Week 5
Chapter 10 – Sensorimotor functions
Introduction
In the Integrated SNP/CHC Model, sensory-motor functions serve as a prerequisite
baseline for all of the higher order processes
E.g., if basic auditory discrimination skills are impaired, then the higher order skill of
sound blending, a basic skill for reading, may be compromised.
Sensory functions
Definitions
Sensory processing disorder (SPD)
o Umbrella term to describe neurological disabilities that interfere with regular
use of sensory functions
Sensory functions
o Ability to process visual, auditory, kinaesthetic, and olfactory information
Sensory dysfunction
o Manifested in many ways
Overstimulation
E.g., very sensitive to a light brush against the skin
Under stimulation
E.g., no reaction when falling down a slide
Sensation seekers
E.g., chewing on shirt until mouth is chapped and bleeding
Sensory discrimination
o Poor discrimination produces difficulties
o E.g., difficulty holding a pencil
Sensory-motor integration
o Difficulty with balance, movement, synchronising both sides of the body,
confusion between left- and right-sided movements
Neuroanatomy of sensory functions
SEEING
Primary visual cortex
o Located in the striate cortex of the occipital lobe
o Regulates sense of sight
Retina
o Located at the back of the eye
o Transmits information via the optic nerve
Optical nerve
o Splits into two parts when traveling to higher cortical areas:
The temporal (lateral)
Continues path to higher cortical regions
Same side of the body
The nasal (medial part)
Continues path to higher cortical regions
Crosses over at the optic chiasm
, o Both parts terminate in the lateral geniculate nuclei or the pulvinar nuclear of
the thalamus and the superior colliculus of the midbrain
Lateral geniculate nuclei
o Final pathway for visual information
o Travels to the primary area of the occipital lobe
HEARING
The primary auditory cortex
o Regulates sense of hearing
o Located in the superior part of the temporal lobe
o Buried within the sylvian fissure
Cochlea
o Auditory sense organ
o Located in the inner ear
o Projections pass through the subcortical relays of the medial geniculate of
the thalamus and then to the supratemporal cortex
TOUCH, PAIN, TEMPERATURE SENSE, LIMB PROPRIOCEPTION
Primary somatosensory cortex
o Regulates the sense of touch, pain, temperature sense, and limb
proprioception (limb position)
o Located in the postcentral gyrus
Two pathways:
o Anterolateral system
Pain and temperature
o Dorsal column-medial lemniscal system
Touch, proprioception, and movement
Vision, hearing, and touch, all have contralateral projections in the brain.
A defect in a right-sided sense organ will show as damage in the left side of the brain
that controls that sense organ.
o Exception: smell
SMELL
Primary olfactory cortex
o Regulates sense of smell
o Located in the ventral region of the anterior temporal lobe
Orbitofrontal cortex
o Secondary area
Lesions
o Left-sided lesion in the right ventral region of the temporal lobe
o Produce a severe deficit when an odour is smelled in the right nostril.
-> Only sense not processed by the thalamus, but instead pathways go directly to the cortex.
Anterior portion of the insular cortex (insula)
o Receives input from all the senses, as well as limbic regions
, o Integrate information for the perception of pain and fear avoidance.
Rapid Reference 10.1
Neuropsychological Terms Associated With Sensory Impairments
Achromatopsia A rare disorder in which colour is not recognized.
Ageusia Loss of the sense of taste.
Anosmia Impaired sense of smell.
Asterognosia Inability to recognize an object on the basis of its three
dimensionality through palpation (a.k.a., tactile
agnosia/dysnosia).
Auditory agnosia Inability to recognize auditory stimuli
Autotopagnosia Disturbed body scheme that manifests itself by the inability to
identify the parts of one’s body.
Barognosia Inability to estimate weight when objects are placed in the
affected hand.
Finger agnosia Inability to recognize a sensory stimulus via the fingers.
Graphestheia Difficulty recognizing shapes or letters written on the hand.
Hemianopia A loss of vision for one-half of the visual field of either one or
both eyes
Hypesthesia Diminished capacity for physical sensation
Kinesthesia The conscious awareness of joint position and body
movement in space.
Pallinopsia Visual perseveration of a stimulus no longer present
Parosmia An abnormal sense of smell
Proprioception The unconscious awareness of sensations coming from one’s
muscles and joints that helps regulate our position in three-
dimensional space
Tactile defensiveness The tendency to react negatively to unexpected, light touches
Tactile localization The inability to localize a stimulus on the skin
disorder
Two-point discrimination The inability to discriminate between sensations arising from a
disorder single touch versus two simultaneous and nearby touches
Visual agnosia Inability to recognize visual stimuli
Motor functions
Definitions
Developmental coordination disorder (DCD)
o Clumsy or awkward
o Marked impairment in the development of motor coordination
o Delays in reaching developmental motor milestones
o Difficulty mastering other gross motor tasks and mastering fine motor tasks
o Males > Females
o Developmental delays in other areas
Expressive and receptive language in isolation or combined, or in
phonological processing.
o DCD is often co-morbid with ADHD, conduct disorder, and pervasive
developmental disorder
Chapter 10 – Sensorimotor functions
Introduction
In the Integrated SNP/CHC Model, sensory-motor functions serve as a prerequisite
baseline for all of the higher order processes
E.g., if basic auditory discrimination skills are impaired, then the higher order skill of
sound blending, a basic skill for reading, may be compromised.
