Central Integration of Visceral Sensory and Motor Signals, part 2

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Duke University의 강좌에서

Medical Neuroscience

1277개의 평가

Duke University

Medical Neuroscience

1277개의 평가

Medical Neuroscience explores the functional organization and neurophysiology of the human central nervous system, while providing a neurobiological framework for understanding human behavior. In this course, you will discover the organization of the neural systems in the brain and spinal cord that mediate sensation, motivate bodily action, and integrate sensorimotor signals with memory, emotion and related faculties of cognition. The overall goal of this course is to provide the foundation for understanding the impairments of sensation, action and cognition that accompany injury, disease or dysfunction in the central nervous system. The course will build upon knowledge acquired through prior studies of cell and molecular biology, general physiology and human anatomy, as we focus primarily on the central nervous system. This online course is designed to include all of the core concepts in neurophysiology and clinical neuroanatomy that would be presented in most first-year neuroscience courses in schools of medicine. However, there are some topics (e.g., biological psychiatry) and several learning experiences (e.g., hands-on brain dissection) that we provide in the corresponding course offered in the Duke University School of Medicine on campus that we are not attempting to reproduce in Medical Neuroscience online. Nevertheless, our aim is to faithfully present in scope and rigor a medical school caliber course experience. This course comprises six units of content organized into 12 weeks, with an additional week for a comprehensive final exam: - Unit 1 Neuroanatomy (weeks 1-2). This unit covers the surface anatomy of the human brain, its internal structure, and the overall organization of sensory and motor systems in the brainstem and spinal cord. - Unit 2 Neural signaling (weeks 3-4). This unit addresses the fundamental mechanisms of neuronal excitability, signal generation and propagation, synaptic transmission, post synaptic mechanisms of signal integration, and neural plasticity. - Unit 3 Sensory systems (weeks 5-7). Here, you will learn the overall organization and function of the sensory systems that contribute to our sense of self relative to the world around us: somatic sensory systems, proprioception, vision, audition, and balance senses. - Unit 4 Motor systems (weeks 8-9). In this unit, we will examine the organization and function of the brain and spinal mechanisms that govern bodily movement. - Unit 5 Brain Development (week 10). Next, we turn our attention to the neurobiological mechanisms for building the nervous system in embryonic development and in early postnatal life; we will also consider how the brain changes across the lifespan. - Unit 6 Cognition (weeks 11-12). The course concludes with a survey of the association systems of the cerebral hemispheres, with an emphasis on cortical networks that integrate perception, memory and emotion in organizing behavior and planning for the future; we will also consider brain systems for maintaining homeostasis and regulating brain state.

수업에서

Movement and Motor Control: Visceral Motor Control

We conclude our survey of movement and motor control by considering the visceral motor system, perhaps better known as the autonomic nervous system. As you study this lesson, consider how the disparate physiology of the viscera has impact not only on the internal state of the body, but also on implicit processing in the forebrain. We will return to this matter when we consider the neurobiology of emotions near the conclusion of Medical Neuroscience

Functional and Anatomical Divisions of the Visceral Motor System, part 111:18

Functional and Anatomical Divisions of the Visceral Motor System, part 213:45

Functional and Anatomical Divisions of the Visceral Motor System, part 310:33

Central Integration of Visceral Sensory and Motor Signals, part 113:30

Central Integration of Visceral Sensory and Motor Signals, part 27:40

Hypothalamus, part 114:05

Hypothalamus, part 216:53

Micturition19:11

강사 만나기

Leonard E. White, Ph.D.
Associate Professor
Department of Neurology, Department of Neurobiology, Duke University School of Medicine; Department of Psychology & Neuroscience, Trinity College of Arts & Sciences; Director of Education, Duke Institute for Brain Sciences; Duke University

Okay, what I'd like to do now is introduce this concept of central

integration of these visceral sensory signals.

so that the motor output can be coordinated by higher brain centers in

the medial and ventral aspects of the forebrain.

So I want to show you. Really, it expanded, or maybe you might

think of this as an exploded version of this illustration, that unpacks exactly

what these structures are and, how they relate to the influx of sensory signals.

And then the output of our preganglionic neurons.

So this is the last slide that I want to show you in this part of our tutorial.

And trust me, it looks actually much worse than it really is.

let me give you a sense of the organization of this chart.

What we have on the right hand side of this chart is basically the ascending

sensory information that is derived from our visceral sensory elements.

