Effects and adaptations of Nervous System to exercise

1. Effects and adaptations of Nervous System to exercise
-Dr. Diksha Gondkar, MPT (Neuro)

2. Objectives:
1. Gain brief knowledge of anatomy of
nervous system
2. Neural control of movement.
3. Effects of exercise on nervous system.
4. Adaptation of neural tissue.

3. 1. Anatomy of nervous system

4. Parts of nervous system:
 Central Nervous System-the brain and the
spinal cord
 Peripheral Nervous System-the nerves
outside the brain and spinal cord
 Two Division of the PNS
 Somatic Nervous System-the nerves that
convey messages from the sense organs
to the CNS and from the CNS to the
muscles and glands
 Autonomic Nervous System-a set of
neurons that control the heart, the
intestines, and other organs

6. Parts of Brain
Forebrain Midbrain Hindbrain
1. brain 2. dienciphelon

7. Cerebrum :
 The Frontal Lobe-
 Contains Primary Motor Cortex-fine movements
 Contributes to shifting attention, planning of action, delayed
response tasks as examples
 The Parietal Lobe –
 Contains the primary somatosensory cortex-receiving touch
sensation, muscle-stretch information and joint position
information
 The Temporal Lobe –
 Contains targets for audition, essential for understanding spoken
language, complex visual processes, emotional and motivational
behaviors
 The Occipital Lobe –
 Contains primary visual cortex

9. Dienciphelon:
 3 parts:
 Thalamus
 Relay Station for Sensory Information
 Hypothalamus
 Regulates homeostasis, body tempreture- ANS
 sexual behavior
 Fighting
 Feeding and thirst.
 Pituitary Gland
 Endocrine gland

10. The Midbrain
 The Midbrain-middle of the brain
1. Tegmentum-”roof or covering”
 Nuclei for third and fourth cranial nerves
 Parts of Reticular formation
 Extensions of the pathways between the
forebrain and the spinal cord or hindbrain
2. Tectum-”roof”
 Superior & Inferior Colliculus-important in
routes of sensory information

12. Hindbrain:
 Posterior part of brain
1. Medulla-controls vital reflexes like breathing, heart
beat, etc
2. Pons-Area where many axons cross from one side of
the brain to the other
3. Reticular formation-control motor areas of the spinal
cord and sends output to cerebral cortex increasing
arousal and attention
4. Cerebellum-control movement, shifts of attention,
balance and coordination

13. • Diagram of a cross section through the spinal cord
The dorsal root on each side conveys sensory information to the spinal cord; the
ventral root conveys motor commands to the muscles.
Spinal cord:

14. Peripheral nervous system:
 Soma=nerves
 It includes mainly nerves arising from the spinal
cord and the cranial nerves.
 Total 12 cranial nerves and 31 spinal nerves.

15. Structural Organization

16. Autonomic Nervous System
Sympathetic-prepares
the body for arousal
 Ex: increased
breathing,
increased heart
rate, decreased
digestive activity
 Form chain of
ganglia just outside
spinal cord
Parasympathetic-
facilitates emergency
responses by the body’s
organs
 Ex: increase
digestive activity,
activities opposing
sympathetic system
 Consists of cranial
nerves and nerves
from sacral spinal
cord

17. THE REFLEX ARC
 Reflexes are unlearned, rapid, predictable motor responses to
a stimulus, and occur over highly specific neural pathways
called reflex arc

18. Neuro-muscular junction:

20. 2. Motor control

22. Motor control and learning
1. Volitional and learned
movements:
2. Sensory input during
movement:
 Movement is initiated by
motor cortex.
 Subcortical areas are also
stimulated simultenously
 sends commands to
spinal cord.
 Meanwhile the cerebellum
compares the movement
and sequential co-
ordinated movement is
established.
 Afferent input from EYES,
INNER EAR, MUSCLE
SPINDLE, JOINTS, SKIN.
 Person performs identical
motor task based on the
different sensory input to
various degrees.
 Concentration and focusing
are the task governed by the
frontal area and reticular
formation.
 New advances have shown
that rubrospinal tract is also
involved in the motor control.

23. 3. Motor Learning:
 Learning will occur not only in cerebellum, hippocampus
and other areas of CNS.
 Recent reseach has found that learning occurs in Ia
afferent fibers, alpha motoneurons and motoneurons
itself.
 When we're spooked or threatened, our nervous systems
jump into action, setting off a cascade of reactions such
as sweating, dizziness, and a racing heart.
 "Exercise in many ways is like exposure treatment,
People learn to associate the symptoms with safety
instead of danger."
 "Exercise may be a way of biologically toughening up the
brain so stress has less of a central impact,"

24. Open loop feed forward command, means using positive
feedback to sustain the activity.
CNS
Positive feedback
Motor
output
Sensory or
internal input
selection execution

25. 3. Adaptations to anaerobic training:

26. Neural component of strength
 In progressive resistance training, strenght and
power require co-ordination of neural activation,
storage and release of muscle elastic energy and
contraction of muscle.
 Strenght α muscle size and NEURAL
ADAPTATIONS

27. Anerobic training may elicit neural adaptations

28. Anaerobic studies and EMG studies
 EMG activity-reflects inc motor unit recruitemnt
or an inc in motor unit firing rate.
 INCREASED EMG ACTIVITY;
In novice- inc EMG activity but no inc in CSA- inc
recruitmnet ability.

29. Graph of neural contribution to strenght gain

30.  INC MOTOR UNIT FIRING RATE:
Firing rate controlled by CNS
By training explosively- inc force rate- inc strenght
and duration of muscle contraction.dia:

31.  RECRUITEMNET OF HIGH THRESHHOLD
MOTOR UNITS:
-Size principle
-but in trained high threshhold recruited
-untrained cannot recruit to that extend
In strenght developmnet, 2 neural adaptations
have implications
1. Recruitemnt of high threshhold units
2. Inc time that this units are activated

32.  MOTOR UNIT CO-ORDINATION:
In elite athelets- effotlessly
1. Neural facilitation of movements:
In plyometrics-reflex activated on sudden high
stretch loads eg-

33. 2. co-contraction of antagonist: eg- sprinters and
distance runners.
3. Synchronization of motor unit firing:- for smooth
accleration
4. Cross training-
- o-40% strenght gains
- Reflexes in CL limb
- Timing
- Enzyme content
after injuries.

34. 5. neurological disinhibition:
GTO and few centers in brainstem and cortex are
inhibited and allow inc muscle contraction.

38. Autonomic nervous system and blood distribution
Regulates vascular tone- towards muscle.
Through:
Nor-adrenalin
1. sympathetic fibres :-mostly α and few β2 receptors
of arteries and veins of skin and viscera-
vasoconstriction (eating)
2.β2 > in arterioles of muscle-noradrenalin-moderate
vasodilatation.

39.  Adrenalin:
1. Stimulates β receptors
- β1 in heart
- β2 in skeletal muscles
2. But stimulates α receptors of peripheral
circulation-vasoconstriction (boxing-staunch)
Vasodilatations-increased blood
flow

40.  Local metabolites:
 Temperature
 pressure

41. reference
 Exercise physiology-george brooks, timothy
white
 Exercise physiology- hale.
 Jack Wilmore-exercise physiology
 Mac’ardle-exercise physiology

42. Thank you