Chapter 13 Salient anatomic features of the cortico-ponto-cerebellar pathway

Brodal, Per; Bjaalie, Jan G.

doi:10.1016/s0079-6123(08)63367-1

Cited by 157 publications

(105 citation statements)

References 103 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The topographical arrangement of pontocerebellar projections was consistent with the organizational scheme described originally by Leergaard et al (1995) for the development of cerebropontine projections in neonate rats and also for the spatial pattern of cerebropontine terminations in adult rat, cat, and monkey (for reviews and references, see Brodal and Bjaalie, 1997;Schmahmann and Pandya, 1997). Injections into the A2-face, C1-forelimb, and C1-hindlimb cerebellar cortical zones resulted, respectively, in cell labeling located in approximately concentric internal to external shells (lamellas) within the pontine nuclei, with virtually no intermingling of cells projecting to different cerebellar targets.…”

Section: Topographic Patterns In the Pontine Nucleisupporting

confidence: 84%

Pontine Maps Linking Somatosensory and Cerebellar Cortices Are in Register with Climbing Fiber Somatotopy

Odeh

Ackerley²,

Bjaalie³

et al. 2005

Journal of Neuroscience

View full text Add to dashboard Cite

The cerebropontocerebellar mossy fiber system is a major CNS sensorimotor pathway. We used a double-retrograde axonal tracing technique (red and green beads) to chart in rats the pontocerebellar projection to different electrophysiologically defined climbing fiber zones in the posterior lobe (face-receiving A2 zone and forelimb-and hindlimb-receiving parts of the C1 zone in the paramedian lobule and copula pyramidis, respectively). Individual cortical injection sites were verified as located in a given zone by mapping the pattern of cell labeling in the inferior olive, whereas labeled cells in the pontine nuclei were mapped using computer-aided three-dimensional reconstruction techniques. A number of topographical differences were found for the pontine projection to the individual zones. Projections to the A2 zone were bilateral, whereas to both parts of the C1 zone, the inputs were mainly contralateral. Furthermore, the A2 (face), C1 (forelimb), and C1 (hindlimb) zone projections were centered in progressively more caudal parts of the pontine nuclei with little or no overlap between them. The areas occupied by cell labeling for each zone corresponded closely to territories in the pontine nuclei shown previously to receive projections from somatotopically equivalent regions of the somatosensory cortex. This precise cerebropontocerebellar topography, defined by climbing fiber somatotopy, is a new principle of organization for linking somatosensory and cerebellar cortices. The convergence of direct and indirect sensory projections is likely to have important implications for cerebellar cortical processing.

show abstract

Section: Topographic Patterns In the Pontine Nucleisupporting

confidence: 84%

Pontine Maps Linking Somatosensory and Cerebellar Cortices Are in Register with Climbing Fiber Somatotopy

Odeh

Ackerley²,

Bjaalie³

et al. 2005

Journal of Neuroscience

View full text Add to dashboard Cite

show abstract

“…Within this context, the precentral gyrus activation we observed, concurrently with the cerebellar activation, may be accounted for by assuming that the cerebellar signal influence the ongoing motor command by modulating the neural signal issued by the primary motor cortex. In agreement with this view, it has been shown that the primary motor cortex receives substantial input from the cerebellum via the ventrolateral thalamus (Asanuma et al, 1983;Brodal and Bjaalie, 1997;Hoover and Strick, 1999). Also, it has been suggested that the motor system is organized in a relative hierarchy such that the primary motor cortex is mainly involved in the low-level aspects of motor control.…”

Section: Functional Anatomy Of Movement Guidancementioning

confidence: 77%

“…This hypothesis is based on the observation that PPC displays three main properties that would be expected from an error detection module. First, it has access to a representation of the target and current hand location through afferent information coming from many sensory modalities (visual, proprioceptive, vestibular), and the main motor structures (Andersen et al, 1997;Brodal and Bjaalie, 1997). Second, it is critical for establishing stable relationships between heterogeneous information, i.e., for merging arm and targetrelated signals into a common frame of reference (Clower et al, 1996;Carey et al, 1997;Colby, 1998;Binkofski et al, 1999;Xing and Andersen, 2000).…”

Section: Functional Anatomy Of Movement Guidancementioning

confidence: 99%

“…However, the motor corrections generated by patients presenting with a lesion of the cerebellum are characterized by excessive deviations and ill-tuned muscle activation patterns. Anatomically, it was shown that the cerebellum receives abundant input from PPC via the pontine nuclei (Brodal and Bjaalie, 1997;Middleton and Strick, 1998). Functionally, it was suggested that one of the main contributions of the cerebellum to movement control is to perform the inverse computations allowing transformation of a desired displacement into an actual muscle command.…”

