Even The Best Neurologists Cannot Crack This Quiz!

There are approximately 45 areas of the brain that have a visual function. These areas are responsible for processing and interpreting visual information received from the eyes. They play a crucial role in various visual processes such as object recognition, color perception, depth perception, and motion detection. The complexity and specialization of these areas allow us to have a rich and detailed visual experience.

At each adherent junction, there are about 3 gap junctions. Gap junctions are specialized protein channels that allow for direct communication and exchange of molecules between adjacent cells. Adherent junctions are cell-cell adhesion complexes that help cells adhere to each other and provide mechanical strength to tissues. The presence of 3 gap junctions at each adherent junction suggests a high level of communication and coordination between adjacent cells, which is important for tissue function and homeostasis.

If a large light stimulus were to fall within the area of 2 adjacent receptive fields, one would expect a sub-optimal response. This is because the receptive fields are responsible for detecting and responding to specific stimuli within their designated areas. When a large stimulus falls within the area of two adjacent receptive fields, it may not be accurately detected or processed by either field, leading to a sub-optimal response.

H1 is the only horizontal cell that has axonal connections to rods (~350-500)
all horizontal cells have a dendritic field that connect ONLY to Cones

When transitioning from photopic conditions to scotopic conditions, the visual system adjusts to low light levels. In scotopic conditions, the increased receptive field size allows for the capture of more photons, enhancing sensitivity to low light. This expanded receptive field size enables the eye to gather more light from the surroundings, compensating for the reduced amount of available light in scotopic conditions. As a result, visual acuity decreases due to the larger receptive field size, which leads to a decrease in the sharpness and clarity of the image perceived.

In a spherule, typically there are two invaginating rod bipolar cells. These cells are responsible for transmitting signals from the rod photoreceptor cells to the bipolar cells in the retina. The spherule is a specialized structure in the retina where the rod photoreceptor cells connect with the bipolar cells. Therefore, it is expected to find two invaginating rod bipolar cells in a spherule.

Rhodopsin is a pigment found in the rods of the retina that is responsible for vision in low light conditions. When rhodopsin absorbs light, it undergoes a chemical change and is converted into bathorhodopsin. This conversion is the only chemical change that occurs in response to light. The other options listed involve the breakdown or conversion of rhodopsin into different compounds, but they do not specifically occur in response to light.

The correct order of ganglion cell conduction velocities from slowest to fastest is W

Ganglion cell axons from the vertical midline of the visual field project towards the posterior aspect of the LGN. This means that the ganglion cells located in the central part of the visual field, along the vertical midline, send their axons to the back part of the lateral geniculate nucleus (LGN). The LGN is a relay station in the thalamus that receives visual information from the retina and sends it to the visual cortex for further processing.

The central 20 degrees of the visual field projects to a very large area of the LGN. This means that there is a significant amount of neural machinery dedicated to processing information from this specific area. As a result, vision in this region is likely to be more precise and detailed compared to other areas of the visual field.

Hypercomplex I cells are simple cells that respond maximally to a stimulus of proper length that fills their receptive field. This means that these cells are specialized to detect specific features of visual stimuli, such as the length of an object, within their receptive field. They do not respond to the presence or absence of light, but rather to the specific length of the stimulus.

MOST of the parvocellular neurons terminate in layer IVb while some of parvocellular neurons terminate in IVa. all of the magnocellular neurons terminate in layer IVc

Pyramidal cells are the dominant cell type in the primary visual cortex (V1). These cells are characterized by their pyramid-shaped soma and long apical dendrites that extend towards the cortical surface. Pyramidal cells play a crucial role in processing visual information, as they receive inputs from various sources and are responsible for transmitting signals to other cortical areas. They are involved in complex functions such as sensory integration, perception, and cognition. Stellate cells, purkinje cells, and type 1 neurons are found in other brain regions and have different functions, making them less likely to dominate in V1.

L cones, also known as long-wavelength cones, are most photosensitive to red light. These cones are responsible for detecting and perceiving longer wavelengths of light, including red light. They play a crucial role in color vision, particularly in perceiving and distinguishing red hues. L cones are most sensitive to light in the long-wavelength range, which corresponds to the red end of the visible light spectrum. This sensitivity allows them to absorb and respond to red light more effectively than other types of photoreceptor cells, such as M cones, S cones, or rods.

The correct answer is high [Na+]. This is because photoreceptor discs are part of the retina and are responsible for converting light into electrical signals. In order for this conversion to occur, there needs to be a high concentration of sodium ions (Na+) inside the photoreceptor disc. This high concentration of sodium ions helps to generate the electrical signals that are then transmitted to the brain for visual processing.

Muller's cells are a type of glial cells that span the entire retina, extending from the innermost to the outermost layers. They are responsible for maintaining the structural integrity of the retina, providing support to neurons, and regulating the extracellular environment. Muller's cells also play a role in the uptake and recycling of neurotransmitters, as well as in the regulation of retinal blood flow. Therefore, they are the correct answer to the question.

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In felines, the ganglion cells that are highest in quantity are Alpha and Beta.