Sensory functions
Definitions
Sensory processing disorder (SPD)
o Umbrella term to describe neurological disabilities that interfere with regular
use of sensory functions
Sensory functions
o Ability to process visual, auditory, kinaesthetic, and olfactory information
Sensory dysfunction
o Manifested in many ways
Overstimulation
E.g., very sensitive to a light brush against the skin
Under stimulation
E.g., no reaction when falling down a slide
Sensation seekers
E.g., chewing on shirt until mouth is chapped and bleeding
Sensory discrimination
o Poor discrimination produces difficulties
o E.g., difficulty holding a pencil
Sensory-motor integration
o Difficulty with balance, movement, synchronising both sides of the body,
confusion between left- and right-sided movements
Neuroanatomy of sensory functions
SEEING
Primary visual cortex
o Located in the striate cortex of the occipital lobe
o Regulates sense of sight
Retina
o Located at the back of the eye
o Transmits information via the optic nerve
Optical nerve
o Splits into two parts when traveling to higher cortical areas:
The temporal (lateral)
Continues path to higher cortical regions
Same side of the body
The nasal (medial part)
Continues path to higher cortical regions
Crosses over at the optic chiasm
, o Both parts terminate in the lateral geniculate nuclei or the pulvinar nuclear of
the thalamus and the superior colliculus of the midbrain
Lateral geniculate nuclei
o Final pathway for visual information
o Travels to the primary area of the occipital lobe
HEARING
The primary auditory cortex
o Regulates sense of hearing
o Located in the superior part of the temporal lobe
o Buried within the sylvian fissure
Cochlea
o Auditory sense organ
o Located in the inner ear
o Projections pass through the subcortical relays of the medial geniculate of
the thalamus and then to the supratemporal cortex
TOUCH, PAIN, TEMPERATURE SENSE, LIMB PROPRIOCEPTION
Primary somatosensory cortex
o Regulates the sense of touch, pain, temperature sense, and limb
proprioception (limb position)
o Located in the postcentral gyrus
Two pathways:
o Anterolateral system
Pain and temperature
o Dorsal column-medial lemniscal system
Touch, proprioception, and movement
Vision, hearing, and touch, all have contralateral projections in the brain.
A defect in a right-sided sense organ will show as damage in the left side of the brain
that controls that sense organ.
o Exception: smell
SMELL
Primary olfactory cortex
o Regulates sense of smell
o Located in the ventral region of the anterior temporal lobe
Orbitofrontal cortex
o Secondary area
Lesions
o Left-sided lesion in the right ventral region of the temporal lobe
o Produce a severe deficit when an odour is smelled in the right nostril.
-> Only sense not processed by the thalamus, but instead pathways go directly to the cortex.
Anterior portion of the insular cortex (insula)
o Receives input from all the senses, as well as limbic regions
, o Integrate information for the perception of pain and fear avoidance.
Rapid Reference 10.1
Neuropsychological Terms Associated With Sensory Impairments
Achromatopsia A rare disorder in which colour is not recognized.
Ageusia Loss of the sense of taste.
Anosmia Impaired sense of smell.
Asterognosia Inability to recognize an object on the basis of its three
dimensionality through palpation (a.k.a., tactile
agnosia/dysnosia).
Auditory agnosia Inability to recognize auditory stimuli
Autotopagnosia Disturbed body scheme that manifests itself by the inability to
identify the parts of one’s body.
Barognosia Inability to estimate weight when objects are placed in the
affected hand.
Finger agnosia Inability to recognize a sensory stimulus via the fingers.
Graphestheia Difficulty recognizing shapes or letters written on the hand.
Hemianopia A loss of vision for one-half of the visual field of either one or
both eyes
Hypesthesia Diminished capacity for physical sensation
Kinesthesia The conscious awareness of joint position and body
movement in space.
Pallinopsia Visual perseveration of a stimulus no longer present
Parosmia An abnormal sense of smell
Proprioception The unconscious awareness of sensations coming from one’s
muscles and joints that helps regulate our position in three-
dimensional space
Tactile defensiveness The tendency to react negatively to unexpected, light touches
Tactile localization The inability to localize a stimulus on the skin
disorder
Two-point discrimination The inability to discriminate between sensations arising from a
disorder single touch versus two simultaneous and nearby touches
Visual agnosia Inability to recognize visual stimuli
Motor functions
Definitions
Developmental coordination disorder (DCD)
o Clumsy or awkward
o Marked impairment in the development of motor coordination
o Delays in reaching developmental motor milestones
o Difficulty mastering other gross motor tasks and mastering fine motor tasks
o Males > Females
o Developmental delays in other areas
Expressive and receptive language in isolation or combined, or in
phonological processing.
o DCD is often co-morbid with ADHD, conduct disorder, and pervasive
developmental disorder
