Sensory - Touch Development

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Touch receptors in mammalian skin.[1]
Skin Pacinian corpuscle

These notes introduce the development of the sense of touch, part of the somatosensory system. Because of the distribution of the sensory structures within the skin, this topic is generally also covered in integumentary development.

Touch links: Integumentary Development | Neural Crest Development | Neural System Development | Student project

Integumentary Links: Introduction | Lecture | Hair | Tooth | Nail | Gland | Mammary Gland | Eyelid | Outer Ear | Melanocyte | Touch | Histology | Abnormalities | Category:Integumentary
Historic Embryology  
1910 Manual of Human Embryology | 1914 Integumentary | 1923 Head Subcutaneous Plexus | 1921 Text-Book of Embryology | 1924 Developmental Anatomy | 1941 Skin Sensory | Historic Disclaimer

Senses Links: Introduction | Placodes | Hearing and Balance | Vision | Smell | Taste | Touch | Stage 22 | Category:Senses

Some Recent Findings

  • A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development[2] "In the skin, touch domes develop in tandem with primary hair follicles and contain sensory Merkel cells. We found dermal Wnt signaling and subsequent epidermal Eda/Edar signaling promoted Merkel cell morphogenesis by inducing Shh expression in early follicles. Lineage-specific gene deletions revealed intraepithelial Shh signaling was necessary for Merkel cell specification. Additionally, a Shh signaling agonist was sufficient to rescue Merkel cell differentiation in Edar-deficient skin. ...Although developmentally associated with hair follicles, fate mapping demonstrated Merkel cells primarily originated outside the hair follicle lineage. These findings suggest that touch dome development requires Wnt-dependent mesenchymal signals to establish reciprocal signaling within the developing ectoderm, including Eda signaling to primary hair placodes and ultimately Shh signaling from primary follicles to extrafollicular Merkel cell progenitors." Sonic hedgehog
  • Unipotent, Atoh1+ progenitors maintain the Merkel cell population in embryonic and adult mice[3] "Resident progenitor cells in mammalian skin generate new cells as a part of tissue homeostasis. We sought to identify the progenitors of Merkel cells, a unique skin cell type that plays critical roles in mechanosensation. We found that some Atoh1-expressing cells in the hairy skin and whisker follicles are mitotically active at embryonic and postnatal ages. Genetic fate-mapping revealed that these Atoh1-expressing cells give rise solely to Merkel cells. Furthermore, selective ablation of Atoh1(+) skin cells in adult mice led to a permanent reduction in Merkel cell numbers, demonstrating that other stem cell populations are incapable of producing Merkel cells. These data identify a novel, unipotent progenitor population in the skin that gives rise to Merkel cells both during development and adulthood."
  • Embryonic maturation of epidermal Merkel cells is controlled by a redundant transcription factor network[4] Merkel cell-neurite complexes are located in touch-sensitive areas of the mammalian skin and are involved in recognition of the texture and shape of objects. Merkel cells are essential for these tactile discriminations, as they generate action potentials in response to touch stimuli and induce the firing of innervating afferent nerves. It has been shown that Merkel cells originate from epidermal stem cells, but the cellular and molecular mechanisms of their development are largely unknown. In this study, we analyzed Merkel cell differentiation during development and found that it is a temporally regulated maturation process characterized by a sequential activation of Merkel cell-specific genes. We uncovered key transcription factors controlling this process and showed that the transcription factor Atoh1 is required for initial Merkel cell specification. The subsequent maturation steps of Merkel cell differentiation are controlled by cooperative function of the transcription factors Sox2 and Isl1, which physically interact and work to sustain Atoh1 expression"
  • Wetness perception across body sites[5] "Human skin is innervated with a variety of receptors serving somatosensation and includes the sensory sub-modalities of touch, temperature, pain and itch. The density and type of receptors differ across the body surface, and there are various body-map representations in the brain. The perceptions of skin sensations outside of the specified sub-modalities, e.g. wetness or greasiness, are described as 'touch blends' and are learned. ...The perception of wetness is generated from the coincident activation of tactile and thermal receptors. The perception of wetness did not, however, differ significantly across body sites and there were no significant interactions between wetness level and body site."
  • A Shift in Sensory Processing that Enables the Developing Human Brain to Discriminate Touch from Pain[6] "When and how infants begin to discriminate noxious from innocuous stimuli is a fundamental question in neuroscience. However, little is known about the development of the necessary cortical somatosensory functional prerequisites in the intact human brain. ... The results suggest that specific neural circuits necessary for discrimination between touch and nociception emerge from 35-37 weeks gestation in the human brain."
  • Identification of epidermal progenitors for the Merkel cell lineage[7] "Epithelial stem cells in adult mammalian skin are known to maintain epidermal, follicular and sebaceous lineages during homeostasis. Recently, Merkel cell mechanoreceptors were identified as a fourth lineage derived from the proliferative layer of murine skin epithelium; however, the location of the stem or progenitor population for Merkel cells remains unknown. Here, we have identified a previously undescribed population of epidermal progenitors that reside in the touch domes of hairy skin, termed touch dome progenitor cells (TDPCs)."
More recent papers
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This table shows an automated computer PubMed search using the listed sub-heading term.

