Neural organization of the second optic neuropil, the medulla, in the highly visual semiterrestrial crabNeohelice granulata

2014 ◽  
Vol 522 (14) ◽  
pp. 3177-3193 ◽  
Author(s):  
Julieta Sztarker ◽  
Daniel Tomsic
Keyword(s):  
Neural Organization ◽  
Optic Neuropil

Language and Aging

2019 ◽  
pp. 294-316
Author(s):  
Jonathan E. Peelle
Keyword(s):  
Language Processing ◽  
Brain Function ◽  
Neural Systems ◽  
Language Abilities ◽  
Physiological Mechanisms ◽  
Cognitive Changes ◽  
Older Adulthood ◽  
Neural Organization ◽  
Age Related ◽  
High Level

Language processing in older adulthood is a model of balance between preservation and decline. Despite widespread changes to physiological mechanisms supporting perception and cognition, older adults’ language abilities are frequently well preserved. At the same time, the neural systems engaged to achieve this high level of success change, and individual differences in neural organization appear to differentiate between more and less successful performers. This chapter reviews anatomical and cognitive changes that occur in aging and popular frameworks for age-related changes in brain function, followed by an examination of how these principles play out in the context of language comprehension and production.

Neural elements of the pineal complex of the frog, rena esculenta, I: Centrally projecting neurons

1990 ◽  
Vol 4 (05) ◽  
pp. 389-397 ◽  
Author(s):  
Peter Ekström ◽  
Hilmar Meissl
Keyword(s):  
Pineal Organ ◽  
Photoreceptor Cells ◽  
Rana Esculenta ◽  
Projection Neurons ◽  
Pineal Complex ◽  
Bipolar Neuron ◽  
Neural Organization ◽  
Hand Functions ◽  
Frontal Organ ◽  
Pineal Tract

AbstractThe pineal complex of anuran &hibians is a directly photosensory organ, encompassing both an extracranial portion, the frontal organ, and an intracranial portion, the pineal organ proper. The projection neurons of the frontal organ respond differentially according to the wavelengths of the light stimuli. The pineal organ, on the other hand, functions mainly as a luminosity meter. Most of its centrally projecting neurons respond to all increases in ambient illumination with decreases in spontaneous firing of action potentials, although some neural units in the pineal organ may respond according to wavelength. This difference in responses to light stimulation may be reflected in the neural organization of the two parts of the pineal complex. In the present study, we have analyzed the morphology of the projection neurons of the frontal and pineal organs of the frog,Rana esculenta, by backfilling of the neurons with horseradish peroxidase through their cut axons. In the pineal organ, several types of centrally projecting neurons were observed: peripherally situated unipolar and multipolar neurons, the dendrites of which extend into a superficial axon plexus that surrounds the pineal epithelium; smaller unipolar, bipolar, or multipolar neurons situated close to the central pineal tract; and radially oriented bipolar neurons, with short dendritic processes oriented towards the lumen of the pineal organ. This latter type was strongly reminiscent of photoreceptor cells. The centrally projecting neurons of the frontal organ were multipolar, and situated in the ventral part of the organ. One photoreceptor-like bipolar neuron was observed in one frontal organ. The neurons of the frontal organ did not form a superficial plexus of neurites. This difference may relate to the different ratio of chromaticity/luminosity units in the frontal and pineal organs.

Neural organization of eyelid responses

2002 ◽  
Vol 17 (S2) ◽  
pp. S33-S36 ◽  
Author(s):  
Jos� M. Delgado-Garc�a ◽  
Agn�s Gruart ◽  
Alejandro M�nera
Keyword(s):  
Neural Organization

scholarly journals Selection for Reinforcement-Free Learning Ability as an Organizing Factor in the Evolution of Cognition

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Solvi Arnold ◽  
Reiji Suzuki ◽  
Takaya Arita
Keyword(s):  
Selection Pressure ◽  
Learning Ability ◽  
Environmental Complexity ◽  
Baldwin Effect ◽  
Neural Structure ◽  
Neural Organization ◽  
Environmental Structure ◽  
Selection For ◽  
Efficient Learning ◽  
Complexity Thesis

