The
brain is a complex system. Abstractions offering
parsimonious explanations and oversimplifications become
essential in characterizing certain aspects of this
multi-scale system. However, it is critical that a
whole-some understanding of this complex system isn’t
stifled by such oversimplifications.
A
central theme of research in this laboratory is that
complexity is an essential device of evolution towards
achieving physiological robustness. From this
perspective, complexity is embraced as the lynchpin that
drives robustness of the nervous system, rather than
being shunned as an inconvenience that makes analyses
difficult. Work in this laboratory focuses on remedying
certain historical oversimplifications in single-neuron
and network physiology:
1.
Oversimplification:
Neurons are simple algebraic summation units with a
threshold nonlinearity.
Remedy:
Active dendrites bestow complex functional
capabilities upon single neurons.
2.
Oversimplification:
Neural circuits are made of repeating homogeneous
computational units.
Remedy:
Neural circuits manifest several forms of heterogeneities
(intrinsic, synaptic, structural, and afferent), which
play crucial physiological roles.
3.
Oversimplification:
Learning and memory in biological systems is
accomplished exclusively through synaptic changes.
Remedy:
Biological plasticity is ubiquitous and is not
limited to synapses. Ubiquitous plasticity, however,
does not mean arbitrary plasticity. There are strong
constraints on how different forms of plasticity
interact towards achieving stable continual learning.
4.
Oversimplification:
There is a unique solution to how biological learning is
accomplished, and our goal is to find that
solution.
Remedy:
Complexity
in a system is characterized by several functionally
specialized subsystems that show a high degree of
functional integration when they interact with each
other. An important characteristic of complex biological
systems is degeneracy, the ability of
structurally different subsystems to yield the same
functional outcome. Degeneracy is ubiquitous across all
scales of the nervous system.
5.
Oversimplification: Extracellular local field potentials exclusively reflect chemical synaptic activation.
Remedy:
Several sub- and supra-threshold active dendritic channels and other transmembrane currents, including those activated by gap junctional (electrical synaptic) inputs, also contribute to local field potentials.
6.
Oversimplification:
Glial cells are glue.
Remedy:
Glial
cells are actively involved in information
processing, plasticity, and learning.
We
employ electrophysiological, imaging, theoretical, and
computational tools towards remedying these and other
oversimplifications.
Click on the images below for research
articles from the laboratory
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