Question

How did Hubel and Wiesel discover that some cortical neurons respond to seeing lines of a specific orientation? a. by using fMRI to study cat brain function during visual tasks b. by inserting electrodes into single cells in the visual cortex c. through surgical removal of cortical tissue d. with EEG

Short answer

Hubel and Wiesel used b: by inserting electrodes into single cells in the visual cortex.

Step-by-step solution

Understand the Question

The question asks about the method used by Hubel and Wiesel to discover the way some cortical neurons respond to visual stimuli, specifically lines of certain orientations. We need to identify the technique they used in their experiments.

Evaluate Each Option

Let's review the options: - fMRI (Functional Magnetic Resonance Imaging) is a technique to study brain activity, but it wasn't used by Hubel and Wiesel, particularly since their work predated common usage of fMRI. - Inserting electrodes into single cells is a method that would allow precise measurements at the cellular level, suitable for checking individual neuron responses. - Surgical removal of cortical tissue doesn't align with discovering response to visual stimuli. - EEG (Electroencephalography) records electrical activity of the brain but is not precise to individual neurons.

Identify the Correct Method

Hubel and Wiesel used the method of inserting electrodes into single cells in the visual cortex of cats. This allowed them to record the activity of specific neurons while the cats were exposed to various visual stimuli.

Confirm the Correct Answer

By understanding the methodology that allows for single-cell recording, it is clear that Hubel and Wiesel's experiments required this precision to identify how neurons respond to lines of different orientations. Thus, option (b) is correct.

Key concepts

Hubel and Wiesel

David Hubel and Torsten Wiesel are renowned neuroscientists who made groundbreaking discoveries in the field of visual processing. Their research focused on understanding how the brain interprets visual information. They explored how different neurons in the brain respond to specific elements of a visual scene. Hubel and Wiesel's work shed light on the neuronal mechanisms behind vision, leading to significant advancements in neuroscience.

In their experiments, they utilized techniques to study the brain's responses to visual stimuli. Their studies showcased that certain neurons are specially tuned to detect particular features, like edges or movements. This means that the brain has a dedicated system that identifies components essential for interpreting the visual world. Hubel and Wiesel were pivotal in expanding our understanding of sensory processing and its complexities.

Visual Cortex

The visual cortex is a critical part of the brain located in the occipital lobe. It's where visual information from the eyes is processed and interpreted. When light hits the photoreceptor cells in the retina, it's converted into electrical signals. These signals travel through the optic nerves to the visual cortex.

In the visual cortex, neural networks work together to analyze different aspects of a visual scene. This area of the brain is responsible for various functions, including:

• Detecting different orientations and edges
• Interpreting color and motion
• Integrating visual information to form coherent perceptions

Hubel and Wiesel's research primarily targeted the visual cortex, as this is where many specialized neurons reside. Their findings highlighted that neurons in the visual cortex are crucial for identifying details of visual stimuli, such as the orientation of lines.

Single-cell Recording

Single-cell recording is a precise method used to study the response of individual neurons to different stimuli. In their research, Hubel and Wiesel employed this technique by inserting tiny electrodes into the visual cortex of cats. These electrodes recorded the electrical activity of single neurons, providing direct insights into how individual neurons respond to visual cues.

This method allowed them to monitor how specific neurons activated when certain visual patterns, such as lines at different angles, were presented. By using single-cell recording, they could pinpoint which neurons were sensitive to various orientations. This precise approach was crucial for understanding the nuanced ways in which the brain processes visual information. The detailed data gathered helped form a foundational understanding of visual processing that continues to influence modern neuroscience.

Orientation Selectivity

Orientation selectivity refers to the phenomenon where certain cortical neurons are highly responsive to specific angles or orientations of lines. Hubel and Wiesel discovered this characteristic through their work with single-cell recording. They observed that some neurons in the visual cortex responded vigorously only when lines of a particular orientation were presented.

This selectivity means that the primary visual cortex contains neurons that act as specialized detectors. Each neuron's orientation preference aids in forming a map of the visual scene. These detectors are crucial for constructing an accurate representation of visual environments. This understanding of orientation selectivity has advanced theories about how our brains interpret and predict visual landscapes, enabling better simulations in computer vision and artificial intelligence.

Neural Response

Neural response involves the activation patterns of neurons when they process any form of stimulus. For Hubel and Wiesel, it pertained to how neurons fired in response to visual stimuli like oriented lines. The degree and pattern of these responses form the basis of how we perceive visuals.

Their research showed that different neurons have varied firing patterns depending on the visual stimulus properties such as angle and orientation. This neural activity intricately contributes to the overall brain functionality, allowing us to make sense of complex visual inputs.

Understanding neural responses also helps in exploring how sensory information is integrated across different brain regions, informing fields such as vision therapy and neuroengineering. Hubel and Wiesel's findings were seminal in revealing how essential specific neuronal responses are to visual perception.