This research explores the relation between environmental structure and neurocognitive structure. We hypothesize that selection pressure on abilities for efficient learning (especially in settings with limited or no reward information) translates into selection pressure on correspondence relations between neurocognitive and environmental structure, since such correspondence allows for simple changes in the environment to be handled with simple learning updates in neurocognitive structure. We present a model in which a simple form of reinforcement-free learning is evolved in neural networks using neuromodulation and analyze the effect this selection for learning ability has on the virtual species' neural organization. We find a higher degree of organization than in a control population evolved without learning ability and discuss the relation between the observed neural structure and the environmental structure. We discuss our findings in the context of the environmental complexity thesis, the Baldwin effect, and other interactions between adaptation processes.

scholarly journals The Causal Role of Left and Right Superior Temporal Gyri in Speech Perception in Noise: A Transcranial Magnetic Stimulation Study

2020 ◽  
Vol 32 (6) ◽  
pp. 1092-1103 ◽  
Author(s):  
Dan Kennedy-Higgins ◽  
Joseph T. Devlin ◽  
Helen E. Nuttall ◽  
Patti Adank
Keyword(s):  
Speech Perception ◽  
Side Effects ◽  
Temporal Lobe ◽  
Language Processing ◽  
Background Noise ◽  
Superior Temporal Gyrus ◽  
Left Temporal Lobe ◽  
Neural Organization ◽  
Left And Right ◽  
Listening Strategies

Successful perception of speech in everyday listening conditions requires effective listening strategies to overcome common acoustic distortions, such as background noise. Convergent evidence from neuroimaging and clinical studies identify activation within the temporal lobes as key to successful speech perception. However, current neurobiological models disagree on whether the left temporal lobe is sufficient for successful speech perception or whether bilateral processing is required. We addressed this issue using TMS to selectively disrupt processing in either the left or right superior temporal gyrus (STG) of healthy participants to test whether the left temporal lobe is sufficient or whether both left and right STG are essential. Participants repeated keywords from sentences presented in background noise in a speech reception threshold task while receiving online repetitive TMS separately to the left STG, right STG, or vertex or while receiving no TMS. Results show an equal drop in performance following application of TMS to either left or right STG during the task. A separate group of participants performed a visual discrimination threshold task to control for the confounding side effects of TMS. Results show no effect of TMS on the control task, supporting the notion that the results of Experiment 1 can be attributed to modulation of cortical functioning in STG rather than to side effects associated with online TMS. These results indicate that successful speech perception in everyday listening conditions requires both left and right STG and thus have ramifications for our understanding of the neural organization of spoken language processing.

The unification of neural activity

1968 ◽  
Vol 171 (1024) ◽  
pp. 353-359 ◽  
Keyword(s):  
Nervous System ◽  
Neural Activity ◽  
Nerve Cells ◽  
General Nature ◽  
Central Importance ◽  
Stimulus Response ◽  
Simple Hypothesis ◽  
Neural Organization ◽  
The Individual ◽  
The Brain

In studying the brain, two levels of investigation emerge naturally. One of these concerns itself with properties of nerve cells, their numbers, patterns of firing, interconnexions, and so forth. The other considers the whole nervous system in what one may call ‘macroscopic’ terms. Thus it discusses ‘stimulus’, ‘response’, ‘decision’, etc. At this latter level, the nervous system operates with considerable unity. The individual nerve cells must therefore be linked in a well-integrated manner and the general nature of this integration has been recognized, especially by neurophysiologists such as Sherrington, to present a problem of central importance for our understanding of the brain. In previously published work, I have put forward a theory of how this unification of neural activity might be achieved and of a possible molecular biological basis of the necessary neural organization. In this talk I restrict myself to the first of these and thus give an account of what might be called the basic logic of the unification. I also indicate briefly how a simple hypothesis about the basis of memory would fit into such a theory.

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