  • Therefore the list of references do not reflect any editorial selection of material based on content or relevance.
  • References appear in this list based upon the date of the actual page viewing.

References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.

Links: References | Discussion Page | Pubmed Most Recent | Journal Searches

Search term: Touch Development

Minpyo Kang, Jejung Kim, Bongkyun Jang, Youngcheol Chae, Jae-Hyun Kim, Jong-Hyun Ahn Graphene-Based Three Dimensional Capacitive Touch Sensor for Wearable Electronics. ACS Nano: 2017; PubMed 28727414

Cheng Zhan, Cheng Lian, Yu Zhang, Matthew W Thompson, Yu Xie, Jianzhong Wu, Paul R C Kent, Peter T Cummings, De-En Jiang, David J Wesolowski Computational Insights into Materials and Interfaces for Capacitive Energy Storage. Adv Sci (Weinh): 2017, 4(7);1700059 PubMed 28725531

Kazuo Nakamoto, Fuka Aizawa, Kei Miyagi, Takuya Yamashita, Mitsumasa Mankura, Yutaka Koyama, Fumiyo Kasuya, Akira Hirasawa, Takashi Kurihara, Atsuro Miyata, Shogo Tokuyama Dysfunctional GPR40/FFAR1 signaling exacerbates pain behavior in mice. PLoS ONE: 2017, 12(7);e0180610 PubMed 28723961

Agnes van den Hoogen, Charlotte J Teunis, Renée A Shellhaas, Sigrid Pillen, Manon Benders, Jeroen Dudink How to improve sleep in a neonatal intensive care unit: A systematic review. Early Hum. Dev.: 2017; PubMed 28720290

Sophie Tremblay, Manon Ranger, Cecil M Y Chau, Jacob Ellegood, Jason P Lerch, Liisa Holsti, Daniel Goldowitz, Ruth E Grunau Repeated exposure to sucrose for procedural pain in mouse pups leads to long-term widespread brain alterations. Pain: 2017, 158(8);1586-1598 PubMed 28715355

Historic People

  • Georg Meissner - (1829-1905) German histologist, physiologist and anatomist. Beiträge zur Anatomie und Physiologie der Haut. (Contributions to the anatomy and physiology of the skin.) Leipzig, 1853.
  • Friedrich Sigmund Merkel- (1845-1919) German anatomist and histologist, the name "Merckel cell" was based upon his first full description of touch cells (Tastzellen) and named by Robert Bonnet (1851–1921). Referred to these cells as Tastzellen or "touch cells" but this proposed function has been controversial as it has been hard to prove.
  • Filippo Pacini - (1812-1883) Italian anatomist, published in 1840, and the name "Pacini's corpuscles" was proposed in 1844 by Henle and also by Kölliker.
  • Angelo Ruffini (1864-1929) Italian histologist and embryologist, the name "Ruffini corpuscles" was based upon his first description of skin mechanoreceptors.

Touch Receptors

Dermatomes the surface map of segmental spinal nerve innervation of the skin surface.

