Powerful new techniques, fMRI, magnetic encephalography, recordings from neuronal ensembles, visualizations of neuronal growth, and neuro-chemical analyses are elucidating brain/mind functioning — the process of experience. These techniques prosthetically extend us across technological platforms, shift our preferences to the synthetic, and our purely human evolution to human/machine evolution. For instance, Nicolelis uses implanted electrodes in volitional cortical motor neuron ensembles to enable control of a mouse cursor, or a robot, from thought alone. Similarly, audio recordings from implanted electrodes in rat brains, extend Matt Wilson’s sensorium, enabling him to “listen in” on rats’ dreams.
Brain evolution is a form of neuroplasticity, as are memory and individual brain development. In the fetus neurons proliferate, migrate into place and make an overabundance of synaptic connections. Used connections are selected and unused synapses are pruned. V.S. Ramachandran theorizes that aberrantly
remaining (unpruned) cross-modal connections between the color and adjacent number area in the brain causes synesthesia, and furthermore that creativity results from a richness of unpruned cross-modal connections forming a high capacity for metaphor.
Paradoxically, memories are unstable during recollection. After removing a memory from storage, the brain reconsolidates it into stable form. Re-storage depends on protein synthesis which, if manipulated, alters the memory (thus explaining the ease of implanting false memories). Different forms of memory are organized distinctively in the brain, i.e. declarative (language based) and non-declarative (procedural/skill based) memory, episodic (personal experiences) and semantic (learned facts) memory, spatial memory, etc.
Mirror neurons, cortical neuron systems that fire both during one’s performance of an action, or expression of emotion, and during the observation of another enacting these, form the basis of empathy and art appreciation. Understanding what others feel occurs by the inner imitation of the observed action or expression. The representation is matched to an existing representation and used to modulate emotional experience. Empathic individuals exhibit unconscious mimicry of other’s postures, mannerisms, and facial expressions more than non-empathic individuals.
How consciousness is integrated into a stream of coherent experiences is called the binding problem. Neuroscientists hypothesize that two brain/mind
systems control the stream of consciousness, the thalamocortical axis and the prefrontal cortex (PFC). Nearly all information from the sense organs passes
through the thalamus. The thalamic reticular nucleus (TRN) generates most of the internal activation of the cortex modulating its gates in “burst firing” or
continuous (tonic) firing mode. In tonic mode, the simultaneous firing of broad neuronal populations leads to neuronal synchrony, triggering looping activation in cortical circuits, and amplifying one loop over others in a recursive process. Interacting re-entry loops reinforce and compete with each other, with the dominant loop(s) becoming conscious. The PFC integrates consciousness by controlling the focus of attention, picking the winner of the looping competition set up by the thalamus and updating representations in working memory.
- Andrea Ackerman (USA) Independent artist, theorist, psychiatrist.
Full text (PDF) p. 22-23