Placing reflexes
Encyclopedia
There are two frequently used placing reflexes. They are tests which allow clinicians to assess the proprioceptive abilities of small domestic animals (cats and dogs in particular). The first test is to lift an animal and bring the anterior/dorsal
surface of a paw up to a table edge. The normal animal will position its paw onto the surface properly. The second (sometimes called the proprioceptive positioning reflex) is similar. The dorsal
(top) surface of an animals paw is placed onto a surface, and a fully healthy animal would flick it back up to be in the normal position (dorsal side up). If the animal cannot do this it implies that there is either a motor deficit or damage to the sensory
pathway for proprioception
, or damage to the centres of the brain
which would normally integrate this response. These brain centres would include the cerebellum
, and possibly (debated) portions of the cerebrum. There is no evidence to suggest whether the cerebrum is specifically involved with this reflex
. Evidence for the involvement of the cerebellum
comes, in part, from the fact that cerebellar ataxia
can lead to a loss of this particular reflex
.
It is sometimes referred to as a "response", to allow for possible conscious cerebral influence of the action.
Dorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
surface of a paw up to a table edge. The normal animal will position its paw onto the surface properly. The second (sometimes called the proprioceptive positioning reflex) is similar. The dorsal
Dorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
(top) surface of an animals paw is placed onto a surface, and a fully healthy animal would flick it back up to be in the normal position (dorsal side up). If the animal cannot do this it implies that there is either a motor deficit or damage to the sensory
Sensory
Sensory may refer to:relating to senses or smellIn biology:* Sensory preference* Sensory system, part of the nervous system of organisms* Sensory neuron, nerve cell responsible for transmitting information about external stimuli...
pathway for proprioception
Proprioception
Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...
, or damage to the centres of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
which would normally integrate this response. These brain centres would include the cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
, and possibly (debated) portions of the cerebrum. There is no evidence to suggest whether the cerebrum is specifically involved with this reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...
. Evidence for the involvement of the cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
comes, in part, from the fact that cerebellar ataxia
Cerebellar ataxia
Cerebellar ataxia is a form of ataxia originating in the cerebellum.-References:...
can lead to a loss of this particular reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...
.
It is sometimes referred to as a "response", to allow for possible conscious cerebral influence of the action.