Touch receptors in mammalian skin cartoon.jpg

Touch receptors in mammalian skin and the neural encoding of reception.[8]

Touch Pathway

Pacinian corpuscle

These receptors are lamellar vibration receptors that produce rapidly adapting responses. They are located in the subcutaneous tissue, deeper in interosseous membranes, and also mesenteries of the gut. The inner core cells form from Schwann cells extending from the nerve terminal.

Pacinian corpuscle histology 01.jpg

Meissner's corpuscle

Located in glabrous skin the mechanoreceptor lies between the dermal papillae for sensitivity to light touch. They are rapidly adaptive elongated receptors formed by a connective tissue capsule that formed by several lamellae of Schwann cells enclosing one or more afferent nerve fibres.

Meissner's corpuscle

Meissner corpuscle 01.jpg

Meissner's corpuscles are located throughout the skin and are seen concentrated in regions of high touch (finger tips, lips, genital regions).

Merkel cell

Merkel cells occur in many species including reptiles, fish, and mammals. Merkel cell complexes mediate slowly adapting type I (SAI) responses, which are characterized by an irregular firing pattern during sustained pressure.

Merkel cells arise in the embryo[4] and in the adult[3] from an epidermal progenitor cell population. These cells express the transcription factor Atoh1 and when differentiated are post-mitotic.

A molecular signalling cascade from Wnt, Eda, and Shh is required for touch dome Merkel cell development.[2] Keratin 8 (K8) and Keratin 18 (K18) are Merkel cell markers identified in late fetal and adult skin.

Merkel cell EM 01.jpg

Isolated Merkel cell (em)

Merkel cell (Merkel-Ranvier cell) integumentary (skin) receptor cell connected with somatosensory afferents.

Cell characteristics a polylobulated nucleus and numerous typical dense-core granules in a clear cytoplasm.

The name "Merckel cell" was based upon Friedrich Sigmund Merkel (1845 – 1919) a German anatomist and histologist, first description of these touch cells (Tastzellen) and named in his honour by Robert Bonnet (1851–1921).

Scale bar 5 µm (Stain - Osmium)

Integumentary touch dome functions.jpg

Integumentary touch dome suggested functions[9]

The Merkel cell is also a part of the touch dome (TD) apparatus, an innervated structure composed of specialised keratinocytes, and may have additional neuroendocrine and immune roles, as they associate with Langerhans cells (dendritic antigen presenting cells) in the epidermis.[9]

In the adult, abnormalities in Merkel cell development can lead to the rare disease of Merkel cell carcinoma (MCC) associated with sun (UV) exposure.

Sensory Modalities


  • Receptors for heat (warmth) and cold (chill) detection.
    • heat - C-fibres
    • cold - Aδ fibres


  • Receptors for encoding and processing noxious stimuli.
    • A-δ nociceptors
    • Polymodal C-nociceptors
    • C- mechano-insensitive nociceptors