Section: Functional Anatomy Of Movement Guidancementioning

confidence: 99%

See 1 more Smart Citation

Functional Anatomy of Nonvisual Feedback Loops during Reaching: A Positron Emission Tomography Study

et al. 2001

View full text Add to dashboard Cite

Reaching movements performed without vision of the moving limb are continuously monitored, during their execution, by feedback loops (designated nonvisual). In this study, we investigated the functional anatomy of these nonvisual loops using positron emission tomography (PET). Seven subjects had to "look at" (eye) or "look and point to" (eye-arm) visual targets whose location either remained stationary or changed undetectably during the ocular saccade (when vision is suppressed). Slightly changing the target location during gaze shift causes an increase in the amount of correction to be generated. Functional anatomy of nonvisual feedback loops was identified by comparing the reaching condition involving large corrections (jump) with the reaching condition involving small corrections (stationary), after subtracting the activations associated with saccadic movements and hand movement planning [(eye-armjumping minus eye-jumping) minus (eye-arm-stationary minus eye-stationary)]. Behavioral data confirmed that the subjects were both accurate at reaching to the stationary targets and able to update their movement smoothly and early in response to the target jump. PET difference images showed that these corrections were mediated by a restricted network involving the left posterior parietal cortex, the right anterior intermediate cerebellum, and the left primary motor cortex. These results are consistent with our knowledge of the functional properties of these areas and more generally with models emphasizing parietal-cerebellar circuits for processing a dynamic motor error signal.

show abstract

“…Parietal͞cerebellar circuitry also is recruited for differentiation of motor functions (36), enhancement of goaldirected behaviors (45,46), judgment of the velocity of moving stimuli (47), spatial event processing (37), elementary visuospatial and memory functions (46), and working memory (48).…”

Section: Discussionmentioning

confidence: 99%

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Weaver

2005

Proc. Natl. Acad. Sci. U.S.A.

177

View full text Add to dashboard Cite

Human brain evolution involved both neurological reorganization and an increase in overall brain volume relative to body mass. It is generally difficult to draw functional inferences about the timing and nature of brain reorganization, given that superficial brain morphology recorded on fossil endocasts is functionally ambiguous. However, the cerebellum, housed in the clearly delineated posterior cranial fossa, is functionally and ontologically discrete. The cerebellum is reciprocally connected to each of 14 neocortical regions important to human cognitive evolution. Cerebellar volume varies significantly relative to overall brain volume among mammalian orders, as well as within the primate order. There is also significant diachronic variation among fossil human taxa. In the australopithecines and early members of the genus Homo, the cerebral hemispheres were large in proportion to the cerebellum, compared with other hominoids. This trend continued in Middle and Late Pleistocene humans, including Neandertals and CroMagnon 1, who have the largest cerebral hemispheres relative to cerebellum volume of any primates, including earlier and Holocene humans. In recent humans, however, the pattern is reversed; the cerebellum is larger with respect to the rest of the brain (and, conversely, the cerebral hemispheres are smaller with respect to the cerebellum) than in Late Pleistocene humans. The cerebellum and cerebral hemispheres appear to have evolved reciprocally. Cerebellar development in Holocene humans may have provided greater computational efficiency for coping with an increasingly complex cultural and conceptual environment.human evolution ͉ Plio-Pleistocene hominins ͉ Upper Paleolithic transition P aleoneurologists agree that increased encephalization is an important dynamic of human brain evolution. However, brain evolution involved more than brain expansion. It also involved reorganization to support specific, uniquely human cognitive tasks, including those involved in linguistic processing and a highly developed facility for manufacturing and manipulating tools. Nevertheless, despite more than a century of effort, there is little consensus about how and when such reorganization occurred.One approach to exploring functional reorganization of the brain in humans has been the analysis of impressions of the brain's surface convolutions (sulci and gyri) on the inner table of the endocranium. However, endocranial markings are notoriously difficult to identify reliably (1, 2). Even where the impressions are fairly clear, taphonomic processes may distort the evidence. In addition, the functional correlates of the brain's surface convolutions, especially in fossils, are literally superficial. Cognitive functions occur through internal connections among brain regions, as well as through the distribution of neuroreceptors that cannot be detected by examining the surface of the brain, let alone from endocranial markings. Therefore, functional inferences based on sulcal patterns are problematic.Another approach to endocran...

show abstract

Chapter 13 Salient anatomic features of the cortico-ponto-cerebellar pathway

Cited by 157 publications

References 103 publications

Pontine Maps Linking Somatosensory and Cerebellar Cortices Are in Register with Climbing Fiber Somatotopy

Pontine Maps Linking Somatosensory and Cerebellar Cortices Are in Register with Climbing Fiber Somatotopy

Functional Anatomy of Nonvisual Feedback Loops during Reaching: A Positron Emission Tomography Study

Reciprocal evolution of the cerebellum and neocortex in fossil humans

Contact Info

Product

Resources

About