Optimal Word Reading Rate as Evidenced by Frequency-tagging Electrophysiology.

Fast periodic visual stimulation (FPVS) coupled with EEG has been used for a decade to measure word-selective neural responses in (a)typical adults and developmental readers. Here, we used this FPVS-EEG approach to evaluate suitable and optimal stimulation frequency rates for prelexical and lexical word-selective responses and relate these rates to typical reading speed and interindividual variability in reading performance. EEG was recorded in 41 healthy adults who viewed words inserted periodically (1 Hz) at four different stimulation frequency rates (4 Hz, 6 Hz, 10 Hz, and 20 Hz).

An objective and sensitive electrophysiological marker of word semantic categorization impairment in Alzheimer's disease.

Objective: Combining electroencephalographic (EEG) recording and fast periodic visual stimulation (FPVS) to provide an implicit, objective and sensitive electrophysiological measure of semantic word categorization impairment in Alzheimer's Disease (AD).

Methods: Twenty-five AD patients and 25 matched elderly healthy controls were tested with a validated FPVS-EEG paradigm in which different written words of the same semantic category (cities) appear at a fixed frequency of 4 words per second (4 Hz) for 70 seconds. Words from a different semantic category (animal) appear every 4 stimuli (i.

Bidirectional and Cross-Hemispheric Modulations of Face-Selective Neural Activity Induced by Electrical Stimulation within the Human Cortical Face Network.

A major scientific objective of cognitive neuroscience is to define cortico-cortical functional connections supporting cognitive functions. Here, we use an original approach combining frequency-tagging and direct electrical stimulation (DES) to test for bidirectional and cross-hemispheric category-specific modulations within the human cortical face network. A unique patient bilaterally implanted with depth electrodes in multiple face-selective cortical regions of the ventral occipito-temporal cortex (VOTC) was shown 70 s sequences of variable natural object images at a 6 Hz rate, objectively identifying deviant face-selective neural activity at 1.

Olfactory-to-visual facilitation in the infant brain declines gradually from 4 to 12 months.

During infancy, intersensory facilitation declines gradually as unisensory perception develops. However, this trade-off was mainly investigated using audiovisual stimulations. Here, fifty 4- to 12-month-old infants (26 females, predominately White) were tested in 2017-2020 to determine whether the facilitating effect of their mother's body odor on neural face categorization, as previously observed at 4 months, decreases with age.

The neuropsychological evaluation of face identity recognition.

Facial identity recognition (FIR) is arguably the ultimate form of recognition for the adult human brain. Even if the term prosopagnosia is reserved for exceptionally rare brain-damaged cases with a category-specific abrupt loss of FIR at adulthood, subjective and objective impairments or difficulties of FIR are common in the neuropsychological population. Here we provide a critical overview of the evaluation of FIR both for clinicians and researchers in neuropsychology.

Linguistic and attentional factors - Not statistical regularities - Contribute to word-selective neural responses with FPVS-oddball paradigms.

Studies using frequency-tagging in electroencephalography (EEG) have dramatically increased in the past 10 years, in a variety of domains and populations. Here we used Fast Periodic Visual Stimulation (FPVS) combined with an oddball design to explore visual word recognition. Given the paradigm's high sensitivity, it is crucial for future basic research and clinical application to prove its robustness across variations of designs, stimulus types and tasks.

Extensive Visual Training in Adulthood Reduces an Implicit Neural Marker of the Face Inversion Effect.

Face identity recognition (FIR) in humans is supported by specialized neural processes whose function is spectacularly impaired when simply turning a face upside-down: the face inversion effect (FIE). While the FIE appears to have a slow developmental course, little is known about the plasticity of the neural processes involved in this effect-and in FIR in general-at adulthood. Here, we investigate whether extensive training (2 weeks, ~16 h) in young human adults discriminating a large set of unfamiliar inverted faces can reduce an implicit neural marker of the FIE for a set of entirely novel faces.

