“It’s like the ABCs - - I have to start at the beginning of the song to remember the whole thing.”
When a baby has not yet learned the oral grasp of the nipple-areolar complex (the latch), or when a baby has not yet relearned how to latch, clinicians often recommend skin-to-skin contact ad lib, beginning with the infant held upright and against the chest, between the breasts. Providing the infant with this rich sensory milieu often facilitates the infant’s self-orchestrated, reflexive creeping movements from the mother’s upper chest down to the breast, i.e., starting at the beginning of the sequence. Infants will often move down to the breast in early hunger, even when held by another adult or an older sibling, and even when the infant is exclusively bottle-fed.
Supporting the infant in beginning the feeding sequence in this manner is often highly effective for healthy term infants, particularly in youngest infants during early learning at the breast. However, in assisting exclusively bottle-fed infants in a hoped-for transfer of learning from skilled bottle-feeding to the acquisition of breastfeeding skills, it is common to observe the older infant who moves in skin-to-skin contact on the chest and down to the breast, and who then struggles with the stimuli of the nipple-areolar complex.
Over the years, we eventually achieve an impressive repertoire of feeding and drinking skills, although we periodically display a performance plateau, a period of time during the learning process in which no overt changes in performance occur. The older baby often displays a preference for a particular style of sippee-cup for a period time, accepting one style of sippee-cup and refusing another style by turning away or pushing the novel object away. For weeks if not months, the older baby and toddler will display “utensil confusion” when learning how to differentiate the proper movements for fork-eating and spoon-eating, struggling to pierce the food with a spoon, as if the spoon is enough like the fork to readily use the spoon in the manner of a fork.
Following the infant’s learning experience with an artificial nipple (a pacifier/soother/dummy or a bottle nipple/teat), there is often a behavioral display by the infant of difficulty in returning to the breast. This breach in the sequencing of movements toward the breast can be measured in real time as a prolonged reaction time to the stimuli of the nipple-areolar complex; a prolonged movement time for achieving and sustaining the oral grasp of the nipple-areolar complex; a prolonged response time; as well as an inhibition of return — the delay in responding to the previously orienting stimulus/stimuli.
Sequencing in motor learning is heavily studied in the cognitive sciences. Included in the studies below is a sequencing study with stroke patients. I wish to emphasize that stroke patients who receive inpatient rehabilitation services typically receive both physical therapy and occupational therapy twice daily in morning and afternoon sessions, as well as daily speech therapy. Stroke patients and patients with traumatic brain injuries (TBIs) receive skilled guidance in relearning how to speak, guidance in how to feed themselves with utensils and swallow carefully without aspirating, and guidance in relearning how to ambulate after a lifetime of skilled performance of these skills.
Health insurance companies are expected to cover the medical expenses of daily physical therapy, daily occupational therapy, and daily speech therapy toward a patient’s recovery of function. In contrast, a number of health insurance companies in the U.S. do not readily cover the fees for educated and trained infant feeding specialists such as IBCLCs who are assisting infants in learning the oral grasp of the nipple-areolar complex, as well as learning effective sucking skills for adequate milk transfer toward adequate and optimal growth. The Patient Protection and Affordable Care Act was signed into law in 2010. Why does this marked disparity in reimbursement continue to exist among various patient populations in the U.S.?
Some new studies in sequence learning:
Title: Sequence learning in the human brain: A functional neuroanatomical meta-analysis of serial reaction time studies.
In: Neuroimage 2020 Feb 15;207:116387. doi: 10.1016/j.neuroimage.2019.116387. Epub 2019 Nov 22.
Authors: Karolina Janacsek, Kyle F. Shattuck, Kaitlyn M. Tagarelli, Jarrad A.G. Lum, Peter E. Turkeltaub, Michael T. Ullman.
