Model for Human Movement Triggered in Brain

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Decoding Action Intentions in Parietofrontal Circuits  Michael Vesia Marco Davare

Single-unit studies in monkeys have implicated specialized parietofrontal circuits in processing sensorimotor information for goal-directed actions. The classical model of the neural control of reaching and grasping movements proposes that:

  • areas located in the posteromedial portion of the intraparietal sulcus (IPS) contribute to the planning of reaching movements toward an object
  • whereas a more anterolateral region of IPS integrates grasp-related information about an object.

Specifically, in monkeys the medial intraparietal area (MIP) and V6A contain neurons associated with a particular direction of reach, while the anterior intraparietal area (AIP) contains visual and visuomotor neurons that are activated by a particular type of grasp. Similar specialized areas also exist in the frontal cortex, namely the dorsal and ventral premotor cortex (PMd and PMv) for arm and hand movements, respectively. Recent findings, however, challenge the view that the reach and grasp components are processed independently. Continue reading

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The Brain Processes of Reaching and Grasping

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Decoding Action Intentions in Parietofrontal Circuits

Decoding intended goals from sensorimotor pathways of paralyzed patients is an important feature for cognitive neural prosthetics. However, it is not clear which brain areas, or combination of areas, are optimal to guide the selection of recording sites and the design and implementation of decoding algorithms.  To date, the ability to predict goal-directed movements based on intention-related cortical signals has mainly been constrained to invasive neural recordings in nonhuman primates. Continue reading

How “Decisions” Really Get Made – Instantly and Unconsciously

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My views on decision making, choice, executive function, cognitive workspace, emotions, consciousness I take from Paul Cisek – bottom line: “decisions” get made in the premotor brain areas, instantly.  The following is a bit technical but if you don’t understand something — Google it! Continue reading

Key for Marketers, Biz and Policy Folks – The Biology of Motivation

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It is a shame economists are so clueless about this basic biology – but they live in their own world.  The related strange world of behavioral econ has no understanding over even awareness of this complexity.

The term motivation refers to a construct that is widely used in psychology, psychiatry, and neuroscience. As is the case with many psychological concepts, the discussion of motivation had its origins in philosophy…..According to a more recent definition, motivation is ‘‘the set of processes through which organisms regulate the probability, proximity and availability of stimuli’’ (Salamone, 1992). Generally speaking, the modern psychological construct of motivation refers to the behaviorally-relevant processes that enable organisms to regulate both their external and internal environment (Salamone, 2010)… Continue reading

Practical Neuroscience: “Scientific evidence that you probably don’t have free will”

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At some point business and policy makers are going to have to accept these scientific facts.  It may take a generation of old thinkers dying off, however.  The below post is excerpted from the full post here @ io9.com.

Scientific evidence that you probably don’t have free will

Humans have debated the issue of free will for millennia. But over the past several years…experiments reveal that our subjective experience of freedom may be nothing more than an illusion. Here’s why you probably don’t have free will.

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The Aging Brain

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As predicted, white matter integrity was associated with probabilistic reward learning. [White matter is the structural infrastructure of the brain, not the processing part].

Specifically:

  • increased white matter integrity in thalamocortical and corticostriatal paths was associated with better reward learning performance
  • diminished integrity in these paths mediated the association between age and poor performance
  • consistent with specificity, individual differences in other cognitive variables and the integrity of other paths could not account for these associations.

Although current analyses focused on the role of structural integrity in mediating age differences, relationships between white matter integrity and reward learning hold when controlling for age. Thus, the findings reveal a more general relationship between individual differences in thalamocorticostriatal integrity and probabilistic reward learning.

These findings build upon and extend existing documented associations between age differences in white matter and a wide range of cognitive variables including processing speed, task-switching, top-down attention, and implicit sequence learning.  The study additionally demonstrates a specific mediated effect of thalamocorticostriatal white matter tract integrity on age differences in probabilistic reward learning.  Since we did not observe age differences in tract integrity along the subcortical thalamostriatal pathways, behavioral and age effects were limited to tracts connected to the pre- frontal cortex.

White matter integrity is thought to facilitate information transfer through neurons. Since thalamocorticostriatal pathways play important roles in reward learning and decision making, the structural integrity of these pathways may facilitate functional throughput.  Although DTI cannot presently provide information about the direction or chemical specificity of neural projections, convergent inferences may be possible by incorporating existing knowledge about the anatomy and neurochemistry of these pathways.  Thalamocortical and corticostriatal projections through the medial prefrontal cortex typically use the neurotransmitter glutamate.  Projections from the prefrontal cortex to the striatum are thought to provide reentrant input that can flexibly guide motivated behavior toward specific goal objects.

Thus, it is possible that reduced structural input through the medial prefrontal cortex to the ventral striatum might impede the formation of new reward associations even while leaving general motivation processes relatively intact.

How the Brain Handles Different Goals

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The best-laid plans: How we update our goals based on new information

Princeton University researchers have identified mechanisms that govern how the brain incorporates information about new situations into our existing goals…. updating goals takes place in a region known as the prefrontal cortex, and appears to involve signals associated with the brain chemical dopamine. …”We have found a fundamental mechanism that contributes to the brain’s ability to concentrate on one task and then flexibly switch to another task,” Continue reading