Neonatal perirhinal cortex lesions impair monkeys’ ability to modulate their emotional responses.

Abstract

The medial temporal lobe (MTL) is a collection of brain regions best known for their role in perception, memory, and emotional behavior. Within the MTL, the perirhinal cortex (PRh) plays a critical role in perceptual representation and recognition memory, although its contribution to emotional regulation is still debated. Here, rhesus monkeys with neonatal perirhinal lesions (Neo-PRh) and controls (Neo-C) were tested on the Human Intruder (HI) task at 2 months, 4.5 months, and 5 years of age, to assess the role of the PRh in the development of emotional behaviors. The HI task presents a tiered social threat to which typically developing animals modulate their emotional responses according to the level of threat. Unlike animals with neonatal amygdala or hippocampal lesions, Neo-PRh animals were not broadly hyper- or hypo-responsive to the threat presented by the HI task as compared to controls. Instead, Neo-PRh animals displayed an impaired ability to modulate their freezing and anxiety-like behavioral responses according to the varying levels of threat. Impaired transmission of perceptual representation generated by the PRh to the amygdala and hippocampus may explain the animals’ inability to appropriately assess and react to complex social stimuli. Neo-PRh animals also displayed fewer hostile behaviors in infancy and more coo vocalizations in adulthood. Neither stress reactive nor basal cortisol levels were affected by the Neo-PRh lesions. Overall, these results suggest that the PRh is indirectly involved in the expression of emotional behavior, and that effects of Neo-PRh lesions are dissociable from neonatal lesions to other temporal lobe structures.

Analysis of the social and cognitive changes of the human brain in autism based on functional properties

“…The weakened functional complexity of the right PHG in ASDs might contribute to the similar functional status between these subregions within the PHG, which might lead to the right PHG in ASD showed increased synchronous input nodal degrees and increased asynchronous output nodal degrees. As shown in this study, the right PHG presented enhanced asynchronous entropy connectivity from the ipsilateral cerebellum 7b (AAL with the recognition of visual stimuli(Ahlgrim et al, 2017), and autobiographical memory(Ritchey et al, 2015).Thus, in our study, those altered functional properties involved in the amygdala and PHG might have negative impacts on social responsiveness and communication, which contributes to the atypical social interaction patterns in autism(Lord et al). Hanna et al, 2010), involved in internal cognitive processes, including emotional processing, self-representation, and autobiographical memory, etc.…”

Intact perceptual ability, but impaired familiarity judgment, after neonatal perirhinal lesions in rhesus macaques

“…At the time of Experiment 1, the animals were an average of 6.9 years old. All monkeys had similar experience with cognitive testing, having previously completed tests of object recognition ( Weiss and Bachevalier, 2016 , Zeamer et al, 2015 ), working memory ( Weiss et al, 2016 ), and emotional reactivity ( Ahlgrim et al, 2017 ). At the time of Experiment 2, the animals had reached 9.7 years old on average, and had additional experience with tasks of Concurrent Discrimination/Reinforcer devaluation, and Safety Signal Learning.…”

Impaired Cognitive Flexibility After Neonatal Perirhinal Lesions in Rhesus Macaques

“…Figure 1 shows pre-surgical and post-surgical MR images of a representative case (Neo-PRh-6). Images from additional cases have been previously published (Zeamer et al, 2015; Weiss and Bachevalier, 2016; Weiss et al, 2016, 2017; Ahlgrim et al, 2017).…”

“…Arrows point to the rhinal sulcus (left column) and to areas of hypersignal (right column). See Zeamer et al (2015), Weiss and Bachevalier (2016), Weiss et al (2016, 2017), and Ahlgrim et al (2017) for illustration of lesion extent for additional Neo-PRh cases.…”

“…Prior to participating in this study, all subjects had experience with cognitive tests including concurrent discrimination learning, reinforcer devaluation, object reversal learning, safety signal learning, and emotional regulation (Ahlgrim et al, 2017). The Neo-PRh, Neo-C and Neo-UC monkeys had additional experience with tests of object recognition (Zeamer et al, 2015; Weiss and Bachevalier, 2016), WM (Weiss et al, 2016), perceptual discrimination and familiarity judgments (Weiss et al, 2017).…”