 They say a picture is worth a thousand words, but hopefully this conveys the idea brilliantly. If you tap the palm of your left hand, a sensory neuron fires - there are receptors underneath your skin for touch, cold, hot, pain, etc across your entire body. The message is sent up the spinal cord to the thalamus and then onto the somatosensory (or primary) sensory cortex. The firing of a neuron in the somatosensory cortex then is a literal representation of your body in space. Put it this way, if I directly stimulated the same neuron in the somatosensory cortex with a small amount of electricity using a probe - you would think you were touching the palm of your hand! (For the Sci Fans, this is part how "The Matrix" would work).
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Neglect is an attentional disorder typically due to damage to the right parietal cortex. People with neglect tend to ignore the left hand side of visual space. Below, are some images drawn by people with neglect.     Great to chat on Sunday with my old friend Paul McCarthy about Cognitive Kali! As promised, lots of links!
TEDx Talk - https://www.youtube.com/watch?v=Wf8xbFo0MpM LA Times Football – https://www.youtube.com/watch?v=ugI6QVob90c PAC 12 Network Football - https://www.youtube.com/watch?v=_5y2OP_UGts Websites; Main Website - https://cognitivekali.com/ Online Courses - https://www.cognitivekali.online/ Upcoming Free Webinars - https://www.cognitivekali.online/pages/webinars Other informative videos; UCLA Research - https://www.youtube.com/watch?v=Cys_UbNB_NQ What is Cognitive Kali - https://www.youtube.com/watch?v=zdGWBUj9sLI  The Premotor Cortex is another key motor planning region in the brain. It works in conjunction with the SMA to plan and execute movements but is specialized as is the SMA. Specifically, the Premotor Cortex seems to play a key role in encoding the direction of intended movements. Further, the Premotor Cortex seems to play a greater role in externally generated movements. The PMC also seems to play a role in controlling movements of the trunk and the parts of the body closer to the midline.
 The Supplementary Motor Area is a key motor planning region in the brain. It is where movements are planned and then sent to the Primary Motor Cortex for execution. It plays a key role in movement sequencing and the generation of internally generated movements. It is also thought to be more focused on controlling the extremities of our body - especially the hands.
 The reticular activating system is a collection of nuclei and thus neurons in the brain stem that have a critical purpose - it helps to "gate" or "filter" information passed through the brainstem to the cortex and from the eyes and ears (see the diagram). The reticular activating system also helps gate outgoing motor output. Deficits in neurotransmitters in ADHD cause differences in the function of the reticular activating system which underlies some of the differences in behaviour we see in people with ADHD.
 The Ventral Tegmental Area (VTA) is the second major dopamine production site in the brain (the other one here adjacent in blue - the SNpc - we talked about last week. The key difference is obvious - the SNpc projects to the midbrain whereas the VTA projects to the cortex - thus its role in reward learning, depression, obsession, and a myriad of other things!
 The substantia nigra pars compacta (SNpc) control some of the dopamine production in the brain. As such - it plays a role in a range of activities from motor control to learning to emotion. When it is damaged, or its projections are damaged, it leads to clinical issues such as Parkinson's Disease.
 The Primary Motor Cortex essentially controls the muscles of the body. When the region of the Primary Motor Cortex corresponding to the right bicep muscle fires, then a neural pathway fires that ends up with the alpha motor neuron of the right bicep muscle contracting (bear in mind there are literally tens of thousands of neurons dedicated to controlling this one muscle). Also - note that the left Primary Motor Cortex controls the right hand side of the body, and the right Primary Motor Cortex controls the left hand side of the body. Finally, note the image below. The number of neurons in the Primary Motor Cortex dedicated to a given body region corresponds to the amount of fine control needed. So, the face requires a lot of fine motor control - think of the array of facial expressions needed - whereas the hip does not to the same extent. So, fine motor control means more neurons means a larger portion of the Primary Motor Cortex dedicated to control.  |
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