The anterior fusiform gyrus: The ghost in the cortical face machine.

Face-selective regions in the human ventral occipito-temporal cortex (VOTC) have been defined for decades mainly with functional magnetic resonance imaging. This face-selective VOTC network is traditionally divided in a posterior 'core' system thought to subtend face perception, and regions of the anterior temporal lobe as a semantic memory component of an extended general system. In between these two putative systems lies the anterior fusiform gyrus and surrounding sulci, affected by magnetic susceptibility artifacts.

Intracerebral electrical stimulation of the face-selective right lateral fusiform gyrus transiently impairs face identity recognition.

Neuroimaging and intracranial electrophysiological studies have consistently shown the largest and most consistent face-selective neural activity in the middle portion of the human right lateral fusiform gyrus ('fusiform face area(s)', FFA). Yet, direct evidence for the critical role of this region in face identity recognition (FIR) is still lacking. Here we report the first evidence of transient behavioral impairment of FIR during focal electrical stimulation of the right FFA.

A neural marker of the human face identity familiarity effect.

Human adults associate different views of an identity much better for familiar than for unfamiliar faces. However, a robust and consistent neural index of this behavioral face identity familiarity effect (FIFE)-not found in non-human primate species-is lacking. Here we provide such a neural FIFE index, measured implicitly and with one fixation per face.

Single neuron responses underlying face recognition in the human midfusiform face-selective cortex.

Faces are critical for social interactions and their recognition constitutes one of the most important and challenging functions of the human brain. While neurons responding selectively to faces have been recorded for decades in the monkey brain, face-selective neural activations have been reported with neuroimaging primarily in the human midfusiform gyrus. Yet, the cellular mechanisms producing selective responses to faces in this hominoid neuroanatomical structure remain unknown.

Stability of face recognition abilities after left or right anterior temporal lobectomy.

Patients with anterior temporal lobe (ATL) resection due to mesial temporal lobe epilepsy (MTLE) have difficulties at identifying familiar faces and explicitly remembering newly learned faces but their ability to individuate unfamiliar faces remains largely unknown. Moreover, the extent to which their difficulties with familiar face identity recognition and learning is truly due to the ATL resection remains unknown. Here, we report a study of 24 MTLE patients and matched healthy controls tested with an extensive set of seven face and visual object recognition tasks (including three tasks evaluating unfamiliar face individuation) before and about 6 months after unilateral (nine left, 15 right) ATL resection.

Automatic, Early Color-Specific Neural Responses to Object Color Knowledge.

Some familiar objects are associated with specific colors, e.g., rubber ducks with yellow.

Spatial Resolution Evaluation Based on Experienced Visual Categories With Sweep Evoked Periodic EEG Activity.

Purpose: Visual function is typically evaluated in clinical settings with visual acuity (VA), a test requiring to behaviorally match or name optotypes such as tumbling E or Snellen letters. The ability to recognize these symbols has little in common with the automatic and rapid visual recognition of socially important stimuli in real life. Here we use sweep visual evoked potentials to assess spatial resolution objectively based on the recognition of human faces and written words.

Intracerebral Electrophysiological Recordings to Understand the Neural Basis of Human Face Recognition.

Understanding how the human brain recognizes faces is a primary scientific goal in cognitive neuroscience. Given the limitations of the monkey model of human face recognition, a key approach in this endeavor is the recording of electrophysiological activity with electrodes implanted inside the brain of human epileptic patients. However, this approach faces a number of challenges that must be overcome for meaningful scientific knowledge to emerge.

Towards an optimization of functional localizers in non-human primate neuroimaging with (fMRI) frequency-tagging.

Non-human primate (NHP) neuroimaging can provide essential insights into the neural basis of human cognitive functions. While functional magnetic resonance imaging (fMRI) localizers can play an essential role in reaching this objective (Russ et al., 2021), they often differ substantially across species in terms of paradigms, measured signals, and data analysis, biasing the comparisons.