Visual acuity is a good test for x-cell function because it measures the clarity and sharpness of vision. X-cell function refers to the ability of the cells in the retina to detect and transmit visual information to the brain. Visual acuity tests assess the ability to see fine details and distinguish between different objects or letters at a given distance. Therefore, a good visual acuity indicates that the x-cell function is working properly, as the individual can perceive and interpret visual stimuli accurately.

The striate cortex, also known as the primary visual cortex or V1, is responsible for processing visual information. Layer IVa and IVb of the striate cortex receive input from the lateral geniculate nucleus (LGN) of the thalamus, which relays visual information from the eyes. The correct intracortical connection for layer IVa and IVb is to layer II and III, where further processing of visual information occurs. Layers I and II do not receive direct input from layer IVa and IVb, so the given connection is incorrect.

The correct order for the number of variations of cells in the retina from most to least is amacrine > ganglion > bipolar > photoreceptors. This means that the retina has the highest number of variations in amacrine cells, followed by ganglion cells, bipolar cells, and finally photoreceptors.

Horizontal cells are responsible for the receptive field surround of ganglion cells. Horizontal cells are specialized cells found in the retina that connect and communicate with photoreceptor cells, bipolar cells, and other horizontal cells. They help in the lateral inhibition process, which enhances the contrast and sharpness of visual perception. The receptive field surround refers to the area surrounding the center of the receptive field, and it is the horizontal cells that provide inhibitory signals to the ganglion cells in this surround region, helping to shape the center-surround receptive field structure.

Parvocellular ganglion cells and magnocellular ganglion cells are two types of ganglion cells found in the retina. These cells are responsible for transmitting visual information from the retina to the brain. The given answer, 90%, suggests that these two types of ganglion cells collectively account for 90% of all ganglion cells in the retina. This indicates that they are the major types of ganglion cells and play a significant role in visual processing.

The correct answer is that the visual system is a combination of the two theories. This suggests that both the hierarchical theory and the parallel theory play a role in visual information processing. It is likely that different aspects of visual processing occur in a hierarchical manner, while others occur in parallel pathways. This combination allows for a more comprehensive understanding of how visual information is processed in the brain.

The correct answer is 60%. This means that approximately 60% of the brain is involved in visual functions. The brain is a complex organ responsible for processing and interpreting visual information, and a significant portion of its resources are dedicated to this task. Visual functions include tasks such as recognizing objects, perceiving depth and color, and interpreting visual stimuli. Therefore, it is important to understand that a large portion of the brain is dedicated to visual processing.

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The correct answer is that the cilium consists of 9 double microtubules that aid in the transportation of ions and newly made proteins. This is true because the cilium is a hair-like structure found on the surface of cells, including photoreceptor cells in the eye. It is composed of microtubules, which are cylindrical structures made of protein. These microtubules provide structural support to the cilium and also play a role in intracellular transport, including the movement of ions and newly synthesized proteins to different parts of the cell.

As you move away from the fovea, the diameter of cone inner segments increases with increasing eccentricity. This means that the size of the inner segment of cone photoreceptors gets larger as you move towards the periphery of the retina. Additionally, rods, which are responsible for low-light vision, increase in population eccentrically. This means that there are more rods in the peripheral regions of the retina compared to the fovea. Therefore, both statements are true.

remember what is considered the optic nerve and what is considered the optic nerve head, oligodendrocytes provide myelination posterior to the lamina cribrosa of the ON, the astrocytes are present anterior to and up to the lamina cribrosa (dont provide myelination but rather control blood flow and maintain blood-ocular barrier)

The reason we have so many vertical rod pathways is that it allows rods to have an expanded range of response capabilities under different lighting conditions. This means that the rods can effectively respond to a wider range of light levels, allowing us to see in various lighting environments. Having multiple pathways also helps to ensure that the rods can adapt and provide accurate visual information in different lighting conditions.

The correct answer is horizontal cell bodies. The distal INL (inner nuclear layer) is the layer closest to the photoreceptors in the retina. Horizontal cells are interneurons that receive input from photoreceptor cells and play a role in lateral inhibition, which enhances contrast and sharpens visual perception. Therefore, their cell bodies would be located in the distal INL, nearest the photoreceptors.

Biplexiform-GC is the correct answer because it is a type of ganglion cell that has a direct connection to mostly rods. This type of ganglion cell is involved in the function of visuomotor reflexes in animals, which suggests that it plays a role in coordinating visual information with motor responses. The other options, alpha-GC, beta-GC, gamma-GC, and ON-rod ganglion cell, do not specifically mention a direct connection to rods or involvement in visuomotor reflexes.

The correct answer is 50%. The fovea is the central part of the retina that contains a high density of cone cells responsible for detailed vision. Ganglion cells receive visual information from other cells in the retina, including amacrine cells. The question asks for the percentage of information that reaches the ganglion cells directly from amacrine cells. Since the question does not provide any additional information, we can assume that 50% of the information reaching the ganglion cells comes directly from amacrine cells.