  • Merkel cell carcinoma (MCC) PMID 12007193


  1. Ellen A Lumpkin, Kara L Marshall, Aislyn M Nelson The cell biology of touch. J. Cell Biol.: 2010, 191(2);237-48 PubMed 20956378 | PMC2958478 | JCB
  2. 2.0 2.1 Ying Xiao, Daniel T Thoresen, Lingling Miao, Jonathan S Williams, Chaochen Wang, Radhika P Atit, Sunny Y Wong, Isaac Brownell A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development. PLoS Genet.: 2016, 12(7);e1006150 PubMed 27414798
  3. 3.0 3.1 Margaret C Wright, Erin G Reed-Geaghan, Alexa M Bolock, Tomoyuki Fujiyama, Mikio Hoshino, Stephen M Maricich Unipotent, Atoh1+ progenitors maintain the Merkel cell population in embryonic and adult mice. J. Cell Biol.: 2015; PubMed 25624394 | J Cell Biol.
  4. 4.0 4.1 Carolina N Perdigoto, Evan S Bardot, Victor J Valdes, Francis J Santoriello, Elena Ezhkova Embryonic maturation of epidermal Merkel cells is controlled by a redundant transcription factor network. Development: 2014, 141(24);4690-6 PubMed 25468937
  5. Rochelle Ackerley, Håkan Olausson, Johan Wessberg, Francis McGlone Wetness perception across body sites. Neurosci. Lett.: 2012, 522(1);73-7 PubMed 22710006
  6. Lorenzo Fabrizi, Rebeccah Slater, Alan Worley, Judith Meek, Stewart Boyd, Sofia Olhede, Maria Fitzgerald A shift in sensory processing that enables the developing human brain to discriminate touch from pain. Curr. Biol.: 2011, 21(18);1552-8 PubMed 21906948
  7. Seung-Hyun Woo, Magda Stumpfova, Uffe B Jensen, Ellen A Lumpkin, David M Owens Identification of epidermal progenitors for the Merkel cell lineage. Development: 2010, 137(23);3965-71 PubMed 21041368
  8. Ellen A Lumpkin, Kara L Marshall, Aislyn M Nelson The cell biology of touch. J. Cell Biol.: 2010, 191(2);237-48 PubMed 20956378 | PMC2958478 | JCB
  9. 9.0 9.1 Ying Xiao, Jonathan S Williams, Isaac Brownell Merkel cells and touch domes: more than mechanosensory functions? Exp. Dermatol.: 2014, 23(10);692-5 PubMed 24862916


Helen C Lai, Rebecca P Seal, Jane E Johnson Making sense out of spinal cord somatosensory development. Development: 2016, 143(19);3434-3448 PubMed 27702783

Seung-Hyun Woo, Ellen A Lumpkin, Ardem Patapoutian Merkel cells and neurons keep in touch. Trends Cell Biol.: 2015, 25(2);74-81 PubMed 25480024

Amanda Zimmerman, Ling Bai, David D Ginty The gentle touch receptors of mammalian skin. Science: 2014, 346(6212);950-4 PubMed 25414303

Joseph Jeffry, Seungil Kim, Zhou-Feng Chen Itch signaling in the nervous system. Physiology (Bethesda): 2011, 26(4);286-92 PubMed 21841076

Ellen A Lumpkin, Kara L Marshall, Aislyn M Nelson The cell biology of touch. J. Cell Biol.: 2010, 191(2);237-48 PubMed 20956378



Sanjeev S Ranade, Seung-Hyun Woo, Adrienne E Dubin, Rabih A Moshourab, Christiane Wetzel, Matt Petrus, Jayanti Mathur, Valérie Bégay, Bertrand Coste, James Mainquist, A J Wilson, Allain G Francisco, Kritika Reddy, Zhaozhu Qiu, John N Wood, Gary R Lewin, Ardem Patapoutian Piezo2 is the major transducer of mechanical forces for touch sensation in mice. Nature: 2014, 516(7529);121-5 PubMed 25471886


Neurobiology of Sensation and Reward. Gottfried JA, editor. Boca Raton (FL): CRC Press; 2011. Chapter 7 - Touch PMID 22593916

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Touch Terms  
  • free nerve endings- abundantly innervate the epidermis, include nociceptors and low-threshold C-fibers.
  • glabrous - smooth hairless skin for example the fingertips, palms, and soles.
  • lanceolate endings - rapidly adapting or down hair afferents sensitive light-touch receptors that depend on Neurotrophin-4 for proper development.
  • Meissner’s corpuscles - glabrous skin mechanoreceptor lie between the dermal papillae for sensitivity to light touch. They are rapidly adaptive elongated receptors formed by a connective tissue capsule that formed by several lamellae of Schwann cells enclosing one or more afferent nerve fibres.
  • Merkel cells - (Merkel's disks, Merkel cell–neuron complexes) mediate slowly adapting type I (SAI) responses, which are characterized by an irregular firing pattern during sustained pressure.
  • Pacinian corpuscles- lamellar vibration receptors that produce rapidly adapting responses.
  • Ruffini endings - proposed to mediate stretch-sensitive slowly adapting type II (SAII) responses, unknown developmental pathbwayreceptors.
  • somatosensory - neural sensation associated with pressure (touch), pain, or temperature.
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Cite this page: Hill, M.A. 2017 Embryology Sensory - Touch Development. Retrieved July 22, 2017, from

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