CNS - Central Nervous System
p.1 The arousal system thus emerging in the human brain drives all of our behavioral responses to stimuli
in a manner best understood through the mathematics of information theory.
p.2 Because arousal is fundamental to all cognition and
temperament, its explanation is a holy grail of neuroscience.
p.2 arousal explains the initiation and persistence of motivated behaviors in a wide variety of
species, not just mammals... Arousal, fueling drive mechanisms, potentiates behavior, while specific motives and
incentives explain why an animal does one thing rather than another.
p.3 Arousal "moves the animal toward readiness for action
from a state of inactivity." ...In this book... I lay bare many of the mechanisms for CNS arousal and add a quantitative,
mathematical approach... Arousal provides the fundamental force that makes
animals and humans active and responsive so they will perform instinctive behaviors or learned behaviors
directed toward goal objects.
p.4 I theorize that explaining arousal will permit us to understand the
states of behavior that lie beneath large numbers of specific response mechanisms.
p.5 "Generalized arousal" is higher in an animal or human being
who is: (S) more alert to sensory stimuli of all sorts, and (M) more motorically active,
and (E) more reactive emotionally.
This is a concrete definition of the most fundamental force in the nervous
system... The primitive arousal responses I discuss comprise the very first, most elementary responses to any sensory stimulus,
preparatory for ever behavioral response that follows.
p.6 It may seem mind-boggling that such an arcane and important function
as arousal can have such a straightforward working definition. Do not be surprised. Complex behaviors need not have
complex explanations.
p.7-8 A = F(KgAg + Ks1As1 + Ks2As2 + Ks3As3... + KsnAsn) where A = arousal, as a function (F) of generalized arousal (Ag) and specific forms of arousal (As). The
plus sign is not meant to imply simple linearity, but rather to indicate that A is an increasing function of the variables
Ag and As(1 to n)
p.8 Surprisingly, the overall conclusion that generalized arousal
accounted for about one-third of our data held true despite different populations of mice, different investigators,
different experimental manipulations and details of response measures, and different configurations of particular factor analysis
solutions involving four to six factors for each experiment.
p.13 Because CNS arousal depends on surprise and unpredictability, its appropriate
quantification (surprisingly!) depends on the mathematics of information. [JLJ - Claude Shannon's work on this subject is
then described]
p.19-20 I base my theoretical approach on the idea that, for a lower
animal or human to be aroused, there must be some change in the environment. If there is change, there must be some
uncertainty about the state of the environment.
p.21 All of the stimulus characteristics listed in Table 1.2
share an opposition to monotonous, regular, predictable situations that kill arousal. All produce and sustain aroused
responses. I propose that reconceiving this large family of responses - in terms of their information content - will
enhance the analysis of their mechanisms
p.23 information theory applications can provide sensitive,
quantitative, and detailed diagnostic profiles of a variety of fatigue states... The ability of informatic
calculations during well-chosen test protocols to reveal unexpected differences or similarities in CNS function and behavior
will add dimensions to our diagnoses of fatigue states... and thus guide therapies.
p.23 Information theory is an essential component
of systems biology. In particular, for this book, it offers us a theoretical entry to the mathematics of arousal.
p.25 I have introduced a system that is universal, natural, and permanent.
It underlies the first responses to all stimuli and therefore influences everything that happens thereafter. This system is
exciting to study because its phenomena... are important for all aspects of human mental and emotional life.
p.41-42 (1) If information passage into the forebrain is to be maximized,
a lack of correlation, an unpredictability of peak activity among the ascending systems, according to information
theory, is required; and (2) it is very good for the health of arousal systems that the separate ascending systems
not be correlated. That is precisely what is needed for stable performance... the lack of correlations among the
systems exemplifies precisely what is needed for high-information, biologically adaptive performance.
p.66 The power of uncertainty, unpredictability, and change to control the
sizes of responses to sensory stimuli by neurons is illustrated dramatically by the phenomenon of habituation. Habituation
refers to the universal observation that steady repetition of the same stimulus causes a steady reduction of response.
p.96 Once you have achieved a high state of arousal, perhaps for an emergency,
how do you turn it off?
p.128 can we envision the mathematics of arousal? Yes.
p.129 [Diagram] BBURP theory: A bilaterally symmetric,
bipolar (bidirectional, ascending and descending) universal (among vertebrates) response potentiating
system. This abstract, theoretical diagram is restricted to the major features of arousal systems that have been conserved
throughout vertebrate phylogeny. [JLJ - okay, looks like we just design one of these BBURP things into our game-playing
machine and we are done. On to the next problem. Oh wait. This BBURP thing is complicated.]
p.129-130 Especially when confronted with dangerous circumstances,
we must move into a state of high alertness and respond rapidly and adaptively. How? To answer this question theoretically,
I suggest that positive feedback steps are required in arousal systems to achieve rapid transitions from
soporific to alert states and to mount very fast and accurate responses.
p.131-132 I hypothesize that arousal mechanisms behave like a pendulum.
They regain equilibrium by a dynamic in which, the farther they are from baseline state, the greater the force to return to
baseline state.
p.133 One of the major themes in control systems engineering
has to do with limitations and bounds within which input and output variables are allowed to swing... These are hardest
to figure out in multiple-input/multiple-output devices for which the relations are resonances among interior loops may not
be anticipated. What are we optimizing...? ...In homeostatic systems even rapid, large-amplitude changes must allow
critical parameters to return to baseline. This becomes a serious problem when feedback control systems are improperly designed
and thus allow wild oscillations of their outputs.
p.136 I have claimed repeatedly that arousal is heightened by surprise,
by change. The natural electrical engineering analogy is to a capacitor in an electronic circuit. A capacitor will
not pass current when the circuit is in steady state. Only a sudden increase in voltage applied to the circuit will result
in the capacitor allowing a peak of current to flow, which will then return exponentially to zero. Its mathematical expression
is the first-order differential of voltage as a function of time, dv/dt.
p.138 The greater the number of possibilities is, the less we know
about their arrangement at time t.
p.143 This book addresses the most elementary question of CNS state: What
determines the ability of an animal or person to mount any response to any stimulus, or to initiate voluntary motor activity,
or to express an emotion? That is, I have reformulated the classic arousal problem.
p.144 Arousal is the function that supports all cognitive abilities
and all emotional expression. Cognition and emotion come together in arousal, which is why understanding this function constitutes
a holy grail in neurobiology.
p.144 Arousal neurobiology is the neuroscience of change, uncertainty, unpredictability,
and surprise - that is, of information science.
p.144-145 Nerve cells actually encode probabilities and uncertainties, with
the result that they can guide behavior in unpredictable circumstances. CNS arousal itself absolutely depends on change,
uncertainty, unpredictability, and surprise... declining information content leads to declining CNS arousal. Thus,
arousal theory and information theory were made for each other.