The two parts of a ribbon synapse are synaptic lamellae and arciform density. Synaptic lamellae refer to the layers of membrane that surround the synaptic ribbon, while arciform density is a specialized electron-dense structure found in the synaptic cleft. These two components play important roles in the transmission of signals between neurons at ribbon synapses.

The correct membrane potential after a rod has been stimulated by light is -60mV. This is because when a rod is stimulated by light, it hyperpolarizes, meaning the membrane potential becomes more negative. The resting membrane potential of a rod is typically around -40mV, so when it is hyperpolarized by light, it becomes even more negative, reaching -60mV.

P beta ganglion cells account for 80% of all ganglion cell types.

The correct answer is left LGN areas 1, 4, & 6. This is because the question states that the nasal ganglion cell axons from the right eye synapse on the LGN. Since the nasal ganglion cells carry information from the contralateral (opposite) eye, the axons from the right eye would synapse on the left LGN. The areas 1, 4, & 6 of the left LGN receive input from the contralateral eye, making them the correct answer.

The explanation for the given correct answer is that the organization of information in layers II and III of the striate cortex is in blobs rather than distinct columns like layer IV. This means that the neurons in layers II and III are arranged in clusters or groups called blobs, whereas in layer IV, the neurons are organized into distinct columns. This difference in organization suggests that the processing of information in layers II and III may be different from that in layer IV.

As the information from 1 ganglion cell travels through the cells in the cortex, it gets distributed and processed by multiple cortical cells. Therefore, the correct answer is 100 cortical cells. Each cortical cell receives and carries the information from the ganglion cell, allowing for parallel processing and integration of visual information in the brain.

Astrocytes in the retina have multiple functions, including helping to hold blood vessels in place and controlling blood flow out of vessels. These functions are crucial for maintaining the structure and function of the retina. Astrocytes provide structural support to blood vessels, ensuring their stability and preventing them from moving or collapsing. Additionally, they regulate blood flow by constricting or dilating blood vessels, thus controlling the amount of blood that enters or exits the retina. These functions are essential for maintaining proper blood supply and nutrient delivery to retinal cells, ultimately supporting optimal vision.

Rhodopsin is a protein found in the rod cells of the retina that is responsible for the initial step in the process of vision. It is a key component in the conversion of light into electrical signals that can be interpreted by the brain. The statement suggests that rhodopsin makes up approximately 50% of the entire disc in a rod. This implies that rhodopsin plays a significant role in the functioning of rod cells and is a major component in the visual process.

sublamina B = closer to the Bipolar cells --> the ON signal is a shorter distance

Neurons in the LGN (Lateral Geniculate Nucleus) project primarily to layer IV of the visual cortex. This is supported by anatomical studies that have shown a direct connection between the LGN and layer IV. Layer IV is known as the primary receiving layer of the visual cortex, where it receives and processes visual information from the LGN. Other layers of the visual cortex (I, II, III, V, VI) may also receive inputs from the LGN, but layer IV is the main target for these projections.

If a child is born with a severe persistent pupillary membrane that blocks 90% of the light from entering the eye, it can lead to the development of amblyopia. Amblyopia, also known as lazy eye, occurs when there is a lack of visual stimulation during the critical period of visual development in early childhood. The visual pathway includes various stages, starting from the retina and ending in the cortex. The correct answer, cortical cells, refers to the neurons in the visual cortex of the brain. If the pupillary membrane blocks a significant amount of light, it can result in reduced visual input to the cortex, leading to the deprivation of cortical cells and potentially causing amblyopia.

Interplexiform neurons are primarily involved with the changes that occur in the receptive fields of ganglion cells with dark adaptation. These neurons connect different layers of the retina and play a role in transmitting signals between different types of retinal cells. During dark adaptation, interplexiform neurons help to adjust the sensitivity of ganglion cells to light by modulating the signals received from photoreceptor cells. This allows the ganglion cells to adapt to low light conditions and enhance their ability to detect and transmit visual information.

cone pedicles have ~ 12-25 invaginations

In the inner plexiform layer (IPL) of the retina, the most common group of cells that would be found synapsing together is 1 ganglion cell, 1 amacrine cell, and 1 bipolar cell. Ganglion cells receive input from bipolar cells and amacrine cells provide lateral inhibition and modulate the signal transmission between bipolar and ganglion cells. Therefore, this group of cells is commonly found synapsing together in the IPL.

The amacrine cell is the first cell in the visual pathway to produce an action potential. It is a type of retinal neuron that receives signals from bipolar cells and sends them to ganglion cells. The ganglion cells then transmit the visual information to the brain via the optic nerve. The action potential generated by the amacrine cell allows for the transmission of visual signals from the retina to the brain for further processing and interpretation.

The correct membrane resting potential of a rod is -20mV. The resting potential refers to the electrical charge across the cell membrane when the cell is at rest. In the case of a rod, the resting potential is -20mV, indicating that the inside of the cell is more negative compared to the outside. This potential is maintained by the balance of ion concentrations and the activity of ion channels in the cell membrane.