Who Needs Emotions? The Brain Meets the Robot

36 brains
A. 5 NH 4Cl
Bacteria in capillary x 10 -4
B.
4
3
2
1
1. SENSORY RECEPTION 2. EXCITATION
attractants
repellents
LiCl
NaCl
KCl
RbCl
CsCl
0
0 100 200 300 400
Salt in capillary, mM
other
attractants
receptor MCP
other
repellents
methyl-
MCP
signal to determine
direction of rotation
of flagella
4. ADAPTATION
change in methylation
of MCP to stop signal
3. MOTOR RESPONSE
flagella
Figure 3.2. (A) Chemotaxis toward monovalent cation salts in Escherichia coli
bacteria. Bacteria are attracted into capillaries, each containing a salt. Salts
are attractants only in certain concentrations, usually near 100 mM. (From
Qi & Adler, 1989, with permission.) (B) Schematic diagram of the mechanism
of bacterial chemotaxis. (From Adler, 1990.) cw = clockwise; ccw =
counter clockwise; mcp = methyl-accepting protein.
Certain genes code for these various steps, and mutants in different genes
produce different deficits in chemotaxic behavior. The whole process is regulated
by chemoreceptors, signal-transducing proteins and calcium, and activation
of a motor structure, the flagella, via transient methylation of a
membrane-bound protein (methyl-accepting chemotaxis protein). The parallels
to complex approach–avoidance behaviors and their underlying bases
in invertebrates and vertebrates are compelling. In his 1966 Science article,
Adler noted the relevance of this phenomenon to modern interpretations of
the neuroscience of motivation.
CCW
CW