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The neocortical microcircuit as a
<i>tabula rasa</i>
Kalisman, Silberberg, Markram · 2005 · Proceedings of the National Academy of Sciences · journal-article
<jats:p>
The neocortex has a high capacity for plasticity. To understand the full scope of this capacity, it is essential to know how neurons choose particular partners to form synaptic connections. By using multineuron whole-cell recordings and confocal microscopy we found that axons of layer V neocortical pyramidal neurons do not preferentially project toward the dendrites of particular neighboring pyramidal neurons; instead, axons promiscuously touch all neighboring dendrites without any bias. Functional synaptic coupling of a small fraction of these neurons is, however, correlated with the existence of synaptic boutons at existing touch sites. These data provide the first direct experimental evidence for a
<jats:italic>tabula rasa</jats:italic>
-like structural matrix between neocortical pyramidal neurons and suggests that pre- and postsynaptic interactions shape the conversion between touches and synapses to form specific functional microcircuits. These data also indicate that the local neocortical microcircuit has the potential to be differently rewired without the need for remodeling axonal or dendritic arbors.
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2020 · How to Educate a Citizen
Nir Kalisman's 2005 research defining the neocortical microcircuit as a 'Tabula Rasa'.
direct The human neocortex arrives in the world as a blank slate without significant pre-written content.
Warrant (implicit): If the initial state of the neocortical microcircuit lacks pre-existing organizational patterns or innate data, then the brain must be understood as a blank slate that relies entirely on external input.
could fail ifThe 'microcircuit' level may appear as a blank slate while higher-level architectural constraints or predispositions for certain types of learning are still genetically encoded.
Hungarian tests on mature, living ('in vivo') neocortical tissues obtained from necessary medical operations.
direct Human neocortical cells are uniquely flexible and conduct operations at the cellular level that enable symbolic functions and language.
Warrant (implicit): Cellular flexibility and unique physiological operations in brain tissue are the necessary and sufficient biological precursors for the development of symbolic language and culture.
could fail ifSymbolic functions might emerge from the complex networking of standard neurons rather than the specific internal operations of individual 'flexible' cells.
Biological testing of mature, living human neocortical tissue conducted in Hungary during necessary brain surgeries.
direct Human neocortical cells are uniquely flexible and conduct operations at the cellular level that enable symbolic functions and language.
Warrant (implicit): Direct physiological observation of living human tissue provides more reliable evidence for species-specific cognitive capabilities than comparative studies of other animals.
could fail ifIn vivo tissues taken during surgery for neurological conditions (like epilepsy) may not be representative of healthy, typical human brain function.
2022 · American Ethnicity
Scientific article arguing that the microcircuitry of the neocortex functions as a tabula rasa rather than a pre-programmed system.
direct The human neocortex is neither instinctual nor pre-programmed; it is essentially a 'blank page' waiting to acquire and integrate material.
Warrant (explicit): If the microcircuitry of the brain's newest evolutionary layer shows high plasticity and lacks fixed patterns at birth, then human learning is primarily a product of external input.
could fail ifNeuroplasticity and a lack of 'pre-programming' do not necessarily imply a 'blank page'; the brain may still have structural constraints and innate learning biases that direct how information is integrated.
Scientific work suggesting the neocortical microcircuit is a tabula rasa rather than pre-programmed for specific culture.
direct The human neocortex is neither instinctual nor pre-programmed; it is essentially a 'blank page' waiting to acquire and integrate material.
Warrant (implicit): Evidence that neural connections are formed through experience implies that the brain lacks inherent, biologically-determined developmental trajectories.
could fail ifNeural plasticity and a 'blank' neocortex do not preclude the existence of genetically determined developmental windows or innate cognitive biases in how information is processed.
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ae:2:29ae:2:44ae:2:51
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Hungary brain research study (unnamed author in text, 2005-present range)Kalisman, Nir, et al., 'The Neocortical Microcircuit as a Tabula Rasa' (2005)Kalisman, Silberberg, Markram, and Merzenich (2005)Nir Kalisman, 'The Neocortical Microcircuit as a Tabula Rasa' (2005)