Natural Contrast Statistics Facilitate Human Face Categorization.

The ability to detect faces in the environment is of utmost ecological importance for human social adaptation. While face categorization is efficient, fast and robust to sensory degradation, it is massively impaired when the facial stimulus does not match the natural contrast statistics of this visual category, i.e.

Low and high frequency intracranial neural signals match in the human associative cortex.

In vivo intracranial recordings of neural activity offer a unique opportunity to understand human brain function. Intracranial electrophysiological (iEEG) activity related to sensory, cognitive or motor events manifests mostly in two types of signals: event-related local field potentials in lower frequency bands (<30 Hz, LF) and broadband activity in the higher end of the frequency spectrum (>30 Hz, High frequency, HF). While most current studies rely exclusively on HF, thought to be more focal and closely related to spiking activity, the relationship between HF and LF signals is unclear, especially in human associative cortex.

A neural marker of rapid discrimination of facial expression in 3.5- and 7-month-old infants.

Infants' ability to discriminate facial expressions has been widely explored, but little is known about the rapid and automatic ability to discriminate a given expression against many others in a single experiment. Here we investigated the development of facial expression discrimination in infancy with fast periodic visual stimulation coupled with scalp electroencephalography (EEG). EEG was recorded in eighteen 3.

Superior neural individuation of mother's than stranger's faces by five months of age.

Human adults are better at recognizing different views of a given face as belonging to the same person when that person is familiar rather than unfamiliar. To clarify the developmental origin of this well-established phenomenon, one group of five-month-olds (N = 22) was presented with pictures of four different unfamiliar female faces at a fixed rate (6 Hz, 166 msec stimulus onset asynchrony), interrupted every 5th stimulus (1.2 Hz) by either their mother's face (mother oddball condition) or, in different stimulation sequences, a stranger's face (stranger oddball condition).

Twenty years of investigation with the case of prosopagnosia PS to understand human face identity recognition. Part I: Function.

Following traumatic brain injury in adulthood, Pierrette Sapey (PS) became suddenly unable to recognize the identity of people from their faces. Thanks to her remarkable recovery of general brain function, liveliness, and willingness to be tested, PS's case of prosopagnosia has been extensively studied for more than 20 years. This investigation includes hundreds of hours of behavioral data collection that provide information about the nature of human face identity recognition (FIR).

Twenty years of investigation with the case of prosopagnosia PS to understand human face identity recognition.Part II: Neural basis.

Patient PS sustained her dramatic brain injury thirty years ago, in 1992, the same year as the first report of a neuroimaging study of human face recognition.The present paper complements the review on the functional nature of PS's prosopagnosia (part I), illustrating how her case study directly, i.e.

Developmental experiences alter the temporal processing characteristics of the visual cortex: Evidence from deaf and hearing native signers.

To date, the extent to which early experience shapes the functional characteristics of neural circuits is still a matter of debate. In the present study, we tested whether congenital deafness and/or the acquisition of a sign language alter the temporal processing characteristics of the visual system. Moreover, we investigated whether, assuming cross-modal plasticity in deaf individuals, the temporal processing characteristics of possibly reorganised auditory areas resemble those of the visual cortex.

A genuine interindividual variability in number and anatomical localization of face-selective regions in the human brain.

Neuroimaging studies have reported regions with more neural activation to face than nonface stimuli in the human occipitotemporal cortex for three decades. Here we used a highly sensitive and reliable frequency-tagging functional magnetic resonance imaging paradigm measuring high-level face-selective neural activity to assess interindividual variability in the localization and number of face-selective clusters. Although the majority of these clusters are located in the same cortical gyri and sulci across 25 adult brains, a volume-based analysis of unsmoothed data reveals a large amount of interindividual variability in their spatial distribution and number, particularly in the ventral occipitotemporal cortex.