Abstract: “Sequence learning underlies numerous motor, cognitive, and social skills. Previous models and empirical investigations of sequence learning in humans and non-human animals have implicated cortico-basal ganglia-cerebellar circuitry as well as other structures. To systematically examine the functional neuroanatomy of sequence learning in humans, we conducted a series of neuroanatomical meta-analyses. We focused on the serial reaction time (SRT) task. This task, which is the most widely used paradigm for probing sequence learning in humans, allows for the rigorous control of visual, motor, and other factors. Controlling for these factors (in sequence-random block contrasts), sequence learning yielded consistent activation only in the basal ganglia, across the striatum (anterior/mid caudate nucleus and putamen) and the globus pallidus. In contrast, when visual, motor, and other factors were not controlled for (in a global analysis with all sequence-baseline contrasts, not just sequence-random contrasts), premotor cortical and cerebellar activation were additionally observed. The study provides solid evidence that, at least as tested with the visuo-motor SRT task, sequence learning in humans relies on the basal ganglia, whereas cerebellar and premotor regions appear to contribute to aspects of the task not related to sequence learning itself. The findings have both basic research and translational implications. Keywords: Basal ganglia; Implicit learning; Procedural memory; Sequence learning; Serial reaction time (SRT) task; Striatum.”
Open access: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268039/
Title: The posterior parietal cortex mediates early offline-rather than online-motor sequence learning.
In: Neuropsychologica 2020 Jul 9;107555. doi: 10.1016/j.neuropsychologia.2020.107555. Online ahead of print.
Authors: Bettina Pollok, Ariane Keitel, Maike Foerster, Geraldine Moshiri, Katharina Otto, Vanessa Krause.
Abstract: “Learning of new motor skills occurs particularly during training on a task (i.e. online) but has been observed between training-blocks lasting up to days after the end of the training (i.e. offline). Offline-learning occurs as further improvement in task performance indicated by increased accuracy and/or faster responses as well as less interference with respect to a distracting condition. Successful motor learning requires the functional interplay between cortical as well as subcortical brain areas. While the involvement of the primary motor cortex in online-as well as early offline-learning is well established, the functional significance of the posterior parietal cortex (PPC) is less clear. Since the PPC may act as sensory-motor interface, a causal involvement in motor learning is conceivable. In order to characterize the functional significance of the left PPC for motor sequence learning, transcranial direct current stimulation (tDCS) was applied either immediately prior to, during or immediately after training on a serial reaction time task (SRTT) in a total of 54 healthy volunteers. While the analysis did not provide evidence for a significant modulation of reaction times during SRTT training (i.e. online-learning), cathodal tDCS decelerated reaction times of the learned sequences as compared to anodal and sham stimulation 30 min after the end of training. The findings suggest that cathodal tDCS over the left parietal cortex interferes with the reproduction of learned sequences.”
Abstract only: https://www.sciencedirect.com/science/article/abs/pii/S0028393220302281?via%3Dihub
Title: The importance of different learning stages for motor sequence learning after stroke.
In: Human Brain Mapping 2020 Jan;41(1):270-286. doi: 10.1002/hbm.24793. Epub 2019 Sep 14.
Authors: Christiane Dahms, Stefan Brodoehl, Otto W. Witte, Carsten M. Klingner.
Abstract: “The task of learning predefined sequences of interrelated motor actions is of everyday importance and has also strong clinical importance for regaining motor function after brain lesions. A solid understanding of sequence learning in stroke patients can help clinicians to optimize and individualize rehabilitation strategies. Moreover, to investigate the impact of a focal lesion on the ability to successfully perform motor sequence learning can enhance our comprehension of the underlying physiological principles of motor sequence learning. In this article, we will first provide an overview of current concepts related to motor sequence learning in healthy subjects with focus on the involved brain areas and their assumed functions according to the temporal stage model. Subsequently, we will consider the question of what we can learn from studies investigating motor sequence learning in stroke patients. We will first focus on the implications of lesion location. Then, we will analyze whether distinct lesion locations affect specific learning stages. Finally, we will discuss the implications for clinical rehabilitation and suggest directions for further research. Keywords: motor cortex, motor rehabilitation, plasticity, sequence learning, stroke.”
Open access: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268039/pdf/HBM-41-270.pdf