reflected the visual cue and goal as soon as the cortex. However, action selection occurred later in the GP than cortex. Thus, the GP seems to play a more important role in goal determination than action selection.
22

Aug 2013

Dopamine Regulates Two Classes of Primate Prefrontal Neurons

Miller Lab

Miller Laboratory, Neuroscience

Miller Lab alumnus Andreas Nieder shows that dopamine (DA) has different effects on two different classes of neurons in the prefrontal cortex. For neurons with a short latency visual response, DA suppressed activity but preserved their signal to noise ratio. For neurons with a longer visual latency (exclusively broad-spiking, putative pyramidal neurons), DA increased excitability and enhanced signal/noise ratio. Thus, DA can shape how the prefrontal cortex processes bottom-up sensory inputs.
Jacob et al
18

Jul 2013

Distinct and Overlapping Frontoparietal Representations of Task Rules

Miller Lab

Neuroscience

Zhang et al studied rule-based behavior by either having human subjects choose the rule themselves or by instructing them to the rule. They found context-dependent and context-independent (chosen vs instructed) rule representations in frontal and parietal cortex. This gives insight into the architecture of cognitive control.
11

Jul 2013

Review: The Brain on Stress: Vulnerability and Plasticity of the Prefrontal Cortex over the Life Course

Miller Lab

Neuroscience, Psychology

Your prefrontal cortex becomes less resistant to stress as you age. McEwen and Morrison tell you all about it.