Implementing Neuroscience Principles to Support Habilitation and ...

ioral and medical interventions. From a behavioral perspective,
children with ADHD are more in control when they participate
alone with an adult (e.g., less inattention. less impulsivity);
in groups, misbehavior escalates. In returning to the
model proposed above, perhaps dysfunction with the internal
mechanisms that support motivation can be overridden by
greater external environmental supports (Dunn, I99 1 a).
From a medical perspective, considering the motivational
system in the CNS offers different medication regime
alternatives. Barkley ( 1990) discriminates children who have
hyperactivity from those who do not within the attentional
deficit population. He proposed that children who have
hyperactivity (i.e., are aggressive, disinhibited and disruptive)
may have a problem in the dopamine system that serves
the prefrontal and limbic systems in the CNS. Children who
are more lethargic may be more likely to have difficulties in
the posterior association cortex, the hippocampus and the
feedback mechanisms from higher to lower CNS centers;
norepinephrine is a more likely neurotransmitter to be
involved in these centers. These possible neurological differences
point out the importance of understanding the underlying
mechanisms in functions like motivation as interdisciplinary
teams collaborate to identify the best possible intervention
options (Dunn, 199 1 a).
Addiction. Addiction might be considered a vigorous
motivational state (Dunn, 199 1 a). Scientists have had to
change both the internal and external environments to mimic
addiction in animal models; for example, prestimulation of
parts of the hypothalamus enhances the expected external
performance in animals (Stellar & Stellar, 1985). Some persons
are more prone to addiction than others; perhaps in their
systems, there is a difference in the optimal conditions for
responding, in which certain chemical inducements more
easily trigger responses. Additionally, in the more primitive
CNS systems many connections are reciprocal, such that
once the cycle of responding begins, it continues for a longer
time that would be desirable. Thus, an interaction between
internal state conditions and the external environment sustain
the behaviors of addiction. There are certainly other factors
that contribute to the patterns of addiction; this is one additional
perspective.
Schizophrenia. The two phases of schizophrenia (i.e.,
positive and negative symptoms) suggest different neurological
disruptions related to the motivational systems (Dunn,
199 1 a; Sachar (1 98%). During positive symptom phases, the
person has delusions and hallucinations; we believe that overactivity
of the dopamine neurons in the limbic system contribute
to this biobehavioral state (the limbic system is a key
structure in the motivational connections of the CNS with the
hypothalamus). Antischizophrenic drugs block this extra
dopamine transmission and reduce these positive symptoms;
this drug intervention may reduce the overactive status of this
aspect of the motivational system. Negative symptoms include
low motivation, shallow affect and social incompetence;
researchers believe that diffuse brain damage has occurred
when these symptoms are present. Drug regimes are not helpful
with diffuse brain damage. Some functional life interventions
supplied by occupational therapy may provide additional
external environmental input to counteract the effects of a
diminished internal state, enabling some level of motivated
performance, particularly for activities of daily living.
Depression. Depression might be considered a dormant
motivational state; persons display loss of interests and an
inability to derive pleasure from situations. Brain stem, limbic
system and hypothalamic connections with noradrenaline
and serotonin neurotransmitters are suspect with depression
(Sachar. 19853). When these pathways are disrupted, input to
key motivational structures may be diminished, leading to an
inability to sustain an internal state that can support motivated
performance. Drug interventions are extremely effective.
suggesting that this internal state can be reestablished, providing
opportunities for responding to the environment more
appropriately.
Brain Trauma. Key structures of the motivational system
form the walls of the brain ventricles. When trauma
leads to enlargement of the ventricles (e.g., bleeding into the
ventricles), these key structures can be disrupted due to the
pressure from the enlarging ventricles. A person can demonstrate
a change in motivational capacity or status due to
internal anatomical and physiological changes such as this;
careful review of available records can alert a provider about
this possibility. Changes in motivational status can be
marked by increased agitation. aggression or a shutdown in
responsiveness. In persons who do not have an identified
brain trauma. these changes must trigger further investigation
through referrals.
Principles for Designing Therapeutic
Interventions Based on Affective System
Functions
AlTect and emotional tone can either provide strong supports
or create barriers to performance. The worksheets outlined
in Tables 8-14 and 8-15 provide a good beginning
framework for therapists to design therapeutic interventions.
Table 8- 18 provides examples of therapeutic intervention
planning for an adolescent who wishes to work, but who displays
poorly modulated internal motivation as identified
from Table 8-1 5.
SUMMARY
The CNS is a complex that supports life and its activities.
The occupational therapist's challenge is to use its principles