Many of these things we've already discussed.

So our end organs are giving rise to first order afferents that are rising

through cranial nerves 9 and 10, and the axons of our anterolateral system.

And the nucleus of the solitary track then becomes a very important integrator

of this information. We've already talked about how nucleus

and the solitary tract gives rise to projections that impact our interneurons

that organize preganglionic neurons of the sympathetic parasympathetic divisions

in the brain stem and spinal cord. And this thereby mediates local reflex

activity that can alter the activity of our end organs.

So, what I want to introduce to you, is the idea of a central autonomic network

that is processing these ascending sensory signals and coordinating the

output of our visceral motor effector systems.

Through a broad, distributed network of elements in the ventral medial parts of

the fore brain, including some the encephalitic regions, including the

hypothalamus. A very important structure that I'll talk

about next, as well as parts of the brain stem.

So from the nucleus of the solitary track.

Inputs are passed into the reticular formation of the brain stem.

They are also distributed directly to the hypothalamus and then indirectly to

another nucleus of the brain stem called the parabrachial nucleus.

This is found very near the superior cerebellar peduncle, as it attaches to

the upper part of the pons. Well this parabracial nucleus, then,

sends input to the medial parts of the thalamus to the hypothalamus and the

amygdala. And once this information has access to

the thalamus and the amygdala, now it can be distributed more broadly to the

ventral and medial aspects of the prefrontal cortex.

The thalamus and the amygdala have connections specifically with the insular

cortex, and the insular cortex in turn has interconnections with the rest of the

orbital and medial sector of the prefrontal cortex.

which becomes very important in integrating the sensory signals that are

being processed and impacting the motor output that eventually feeds its way down

towards our brain stem and spinal cord networks of neurons.

Well, let me just pause for a moment and highlight the importance of this insular

cortex. We can think of this insular cortex as

being the sensory cortex for the viscera. So, one aspect of this insular cortex

that I think is really interesting is its capacity to Integrate these visceral

signals and then use that information as a way of informing other kinds of

networks that mediate different dimensions of cognition.

So here's an example, let me ask you a question, how do you feel right now?

Well, if you're like me, you may respond based on information that is derived more

so from the viscera than, let's say from our cutaneous surfaces.

Now, of course, you may have a condition by which your cutaneous surfaces or your

muscloskeletal systems really drive the answer to that question how do you feel.

But I think for many of us, that response, whether we think of it in this,

these terms or not, is really derived from our visceral senses.

And that is a signal that is processed here, in this insular cortex.

So, I think this insular cortex is very important for this notion of feeling.

So how do you feel today? Well, let your insular cortex inform the

rest of your cognitive networks as you consider your reply to that question.

All right, well, let's move from the right side of this figure then, to the

left side. So as the insular has interaction with

the rest of the medial and orbital aspects of the prefrontal cortex.

We begin to coordinate and organize our plan of action.

Our governments of our visceral motor output.

And this happens through multiple relays. Some of which run through the amygdala.

And then through the hypothalamus others enter the amygdala and hypothalamic

systems. And then have more or less direct access

to brain stem networks that organize our preganglionic sympathetic and

parasympathetic neurons. Well, eventually, from that level, then,

of course, we have our motor outflow to our ganglionic neurons that can alter the

activity of our end organs. So we might think of this medial

prefrontal cortex, then, as the principal coordinator of outflow that is going to

alter, either our homeostatic state, or, prepare our body for action.

That is, for allostasis. To change the state of the body, in order

to, once again restore conditions of homeostasis.

Well, an important mediator then, of activity from the level of the cortex to

these brain stem effector systems, in the reticular formation and the preganglionic

themselves, is this part of the ventral diencephalon called a hypothalamus.

The amygdala is important too, but we'll talk about that in a later session in the

following unit of the course. I'd like to take a few minutes speaking

with you about the hypothalamus, and highlight for you its key role in

integrating visceral sensory signals. As well as command signals, contextual

signals derived from the level of the cerebral cortex.

And then the outflow from the hypothalamus is largely directed at our

visceral motor effective systems as we'll see in the next part of this tutorial.

So if you hang with me we'll move from this rather lengthy first part of the

visceral motor tutorial. And I want to spend spend some time with

you talking about the hypothalamus. But before we get there, consider the

study question, and I think you'll be ready to move on after that.

So, I'll see you in just a minute, and we will pick up talking about the

hypothalamus.

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