Proprioception

Miller, L. and Miller, S., Caffeine enhances initial but not extended learning of a proprioceptive-based discrimination taskin non smoking moderate users. Percept Mot Skills 82(3), 891-898, 1996. 

The involvement of the cerebellum in the psychoactive effects of marijuana and in changes in rCMR is consistent with the view that THC interacts with the high concentration of CB1 receptors in this brain area. Decreases in the cerebellar rCMR in habitual marijuana users may reflect the effects of chronic exposure to the drug. Functions known to be associated with the cerebellum, such as motor coordination, proprioception, and learning, are adversely affected both during acute marijuana intoxication and in habitual users. 

Fine touch discrimination (ability to recognize size, shape, and texture of objects and their movement across the skin) proprioception vibration from legs and lower trunk crossed... 

Fine touch discrimination proprioception vibration from neck, arms, upper trunk crossed Proprioception (important for muscle tone and posture) uncrossed Proprioception crossed Pain temperature crossed Light touch pressure crossed... 

X5 NM 175080 Proprioceptive neurons of mesencephalic trigeminal nucleus, sensory ganglia... 

In the periphery, NT3 uniquely supports proprioceptive neurons in sensory ganglia. These neurons and their peripheral targets, the muscle sensory organs, are lost in NT3 knockout mice. Mice in which the NT3 receptor TrkC has been knocked out do not live long and have abnormal movements as a consequence of their loss of proprioception. 

Megadosage vitamin B6 (pyridoxine) and cisplatin cause sensory neuronopathy. Pyridoxine toxicity, usually the result of inappropriate self-overmedication, kills dorsal root ganglion neurons. Affected individuals become severely ataxic because of loss of proprioceptive afferent input to the cerebellum. A similar syndrome is elicited by cisplatin chemotherapy. Neurotrophin-3 treatment is effective in protecting dorsal root ganglion neurons in experimental animals against these toxins [48,49]. 

Most multicellular organisms exploit mechanoreceptors — specialized cells that detect external mechanical forces — to help construct their internal view of the external world. The senses of hearing, balance and touch all rely on mechanoreceptors, as do the proprioceptive sensations that tell an organism how it is situated in the environment. Mechanoreception is probably one of the most ancient of the senses. 

Primary sensory neurons sense pain and convey it to the spinal cord. Nociceptors have unmyelinated (C fiber) or thinly myelinated (AS) axons, while the low-threshold Ap-fiber mechanoreceptors involved in tactile and proprioceptive perception have large myelinated sensory neurons (Table 57-1). The peripheral terminals of primary sensory neurons convert changes in the environment into neuronal activity by transducing mechanical (Ch. 51), thermal or chemical stimuli into ion fluxes across their... 

Large calibre myelinated Aa Proprioception Low Fast Large (>40 pm) 20%... 

The functional unit of the central nervous system (CNS) is the neuron, and most neuropharmacological agents have the neuron as their primary site of action. CNS neurons are capable of transmitting information to and receiving information from other neurons and peripheral end organs, such as muscle cells, glandular cells, and specialized receptors, for example, those involved with proprioception, temperature sensing, and so on. 

Nerves differ in their sensitivity to local anaesthetics. When lidocaine (lignocaine) is applied to a mixed peripheral nerve the onset of the block is in the order, vasodilatation (B fibres), loss of pain and temperature (C and A6 fibres), muscle spindle reflex (Ay fibres), motor and pressure (A(3 fibres) and large motor and proprioception (Aa fibres). This phenomenon is called differential block. There are other minor variations in this ranking order among the local anaesthetics. The basis of differential block is thought to be the result of variability in the sensitivity of different nerves to the same agent. 

After 4 months, he developed numbness and paresis of the legs and hyperalgesia at dermatomes T3 and T4. After 10 months he had marked disturbance of proprioception combined with spinal ataxia and an increasing loss of motor bladder control. There was an intraspinal epidural lipoma in the dorsal part of the spine from Tl-10. The fat was removed surgically and within 4 weeks his gait disturbance and proprioception improved, the sensory deficit abated, and the bladder disorder disappeared completely. 

Change in the active body image, the way the body feels when in motion, the proprioceptive feedback signals that guide actions... 

The local injection of 0.1 to 2% procaine or other anesthetics blocks the centripetal proprioceptive impulses and thereby relaxes muscular tonus, normal and abnormal, such as spasmodic torticollis. It effects almost instantaneous relief of the pain, stiffness, malposition, and incapacity of fibrositis, lumbago, and acute sprains and fractures. The site of greatest tenderness may be infiltrated with 10 to 30 cc of 1 or 2% procaine hydrochloride. Injected systemically, it relaxes traumatic tetanus and removes decerebrate rigidity, so that spontaneous movements of the limbs and of the respiration return. Its curare action may also be concerned in this effect. It relaxes parkinsonian, but not myotonic, rigidity. 

PCP and ketamine produce detachment, disorientation, distortions of body image, and loss of proprioception. Somatic symptoms and signs include numbness, nystagmus, sweating, rapid heart rate, and hypertension. Overdosage has been fatal, as contrasted with the absence of known human fatalities directly caused by drugs of the LSD group. 

Chen, X. J., Levedakou, E. N., Millen, K. J., Wollmann, Ik. L., Soliven, B. and Popko, B. (2007) Proprioceptive sensory neuropathy in mice with a mutation in the cytoplasmic Dynein heavy chain 1 gene. J Neurosci 27, 14515-14524. 

Mutant dynein (Loa) triggers proprioceptive axon loss that extends survival only in the SOD 1 ALS model with highest motor neuron death. Proc Natl Acad Sci USA 105, 12599-12604. 

Non-ciliated receptors show much variation. Some resemble ciliated receptors in that they have a terminal dendritic bulb with a basal body but no distal cilium (85, 942). Others, as in H. nana (Fig. 2.9), show little structural specialisation and appear to be little more than free nerve endings which may have a single, double or triple structure. Endings which do not penetrate the tegument to the external environment may have a mechanoreceptive or proprioceptive (i.e. receptive to internal stimuli) -rather than chemoreceptive - function (12, 206, 942). 

The SN often associated with the Hu antibody is characterized by primary damage to the nerve cell body. The patient suffers from progressive, painful sensory disturbances evolving subacutely, usually with a Rankin score of 3 within 12 weeks of the onset of symptoms [14]. Presenting symptoms include paresthesia, hypoestesia, and very often proprioceptive loss in the affected areas sensory ataxia is common. The upper limbs are often involved [97], The distribution of the SN is often atypical for peripheral neuropathy. The involvement is usually asymmetrical, especially at the onset of symptoms, and may affect the face or upper limbs only. SN is often the presenting symptom of the PEM/SN syndrome, but signs of CNS involvement usually evolve, and autonomic disturbances are common [36]. 

Spinocerebellar disease Ataxia, positive Romberg sign Decreased proprioception and vibratory senses Loss of deep tendon reflexes Night blindness... 

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